From: bakc@giraffe.ru.ac.za (MR KR COMAN)
Newsgroups: rec.autos.tech
Subject: Re: Pumping pedal restores braking - why?...........
Date: 5 Nov 92 13:01:39 GMT
Article-I.D.: giraffe.bakc.195.720968499
Organization: Rhodes University, Grahamstown, South Africa

In article <1992Nov3.235127.10353@nezsdc.icl.co.nz> derek@nezsdc.icl.co.nz (Derek Tearne) writes:
>Subject: Re: Pumping pedal restores braking - why?...........
>From: derek@nezsdc.icl.co.nz (Derek Tearne)
>Date: Tue, 3 Nov 92 23:51:27 GMT
>sgm@otter.hpl.hp.com (Steve Methley) writes:
>
>>My LandRover developed a brake fault after some serious off roading.  Brakes
>>are now poor when normally applied, but very good (as normal) when 'pumped'
>>once or twice before main application.  When not pumped there is much pedal
>>travel for little effect.  No obvious damage to brake lines and no drop in
>>fluid level discerible.  System is dual circuit servo assisted.

>Our Landrover developed exactly this situation after some serious driving
>(Africa).  It was finally cured after fixing the following.
>
>Brake master cylinder (probably not necessary)
>New front pads.
>Adjusting then relining (and re adjusting) the rear brakes.
>Overhauling the (leaking) rear wheel cylinders.
>
>Relining the rear brakes surprisingly made the biggest difference.
>The air was being introduced into the system through the rear wheel cylinders.
>This was hard to trace as you have to expose the brakes before you can see 
>what's happening.  You may also try simply adjusting the rear brakes (two
>snail cams on each wheel) which may make a difference.

	My own 1958 Series 2 has *exactly* the problem described; drive, 
wanna stop, one-two quick touches on the brake pedal, then I get a nice hard 
pedal that 'takes' close to the start of its travel.  I've spent hours on 
this and, for what its worth, here's my solution.   Primary cause is the 
excessive travel of the wheel cylinder plungers that act on the brake 
shoes  (hence the 'one-two' routine to bring them out) because the brake 
shoe adjusters (snail cams) are allow excessive brake shoe movement before 
contacting the brake drum.  OK, so tighten up the adjusters and see what 
happens.   	

My Landies' problem however is that when the brake shoes are 
adjusted to give a really hard pedal, they are so close to the brake drum 
that they tend to bind....some fine compromise-adjustment is thus needed.    

	Another thing to note is that all it takes is for one wheel's brakes 
to have excessive slack and the brake pedal reverts to its old tricks 
again.  
	In service, I find that I have to adjust the brakes every 300-
500 miles to take up the slack -- rather like an old car with cable 
brakes!!  This may explain the sudden problem after your off-road 
adventures; used the brakes a lot??	

	Finally a little cautionary note.  On some Landies if you drain the 
brake fluid out of the master cylinder there is a strong chance that you 
will not be able to bleed all the air out of the cylinder itself cos of a 
small air bubble being trapped in the master cylinder itself (some MG's also 
had this problem).   One set of advice is to get the nose of the car up at 
about 45degrees and then go thu your pump 'n squirt act.  Far better is to 
pressurise the fluid in the reservoir.  I used a spare brake fluid reservoir 
cap and fitted it with the valve-stem from a section off an old inner tube.  
Remove the cap, screw on said 'special tool', connect up the old tyre pump 
and give it maybe half a push.  Was a *big* help to me!!	

Landies are the ONLY way to travel!!!!

Cheers
Keith Coman

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"Condemning a research report on the basis of :  Dept of Management
 invalid and unreliable methodology is the    :  Rhodes University
 cheapest shot in the book."                  :  Grahamstown, 6140
                                              :  Rep of South Africa
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Newsgroups: rec.autos.tech