Ok guys,I've just finished up bleeding my master cylinder until there were no more bubbles,then I did it some more.I then put it back on the car and proceeded to bleed the brakes(3 times)and Im positive that thers no air in the system.And I still get nothing even closely resembling pedal pressure.The master and booster were bought new off of e-bay 6 months ago. I have another master I might try that came off of a Caprice with power disc/drums. Any clue as to what it could be???? Thanks, Philip
same problem...!! Hi Philip...we had them same prob when I did the front brakes over a couple of months ago.....I must have run a gallon through the darn thing....would have pedal sometimes and others nothing !!! Ended up just closing the system off when we had some peddle and leaving it...works fine but I think I need to do it again...hope you get some info as I would like to hear it also.... Mark
Since I can't afford a power bleeder, I've been known to bleed the brakes on my 'Lark with the engine running. I've done other cars the normal way, but for some reason the 'Lark has problems bleeding the rear brakes. Just an idea.
heres what I dont understand,I have alot of pressure too.When you open the bleeder and pump the pedal,fluid squirts out with alot of pressure.But there is NO pedal when the car is running.I don't know I'll try It with the car running.
what brakes do you have ? drum rear?i would blame master . had a 77 regal and kept buyng bendix masters replaced 3 then tried a fourth and was good. also had a problem with drum wheel cyl sticking and no pedal. if you can jack up whole car have someone push brakes down then check if and wheels will spin by hand. andy
I have a-body disc's in front from a 70 chevelle and stock drums in the rear.I'll check the rears because I don't think the cyclinders were ever done in the past 12 years the my dad had it.Thanks for all the info guys!
Once you're POSITIVE the master is bled correctly......I mean only after ALL the air is gone.....pump the pedal SLOWLY when you first get started.....then open up all your bleeders and gravity bleed it. This may take a couple hours, but once you get the fluid back there gravity will take over.....this requires getting some fluid into the rear lines first. Check the fluid level every 10 minutes or so....if the reservoir goes empty you'll have to start over so be careful! Also, if you master is on an angle on the firewall, you have to bleed it while it's level. Sometimes that means removing it from ther car and bench bleeding it in a vise or raising the rear up about a foot or two. (be very careful if you do that....removing it is safer) Anytime I had this problem it was b/c I had air in the master....also be sure your helper isn't letting the pedal back up when you have the bleeders open. :Smarty:
not trying to flame here but... If you are going to bleed the brakes you should never "PUMP" up the brakes before you open the bleeder screws. Think of it like trying to get the air bubble out of a water bed. The big air bubble is easy to work out but all the little bubbles work around you or stick. When you pump up the pedal you just crashed the big air bubbles into little ones that will stick around then work their way back together once a little heat and vibration are applied. (like when you drive it later) but they won't bleed out... Best way to go is start at the corner farthest from the master cylinder and work your way around the car getting closer to the master cylinder. Try these steps: 1. Open the bleeder, tell your buddy to push the pedal gently to the floor and hold. 2. Lock the bleeder back down. 3. Tell helper to let off the pedal 4. go back to step #1 and repeat. Until you get a good solid stream or clean fluid (depending on if you are starting with all new fluid or not) 5. I like to let the car gravity bleed a bit before I lock the bleeder down. 6. If you use a piece of tubing over the bleeder and a clean container there is no reason you can't re-cycle the fluid. [give a hoot don't polute! ] I also have a Mity-Vac bleeder that makes this a one man job on most cars but some cars (especially ABS equiped newer ones) don't seem to respond to the ol' Mity-vac and the old way works fine it just takes 2 people. Preassure bleeders are nice but you need compressed air, they aren't cheap plus if you set them up wrong you can douche your car in brake fluid! A problem some people seem to have is an air bubble takes up residence in the proportioning/delay valve. If this happens try going back to the RR wheel, open the bleeder screw and bleed again, only this time instead of gently pushing the pedal have your buddy "JAM IT DOWN". This seems to get the evil bubble moving down the lines more often than not. Do this about 5-10 times then re-bleed and clean up your mess. Don't forget, as mentioned in one of the other postings here. If you don't bench bleed the master cylinder properly before installation you will have a crappy pedal no matter what you do forever and ever! The nose of the MC points up and the air collects there and will never bleed once installed! Remember a good mechanic will stand behind his work but he'll stand behind or in front of good brake work! :Smarty: regards
bench bleeding? how do you bench bleed a master cylinder? i've never heard of this before, and have always had poor pedal pressure on my 70 skylark. is this something that is only required on buicks? I owned a 65 chevy pick up that i put a 350/350 buick in (the original out of my skylark, which now has 455/400) i replaced the mc on it strait out of box, never had any trouble. it wasn't power brake boosted however. does that make any diffrence?
Nearly every master cylinder i've bought over the last 25 years has come with the 2 little generic plastic adaptors and 2 pieces of clear tubing. If not I'm pretty sure the HELP section at the parts store sells them for a few bucks. Again I like having a helper to do this. 1. install the adaptors into the brake line holes of the master cylinder. 2. push the tubes onto the adaptors and tuck the other ends into the resovoir 3. fill with clean brake fluid while your helper holds the M.C. 4. using a big phillips screw driver compress the piston at the rear of the M.C. 5 You will see lot of air bubbles for awhile, when you can actuate the piston and see no air bubbles your are pretty much done. 6 before installing on the car try lightly tapping on the bottom of the master cylinder with the handle of your screw driver to help dislodge any air bubbles that may be hanging on. Also tip the M.C. a bit nose down and actuate the piston then a bit nose up and actuate. That should pretty much do it... I've only had 1 master cylinder that would not bench bleed (was the 16.99 AutoZone model) and it was like one of the circuits just was not pumping (no seal/bad seal?). Otherwise install and start bleeding all 4 wheels. Don't be like the guys on HP TV that install a 502 crate engine in a 307 Chevelle and leave the original non-power 4 wheel drums on the car. Going fast is a lot of fun but you will loose "cool points" faster when you can't stop that 2 ton barge! regards
thanks thanks a lot, mr. warner, good info. will do this as soon as i get my car rolling again. right now i'm working more on the "go" than i am the "woah". Drove it off a used lot in '96 with brakes just enough to stop it. thought a new booster would do the trick. new booster and mc seemed to help but always had a "squishy" pedal. but like the saying goes if i knew then what i know now. :TU:
Brake Problems All the information so far my the members is right on!! :TU: and if you have bled the system from all 4 corners and there are no leak and all brakes are adjusted your problem has to be in the master cylinder. I have seen this happen where the fliud buy passes in the master cylinder it self. AL.
Guys, One other possibility. On all disc/drum brake systems, there is a hold off function built into the combination valve (on a 1970 it's seperate). The job of the hold off function, is to limit pressure to the front discs until the rear drum lines develop some pressure. Disc pads are virtually in contact with the disc at all times, so they develop braking force immediately. There is some clearance between the shoes and drums though, so they take slightly longer to apply. The hold off valve delays the front brakes until the rears apply. This can interfere when you try to bleed the brakes, think about it. In the Buick chassis manual, they instruct you to depress the pin(under the rubber boot) at the front of the combination valve while bleeding. This is the only difference when bleeding disc brakes.
Brake Problems Larry, good call!! I've been at it all most 30 years and never seen this as a issue as far as a no pedal complaint, it is possable. Every time I read your posts I pick up something :Smarty: :TU: AL.
reid, are correct about how to vice the mc & i do it that way. i have seen mcs clamped by the cylinder. i have found that bleeding these a-body cars is difficult even following the instructions in the shop manual. the easiest bleeding on an mc was that for my 81 cutlass. easy, easy.
Is this a brand new master cylinder? If it is, bear in mind that the power piston inside the m/c may not be the same length as your original. This happened to me 4 years ago. New m/c, bled the brakes- no pedal. Long story short, I was uncovering the supply orifice on one half of the m/c, and the return on the other. I lengthened the power piston rod and suddenly I had a pedal. Scratched my head for three days over it
Do you guys know which hole the rod is in on your brake pedals?Mine is in the bottom hole.How would one go about adjusting the pushrod?I've got it adj. to where it goes in the hole when the pedal is almost "locked-out" meaning it can't come any closer to the driver.I'll be trying all of your suggestions this weekend,and reporting back depending on how it goes.I just need to get this thing running and driving so I can finish breaking it in and start on the body work(rusty rear window channel),which means a 100 mile trip to a buddies house,so brakes would be good lol. Thanks, Philip
