conocon 0 Posted April 3, 2006 Hi guys, im looking for some advise,while driving my 1.9 GTI on fri i lost all brake pressure on the brake pedal,pumping the brakes will slow me down but the pedal never goes hard no matter how often i pump the pedal.The is no fluid leaks in the system,not loosing any brake fluid.My guess is vacuum issues(pipe is attached but i will replace the pipe today),but if it was lackin vacumn would the pedal not go hard?? Cheers for the help Conor Share this post Link to post Share on other sites
Jonmurgie 2 Posted April 3, 2006 Yes, if the servo lost vacuum then the pedal would go rock hard (happend to me @ Combe the other week). So this basically happend all of a sudden and now the pedal won't stiffen up? Has the fluid go down at all? Was this just road driving or on track? Share this post Link to post Share on other sites
Rippthrough 98 Posted April 3, 2006 Got to be a fault in the hydraulic circuit, not the servo. Share this post Link to post Share on other sites
jackherer 543 Posted April 3, 2006 if its not leaked any fluid externally then its probably the master cylinder letting fluid back past its seals internally. if you hold the pedal down does it slowly sink? Share this post Link to post Share on other sites
conocon 0 Posted April 3, 2006 Road driving,i havent driven it hard in a while so it wasnt abuse that caused this.iJust driving normally,tapped the pedal to slow down(from about 30mph!) not even under heavy braking,pedal just went to the floor,at first i thought it was fluid leakage somewhere in the system but when i checked fluid level it was perfect.It looks like a piston isnt doing its job in the master cylinder.Anyone have any experience with one of these??I took off the vaccum pipe off the pump and still no hardening of the pedal.??No wettness around the mastercylinder and fluid level not dropping,any other test i should try?? Has anyone ripped the master cylinder,i was advised not to and just buy the whole unit?? Pedal slowly sinks,but the harder you press the faster it goes away from you Share this post Link to post Share on other sites
Rippthrough 98 Posted April 3, 2006 Road driving,i havent driven it hard in a while so it wasnt abuse that caused this.iJust driving normally,tapped the pedal to slow down(from about 30mph!) not even under heavy braking,pedal just went to the floor,at first i thought it was fluid leakage somewhere in the system but when i checked fluid level it was perfect.It looks like a piston isnt doing its job in the master cylinder.Anyone have any experience with one of these??I took off the vaccum pipe off the pump and still no hardening of the pedal.??No wettness around the mastercylinder and fluid level not dropping,any other test i should try?? Has anyone ripped the master cylinder,i was advised not to and just buy the whole unit?? Pedal slowly sinks,but the harder you press the faster it goes away from you I'd check your entire hydraulic circuit first, preferably with an assistant applying a little pressure to the pedal. Share this post Link to post Share on other sites
conocon 0 Posted April 3, 2006 I'd check your entire hydraulic circuit first, preferably with an assistant applying a little pressure to the pedal. i needed the car over the wkd and in my maddness drove about in it.few scary moments but im still alive and want it sorted asap as you can imagine!!As it takes only a few pumps of the pedal to empty the brake system if you have a leak or bleeding the system and there has been no movement in the level in the car im pretty satisfied that its not a leak.Wish it was though! Share this post Link to post Share on other sites
Rippthrough 98 Posted April 3, 2006 i needed the car over the wkd and in my maddness drove about in it.few scary moments but im still alive and want it sorted asap as you can imagine!!As it takes only a few pumps of the pedal to empty the brake system if you have a leak or bleeding the system and there has been no movement in the level in the car im pretty satisfied that its not a leak.Wish it was though! Not if it's a pinhole. Worth taking some time to check before spending on a MC, even if that is the most likely candidate. Share this post Link to post Share on other sites
jackherer 543 Posted April 3, 2006 If the pedal sinks and its not losing fluid then its def the master cylinder. Just chuck a new one on, they are'nt much money new. Share this post Link to post Share on other sites
conocon 0 Posted April 3, 2006 If the pedal sinks and its not losing fluid then its def the master cylinder. Just chuck a new one on, they are'nt much money new. Is it just a few bolts to take it out??1 hours work?? Share this post Link to post Share on other sites
smckeown 1 Posted April 3, 2006 and and stop driving the car on the public highway, it's not just your life you are endangering! A new M/C costs peanuts, and also make sure you check all pipes, from the M/C to each caliper/drum Share this post Link to post Share on other sites
Rippthrough 98 Posted April 3, 2006 Is it just a few bolts to take it out??1 hours work?? 2 nuts, about 5 minutes + bleeding. Share this post Link to post Share on other sites
jonah 1 Posted April 3, 2006 Yep, 100% definitely the master cylinder, there's nothing else it can be if you're certain it's not losing fluid. One of the internal piston seals must have split. Share this post Link to post Share on other sites
Patches 0 Posted April 22, 2006 Yep, 100% definitely the master cylinder, there's nothing else it can be if you're certain it's not losing fluid. One of the internal piston seals must have split. Just resurreting this thread as same has just happend to me - drving along, pedal went very spongy, had to use handbrake to stop, now overnight, the pedal had gone very hard to apply, its possible but not without a lot of force and has no impact on stopping of course.. (notr driving her anymore ..) Now - Ive just been quoted £46.99 for the MC from a local auto spares co, which seems reasonable - but quoted £75 to fit from a local garage!... Is this something realistically I can do myself? I have tools ,but no knowledge!! Cheers Michelle Share this post Link to post Share on other sites
Guest rick03054 Posted April 22, 2006 It's really easy. Take the brake fluid out, take the 3/4 brake pipes off, 2 nuts hold it onto the servo. Share this post Link to post Share on other sites
hengti 2 Posted April 22, 2006 Just resurreting this thread as same has just happend to me - drving along, pedal went very spongy, had to use handbrake to stop, now overnight, the pedal had gone very hard to apply, its possible but not without a lot of force and has no impact on stopping of course.. (notr driving her anymore ..) Now - Ive just been quoted £46.99 for the MC from a local auto spares co, which seems reasonable - but quoted £75 to fit from a local garage!... Is this something realistically I can do myself? I have tools ,but no knowledge!! Cheers Michelle when the m/c intermitently goes, you tend to lose pretty much all of the braking capability and the pedal sinks to the floor. if your pedal is just spongy i'd have thought it more likely that you just need to change the fluid and bleed the brakes the hard pedal sounds like a vacuum servo fault - can you hear a hissing sound as you press the pedal? if not, there's a servo problem best place to check out how to change fluid/bleed brakes/master cylinder (if that's what's needed) is the Haynes book, or a search on here (think someone did a brake bleeding guide recently - i'm going to look for it myself in a mo as i'm having bleeding trouble at the mo too) Share this post Link to post Share on other sites
