Benno Posted July 19, 2016 Share Posted July 19, 2016 I'm pretty sure my brake booster has developed a vacuum leak. When I get on the brakes, the engine seems to lean out, stumble and will sometimes even stall. The wideband gauge also reads lean. I will confirm the brake booster is to blame for sure by going for a quick drive with the booster disconnected/blocked off, but would be surprised if it wasn't the problem. As it doesn't vacuum leak when the brakes are not applied, I am pretty sure it is not just the check valve. Is this something I can fix myself? Most websites seem to say I should just send it off to an expert. If so, how much would a new diaphragm etc cost me? Is it fairly self explanatory and easy to figure out? If not, any recommendations on somewhere (ideally Christchurch) that I should send it, and how much would I expect to pay? When I take the master cyl off I will have a look at that too, may turn out it's leaking fluid or something. Quote Link to comment Share on other sites More sharing options...
Mr Vapour Posted July 19, 2016 Share Posted July 19, 2016 I'm sure that sr2 (Simon) will be along soon to tell you all you need to know. Quote Link to comment Share on other sites More sharing options...
tim13 Posted July 19, 2016 Share Posted July 19, 2016 that , or cantabury brake and clutch are pretty good Quote Link to comment Share on other sites More sharing options...
sr2 Posted July 19, 2016 Share Posted July 19, 2016 Hi Ben, I'll need to know what car it's fitted to and then I can talk you through the correct diagnosis. Once that's established we can either fix the fault, buy a 2nd hand replacement part or pass the offending component to a local shop for repair. Cheers, Simon. 2 Quote Link to comment Share on other sites More sharing options...
Benno Posted July 19, 2016 Author Share Posted July 19, 2016 Hi Simon, booster is fitted to a ford escort mark 2. Quote Link to comment Share on other sites More sharing options...
Steelies Posted July 19, 2016 Share Posted July 19, 2016 i have a remote booster vf44 or something, for years my wag would be a bitch in traffic. only when it got really bad (while towing of course) did i realise what was going in, leaking booster. surely enough, split diaphragm. the booster was showing its age quite badly overall so i bit the bullet and bought a new one from some crowd in chch (cant remember who it was sorry, can dig out receipt though) and problem solved. think it was round the $200 mark. was quite refreshing being able to buy a new replacement part, put it in, and solve the problem! instead of sifting through old shit to put together a collection of old shit to have something work like it's old, and shit. Quote Link to comment Share on other sites More sharing options...
sr2 Posted July 20, 2016 Share Posted July 20, 2016 Hi Ben, sounds like you're well on the way with diagnosing the problem. Remember that boosters are vacuum suspended (i.e. the have vacuum on both sides of the diaphragm at rest) and when actuated introduce the atmosphere to the rear chamber to assist the brakes. I’d put my money on a ruptured main diaphragm, pinch off the vacuum supply line with a pair of vice grips (wrap tape around the jaws to avoid damage) and confirm the engine issues disappear. The most likely cause is master cylinder that is leaking from the rear seal; the brake fluid gets into the booster and eats the diaphragm for breakfast! If the above test points to the diaphragm, pull of the master cylinder and look for signs of leakage and report back. 1 Quote Link to comment Share on other sites More sharing options...
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