jara Posted March 10, 2013 Report Share Posted March 10, 2013 For the past few days my brakes have had a mind of their own about stopping my car. some trips they work like usual, other trips, they barely work and i roll slowly for a while before coming to a stop. I can't see any leaks, the shoes are fine and yesterday i took it out and gave the brakes a good testing and they were all good. but today on the way back from the shops, they stopped working again. usually i can hold my brakes down with the car in drive and rev the car without it moving. but when i have the problem, the tiniest little touch of the accelerator will move the car. any thoughts? Quote Link to comment Share on other sites More sharing options...
rian Posted March 10, 2013 Report Share Posted March 10, 2013 (edited) I bet you have a hole in the seal inside the master cylinder. If you try and stop really fast the brakes should work, but holding your foot on the brake pedal or slowly coming to a stop you will lose all the pressure inside the master cylinder and the brakes will no longer work. I'd say pull the master cylinder apart and have a look. Edited March 10, 2013 by rian Quote Link to comment Share on other sites More sharing options...
altezzaclub Posted March 10, 2013 Report Share Posted March 10, 2013 Does it have a booster? Does the pedal go down any further at different times, or does it always feel pretty good?? maybe the booster is not working sometimes, or not getting vacuum. If you just sit there with you foot pushing on the pedal for two or three minutes, will it slowly go down? When you say there are no leaks, does it use fluid, or does it have fluid under the master cyl running down the booster, or does it have fluid way under the dashboard where the rod joins the pedal?? Quote Link to comment Share on other sites More sharing options...
jara Posted March 10, 2013 Author Report Share Posted March 10, 2013 i'll give it a shot at trying to stop fast i think the pedal might not go all the way down when its playing up,or it could be my imagination. I'm not quite sure what you mean about the fluid. best i can say is that there is a brake fluid container for the front and rear brakes. i'll see if the pedal goes down tomorrw. thanks guys Quote Link to comment Share on other sites More sharing options...
altezzaclub Posted March 10, 2013 Report Share Posted March 10, 2013 I'm not quite sure what you mean about the fluid. Well, when you say you can't see any leaks and the shoes are fine, I assume you pulled the drums off and checked the slave cyls and the front disc pistons. But if the master cyl leaks it will go out the back of the master and trickle down the front of the booster, or leak inside the booster, or if you don't have a booster it dribbles down behind the brake pedal inside the car. usually they all just give consistantly poor brakes and maybe a slowly depressing pedal if you keep your foot on it. It sounds more like a booster that doesn't work sometimes, but I can't imagine why. Quote Link to comment Share on other sites More sharing options...
jara Posted March 10, 2013 Author Report Share Posted March 10, 2013 yes, i pulled the drums off, but i only checked for obvious leaks, i didnt know about the slave cyls and the front disc pistons. i've never seen any leaks in the engine bay, but i'll give it another check next time it plays up. should i get the booster rebuilt? or pick up a used one? or is it simple enough to tackle myself? Quote Link to comment Share on other sites More sharing options...
altezzaclub Posted March 10, 2013 Report Share Posted March 10, 2013 I'm sure you would've noticed the brake fluid going down if it was losing very much. I'd just gather as much information about when it happens (how fast were you going, was the motor cold or warm, did the pedal go hard when they didn't work, or did it stay normal-soft and they didn't work...) then go see a brake place. If you can get someone professional to diagnose it for you then you can decide to tackle it yourself or not. It might need a special tool to rotate the booster halves apart, so its either get it rebuilt at a shop, grab one from a wrecker or buy a new one. If it is a brake cylinder problem you can easily do it yourself. Quote Link to comment Share on other sites More sharing options...
jara Posted March 11, 2013 Author Report Share Posted March 11, 2013 thanks, i'll do exactly that. i might end up back here about it though. thanks guys Quote Link to comment Share on other sites More sharing options...
jara Posted March 21, 2013 Author Report Share Posted March 21, 2013 ive noticed that when i push my brakes for the second time in a row, it's missing something, maybe pressure. the mechanic reckons I'm up for a whole new booster. but he's been wrong before. whatdo you guys reckon? Quote Link to comment Share on other sites More sharing options...
parrot Posted March 21, 2013 Report Share Posted March 21, 2013 (edited) vague ifs buts and maybe's are impossible to diagnose without looking at the car. You need to have it looked at by someone who knows what they are doing before you get in an accident. Diagnose it properly rather than randomly replacing parts. If you don't trust your usual mechanic, get someone else to look at it. Edited March 21, 2013 by parrot Quote Link to comment Share on other sites More sharing options...
springersrolla Posted March 21, 2013 Report Share Posted March 21, 2013 pull the drums off and gently pry back the rubber boots on the wheel cylinders, you will see fluid pour out of them if they are busted, are you losing fluid or just pedal feel? When was the last time you properly bled the system starting from back left back right front left front right? if your not down on fluid i would still bleed the system and then look at your options Quote Link to comment Share on other sites More sharing options...
GJM85 Posted March 21, 2013 Report Share Posted March 21, 2013 (edited) Have you bled the system? Start with the wheel furthest from the master and work toward it. Edited March 21, 2013 by GJM85 Quote Link to comment Share on other sites More sharing options...
jara Posted March 23, 2013 Author Report Share Posted March 23, 2013 (edited) not losing fluid but and it was bled about 18 months ago, but i'll give it a shot when i get the chance thanks guys Edited March 23, 2013 by jara Quote Link to comment Share on other sites More sharing options...
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