Brake Caliper Service

**Please read the whole tutorial before beginning. Print out and use as reference if needed.** To keep your brake system in top order some people suggest that you perform this caliper service every time you change the pads. The Clymer manual, on the other hand, suggests that you only do it when "absolutely necessary." How often you do it is up to you. You may want to wear gloves to handle the brake fluid since it can leave your fingertips wrinkly for a day or two.

[hide]
* 1 Common Problems
	+ 1.1 A short list of the problems and the causes.
		- 1.1.1 Soft lever or lever goes to the bar
		- 1.1.2 Pulsing in sync with wheel rotation.
		- 1.1.3 Cupped, coned, or warped disc
* 2 Tools & Supplies
* 3 Preparation
	+ 3.1 Removing the rear fairing for rear brake maintenance
	+ 3.2 Remove the exhaust can for rear maintenance
* 4 Removing the rear caliper
* 5 Removing the brake pads
* 6 Removing the brake cylinders
* 7 Disconnecting the caliper from the hose
* 8 Disassembling the caliper for cleaning
	+ 8.1 Inspection of caliper parts
* 9 Reassembly of the caliper
* 10 Re-filling the brake fluid
* 11 Bleeding the Brakes (removing air)
* 12 Rear Master Cylinder Disassembly (note front is similar)
* 13 Credits

## Common Problems

(Taken from FOG's post in the howto/fyi section with minor modifications)

Many folks have posted here with a variety of front brake problems. Many of which are attributable to the lack of proper maintenance. Here’s how you can always have a brake like when your bike was new.

A pictoral DIY for the front caliper can be found here - [[1] (broken link)] to accompany these instructions.

### A short list of the problems and the causes.

#### Soft lever or lever goes to the bar

The usual cause is the pistons are pushed too far back into the caliper by a flexing a warped, or coned, disc. The result is that the piston must travel farther to reach the rotor.

Another possible cause is that the sliding pins are binding. The caliper on the EX-500 only has pistons on one side, so as the pads wear the caliper must shift toward the rotor to apply even pressure to both sides of the disc. To do this the caliper floats on two pins. The caliper will not move properly if these pins get dry (no grease), dirty or bent. When the caliper is no longer centered, more lever travel will be required. This will eventually cause a warped disk if not corrected.

#### Pulsing in sync with wheel rotation.

The disk is worn and has variable thickness. This causes more braking force on the thicker parts of the rotor, and less on the thinner pars.

#### Cupped, coned, or warped disc

Unfortunately this is a common problem with EX’s the cause is the disc is stretched in the center due to being rigidly bolted to the wheel. The huge force of braking is transmitted to the wheel through the webbed center of the disc which gets stretched and becomes larger than the space it occupies in the center of the disc. This causes the center to push to the side trying to find room for itself. This results in a cone shaped disc.

## Tools & Supplies

* 3/8” drive 12mm socket
* 3/8” drive extension (\*optional)
* wire brush or steel wool
* 14mm open end wrench
* 12mm open end wrench
* 10mm open end wrench
* #3 Philips screw driver
* #2 Philips screw driver
* dull/blunt pick tool or flat blade screw driver
* Multi-purpose high temp grease
* Brake pads (if replacing - sintered rather than cheaper organic pads are highly recommended) front pads should be reference #FA129 and rear #FA67/3
* 1 can of brake cleaner
* Container to catch old brake fluid and/or a bleeder kit, such as Ampro one man bleeder kit

## Preparation

### Removing the rear fairing for rear brake maintenance

We will remove the right side rear fairing to provide access to the brake fluid reservoir.

* We'll start by removing the seat to access the bolts for the rear grab bar.
* Remove the grab bar by removing the 2, 12mm bolts.

* You can now pop the front end of the plastic out of the retainer and push it backwards to free it from the rear retainer.

### Remove the exhaust can for rear maintenance

For unobstructed access to the hex bolts that hold the caliper to it's mount you will need to remove the exhaust can. Turning the caliper bleed valve is also very hard unless you do this. Removing the can is quick but it's your call if you want to leave it on.

## Disassembling the caliper for cleaning

### Inspection of caliper parts

* We will assume the master cylinder is in good working order here.
* Don’t remove the disc unless you intend to replace it. It will assume a new shape if it is stressed and will not be flat again. You can try to check its condition by placing a straight edge across the face of the pad swept area looking for any distortion.
* Check brake hoses for cracks and/or leaks. Replace if necessary.

## Reassembly of the caliper

Re-inserting the piston can be tricky the first time since the inner packing seal attaches tightly to the piston, making the piston hard to insert. Also, the piston boot is delicate and can be torn. It should be ok if you take your time and lubricate the piston with brake fluid.

## Re-filling the brake fluid

* Connect the hose to the caliper, keeping it above the Master Cylinder.
* Open the bleeder valve on the caliper, while holding the bleeder valve at it's highest point, pump the pedal until brake fluid starts to flow from the bleeder valve, then close the valve.
* Pump a little more fluid into the caliper, be careful not to push the piston all the way out of the caliper.
* Squeeze the piston all the way back into the caliper body.
* Install the new brake pads.

*It would be great if anyone can supply pics for these steps.*

* Cap the rear reservoir.
* Reinstall exhaust can onto header pipe, and install rear plastic.

## Bleeding the Brakes (removing air)

Using the Ampro bleeder kit.

* If you messed up any of the fluid filling outlined above, you may need to manually bleed the brakes. Personally, for peace of mind, I still performed the bleeding procedure by attaching the Ampro one man bleeder kit to the bleeder nozzle.

* Bleeding air from brake system, a step by step guide
	1. attach a collector bottle to the bleed screw, this is often called a one man bleed kit and is cheap at roughly $5-$7. Position the socket side of the wrench over the bleed screw first so the collector hose does not have to be removed to tighten or loosen the bleed screw
	2. unscrew bleeder roughly 1/2 a turn
	3. squeeze brake lever or brake pedal - continuing to hold it down after squeezing and NOT releasing it
	4. tighten bleeder to close
	5. release brake lever or brake pedal
	6. repeat steps 2 to 5 until air bubbles cannot be seen in clear hose leading from bleeder screw to brake fluid collection bottle. Do not allow the brake reservoir to run dry during this process. If it does run dry it will draw air into the system and you will need to start from the beginning.

* You might also decide to use a vacuum kit to suck out troublesome air. When using such a kit set you won't need too much suction (negative pressure) about 15 kPa should do. Make sure that the tube attaching to the bleeder valve is on tight and not leaking air. How to tell if it's leaking air? With a little brake fluid in the tube above the bleeder valve, apply about 15 kPa of suction. Keep the bleeder valve shut. If you see bubbles going through the fluid then air must be leaking between the suction tube and bleeder valve. Use a tighter tub or seal with teflon tape (plumber's tape). To bleed the system apply suction and open the valve. Any trapped air should now be sucked out: you should see a few bubbles followed by clear brake fluid. If you see an endless stream of bubbles it means that air is leaking around the threads of the bleeder valve. You will need to remove the valve and wrap a little teflon tape around the threads then re-install.

## Rear Master Cylinder Disassembly (note front is similar)

* In the event that you need to disassemble the rear master cylinder for a rebuild, you may find this video (compliments of bobthebiker) helpful.

## Credits

* Zeroaffiliation 13:16, 11 August 2008 (UTC)
* Some sections borrowed from FOG's rear caliper service write-up.
* Rear master cylinder disassembly guide provided by bobthebiker