Occasional hard brake pedal

[rynaqui]

After startup, I normally have a very hard brake pedal when driving a few metres then it goes ok after about 1 minute. Occasionally during driving I get that same feeling, very hard brake pedal and almost no assistance when braking, what could the problem be in this case? Perhaps I need to re-bleed the brakes?

Think the accumulator is working fine as after startup then the pressure builds fine. Also I do have two rear daff ABS sensors (I think two at least!) would that have anything to do with it? Cheers

[jade]

After startup, I normally have a very hard brake pedal when driving a few metres then it goes ok after about 1 minute. Occasionally during driving I get that same feeling, very hard brake pedal and almost no assistance when braking, what could the problem be in this case? Perhaps I need to re-bleed the brakes?

Think the accumulator is working fine as after startup then the pressure builds fine. Also I do have two rear daff ABS sensors (I think two at least!) would that have anything to do with it? Cheers

I had that when my servo went Bad

[rynaqui]

I have been fearing this actually..

Are there any more suggestions before I take the plunge on a new brake servo? My accumulator is new (only 1 year old).

Can't really get this car finished can I

[Cottis]

It is endless Ryan. Mine is now all sorted and then my temp gauge starts reading a bit low. Now my brakes seem to be short of assistance for a mile or so after startup before feeling fine. Assume that might be a weak bomb but like you say, these cars are never perfect.

Good luck with it.

[Human Joist]

Correct me if wrong but isn't that the brake bomb. From what i understand it keeps pressure in, so your brakes will be efficant when you first drive off as the servo takes a few seconds. But this should also throw a light on with the issue ...... Or have I got it wrong. Sorry if I have got it wrong.

[Monkeymagic]

You refer to the accumulator Jim. Ryanaqui make sure the wires to the pressure switch are actually connected.
my bmob failed after a year the check valve stuck open causing the car to dump pas fluid

[rynaqui]

You refer to the accumulator Jim. Ryanaqui make sure the wires to the pressure switch are actually connected.
my bmob failed after a year the check valve stuck open causing the car to dump pas fluid

They are connected and I never get the light, I used to get the light before I replaced the brake bomb so I am sure it is working fine. Also I got it when I replaced my hydraulic fluid with genuine Audi G00400.

The problem started when I had the car sat for about four months, new rear brake kit and front calipers rebuilt, so all the fluid was drained and bled. Maybe I could try and bleed the system properly again..

[UrS4boy]

I'm a Doctor Jim, not a bomb disposal expert

Correct me if wrong but isn't that the brake bomb?

You refer to the accumulator Jim.

[Rusty]

Does the pedal pulse when it goes hard?

[S2central.net]

Anybody else notice the difference in consistency of the rather gloopy G002000 OE fluid version it's replacement G004000 ?

They are both green but the new stuff feels desperately thin in comparison. Sorry for slightly OT.

[quattrostyle]

Just go vacuum Ryan.

[bartolomeus]

Check the pas pump.

[Error404]

Bad servo

[Tonks4x4]

I have a few second hand hydraulic servo's if required... £45 + post

[rynaqui]

Just an update on the situation.

The brake pedal is now taking a good 3 minutes or so to free up. After stopping at a petrol station and chatting with some friends then starting up again, the pedal is also hard and took a while to free up.

What do you guys think? I was pointing towards brake bomb but the light isn't coming on and I get a good 40 pumps from the pedal when turned off before it goes hard.