peoblems with master cylinder??
Thread Starter
|
Tuned
Joined: Apr 2001
Posts: 443
Likes: 1
From: Athens, AL
peoblems with master cylinder??
I have all new brake parts on my 79 Bronco, including lines. I have been having the biggest probl;em trying to bleed the rear brakes. No matter how or how much I bleed them, I can't get a good pedal. The MC bench bled well, and there was less than 1/8 travel, with no air bubbles.
I first tried bleeding the brakes with a helper. I was only getting drops of fluid at the wheel cylinders. I tried vacuum bleeding, but couldn't get anything out. Then I vacuum bled with the rear axle brake line in fluid and the vacuum pump at the MC line. Still no rear brakes.
Now I am pressure bleeding, but still not getting fluid out at the wheels. I took the line off the MS, and at 15-20#, I'm only getting drops of fluid.
This is a new anodized MC from O'Reilly, part number MC97934:
O'Reilly Auto Parts - Results for Shopping Search
Is there a chance the MC has some kind of flow blocker that only allows flow with the pedal pressed, or is a faulty MC more likely?
I first tried bleeding the brakes with a helper. I was only getting drops of fluid at the wheel cylinders. I tried vacuum bleeding, but couldn't get anything out. Then I vacuum bled with the rear axle brake line in fluid and the vacuum pump at the MC line. Still no rear brakes.
Now I am pressure bleeding, but still not getting fluid out at the wheels. I took the line off the MS, and at 15-20#, I'm only getting drops of fluid.
This is a new anodized MC from O'Reilly, part number MC97934:
O'Reilly Auto Parts - Results for Shopping Search
Is there a chance the MC has some kind of flow blocker that only allows flow with the pedal pressed, or is a faulty MC more likely?
Post Fiend
Joined: Jan 2005
Posts: 8,402
Likes: 10
I could be wrong but I can`t see the flow blocker theory. It sounds to me like the little port that allows fluid from the resevoir into the rear brake portion of the master cylinder is restricted, either from faulty manufacture or from the pedal rod holding the piston too far forward. I would try loosening the bolts that hold the master cylinder on to the booster and pulling the M/C forward about 1/8in and try the pressure bleeder then.
Just my thoughts.
Just my thoughts.
Thread Starter
|
Tuned
Joined: Apr 2001
Posts: 443
Likes: 1
From: Athens, AL
Yep....been there, done that.
I just took it off and went to exchange it. The new new one pressure bled fine and now I have a pedal!!!
It still won't lock the brakes, but at least it stops now.
I just took it off and went to exchange it. The new new one pressure bled fine and now I have a pedal!!!
It still won't lock the brakes, but at least it stops now.
Thread
Thread Starter
Forum
Replies
Last Post
Fords412
1999 - 2016 Super Duty
27
Jan 19, 2019 08:30 PM
51-f1-bob
1948 - 1956 F1, F100 & Larger F-Series Trucks
4
May 19, 2012 12:29 PM
BruceF350
1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks
5
Feb 28, 2010 01:55 PM
Jeremy Ruppert
1973 - 1979 F-100 & Larger F-Series Trucks
9
Oct 30, 2009 01:13 PM
