Firm brake pedal the softening
Firm brake pedal the softening
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Discussion

Philippo

Original Poster:

107 posts

248 months

Friday 14th April 2006
quotequote all
Hello

Just got home in the Griff (1998) and stopped outside house which is on a hill, whilst gates opened. Holding the car on the brakes I noticed that though the pedal was initally firm, after a few seconds it had to be pressed down further to hold the car on the slope.

Took the car out again, there's no air in the brakes (pedal always very firm on first use) and I don't appear to have any visible leaks nor has fluid level gone down in resevoir. Relatively new owner of car but can't imagine this is normal phenomenom.

Could it be a leaking seal in the master cylinder?

Regards

Philippo

GreenV8S

31,017 posts

313 months

Friday 14th April 2006
quotequote all
Philippo said:
Could it be a leaking seal in the master cylinder?


That's the only reason I can see for a sinking pedal without fluid loss.

philippo

Original Poster:

107 posts

248 months

Saturday 15th April 2006
quotequote all
Ok, this morning tried brake pedal with engine off and it's firm and doesn't soften. So presumably that must mean problem is servo related, yes? Will look at hose from plenum to servo.

Philippo

john57

1,869 posts

257 months

Saturday 15th April 2006
quotequote all
FWIW you may know this already but ......

To check the servo is working correctly with the engine off pump the brake pedal until it had gone rock solid underfoot ..... then, keeping your foot on the pedal start the engine. Once the engine starts the pedal should soften and go away a fair bit from you. This will show the servo is working correctly. If it doesn't do this something is wrong with the servo.

philippo

Original Poster:

107 posts

248 months

Wednesday 19th April 2006
quotequote all
Well, tested servo as suggested and it's fine. Tried pedal again with engine off and unfortunately it does sink very gradually, so new brake master cylinder it is.

Understand this is bit of a pig, though given that a) the drivers seat was going to come out anyway for modification to lumbar and b) I'd planned to replace the brake fluid, then timing is not bad.

Using search on the forums it would appear that this item can only be ordered from TVR. Is this still the case or has anyone found an alternative source?

Regards

Philippo

Philippo

Original Poster:

107 posts

248 months

Wednesday 19th April 2006
quotequote all
Thanks Quinny, definitely looks like it is master cylinder that needs replacing. Hope to pick one up when in the UK next week.

Philippo