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Discussion Starter · #1 ·
After conversion to vacuum brakes the pedal requires too much travel and the car dosn't stop fast enough. I have plenty of assist and I beliave the booster is good.


I bench bleed the master cylinder before installing it in the car. I then bled all 4wheels with the help of a friend. The pedal isn't as firm as it should be and it requires the whole travel to stop.
Next I bleed all 4 wheels again with the same result.
I then rebleed the master cylinder, still no improvement.

I can't get anymore air out of the system.


The factory service manual says under Excessive Brake Pedal Travel:
Leaking Master Cylinder
Air in Brake System
Uneven brake lining wear
Faulty Automatic Adjusters
Brake Assembly Attachments Missing or Loose
Faulty Meetering valve
Incorrect Wheel bearing adjustment
Improperly Adjusted Master cylinder pushrod. (I didn't see any adjustment to the pushrod)
 

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Resident Idiot
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If you have a check valve in place, make sure it's not backwards.
 

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I had a similar problem with my brakes when I converted to vacuum set up. I re checked everything bled all lines and I finally swapped master cylinders to see if that was the problem (didn't think it was because it was new with the kit) but mine turned out to be a bad master cylinder. HTH
 

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Discussion Starter · #4 · (Edited)
turbojd said:
I had a similar problem with my brakes when I converted to vacuum set up. I re checked everything bled all lines and I finally swapped master cylinders to see if that was the problem (didn't think it was because it was new with the kit) but mine turned out to be a bad master cylinder. HTH
That is what I was afraid of. I think I'll try bleeding them again one more time before I swap out master cylinder.
 

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Older--but Getting Wiser
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Eyup--sounds like possibly a bad MCyl (was yours new?--doesn't really matter tho). However, you're on the right track to bleed all 4 again b4 replacing MCyl.

Good Luck!
 

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Discussion Starter · #6 ·
new master cylinder fixed the problem.
 

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OK! Who Farted Again??
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Man, seems like you hear of bad "new" master cylinders more often lately? Wonder why the quality is down? Made in China parts??
 

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Discussion Starter · #8 ·
Just a Six?? said:
Man, seems like you hear of bad "new" master cylinders more often lately? Wonder why the quality is down? Made in China parts??
I had gotten everything from a junkyard, booster, master and pedal. The master ended up being bad. But the booster is good, even the check valve it held vacuum overnight.

Now I have to figureout a way to repaint my brake booster on the car. I had painted it when it was off the car, now I got brake fluid on it and it took some of the paint off. Maby I'll take the master back off so it is out of the way then mask everything off and paint it. I am not taking the booster back off the car too much work.

I am going to replace the brake hoses sometime soon, so I'll do all this at once so i only have to bleed it once.


Does anyone know how to get that snapring off that holds the piston into the master cylinder. I wanted to open it up and see what was wrong in there but there are no eyes on the snapring.
 

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It's me, really
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You can pry it out with an awl and work it around with a small screwdriver. Probably won't find anything; the take-up valve is usually the problem. It's the round plastic bulge in the rear cylinder with a small hole in it. They are non-servicable even on remans.
 

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Older--but Getting Wiser
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Good job--I wouldn't worry about problem w/ old MCyl. With rebuilts <$30 exch. & new <$60 outright--just move on man (crapola--rebuild kits are near $20??),,, Like stated--it's unlikely you'll visually detect problem w/ old one anyhow.

Tough luck with the brake fluid on the booster. I did the same thing and am still just ignoring it for now--too many other issues! Anybody needing ideas for a good paint stripper???
 
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