Brake pedal travel issues (long story)

Hi guys and girls, I need a little help with a 2002 TD5, 70,000 miles, the car had regular use but only short runs and would often stand for days in between. It is LHD but I do not think this adds any complication, no warning lights on the dashboard. ABS works fine, car stops in a straight line.

Some history to help with diagnosis:

Brake pads front and rear have plenty of material and are contacting the brake discs evenly.

The wheel bearings have no play so this is not pad 'knock off'.

No leaks anywhere and fluid does not fall

No leaks in the vaccum system

About a year ago the owner complained to his mechanic that the brake pedal was travelling and that a 'double pump' brought the pedal up and all was OK until the brakes were needed again a few miles later down the road and the travel reappeared. His mechanic bled the brakes and this did not really improve it and then the mechanic shyed away saying he was not sure ect. The owner took the car to 2 spanish garages and they both shrugged there shoulders so he quickly left. I then come on the scene and with the engine running and a hard pressure on the brake pedal the pedal holds steady, ease up on the pressure and the pedal falls slowly towards the floor but not quite reaching it. I suspected the master cylinder but bled the system anyway and this changed nothing, I bled from the furthest wheel working towards the master cylinder and with the engine running.

The fluid was black before I started bleeding further adding credence to my suggestion that the master was toast. We purchased a new one and fitted and bled the system it was perfect! Until he drove about 60 miles and the brakes came on by themselves and slow but sure he was brought to a stop. Now I have seen this before and would normally indicate the brake servo has been badly adjusted, I went on the call out and shimmed the master away from the servo by using a couple of thin washers and all was well. A few day laters I removed the master and wound in the adjuster one and a half turns and the pedal has some travel but no more 'auto active' brakes. Futher enquiries reveal that the previous mechanic had wound out the servo pushrod to bring up the pedal!

Now before I go removing the master for the second time adjusting the rod out a little bit again perhaps half a turn and rebleeding ect I need to know three things:

1, is there any other bleed nipples on the TD5 other than one on each wheel?

2, is there a known measurement for the servo pushrod?

3, Am I missing something completely here and just being plain thick?

Thanks for anything you can offer guys.

regards

Dave

Hi Dave,
have you sorted the problem. i have the same problem,the original master cylinder was worn i had to pump the pedal three times to get it to the right place and with a new master cylinder after about 10 k the brakes lock up i tried another master cylinder of another car and to much pedal travel but when i put it back on the other car the brakes are fine the distance from the face of the servo to the tip of the pushrod is exactly the same for both vehicles and i have also measured another to check i wasn't going mad and its the same as well.i reduced the length of the pushrod by 2mm and its exactly the same but when i fit another master cylinder the i have to pump the pedal 4 times so obviously its making a difference.What brand of master cylinder is fitted to the disco is it cast iron one? Getting desperate now 8litres of brake fluid £158 to unlock my hawkeye to power bleed the brakes and had to drive the customer home last night at 10 o'clock(180 km) after he cam in yesterday morning for a 1 1/2 hour job!
seb

Well no doubt you have seen how long I have waited for a reply which to be honest is unusual. Perhaps a lot of members were preparing or had gone on early holidays of perhaps they too have given up? Anyway, I did spend a lot of time getting as close as can be, this was done by trial and error. I wound the pushrod in/out anumber of times untill the pedal was very long I then wound out the rod about two turns and then drove the car for about half an hour, the brakes were real good but then the car slowed to a halt as the brakes heated and the servo held them on. As a quick fix I simply removed the two nuts holding the new (cast iron) master cylinder on and slipped a washer on each of the studs and replaced the cylinder, this can be done without fluid loss. This released the brakes and allowed me to drive home but of course the pedal travel had returned, the vehicle needing two good pumps to bring it up. Now apparently this model is renowned for a 'long' pedal so I was not expecting miracles. When I got back to the garage I used a micrometer to measure the washers and then reduced (wound in) the push rod by half the measurement using a depth gauge. I then re bled and drove the car for about an hour, no brake dragging issues and only a slightly long pedal. I think I am about as close as I can get, 1 mm can be the difference between reasonable pedal and locked brakes.

regards

Dave

HI ,
continuing the saga i left the car overnight with locked brakes and in the morning the were free(nothing unusual!)i then drove the car for half an hour and the brakes don't lock up but now the more i drive the longer the pedal,also i drive down a long hill just slowing the vehicle with my foot on the brake pedal it creeps and after a 100 m or so the pedal is on the floor and i have to release it and the next press the brakes are perfect but after a few metres the pedal starts to creep i have tried 1 new master cylinder(britpart cast iron) and 2 second hand (genuine) one of which is of a good car and which i have refitted to the other car and the brakes are working fine.i have found that there was a land rover safety recall Rb148 which involved changing a couple of plates on top of the modulator to retain the original plates over the valves which were prone to cracking but this has been done.
I am really stuck now the customer wants to go on holiday in his car on Friday,but obviously would like brakes, a long pedal would be ok but not one that goes to the floor especially as we live in the mountains!
any ideas any one?
Seb

Hi just wondering if any one can help I have the 3 lights on on the dash of my 2000 reg disco td5 abs hill decent and tc and this morning my brakes have nearly gone if a abs pump gives up dose this effect ur brakesits already had a new master cylinder

Melanies said:

Hi just wondering if any one can help I have the 3 lights on on the dash of my 2000 reg disco td5 abs hill decent and tc and this morning my brakes have nearly gone if a abs pump gives up dose this effect ur brakesits already had a new master cylinder

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Hi, Do a search for the Three Amigos. That'll give you a good start.
Griff