Abstract:
An air ride suspension assembly or kit is provided for converting a leaf spring suspension arrangement on a motor vehicle having a solid rear axle to one supported by an air ride suspension assembly is disclosed in order to leverage the benefits of such air ride suspension systems to the conversion suspension assembly is disclosed. A leaf spring is removed and replaced with an upper support arm which is secured to the pre-existing leaf spring attachment sites on the chassis. A mount is then attached to the rear solid axle to which multiple connections are made from the upper support arm including an air bladder. The air ride conversion system can be supplied as a kit for installation by owners of vehicles where they routinely move heavy loads directly with the vehicle or by towing.

Description:
FIELD OF THE INVENTION 
     This invention relates to motor vehicle air ride suspension assemblies, and more particularly, to an air ride suspension assemblies or kits for converting an original equipment leaf spring suspension arrangement supporting a solid rear axle of the motor vehicle to one supported by an air ride suspension assembly. 
     BACKGROUND 
     A solid rear axle employing a leaf-spring suspension system as the means of attaching the solid rear axle to the chassis of the vehicle is a standard solution employed in a wide range of original equipment supplied motor vehicles such as cars, pick-up trucks and SUV&#39;s. Such leaf-spring suspensions provide, during normal usage, for the vehicle chassis to remain relatively level to the ground whilst variations in surface height are absorbed by the leaf-spring suspension in conjunction with shock absorbers. However, when subjected to increased loading, which is generally experienced only or predominantly at the rear axle of the vehicle, then these leaf-spring suspensions allow for the chassis to move downwardly towards the axle under the loading whilst maintaining the suspension&#39;s properties of isolating the chassis from the variations in the surface height within the design range of the suspension. However, the result is a chassis that is tilted downwards from front to back such that the vehicles headlights and driver&#39;s default vision are elevated away from their normal positions. 
     In contrast, larger articulated tractor-trailer units and heavy duty trucks typically exploit and are originally equipped with air ride suspension systems which supports the solid rear axle to the vehicle chassis and which include an air ride control system for controlling the air flow into and out of the air bladders in the air ride suspension assembly such that the air ride suspension system maintains the spacing between the axle and chassis at a predetermined distance, or within a predetermined range, regardless of the weight loading experienced by the axle. Accordingly, air ride suspension assemblies of this nature characteristically avoid unwanted rear end depression of the vehicle chassis when undergoing or experiencing increased or heavy loading over the rear axle. As such, air ride suspension systems offer enhanced performance relative to leaf spring suspensions for SUVs, trucks etc. when loaded and/or towing substantial weights. 
     However, despite the existence of air ride suspension systems, most leading selling SUVs and trucks are only sold by their original equipment manufacturers (OEMs) with leaf spring suspension systems. Accordingly, there exists a requirement for after-sales conversion by owners and operators of motor vehicles equipped with conventional leaf spring suspension systems to air ride suspension assembly thereby providing improved load handling and operational characteristics for their vehicles. 
     Other aspects and features of the present invention will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures. 
     SUMMARY 
     It is an object of the present invention to mitigate limitations in the prior art relating to motor vehicle air ride suspension assemblies, and more particularly, to an air ride suspension assemblies or kits for converting an original equipment leaf spring suspension arrangement supporting a solid rear axle of the motor vehicle to one supported by an air ride suspension assembly. 
     In accordance with an embodiment of the invention there is provided an air ride suspension kit formed as a replaceable unit for converting a motor vehicle having a solid rear axle supported by a leaf spring suspension assembly to one supported by an air ride suspension assembly, said kit comprising for a side of the vehicle:
     a) an upper support arm to be positioned above the axle and configured for removable attachment in a fixed non-adjustable predetermined location relative to the chassis of the motor vehicle;   b) first and second connectors at each end of the upper support arm, each connector being configured to receive pre-existing leaf spring mounting posts such that when a leaf spring set has been detached and removed from leaf spring attachment sites the upper support arm can be mounted to the leaf attachment sites by at least the leaf spring mounting posts and wherein the first and second leaf spring attachment sites are disposed to the front and rear of the motor vehicle either side of the axle;   c) an upper axle mounting plate and a lower axle mounting plate, each configured for removable attachment to each other and for mounting to the respective top and bottom of the axle in a predetermined location;   d) an upper adjustable support bar for removable attachment between the upper axle mounting plate and a predetermined position on the upper support beam;   e) a lower support bar for removable attachment between the lower axle mounting plate and a predetermined position on the upper support beam; and   f) an air bladder forming part of an air control system, wherein the air bladder is disposed between the upper axle mounting play and the upper support beam.   

     In accordance with an embodiment of the invention there is provided an air ride suspension kit formed as a replaceable unit for converting a motor vehicle having a solid rear axle supported by a leaf spring suspension assembly to one supported by an air ride suspension assembly, said kit comprising: 
     first and second air ride suspension assemblies for each side of the vehicle, each air ride suspension assembly comprising: 
     
         
         
           
             a) an upper support arm to be positioned above the axle and configured for removable attachment in a fixed non-adjustable predetermined location relative to the chassis of the motor vehicle; 
             b) first and second connectors at each end of the upper support arm, each connector being configured to receive pre-existing leaf spring mounting posts such that when a leaf spring set has been detached and removed from leaf spring attachment sites the upper support arm can be mounted to the leaf attachment sites by at least the leaf spring mounting posts and wherein the first and second leaf spring attachment sites are disposed to the front and rear of the motor vehicle either side of the axle; 
             c) an upper axle mounting plate and a lower axle mounting plate, each configured for removable attachment to each other and for mounting to the respective top and bottom of the axle in a predetermined location; 
             d) an upper adjustable support bar for removable attachment between the upper axle mounting plate and a predetermined position on the upper support beam; 
             e) a lower support bar for removable attachment between the lower axle mounting plate and a predetermined position on the upper support beam; and 
             f) an air bladder forming part of an air control system, wherein the air bladder is disposed between the upper axle mounting play and the upper support beam; and
 
a sway bar for connecting between the first and second air ride suspension assemblies at predetermined locations on each once the first and second air ride suspension assemblies have been mounted to the vehicle.
 
           
         
       
    
     In accordance with an embodiment of the invention there is provided a method of converting the rear suspension of a motor vehicle comprising: 
     removing left and right leaf spring assemblies from their locations; 
     assembling an air ride suspension kit in place of the left and right leaf spring assemblies, said kit comprising: 
     
         
         
           
             a) an upper support arm to be positioned above the axle and configured for removable attachment in a fixed non-adjustable predetermined location relative to the chassis of the motor vehicle; 
             b) first and second connectors at each end of the upper support arm, each connector being configured to receive pre-existing leaf spring mounting posts such that when the leaf spring set are detached and removed from leaf spring attachment sites the upper support arm can be mounted to the leaf attachment sites by at least the leaf spring mounting posts and wherein the first and second leaf spring attachment sites are disposed to the front and rear of the motor vehicle either side of the axle; 
             c) an upper axle mounting plate and a lower axle mounting plate, each configured for removable attachment to each other and for mounting to the respective top and bottom of the axle in a predetermined location; 
             d) an upper adjustable support bar for removable attachment between the upper axle mounting plate and a predetermined position on the upper support beam; 
             e) a lower support bar for removable attachment between the lower axle mounting plate and a predetermined position on the upper support beam; and 
             f) an air bladder forming part of an air control system, wherein the air bladder is disposed between the upper axle mounting play and the upper support beam; and
 
assembling an air system onto the motor vehicle, said system comprising:
 
             g) an air tank and air tank mounting brackets for mounting the air tank to the motor vehicle to provide air under pressure to the air bladders when the air ride suspension is installed and operational; 
             h) an air compressor and compressor mounting brackets for mounting the air compressor to the motor vehicle and maintaining the air within the air tank at a predetermined minimum pressure when the air ride suspension is installed and operational; 
             i) a sensor linked to a control system for controlling the air compressor; 
             j) a control valve for controlling at least one of the ingress and egress of air with respect to the air bladders; and 
             k) tubing to link the air compressor, the air tank, the control valve, and the air bladders in predetermined configuration. 
           
         
       
    
     Other aspects and features of the present invention will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments of the present invention will now be described, by way of example only, with reference to the attached Figures, wherein: 
         FIG. 1  depicts upper support arm variants for secondary market installation/sales (SMIS) for a leading North American truck according to an embodiment of the invention; 
         FIGS. 2 to 4  depict individually the elements added to a rectangular frame in order to form the upper support arm variants depicted in  FIG. 1  for a SMIS air ride suspension system (ARSS) according to an embodiment of the invention; 
         FIGS. 5 and 6  depict axle mounting brackets for a SMIS air ride suspension system (ARSS) according to an embodiment of the invention; 
         FIG. 7  depicts sway bar and lower axle support bars for a SMIS air ride suspension system (ARSS) according to an embodiment of the invention; 
         FIG. 8  depicts upper adjustable axle support bar and sway bar adjustment bar for a SMIS air ride suspension system (ARSS) according to an embodiment of the invention; 
         FIG. 9  depicts a sequence of steps for the removal of an OEM leaf-spring suspension according to an embodiment of the invention; 
         FIG. 10  depicts a flow schematic for the initial sequence of installing an upper support arm and installing SMIS air ride suspensions according to either U.S. Pat. No. 8,870,203 by the inventors or an embodiment of the invention; 
         FIG. 11  depicts a sequence of steps for the addition of the air compressor/pump and air tank for control system SMIS air ride suspensions according to either U.S. Pat. No. 8,870,203 by the inventors or an embodiment of the invention after the flow depicted in  FIG. 10  has been completed; 
         FIG. 12  depicts a flow schematic for the remainder of the installation sequences for SMIS air ride suspensions according to either U.S. Pat. No. 8,870,203 by the inventors or an embodiment of the invention after the sequence of steps depicted in  FIG. 11 ; 
         FIGS. 13 to 15  depict sequences of steps described by process blocks within  FIGS. 10 and 12  for an SMIS air ride suspensions according to U.S. Pat. No. 8,870,203 by the inventors or an embodiment of the invention after the sequence of steps depicted in  FIG. 11 ; 
         FIGS. 16 to 18  depict sequences of steps described by process blocks within  FIGS. 10 and 12  for an SMIS air ride suspensions according to embodiment of the invention after the sequence of steps depicted in  FIG. 11 ; and 
         FIG. 19  depicts the SMIS air ride suspensions according to embodiment of the invention after installation. 
     
    
    
     DETAILED DESCRIPTION 
     The present invention is directed to motor vehicle air ride suspension assemblies, and more particularly, to an air ride suspension assemblies or kits for converting an original equipment leaf spring suspension arrangement supporting a solid rear axle of the motor vehicle to one supported by an air ride suspension assembly. 
     The ensuing description provides exemplary embodiment(s) only, and is not intended to limit the scope, applicability or configuration of the disclosure. Rather, the ensuing description of the exemplary embodiment(s) will provide those skilled in the art with an enabling description for implementing an exemplary embodiment. It being understood that various changes may be made in the function and arrangement of elements without departing from the spirit and scope as set forth in the appended claims. 
     Within the ensuing description an air ride suspension system (ARSS) intended for secondary market installation/sales (SMIS) is described and depicted with respect to exemplary embodiments of the invention. With respect to  FIGS. 1 to 4  and the design of the upper support arm the design depicted represents one for a Ford F-250 although it would be evident to one skilled in the art that the principles described are applicable to other trucks, SUVs, and vehicles through adjustment in the design/dimensions. 
     Referring to  FIG. 1  there are depicted first and second upper support arms  100 A and  100 B for SMIS ARSS for the F-250 truck according to an embodiment of the invention wherein first upper support arm  100 A is mounted to the left hand side (LHS) of the F-250 and second upper support arm  100 B is mounted to the right hand side (RHS) of the F-250. Each of the first and second upper support arm variant  100 A and  100 B comprises:
         High strength steel (HSS) tube  108 ;   First leaf spring mount  102 ;   Support plates  103 ;   First blanking plate  104 ;   Mounting bracket  105 ;   Stop housing  106  and stop housing bushing  107  (not depicted for clarity on second upper support arm variant  100 B but depicted on first upper support arm  100 A);   First mount  109 ;   Second mount  110  which is attached to third mount  111 ;   Second blanking plate  112 ; and   Second leaf spring mount  113 .       

     Second upper support arm variant  100 A also comprises:
         Fitting  114 ;   Plate  115 ; and   Supports  116 .       

     As noted, each of the depicted first and second upper support arm variants  100 A and  100 B respectively with appropriate dimensions L 1  to L 8  are intended to SMIS ARSS to an F-250. The dimensions L 1  to L 8  as well as those of elements including, but not limited to, second and third mounts  110  and  111  respectively, first and second leaf spring mounts  102  and  113  respectively, first mount  109  and plate  115 . 
       FIGS. 2 to 4  depict individually these multiple elements added to the HSS tube  108  forming the primary element within first and second upper support arm variants  100 A and  100 B respectively. The HSS tube  108  is 78 inches long and cross-section 3×2×¼ inch. These other elements being:
         First leaf spring mount  102  of ⅞ inch diameter circular pipe with ⅛ inch wall and length 3½ inches;   Support plates  103  of thickness ¼ inch and 3×3 inch;   First blanking plate  104  of thickness ¼ inch and 3×1⅝ inch;   Mounting bracket  105  of thickness 5/16 inch and 3×1½ inch which is profiled by bending;   Stop housing  106  of 2¾ inch diameter circular pipe with ¼ inch wall and length 3½ inches and stop housing bushing  107  of diameter 4 inches and thickness ⅛ inch with inner diameter of 2¼ inches;   First mount  109  comprising L-shaped 1½×1½× 3/16 inches and length 3½ inches;   Second mount  110  of plate ⅜×2½ inch and length 8½ inches which is attached to third mount  111  of plate ¼×12 inch and length 9 inches, wherein both are profiled and bent to shape;   Second blanking plate  112  ¼×1 inch and length 3 inches; and   Second leaf spring mount  113  of 1⅛ inch diameter circular pipe with 3/16 inch wall and length 3½ inches;   Fitting  114  plate ⅜×1½ inch and length 6 inches which is profiled and bent to shape;   Plate  115  of dimensions ⅜×4 inch and length 10 inches which is profiled and bent to shape;   Supports  116  which are ½ inch diameter rods of length 8¼ inches.       

     Now referring to  FIGS. 5 and 6 , there are depicted axle mounting brackets for a SMIS air ride suspension system (ARSS) according to an embodiment of the invention. In  FIG. 5 , the lower axle mounting bracket  200  is depicted in first to third views  200 A to  200 C respectively for the side elevation, front elevation and rear elevation. As evident, lower axle mounting bracket  200  comprises recess  210  which mates to the lower portion of the circular rear axle.  FIG. 6  depicts first and second axle mounting brackets  300  and  400  respectively for the left and right hand sides of the truck. First axle mounting bracket  300  is depicted in first side elevation  300 A, front elevation  300 B, second side elevation  300 C, and rear elevation  300 D. Second axle mounting bracket  400  is depicted in first side elevation  400 A, front elevation  400 B, second side elevation  400 C, and rear elevation  400 D. As depicted, each comprises a central plate to which are attached a first mounting “U” element and an angled bracket. Each of the angled brackets has attached an angled second “U” element with mounting holes of axis relative to the mounting bracket. 
     Now referring to  FIG. 7 , there are depicted sway bar  500  and lower axle support bar  600  for a SMIS ARSS according to an embodiment of the invention. As depicted, sway bar  500  is presented in first to third views  500 A to  500 C representing plan, front, and end elevations respectively. Lower axle support bar  600  is depicted in plan view  600 A and front view  600 B respectively. Referring to  FIG. 8 , there are depicted upper adjustable axle support bar  700  and sway bar adjustment bar  800  for a SMIS ARSS according to an embodiment of the invention. Upper adjustable axle support bar  700  is depicted in top elevation  700 A, front elevation  700 B, and bottom elevation  700 C as comprising first and second mounting elements  710  and  720  with clamping regions  730  and  740  respectively as mounted to central rod  750 . Sway bar adjustment bar  800  is depicted in first and second views  800 A and  800 B representing plan and front elevations respectively. As depicted, the sway adjustment bar  800  comprises a mounting element  830 , rod  820 , and threaded rod portion  810 . 
     Referring to  FIG. 9 , there is depicted a flow  900  depicting a sequence of steps  905  to  945  for the removal of an OEM leaf-spring suspension for the subsequent installation of an SMIS ASRSS according to an embodiment of the invention. As depicted, once the installer has identified and purchased the correct SMIS ARSS kit for the vehicle being modified, then they:
         First step  905  wherein the installer measures the ride height of the vehicle and the pinion angle;   Second step  910  comprising removal of spare tire for easy install if located in a position impacting access to the rear axle;   Third step  915  with lift the rear of the vehicle off the ground and securing it;   Fourth step  920  with removal of both rear tires;   Fifth step  925  with removal of the U-bolts holding the leaf springs in position;   Sixth step  930  wherein the leaf springs are removed from both sides of the vehicle;   Seventh step  935  wherein the OEM shock absorbers are removed;   Eighth step  940  wherein, for a Ford and potentially other OEM vehicles/brands, helper spring brackets are removed; and   Ninth step  945  wherein the rear leaf spring shackles are removed from the leaf springs and are attached to the rear of each upper support arm.       

     Optionally, any OEM installed sway bar is removed during this dismantling of the OEM installed rear leaf spring assemblies. Now referring to  FIG. 10 , there is depicted a flow  1000  depicting the initial sequence of installing through steps  1010  to  1070  a SMIS ASRSS according to an embodiment of the invention. From process flow  900  the flow  1000  proceeds to first step  1010  wherein the installer installs the first and second upper support arms  100 A and  100 B to the vehicle on the left and right hand sides of the vehicle. If the installer is installing a SMIS ARSS according to the design presented by the inventors within U.S. Pat. No. 8,870,203 entitled “Vehicle Leaf Spring to Air-Ride Suspension Conversion Assembly” (referred to as “AutoFlex”) then the flow  1000  proceeds via first flow  1300 , second step  1020  associated with flow  1300  in  FIG. 13 , third and fourth steps  1040  and  1050  respectively, and fifth step  1060  associated with flow  1400  in  FIG. 14  before proceeding to flow  1100  in  FIG. 11 . If the installer is installing a SMIS ARSS according to an embodiment of the invention (referred to as “Ultra”) then the flow  1000  proceeds via sixth step  1030  associated with flow  1600  in  FIG. 16 , third and fourth steps  1040  and  1050  respectively, and seventh step  1070  associated with flow  1700  in  FIG. 17  before proceeding to flow  1100  in  FIG. 11 . 
     Third step  1040  relates to installation of the sway bar  500  together with sway adjustment bar  800  which is left loose at this point and fourth step  1050  relates to the installation of the new shock absorbers onto the vehicle. From flow  1000  the process proceeds to flow  1100  in  FIG. 11  depicting the sequence of steps for the addition of the air compressor/pump and air tank for an SMIS ARSS which are common to both the AutoFlex SMIS ARSS according to U.S. Pat. No. 8,870,023 by the inventors and the Ultra SMIS ARSS according to embodiments of the invention. As depicted, flow  1100  comprises first to eighth steps  1105  to  1140  wherein the installer:
         First step  1105  wherein the installer installs a leveling valve bracket to front side of spare tire rack facing to the front of the vehicle (leveling valve bracket not depicted within  FIGS. 1 to 8 );   Second step  1110  comprising installing an adjustable link tab to the axle housing;   Third step  1115  wherein leveling valve and adjustable link are bolted for adjustment later;   Fourth step  1120  with installation of the air tank brackets on chassis on the passenger side;   Fifth step  1125  with installation of the air tank with its two ports facing rear;   Sixth step  1130  wherein installation of the air compressor bracket to frame is made, this being close to air tank;   Seventh step  1135  wherein the air compressor is installed; and   Eighth step  1140  wherein the wiring harness is run from compressor to front of vehicle on the driver&#39;s side and the wiring connected to the vehicle&#39;s electrical system.       

     Now referring to  FIG. 12 , there is depicted a flow  1200  for the remainder of the installation sequence for an SMIS ARSS wherein flow  1200  follows from flow  1100  in  FIG. 11 . As depicted, the installer performs first and second steps  1210  and  1220  before progressing. Within first step  1210  the installer runs the air lines from the air tank to the left and right hand airbags whilst in second step  1220  the installer adjusts the sway bar  700 , measures from the vehicle frame to hub face on either side and tightens via sway adjustment bar  800 . If the installer is installing a SMIS ARSS according to the design presented by the inventors within U.S. Pat. No. 8,870,203 entitled “Vehicle Leaf Spring to Air-Ride Suspension Conversion Assembly” (referred to as “AutoFlex”) then the flow  1200  proceeds via third and fourth steps  1230  and  1240  respectively, first flow  1280  associated with flow  1500  in  FIG. 15 , and fifth to seventh steps  1250  to  1270  respectively. If the installer is installing a SMIS ARSS according to an embodiment of the invention (referred to as “Ultra”) then the flow  1200  proceeds via second flow  1290  associated with flow  1800  in  FIG. 18 , and steps third to seventh steps  1230  to  1270  respectively. In each instance the installation is complete. 
     Accordingly, third to seventh steps  1230  to  1270  respectively are:
         Third step  1230  wherein the installer installs the rear wheels;   Fourth step  1240  wherein the installer sets the ride height, measures the vehicle, and sets via the adjustable link;   Fifth step  1250  wherein the installer checks for leaks on the air system;   Sixth step  1260  wherein the rear wheels are torqued to factory specifications; and   Seventh step  1270  wherein the spare wheel is re-installed into its original place in the frame under the rear of the vehicle.       

     Referring to  FIGS. 13 to 15 , there are depicted flows  1300  to  1500  representing the sequences of steps associated with these flows within  FIGS. 10 and 12  for an SMIS air ride suspensions according to U.S. Pat. No. 8,870,203 by the inventors. Referring to  FIG. 13 , flow  1300  comprises first to fourth steps  1310  to  1340  wherein:
         First and second steps  1310  and  1320  wherein the installer installs trailing arms to each of the first and second upper support arms  100 A and  100 B respectively;   Third step  1330  wherein the installer installs bolts into the pivot to the axle;   Fourth step  1340  wherein each trailing arm is tightened to the axle through the bolts.       

     Now referring to flow  1400  in  FIG. 14 , this comprises first to third steps  1410  to  1430  comprising:
         First step  1410  wherein the fittings are installed to the air bladders;   Second and third steps  1420  and  1430  respectively wherein the two airbags are installed on the trailing arm ledge such that they are disposed between the ledge of the trailing arm and the bottom of the upper support arm.       

     The upper bracket  1425  between the airbags on the left and right sides and the first and second upper support arms  100 A and  100 B respectively in the SMIS ARSS kit for the AutoFlex approach may be bolted to first and second upper support arms  100 A and  100 B respectively allowing a common design of upper support arm to be employed in both AutoFlex and Ultra configurations. Referring to flow  1500  in  FIG. 15 , this comprises step  1510  wherein the bolts on the trailing arms are torqued to the specification of the AutoFlex specifications. 
     Now referring to  FIGS. 16 to 18 , there are depicted flows  1600  to  1800  representing the sequences of steps associated with these flows within  FIGS. 10 and 12  for an SMIS air ride suspensions according to an embodiment of the invention. Referring to  FIG. 16 , flow  1600  comprises first to fifth steps  1610  to  1650  wherein:
         First and second steps  1610  and  1620  wherein the installer mounts on the lower side of the rear axle on both left and right sides a lower axle mounting bracket  200  and on the upper side of the rear axle on the left and right sides the respective one of the first and second upper axle mounting brackets  300  and  400  respectively;   Third step  1630  wherein an installed lower axle mounting bracket  200  and upper axle mounting bracket ( 300 / 400 ) are depicted with the upper support arm ( 100 A/ 100 B) above;   Fourth step  1640  wherein an upper adjustable axle support bar  700  is depicted installed between the upper support arm ( 100 A/ 100 B) and upper axle mounting bracket ( 300 / 400 ) wherein the first and second mounting elements  710  and  720  have not been clamped using clamping regions  730  and  740  to the central rod  750  allowing the setting of the SMIS ARSS once installed; and   Fifth step  1650  wherein a lower axle support bar  600  is depicted installed between the upper support arm ( 100 A/ 100 B) and lower axle mounting bracket ( 200 ).       

     Now referring to  FIG. 17 , there are depicted first to third steps  1710  to  1730  comprising:
         First step  1710  wherein the installer installs limiters comprising a rising limiter and falling limiter for raising/dropping of the axle relative to the vehicle body wherein the rising limiter comprises a hollow pillow which is inserted into the ring  106  on the upper support arm and is retained by interference fit and the falling limiter comprises a resilient member between the upper support arm and the upper axle mounting bracket (optionally the falling limiter may be attached between the upper support arm and the lower axle mounting bracket);   Second step  1720  wherein the installer installs an air bladder on each side of the vehicle between the upper axle mounting brackets ( 300 / 400 ) on the rear axle on either side and the first and second upper arms  100 A and  100 B respectively; and   Third step  1730  wherein replacement shock absorbers are attached on either side of the vehicle wherein the sway bar  500  may be shaped to go around the shock absorbers depending upon the mechanical configuration of the vehicle.       

     Now referring to  FIG. 18 , there is depicted first step  1810  wherein the upper adjustable axle support bars  700  on either side of the vehicle are set such that the first and second mounting elements  710  and  720  are spaced equally on either side of the vehicle to a predetermined spacing and clamped to the central rod  750  via clamping regions  730  and  740 . Accordingly, once the mechanical installation is completed through flow  1800  prior to installation of the tyres in step  1230  in flow  1200  and completion of the SMIS ARSS installation, the assembled ARSS according to an embodiment of the invention is depicted in first and second images  1910  and  1920  using first and second upper support arms  100 A and  100 B respectively on the right and left sides of the vehicle, in this case a F-250 truck. Accordingly, the interconnection between the upper support arms  100 A and  100 B and the upper and lower axle mounting brackets  200  and  300 / 400  respectively via upper adjustable axle support bars  700  and fixed lower axle support bar  600  can be clearly seen. Equally, sway bar  500  can be seen in first image  1910  running from the upper axle mounting bracket  300 / 400  to the other side of the truck under the chassis. In each of the first and second images  1900 A and  1900 B, respectively, the air bladder on either side is also clearly evident between the upper support arms  100 A and  100 B and the upper axle mounting brackets  300 / 400  together with their air interconnections and air pressure indicator in second image  1920  (not described during installation for ease). 
     Accordingly, it would be evident that the SMIS ARSS described in respect of an embodiment of the invention provides for the after sale retrofitting of an air ride suspension system to a vehicle having an OEM installed leaf spring suspension system. Whilst the dimensions and relative positions of elements may change according to the specific vehicle being retrofitted with the ARSS the overall assembly comprises the same elements and their relative positions/associations such as described and depicted within the specification supra. Further, it would be evident to one skilled in the art that the ARSS as described and depicted differs from the SMIS ARSS described within U.S. Pat. No. 8,870,203 also by the inventors. 
     It would be evident to one skilled in the art that the ARSS as described comprising air bladders disposed on either side of the chassis to the rear axle, the compressor and air tank form part of an air control system associated with the ARSS. The air bladders rely upon an air source, such as the compressor, which draws power from a source such as the motor vehicle itself, i.e. via the battery and/or a generator coupled to the engine. The connection between power supply and compressor is made through a regulator which in conjunction with a sensor determines whether air pressure should be maintained or increased. The sensor within an embodiment of the invention may be a levelling valve that can serve to increase or decrease the pressure in the air bladders as needed. If a decrease in air pressure is required, the levelling valve, can provide air bladders with the means to exhaust air by putting the bladders in fluid communication with the outside environment, thus allowing the bladders to vent. The exhausting of air can be continued until the desired bed level is reached and the levelling valve closes. 
     Between compressor and the air bladders, is an air tank that can be kept under pressure so that the inflation of the air bladders can be performed quicker than would be possible if they were directly connected to air compressor. When using air tank, flow from the tank can be run through the sensor to the dump valve (which can be implemented as a three way ball valve). In such a configuration, the levelling valve has three states, an inflation state, a maintenance state and a deflation state. The choice of states is controlled by the ride height as determined by levelling valve. The use of a single air passage to each of the air bladders (through both levelling valve and dump valve, for both inflation and deflation, results in an easier to install system. Dump valve can be used to provide the user with the ability to control the ride height of the vehicle bed, or to control the air pressure in tank when the system is powered down. 
     Whilst a single air bladder is depicted disposed between the upper axle mounting bracket and upper support arm it would be evident that multiple air bladders may be deployed within the same footprint or that with appropriate modification to the upper axle mounting brackets that multiple air bladders may be employed with a larger footprint. 
     In operation, a sensor determines whether the bed is at the desired level (ride height). The bed can be at the level, in which case, no changes to the air pressure in the air bladders is needed; it can be too high, in which case the air bladders need to be deflated; or it can be too low in which case the air bladders will need to be inflated. When sensor determines the applicable state it selects between its three states. In a first state, a seal is effectively maintained, so that the air pressure in the bladders is maintained. In a second state, the bladders are put into fluid communication with the air tank, which is at a higher pressure than the bladders. The air in the system will seek to find equilibrium, and thus will flow to the air bladders, inflating them in the process. When the desired level has been reached, the sensor will seal access to the bladders. In the third state, the air bladders are put into fluid communication with a lower pressure environment, which can be done by opening a valve to the open atmosphere. Once again, the air in the system will seek equilibrium, which in this case will empty the air bladders. In such a system the regulator provides power to the compressor from the power source based on the air pressure in the tank. Dump valve can be used to provide manual control of the pressure in various components of the system. 
     In standard operation, dump valve allows the air tank to be in fluid communication with the air bladders, a communication controlled by sensor. However, when in a powered off state, the user may want to lower the bed of the vehicle which is achieved by venting the air bladders to the atmosphere. In such a case, dump valve can be used to empty the bladders. In some embodiments, dump valve can also be used to vent pressurized air stored in tank if so desired. Additional control elements including check valves, shut off valves and couplers to allow the pressure in the air tank to be released can be provided. The use of these systems will be well understood by those skilled in the art. 
     It would be evident that other types of sensors can be employed as sensor. In the illustrated embodiments, a levelling valve is employed to allow for the creation of a simple pneumatic control system. This valve can be preset so that there is a desired level at which the bed of the trailer is to be maintained. When the bed of the trailer is not at this level, air pressure in the bladders is increased or decreased accordingly. Optionally, an air gauge can be employed to measure the pressure in the suspension system, which is directly related to the pressure in bladders. Because the weight of the bed in any given installation is constant, when the bed is level the pressure of the suspension system is directly proportional to the weight of the load carried by the vehicle. Thus an air gauge can also be employed to provide a rudimentary load scale on the vehicle. 
     Though described above as using a mechanical control system regulated by a levelling valve, the system of the present invention can be controlled through the use of an electronic control system that can be responsive to a number of different inputs, such as the height differential between the upper support arm and the upper axle mounting, the angle between the upper support arm and the trailing arms upper or lower axle mounting, a direct measure of the ride height, or a manual input such as one set through external controller interface. Those skilled in the art will appreciate that the implementation of such a system does not depart from the scope of the present invention. 
     Specific details are given in the above description to provide a thorough understanding of the embodiments. However, it is understood that the embodiments may be practiced without these specific details. For example, circuits may be shown in block diagrams in order not to obscure the embodiments in unnecessary detail. In other instances, well-known circuits, processes, algorithms, structures, and techniques may be shown without unnecessary detail in order to avoid obscuring the embodiments. 
     The foregoing disclosure of the exemplary embodiments of the present invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many variations and modifications of the embodiments described herein will be apparent to one of ordinary skill in the art in light of the above disclosure. The scope of the invention is to be defined only by the claims appended hereto, and by their equivalents. 
     Further, in describing representative embodiments of the present invention, the specification may have presented the method and/or process of the present invention as a particular sequence of steps. However, to the extent that the method or process does not rely on the particular order of steps set forth herein, the method or process should not be limited to the particular sequence of steps described. As one of ordinary skill in the art would appreciate, other sequences of steps may be possible. Therefore, the particular order of the steps set forth in the specification should not be construed as limitations on the claims. In addition, the claims directed to the method and/or process of the present invention should not be limited to the performance of their steps in the order written, and one skilled in the art can readily appreciate that the sequences may be varied and still remain within the spirit and scope of the present invention.