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Old 11-06-2014, 10:16 AM   #1
rkufahl
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Power Brakes

Hey guys I'm new to the forum. I just put power brakes on my 71 C10. I'm having problems with the brake pedal return to its position after I step on the brakes. It comes back some but doesn't release all the way, so I have to pull up with my foot to fully release the brakes. I've tried a new brake pedal spring thinking the other may have been worn out but that didn't help. I've adjusted the pedal travel distance. Is there such a thing as too much vacuum? The booster is a bolt on kit from classic performance products. Any thoughts would help?
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Old 11-06-2014, 11:37 AM   #2
69worktruck
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Re: Power Brakes

Disc or drum brakes? Is the brake pedal rod binding? Does the brake pedal have more than one hole for the brake rod?
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Old 11-06-2014, 11:41 AM   #3
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Re: Power Brakes

Disk in the front and drums in the back. Only 1 hole on the brake pedal. It doesn't appear to be binding up. If i disconnect the vacuum hose from the manifold it works like manual brakes and the pedal returns normally?
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Old 11-06-2014, 11:54 AM   #4
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Re: Power Brakes

Are the disc brakes stock or did you convert from drum?
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Old 11-06-2014, 11:57 AM   #5
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Re: Power Brakes

stock
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Old 11-06-2014, 12:46 PM   #6
69worktruck
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Re: Power Brakes

If nothing is binding, The internal booster spring isn't strong enough to overcome the vacuum or air is being trapped behind the booster diaphragm. I would call CPP and ask them about it. I don't ever remember seeing anything in-line to reduce vacuum going to a booster.
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Old 11-06-2014, 01:58 PM   #7
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Re: Power Brakes

Any hissing under the dash? It could be the valve is sticking open.
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Old 11-06-2014, 07:49 PM   #8
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Re: Power Brakes

no there is no hissing either
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Old 11-06-2014, 08:59 PM   #9
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Re: Power Brakes

Unhook the booster (plug the vacuum line) and see if that makes a difference. If not, then its likely not related to it at all.

When I did my drum-disc conversion I used a bunch of new parts so had to reset the pedal depth with the turnbuckle rod (or whatever its called). I was able to bring the pedal back enough to touch the stop on return (then adjusted to spec).

The shop manual has both the procedures on how to do it and the specs on where it should wind up, and the tolerances for how far it can be out. I'd follow that set of adjustment steps and see where it winds up.

If no parts have changed, however, a failure is more likely than a misadjustment.
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