olie05 Posted December 6, 2005 Share Posted December 6, 2005 Hello, I have replaced my master cylinder and booster with remanufactured units, booster has about 1 year on it, and MC has about 2 months. The problem I have been having, even with proper bleeding, is that the brake pedal will go down on the first initial push, to about 2 or 3 inches below the accelerator pedal. On the second push of the pedal, if done relatively quickly after it has been released from the inital push, the pedal will only travel down to about an inch above the accelerator. From all the searching I have done, I have come up with a few possible problems with my brakes, (i.e. reaction disk, rear adjusters...) but I want to hear what you all have to say about this problem. Thanks!! -Oliver Quote Link to comment Share on other sites More sharing options...
rudypoochris Posted December 6, 2005 Share Posted December 6, 2005 Car on or off... Are you sure your just not giving the booster time to rebuild vacumm? Quote Link to comment Share on other sites More sharing options...
olie05 Posted December 6, 2005 Author Share Posted December 6, 2005 I just went out to do a quick test since I realized I probably did not post enough information. Car off- first pump was hard and went down to just above the accelerator pedal. That same level was consistent for every pump after that. This does change if you have JUST turned the car off, and It will act as if the car was on. Car on - Pedal goes down to the floor with first push while trying to do an emergency stop, and on second push (if done right after the first push) does have enough travel to lock up the (front) wheels. There is also a clicking sound comming from the left rear drum everytime I hit the brakes, no matter how I actually hit them. Hope that helps to diagnose the problem! -Oliver Quote Link to comment Share on other sites More sharing options...
2003z Posted December 6, 2005 Share Posted December 6, 2005 sounds like air in your lines to me. Did you bleed the MC after installation? Quote Link to comment Share on other sites More sharing options...
Cruez Posted December 6, 2005 Share Posted December 6, 2005 I agree, air somewhere in the system.. Sounds like in the master... Quote Link to comment Share on other sites More sharing options...
olie05 Posted December 6, 2005 Author Share Posted December 6, 2005 I bench bled the MC and all the lines, and the MC once on the car, but I think another bleed may fix it. If you think about it, what could be happening, is that air in the system is compressing and then when I hit the pedal again, more fluid is pushed in through the lines, and this time, instead of compressing the air it actually moves the pistons on the calipers. Ill post again after I bleed again. thanks for the speedy replies! -Oliver Quote Link to comment Share on other sites More sharing options...
ezzzzzzz Posted December 6, 2005 Share Posted December 6, 2005 I bleed my brakes from the wheel cylinderscalipers to the MC using a simple pressurized setup. Some don't like the idea of introducing moisture in this process though. I've never had a problem and actually bleed then refresh the fluid every couple of years. All but silicone is hydroscopic (it attract H2O) and will collect it past the seals or MC cap over time. Anyhow, it does sound like you've not bleed the brakes properly or it could be a crappy MC right out of the box. Quote Link to comment Share on other sites More sharing options...
mom'sZ Posted December 7, 2005 Share Posted December 7, 2005 I bleed my brakes from the wheel cylinderscalipers to the MC using a simple pressurized setup. ezzzzzzz: how? I've heard of pressure bleeding and seen big pressure bleeders but never figured out how to do it. You can do it with just a little hand pump made for the job, or do you have some other method? Please... do tell Quote Link to comment Share on other sites More sharing options...
olie05 Posted January 13, 2006 Author Share Posted January 13, 2006 Ok got around to bleeding the whole system, VERY thoroughly. I still get the same feel of the pedal, It will go down about half way, but if I stab the pedal first and then hit it again, all is normal. I have decided to take the brake MC back to oreilly's as it has a lifetime warranty, And I am definitely suspecting it. I really want to get my brakes working properly!!! -Oliver Quote Link to comment Share on other sites More sharing options...
olie05 Posted March 1, 2006 Author Share Posted March 1, 2006 this is taking a long time to update... but i found another link that might lead me to my problem. I found a small puddle of brake fluid one morning by the left rear drum, and later found out that the brake cylinder was leaking. I replaced that, bled thoroughly, and i still have the same problem. Of course, now when I stab the brakes and hit them again, the car stops very predictably. I also found that my automatic adjusting mechanism was not working at all on the left side, so thats fixed now, and my e-brake is tighter than ever! Ok, now I gotta get off my Lazy A$$ and take back that brake MC. Oh yeah, the reason why i suspect the brake MC is that when you first hit the brake pedal, there is a very short hissing sound that maybe lasts about 1/2 a second. I'm guessing that is either air or fluid running past the rubber pistons inside the bore of the MC. Hopefully replacement will fix this problem... Quote Link to comment Share on other sites More sharing options...
buZy Posted March 1, 2006 Share Posted March 1, 2006 Did you do test to measure how much available vacuum the motor has? Check test the booster... even though you just replaced it. Check test the check valve. They should both hold vacuum for quite sometime after the motor has stopped running. Check all connections. I just did this actually last weekend. The system held vacuum over night with out dropping a single inch point. Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted March 1, 2006 Share Posted March 1, 2006 I vote MC. Have experienced this first hand and that was always the fix. BTW, do not drive your car on the street until this is fixed. Eventually it might start taking 3 or 4 jabs at the brakes before they work. Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted March 1, 2006 Share Posted March 1, 2006 Warped rotors or drums? Bent brake pad shims? Check your bleeding technique. Try leaving the handbrake on a click or two while driving to see if it improves feel. Quote Link to comment Share on other sites More sharing options...
olie05 Posted March 2, 2006 Author Share Posted March 2, 2006 I fixed it!!!! It was the MC all along. I suspected it from the "very short hissing sound that maybe lasts about 1/2 a second." either way a good bench bleed and good all wheel bleed helped me get the pedal consistent. E-brake just keeps getting better too!!! Now i just have to adjust the pedal itself. Any tips on that? I want to adjust it as much as possible without actuating anything. Obviously that is the point of adjusting the pedal in the first place, but how do I know where that point is? Quote Link to comment Share on other sites More sharing options...
JMortensen Posted March 2, 2006 Share Posted March 2, 2006 You DO NOT want to adjust it right to the point of actuating. You need a little free play in there, like 1/8" to 3/16". If not you'll have a thread in a couple days saying "I just replaced my master cylinder, and as I drive the brakes progressively start locking up worse and worse until the car just won't drive anymore. If I let it sit for an hour then I can drive again, but then the same thing happens!" It's come up here a couple times, and happened to me on my clutch. Went to a track day and the more I drove the more the clutch slipped, same deal. The fluid in the master expands when it gets hot and this trys to force the master cylinder cups past the fluid return hole. Once it expands to the point where the return port is blocked off, the pressure in the master can't be released back into the reservoir. You need slack in there so that the master can fully release even when the fluid gets hot. Quote Link to comment Share on other sites More sharing options...
mom'sZ Posted March 2, 2006 Share Posted March 2, 2006 It was the MC all along. I had to go back to the beginning of the thread to check and make sure... sure enough, that's what I thought, the master cylinder was only two months old. So... another case of a 'brand new' rebuilt master being junk. I swear there was another thread just like this a month or so back, same deal, rebuilt master, drove the guy nuts, bled the thing twenty times, replaced other stuff, checked the disc thingy, finally replaced the 'new' master... and that was it!!! I replaced my master when I first got my car with a rebuild from the local discount auto parts place and it seems to work OK. Saved the original one, plan to get a factory rebuild kit for it. If I'm not mistaken, Courtesy still sells OEM new masters. Got a clutch master from them a while back, nice... not NOS but new!! Has the cup and cap and is complete unlike the discount auto ones that are just the cylinder themselves. Quote Link to comment Share on other sites More sharing options...
ezzzzzzz Posted March 2, 2006 Share Posted March 2, 2006 I bought a simple hand-pumped sprayer at the local DIY. I first crack open the bleed screws, one at a time, starting with the furthest out (usually the driver's rear) and pump the fluid out into a catch container. As a note, I use speed bleeders on my calipers. I then remove the speed bleeders and install regular bleed screws with a bit of teflon sealant or tape on the threads. The spray wand is removed so there is only the hose remaining (you may have to adapt a hose to fit the bleed screws). A simple cutoff valve in placed in the hose to stop the brake fluid flow at my disgression. With the sprayer filled with enough fresh brake fluid to do the job, I pump it up to build some pressure. The hose is attached to the furthest bleed screw (cracked slightly open) and the valve is opened to start the flow of fluid. I watch the MC reservoir for fluid rising until there are no air bubbles. I continue through the remaining bleed screws. Once here, I let the system sit so any air in the lines while migrate to localized areas. A couple hours will more than suffice. I replace the bleed screws with my speed bleeders and do a normal brake bleed usng the brake pedal and a catch container. The speed bleeders make it a one man job. One nice part about this method is it properly bleeds the MC for you without that extra step involved. That's all there is to it. Quote Link to comment Share on other sites More sharing options...
mom'sZ Posted March 2, 2006 Share Posted March 2, 2006 I bought a simple hand-pumped sprayer at the local DIY. Brilliant!!!!!!! you mean like a bug sprayer or something like that from home depot or lowes right? I think I have one out in the shed. Thanks ezzzzzzz Quote Link to comment Share on other sites More sharing options...
ezzzzzzz Posted March 2, 2006 Share Posted March 2, 2006 Yep Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted March 2, 2006 Share Posted March 2, 2006 An empty mayo jar and a 2' piece of clear tubing work just as well and allow you to see the bubble and dirty fluid as it comes out of the caliper. The advantage of the empty jar with a lid is you can store it on a shelf between bleed jobs and the whole mess goes in trash once the jar is full. Don't understand why anyone needs speed bleeders to make bleeding brakes a one man job but hey, given the number of threads on bleeding brakes it must be more difficult for some than others. Quote Link to comment Share on other sites More sharing options...
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