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The master does not sit level in the car and air in the actuation portion of the master cylinder gets trapped. The master has to be removed and put on a bench in the horizontal position and bled. I have mounted the master slightly nose up and then nose down as I bled the unit to ensure all the air is removed.
Ok, MC was bench bleed after I fetched it from out in the bush. I did notice that you get more stroke from bench bleeding than in the car. I cut some old steel lines and put the plastic lines to it to get a better seal with the MC and it actually worked much better. Now I'm going to get some beer, this should get better.....
2025 c3 ('74-'82) of the Year Finalist - Unmodified
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Originally Posted by BB72
Ok, read part of the sticky. Did I read correctly that while bleeding the master the pedal should get hard?
A brand new M/C can be bad out of the box.
After bench bleeding it will NOT get rock hard unless you remove the bleed tubes and replace them with FLARED PLUGS.
Tom454's sticky suggests to bleed the M/C on a bench rather than on the car because the M/C is not level in the car and you could leave an air pocket.
If you bought it locally I would get an exchange since you have to remove it to bench bleed it again anyway.
Well, back with the beer. Having bench bleed, not car bleed it , it should have a different outcome. I will try to gravity bleed with the assistance of a little vacuum. I hope somebody is learning from my mistakes. I've always been able to do the brakes my way, I guess I may have just been lucky.
Well, got fluid out the front calipers. Unfortunately the front right was leaking, I'm hoping it straightens out when I get good pressure to it. As far as the rear goes, I have no fluid using vacuum. The pistons all pull in(both sides) when vacuum is put to it but no fluid. I don't hear any leaks either. I have blown out the line earlier, it's clear.
Thanks Danny...for the correct bench bleeding lesson. Well, had I have taken the bench bleeding term seriously I would have given up my old ways. I know , I'm stubborn. Success...somewhat. Want to come over for a beer tomorrow Danny?
Well, Dannyman came over today to give me a hand, thanks Danny, we still weren't able to get any fluid to back brakes and when we got fluid to the front it was really slow flowing. We've decided to just let it gravity bleed for a while.
Just a question , is there a different procedure for bleeding brakes with hydroboost?
From what I can determine the brake bleed procedure should be the same for a booster or a hydroboost system.
Leaves me thinking that the issue is;
1) air still in the master,
2) brake push rod too short, or
3) the proportioning/combination valve is off center.
Is the master cylinder matched to the hydroboost? Just curious if the pushrod is the correct length.
Hopefully the gravity bleed gets fluid moving.
With any luck some hydroboost operators will chime in.
The master does not sit level in the car and air in the actuation portion of the master cylinder gets trapped. The master has to be removed and put on a bench in the horizontal position and bled. I have mounted the master slightly nose up and then nose down as I bled the unit to ensure all the air is removed.
No need to remove the mc...you can jack up the car to level the MC
How about an update here Rob. Did you get it bled?
No real update, between work and getting my lawn tractor going again I've been busy. Get this, the positive power cable on my tractor sent 12v through the system until the cable went under load and power cut right off. Trouble shooting night mare with these intermittent problems.
Anyhow, I went to Princess Auto and bought that hand vacuum bleeder , it was on sale so no big deal but it didn't do a thing. I'm rigging up something now , and if it works I'll let you know. It's under the same concept as the Motive bleeder. If it doesn't work then it never happened. . I did take that little bleeder can that I had and put a small amount of pressure to it, pushing fluid seemed a lot easier than pulling. That spool in the proportioning valve keeps shifting on me , what a pain.
The good thing is Danny and I got a solid pedal on the front brakes. Updates on Monday of Tuesday.
Positive update, a few tip that you might want to know. I bleed the brakes using positive pressure, not vacuum. That sucks. If you look at the picture you can see how I did it.A plate of steel, a big piece of rubber(helps to work for Goodyear) a small fitting, a drill, a pipe tap, a ball valve, some line and fittings and you're good to go. I had all the stuff in the shop so no problems.
The only draw back is that you have to keep checking the master to make sure you don't run out of fluid. I did and you have to rebleed that side. Not everybody has this stuff but it's not hard to get. I only used between 10 and 15 psi too.