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brake system question (Disco 200Tdi)

People Hi,

I would be grateful to have your input on the following problem. The car is a 1994 evented Camel Trophy Discovery 200Tdi with 82.000 Km on its clock.

Over the last few days I have noticed that when I press the brake pedal more than three times one after another it appears like the brake pedals gets a "bricky" feel. And it does need far more strength from my foot to stop the car.

I have just changed the brake pump but I fear that the servo is damaged. While changing the brake pump yesterday I noticed that while removing the old pump from the servo there was a very strong hiss from the servo. Was this due to leakage from the servo's diaphragm which cause the loss of assistance to the pump and therefore the "bricky" feel when I step on the brakes repeatedly over a very short time?

I will also be changing the pads because they must be on their way out.

Thanks for your input Pantelis

Reply to
Pantelis Giamarellos
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It certainly sounds like you are losing vacuum somewhere. Normally the vacuum pump can keep up, but as you have aleady replaced that it would be reasonably safe to assume that the problem is either the plumbing or the servo. If the servo was completely knackerd (they tend to either work or not) then, with your foot on the brake, starting the engine the pedal will not go down a bit as it should. Before condemming the servo, check there are no leaks in the vacuum pipe, or the joints.

Richard

Reply to
beamendsltd

On or around Wed, 10 May 2006 07:44:33 +0300, "Pantelis Giamarellos" enlightened us thusly:

sounds like lack of vacuum. Pump is the obvious candidate, which you've changed. Try pressing the pedal before starting the engine when it's been standing a while - the servo should still have some vacuum. If you get full-on brick mode then it sounds like an air leak into the servo.

Is it losing brake fluid?

Reply to
Austin Shackles

Does this one have a vacuum pump on the back of the altenator? I wonder if that could keep up as well as an induction manifold connection?

Reply to
GbH

pantellis .

i have just changed the servo unit on my 90 defender[ 300tdi ] .

i had same problem as you, i could also hear a hiss when i switched engine off but couldnt find where it came from .

in the end i put a pipe into the servo hole and blew air into it, and with some soapy water i found that the servo casing was cracked just next to the mounting points for the master cylinder studs .

i have the large diameter and thin servo unit which is fitted to all

300tdis .

on the servo front there is a 125mm diameter circle , which the master cylinder sits on , and on the edges of the circle just to each side of the mounting studs mine was cracked , where the bend in the plate of the casing is .

it is all caused by the brake cylinder weight and bouncing up and down when driving which makes the servo case crack in these 2 places .

if you replace servo then also change the master cylinder at same time .

servo is easy to change , its just a little fiddly to remove the pin in the rear fork of servo , dont drop pin into the hole .

you do not need to remove the pedal box, the master cylinder and servo will come off from the front .

remember that there is an O-RING on the master cylinder to seal it when fitted to servo .

mine now brakes very well .

Reply to
m0bcg

Richard thanks.

I will perform the foot on brake pedal while starting the engine test and then check the "plumbing" for leaks.

Thanks again Pantelis

Reply to
Pantelis Giamarellos

Thanks to everybody for providing your valued input on this case.

I have just performed the test and the brake pedal does go down when I start the engine. In fact it progressively goes down as long as I keep my foot pressing the brake pedal.

It also has some travel when the engine is switched off. It goes up and gets harder upon the second and third pressing (with the engine switched off)

BUT those tests revealed that my second camel does have a problem since the brake pedal is rock hard when the engine is switched off. The pedal goes down when I start the engine though. So the secondhand one (in very good condition bought from a friend here in Greece) I bought will be useful.

Thanks again. Pantelis

Reply to
Pantelis Giamarellos

The vacuum pump is on the engine's side, not on the back of the alternator.

Take care Pantelis

Reply to
Pantelis Giamarellos

On or around Thu, 11 May 2006 10:22:22 +0300, "Pantelis Giamarellos" enlightened us thusly:

that's normal. what happens if you leave it for say half an hour or and hour, then press the pedal without having started the engine? You should get some residual vacuum in the servo - if the servo is leaking you'll get a hard pedal almost immediately.

depending on the brake system, you exhaust the servo vacuum in anything from about 2 to 5 brake applications.

Reply to
Austin Shackles

Austin Hi,

It does go down with the engine switched off for several hours. And it does give about three brake applications before the pedal gets this "bricky" feel. So I guess the 1994 Disco is OK.

Testing revealed that the 1993 one does have a faulty servo though.

Thanks to everybody for helping into sorting this out

Take care and have a nice weekend Pantelis

Reply to
Pantelis Giamarellos

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