Brake servo query

[Sheepdip]

Does anyone know what the symptoms are of brake servo failing? The servo still works on mine but sometimes seems "soft"and I've wondered if the weak engine mixtureis down to servo vacuum leaking. How long should servo hold vacuum (if this is an indication) with engine stopped?

Paul

[DJT]

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Paul,

The servo won't hold vacuum for long. The MOT test is to push the brake pedal a few times to exhaust the vacuum then, with the brake pedal depressed, start the engine. The brake pedal should then sink towards the floor as the vacuum builds and the assistance takes effect.

Dave

[Sheepdip]

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Thanks Dave, so presumably it should hold enough for a few presses only. If I press with engine running I can hear a sort of squishing noise which may be the cylinder rubbers. Its just that sometimes when I press the pedal it feels different to the previous time, a little bit lower and softer, hard to explain unfortunately. Its still stopping ok, pedal doesn't sink.

[Stagdad]

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Can also show up as a hissing inside the cab as in the Taxi i traveled in last week.

When i asked what the hissing noise was he said oh thats the brake servo:shock:

[Coppo]

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Hi Paul.

Had exact same hissing whilst I was in Norway....Servo Kaput..... not much funwhen braking had to make sure I had extra braking distance. Had to get new one sent over, what a difference when the new one was fitted.

Paul.

[Sheepdip]

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Chaps, thanks for feedback. Looks like it could be an idea to try another servo.

Cheers

Paul

[Arbman Al]

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Sheepdip wrote:

Chaps, thanks for feedback. Looks like it could be an idea to try another servo.

Cheers

Paul

Hi Paul,

How about the BMW one that others have fitted?

Rgds....Al.

[Sheepdip]

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Hi Al. Now you mention recall some info on it - don't you have to slightly modify the inner wing? I don't find the brakes too bad on the Stag so would be happy with the original.

[Arbman Al]

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Sheepdip wrote:

Hi Al. Now you mention recall some info on it - don't you have to slightly modify the inner wing? I don't find the brakes too bad on the Stag so would be happy with the original.

Hi Paul,

Apparently some modifying is needed:- see Kevin's comments in this thread

http://stagownersclub.mywowbb.com/vi...ight=bmw+servo

Rgds....Al.

[nib]

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Hi Paul

If you require any seal kits for brakes or related go to Past Parts in Bury St Edmunds,they keep all repair kits in stock.

[Sheepdip]

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Thanks for the link Al, thought I'd seen it somewhere. Didn't realise it came with new master as well. I donb't think I'll go down that route tho unless the master looks shagged when I take it off.

Nib - thanks for useful info, did enquire locally and none of my suppliers do servo bits.

Cheers

Paul