Bizzare Problem
Turbo Mini Forums

Hi guys new to the site but have been reading for a while now, i own a 1.3 turbo mini, the problem i am having is when pressing the brake pedal it causes the engine revs to increase by around 1k revs and since this problem has start the brakes are not as responsive and to slow the car down i need to use the pedal more, i am at a complete loss with this and any help would be greatful i beleive all the braking system is from a cooper S if that helps look forward to a reply.

I'm thinking that it has a brake servo?

If so look to the vacuum pipes and servo, maybe there is a vacuum leak that is not only stopping the servo from working properly but affects the engine.. Though I would have thought it would stall the engine rather than speed it up..

split pipe? check valve? servo diaphram?

terry

Edited by Turbo Tel on 30th Mar, 2008.

website:- http://www.terryhunt.co.uk

yeh i do beleive it has a brake servo sorry im completly new to the car and minis lol. can u shed a bit more light on where i should look e.g check valve and servo diaphram??

There is a vacuum pipe from the manifold to the servo, check it for leaks. somewhere in it should be a one way valve that keeps the vacuum in the servo. (not sure where that is on a cooper S remote servo, is it the "air valve") you should be able to blow through it one way but not the other. Inside the servo is a rubber diaphram, it should not leak, not sure how to test that... according to Minispares..

http://www.minispares.com/Product.aspx?pid=34993

"If you are slowly loosing brake fluid or you see white smoke out of the tail pipe, then the main diaphragm is leaking. If your pedal pressure is too high for the stopping distance, then the main seals are bypassing"

website:- http://www.terryhunt.co.uk

accelerator and break at the same time, check the two pedals arnt touching eachother // or your feet are, it will seem like the car has less effort due to the acellerator still being on. have you checked thAT?

Drives
-Ford S-max Mk2 Ecoboost
-Rover 100 VVC #2 - track project

Searching is all you need on TurboMinis

Edited by Turbo Tel on 30th Mar, 2008.

website:- http://www.terryhunt.co.uk

thanks for the replys, i had already checked it wasn't any thing silly with the pedals, so now i reccon its the servo diaphramcause when i remove the vacum hose it solves the issue of increasing revsi have not yet removed the brake servo its a job for tomorrow thanks for all the info turbo tel much appreciated

sound like it could be the non return valve in the vaccum line to the servo