'71 with brake bleeding issue
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'71 with brake bleeding issue
My 71 F100 has disc in the front and drum in the back. I never had an issue with brakes until I replaced a ruptured line to the back. When trying to bleed the rear brakes, the pedal became firm while there was still air in the lines. The front brakes are working fine but I can no longer get any fluid/air from rear. I have never bled this kind of system before, only systems with drums all around. Is there a different procedure I should be following or does this sound like a problem with a prop. valve?
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Joined: Dec 2012
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From: Tennessee
Sounds like Prop. valve is stuck . Try tapping it with a small hammer ,TAPPING not a sledgehammer . There are more tips on them . I have luck tapping them, then gravity bleed . If you have too much air and try to pump ,the valve will trip , back to square one .You can also have a helper hold brakes and crack a front bleeder , that can unstick a prop. valve . Then gravity bleed , not pump bleed . After all air is gone you can pump bleed if needed .
Last edited by JWC 3; Feb 19, 2013 at 08:12 PM. Reason: comma
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Joined: Sep 2012
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From: Fremont
They also sell the one man brake bleeding kit, where you connect the brake bleeder kit to the bleeder valve/screw on each disc brake corner, then you will use the supplied hand pump to evacuate air from the line.
I once changed front brakes, calipers, and pads on a car with disc brakes in front and drums in the rear - after changing everything over and bleeding the brake line, I noticed that the brake pedal was stiff.
Remedy: I bought two new bottles of brake fluid and then started back to pumping air out of the lines.... somehow there was still air in the line.
Quick tip: when bleeding brakes, make sure the master cylinder level doesn't drop below half, or there is a good chance of re-introducing air into the line. becomes
I once changed front brakes, calipers, and pads on a car with disc brakes in front and drums in the rear - after changing everything over and bleeding the brake line, I noticed that the brake pedal was stiff.
Remedy: I bought two new bottles of brake fluid and then started back to pumping air out of the lines.... somehow there was still air in the line.
Quick tip: when bleeding brakes, make sure the master cylinder level doesn't drop below half, or there is a good chance of re-introducing air into the line. becomes
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Joined: Jun 2007
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From: Butler, IN
What very few people know, that to bleed the rear brakes with a proportioning valve, with disc brakes, a pin either has to be pushed in (GM) or pulled out (Ford) on the proportioning valve. Some have used vise grips to pull open this valve but I recommend the correct tool to hold it open. You will find the correct bleeding procedure in this thread......https://www.ford-trucks.com/forums/9...ak-brakes.html
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I have examined the prop. valve and have not found a pin. However, I did not look for a pin until after I had experienced the problems. Could this pin be pulled in flush or would it be more likely there isn't one on this model? It is a 71 sport custom the best I can tell. However, I bought it a few years ago and there is no telling what it went through pre me. I suppose the disc up front could have been transplanted from something else.
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From: Butler, IN
The early trucks with drum brakes don't have a pin. The block is much smaller, 2 1/2" maybe as the prop valve is at least four inches long. Maybe some one did do a disc brake conversion and didn't change to a prop valve. (Disc brakes weren't standard until 1973) Prop valve also has bigger nuts on the brake lines. Pics would help as to what you do have there.
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