Brake bleeding help

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Gerry
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Brake bleeding help

Post by Gerry »

At beginning of restoration(5 yrs ago) I replaced the complete brake system adjusted and bled but never drove. I recall when I rolled it out of garage a couple yrs ago I had some brakes but not much.I tried the pump up method to bleed with no luck so I purchased a suction type bleeder and attempted again. I think they are worse.Pumping pedal now gives me no pressure. SO multiple questions.
How much fluid should it take to flush air out? Seems I never could get all the air out.
Should I open up bleeder all the way or only partial. Want to make sure refill keeps up with what I am taking out.
When I pumped pedal I could watch fluid go down but is it possible master is still bad.
If not Im guessing air leak?
Any and all help appreciated and dont be afraid to ask dumb questions.
Thanks
Gerry

53 M37
Kaegi
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Re: Brake bleeding help

Post by Kaegi »

don't pump it if there is nothing to pump. open bleeder with NO pressure on pedal, push pedal down most the way not all the way, close bleeder, let pedal up, repeat many times at each wheel keeping master full. the master will go dry fast. check after every 3 pedal pushes. then after fluid is coming out clear at all 4 wheel if you want you can pump it up then crack a bleeder. you can also try gravity bleeding if you are alone. open one bleeder at a time and let it drip for 5 minutes or until its consistently dripping. vacuum bleeders never really work well. pressure is the way to go if wanting a tool for it. these trucks should bleed out easy the manual way.
Cal_Gary
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Re: Brake bleeding help

Post by Cal_Gary »

Don't waste your time with that suction pump-I wasted my money on one, then sprang for the Motive Pressure Bleeder-made all the difference in the world!
Gary
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w30bob
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Re: Brake bleeding help

Post by w30bob »

Gerry,

How about a bit more background info;

When you say you replaced the "complete braking system" are we talking new brake shoes, wheel cylinders, brake lines, and master cylinder?
Did you check your rotor dimensions to see if they're within spec?
Did you manually adjust the brake shoes per the manual?
When you r"eplaced/adjusted/bled but never drove" did you have full pedal pressure?
By "pump up method" you mean with someone pumping the brake pedal while you cracked the bleeders?

Questions;
How much fluid should it take? Really depends on the amount of air in the lines. Sometimes it's a real bitch to get all the air out.
How far to open the bleeder? Once it's cracked it's pretty much open. Another half turn or 3 turns won't make any difference.
"Want to make sure refill keeps up".......bleeding brakes manually is a two-man job. The refiller and pedal pumper.....and the bleeder cracker. You don't want to push the pedal all the way to the floor....you should put your other foot under the pedal and let it bottom out on that. Going all the way to the floor pushes the master cylinder plunger too far and the rubber seal can get hurt. Once you hurt the seal it will fail shortly thereafter. You also need to start bleeding at the furthest brake cylinder (passenger side rear) and work your way forward to the closest cylinder. Any other order won't work.
If you had an air leak the break fluid would find it and leak out........so you'd see it.
I've never used a suction bleeder, so I can't comment on that.

Let's stop here and see what you have to say.

:D

regards,
bob



At beginning of restoration(5 yrs ago) I replaced the complete brake system adjusted and bled but never drove. I recall when I rolled it out of garage a couple yrs ago I had some brakes but not much.I tried the pump up method to bleed with no luck so I purchased a suction type bleeder and attempted again. I think they are worse.Pumping pedal now gives me no pressure. SO multiple questions.
How much fluid should it take to flush air out? Seems I never could get all the air out.
Should I open up bleeder all the way or only partial. Want to make sure refill keeps up with what I am taking out.
When I pumped pedal I could watch fluid go down but is it possible master is still bad.
If not Im guessing air leak?
Any and all help appreciated and dont be afraid to ask dumb questions.
Thanks
PoW
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Re: Brake bleeding help

Post by PoW »

A pressure bleeder is the only way to go. Fast, efficient, one=person job.

Either buy one or build one. Essentially it is a pot full of fluid with a hose into the top of the MC. Air pressure is applied to force the fluid into the system, and you bleed each wheel, no pumping.

The pumping method sux.

DDG
Gerry
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Re: Brake bleeding help

Post by Gerry »

Bob,
Replaced everything. Bought drum that was turned with hub from vendor supposedly in spec. Adjusted per manual but drums must have been off trailer because they didnt have slots( if I recall correctly.) Last time I had some pedal but not full but wasnt concerned at the time since I didnt have an engine installed. Yes bleed using two people opening each bleeder.

Thanks
Gerry

53 M37
just me
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Re: Brake bleeding help

Post by just me »

I must be the odd man. I've been using the vacuum eductor bleeder system for years with great results. There are some tricks that make it work well. Just crack the bleeder. Push the brake pedal just slightly to uncover the port in the MC. Use a feeder to the MC so it doesn't get low. Don't be in too big a hurry. It is still way faster than the pump/bleed method.
Always do a final pump bleed on each wheel cylinder/caliper.
"It may be ugly, but at least it is slow!"
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