Hello Everyone, I'm having alot of brake bleeding troubles on my 1953 pontiac. -Everything in the brakes is new, except two distribution blocks (i reused these) -I tried every method of bleeding, including a mityvac hand pump, several times each and have no peddal. -No leaks anywhere. -I'm thinking my new master is bad, or i may have "bottomed it out" and blew out the rear seal. I'm hesitant to replace this as they are hard to find, and cost 130$. What's the deal with bottoming these single bore masters out, i get the concept, but it seems really stupid to make something that stops a car to be able to loose fluid so easily. IF you blow out this seal, and its new, can i take the master apart and pop it back in place? Do these cars need Residual pressure valves? I was told they dont. Pleas help as im very frustrated!!! Thanks! Chris
Have the brakes worked in the past or is this a new problem? Disc or drum? New shoes and wheel cylinders?
Did you bench bleed the master cylinder? did you replace the brake lines Are you sure that all the lines are tight? I've had to fix multiple owner installed brake systems because they were ****ing air at loose line fittings when using a vacuum pump/ didn't bench bleed.
I suggest going over the whole system, and tightening every connection again. Look for traces of fluid that indicate a leak. I have best luck with the old technique of having a helper pump the pedal three times, hold it down, and I open the bleeder, let whatever come out, then close the bleeder, then repeat.
did you let them gravity bleed before pressure bleeding? I could go on for days about brakes and suspension. I work for les schwab
I think hitchiker might be on the right track. check to make sure the push rod is actually pushing the master cylinder into its bore.
master, lines, wheel cylinders, shoes area all new. The master is lower than the wheel clyinders, can you still Gravity bleed this? i bleed the M/C with the mityvac. did it till all the bubbles were out while it was bolted in the car. I'm really curious about this master blowing out the rear seal when it bottoms out. Is anyone familiar with this? When i try to bleed the brakes i only get a weep of fluid out of the WC bleeder, not a stream like you usualy do. Tried the only fasion brake bleeding method a bunch of times. Oh. almost forgot. The cap on my Master is shooting fluid out of the pin hole in the cap (maybe every other pump) whats up with that?
did you over fill the master cylinder? does the cap have it's baffle? Bench bleeding means to take the master cylinder out of the car, and bleed it on your work bench--either by blocking the output port or running a tube from the output port to the reservoir.
you can "bench bleed" it in the car.. take off the lines going to the front and rear brakes..make two small brake lines that go from the "out" ports back into the MC pot (below the fluid level) fill the pot with good clean brake fluid and slowly pump the brake pedal until you see no more bubbles coming out of those two lines you made.. the MC will be bleed after that.. re-atach your lines and go from there, check real good for any possible small leaks
I see a few problems here. 1) you need to Bench bleed the master off the car. There are a few ways to do this. One way is to make a line that goes from the output port back to the reservoir and under the fluid level and slowly depress the cylinder with a screw driver not letting the bore travel more than 3/4 to 1 inch until no more bubbles. they way I do it is just clamp it in a vice put a bucket under the port and let it drip. takes about an hour. but you can work on other things on the car while it bleeds....just my method. 2)with the master being lower than the wheel cylinder it is recommended that you back bleed the system. they recommend using an oil can and small piece of hose, but i do this with a old bike pump. you have to make sure it's clean inside! cut off the fitting for the tire, Stick the hose in the bottle, extend the pump handle and fill the reservoir. Then with the bleeder open and the pump hose clamped to the bleeder I depress the fluid back into the system to the M/C. Make sure you do this slowly and have another person with a turkey bastor removing fluid from the m/c reservoir. do it till you don't get any bubbles coming from the master. 3) If you blew the seal i would suspect that the master would start leaking. You can always take it apart and inspect it for damage. not sure about the hole in the cap.
If you are rebuilding the original brakes with original replacement parts (it sounds like that) then you don't need to add anything. The M/cyl can be bench bled in place. Simply run a short piece of tubing from the M/cyl port up into the reservoir and down under the fluid level. Slowly pump the pedal until no air bubbles come out of the tubing. Then you can reconnect the brake line and pump as Squirrel suggests bleeding at the W/cyls. If is sometimes easier to do it in a vise (hence the term bench bleed) If on the other hand you have updated to more modern components then you will need to provide more information. Trying to solve problems on the HAMB with out all the info is impossible.
how would you over stroke the MC if you are still using the original brake pedal set up and MC placement?..i could see over stroking it on the bench , because there are no stops or mechanical limits, more so than still in the car.. I havent had problems doing it this way for over 30 years, but..who knows maybe im getting lucky
how can you say this is true and on my reply its not a good idea? when we basically said the same thing?
maybe because you have a 6:1 or so lever on the car (the brake pedal), while on the bench you are just applying force directly to the piston, so you won't push it so hard.
To square up on the bench bleeding of the master. the master was in the car (yeah i get the bench bleed thing), but here is what i did, tell me if this is no good. I took a brake line off, and screwed in a new six inch piece of brake line and pumped the air out with a va***e pump(mityvac) is this not an acceptable way to do this? If not tongiht i can pull the MC out and run a line back into the fluid. Is there anyway i can check this peice that can "Blowout" while i have the MC out? Yes, im using all original parts in this brake system. Thanks for all the help so far.
Think about it like this. If you loose all the fluid in your system the pedal goes to the floor and the rod travels further in the bore. He isn't pushing any fluid So I'm treating it like a dry system without any pedal pressure
I guess so..i take it easy when i do this, so maybe thats why ive been successful at it...slow and easy..like the whitesnake song says
I meant this "If on the other hand you have updated to more modern components then you will need to provide more information. Trying to solve problems on the HAMB with out all the info is impossible" I'm not try to say your method is wrong by any means. It works very well. You just have to be careful. Since the OP is worried about bottoming out the M/C i was just stating that it "could" happen.
there should be a snapring on the back side of the m/c that holds everything in. I'm not really familiar with your exact car. so I can't picture all the pieces. But if you remove that clip everything should slide out. I need to use multiquote....
You hope that you ****ed all the air out. Running the tube under the fluid level lets you actually see when all the air is eliminated. No guessing.
if you put new brake shoes in make sure they are adjusted up tight. if the shoes are not moving out enough to tighten the wheel cyl will just move out and not have any backpressure on it. have had this happen just a thought.
As usual with brakes some good advice and some off the wall stuff. On this type of master cylinder the residual valve is inside the master cylinder in most cases. There is a chance that who ever ***embled the master cylinder could have put it in backwards or left it out but I would think you have other problems if you can't get any pedal at all. 1. have you adjusted the brake shoes ? It is easier to get drum brakes to bleed if you have them adjusted correctly. 2. As a couple of guys have mentioned are all the fittings tight? 3. As Squirrel said, it is usually easiest to have a helper pump the brakes while you bleed them and he is dead on on method. I've found that way too many helpers pump the pedal too fast and end up getting air back in the system rather than getting it out. Fill the master cylinder Have the helper pump the brakes slowly and hold the pedal down. open the bleeder, let any air of fluid out. Close the bleeder tell them Ok pump it again Repeat. After about three times on one wheel check the mc and add the necessary fluid. Do not let it run out of fluid or you start all over again. There is a link that tells how to make a pressure bleeder out of small garden sprayer that probably would end up costing less than 25.00 if you caught the sprayer on sale at Ace or another store. http://www.bmw-m.net/TechProc/bleeder.htm You would need an extra cap that fit your mc to make it but it might be something that would help a lot in this case. <input id="gwProxy" type="hidden"><!--Session data--><input onclick="jsCall();" id="jsProxy" type="hidden">
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