The Stovebolt Site Forums The Shop Area The HiPo Shop These &@$%#ing brakes!!!

:mad:

Okay, so I've searched just about every one of the 186 pages that came up when I searched for "brakes" on this site, and I've come to the conclusion that I'm just stupid or completely missing something.

I've got a '65 C10 with a 230 that I just redid virtually the entire brake system on -- new wheel cylinders/shoes/drums, lines, and converted the front to disc. I have a new power booster, M/C, proportioning valve, spindles, rotors, calipers and, of course, pads. I've bled and bled and bled and bled the system, adjusted this, tweaked that, and this truck STILL doesn't want to stop very much at all. It more or less thinks about it when I hit the pedal and then I guess it just figures it has nothing better to do. This change was prompted by first a rupture of the original rusted lines, and then the original M/C went out. With the original M/C, the pedal didn't have to be pressed very far at all to get a reaction out of the brakes, but now, with everything supposedly properly adjusted, I nearly go to the floor with the pedal before I get any reaction out of the brakes! Call me silly, but I'm certain that isn't right.

Now, here's the big question: the vacuum line. I have the vacuum line (rubber) hooked up to a spot on the intake manifold (as advised by a couple of people) that had a square-headed plug screwed in it. I really don't know if that is where it is supposed to be hooked up, and I really have no idea where else I COULD hook it up...

Somebody, for the love of God and everything Holy, please, PLEASE help me! The idea of collecting insurance on an 'accident' is looking better and better...

did you bench bleed the master?

DearthVader,

I think your vacuum location is fine. You have another problem...what, I don't know. Poor or no vacuum would only show up as very hard pedal, not poor braking.

Stuart

No, I didn't. I've changed out masters before, and I've bled them both ways (both bench, and after install). Bleeding after install takes a bit longer, for sure. If it is a bleeding issue, then the only thing that I can think of is that this particular master has a little pocket of air that it is holding onto that normally isn't there...

atomarc,

You don't think that I have too much vacuum, do you? Is that possible?

Too much vacum should not be a problem,as 47 chevy said, too little might be but would result in a very hard pedal. However from what you've described, I would lean more towards there still being air in the system. If you have access to a power beeder, I would try that first.

DearthVader,

I'm no pro, but I don't think you can have too much vacuum. The vacuum merely affects the dead side of a diaphragm and provides extra 'muscle' that gives you the power effect. There is a brake return spring that overcomes engine vacuum and pulls your pedal back up.

If you were to disconnect and plug the vacuum line, ideally you should have great brakes...just a lot of pedal effort. The vacuum thing is different than a slug of air or faulty proportioning valve or some other mechanical problem.

I'm not real clear from your post exactly what your problem is. Is it 'hard' pedal with good brakes or mushy, funky brakes. Unhook and plug the vacuum line (engine side) and see what manual brakes feel like...is the problem you describe still there?

Stuart

The rod between the master cyl. & booster may be too long not letting the piston come back all the way. You either have air in the system or the shoes are not adjusted up. You emergency brake may be too tight pulling the rear shoes off the anchors. I think I nwould snatch off the MC & bench bleed it making shure you have pressure at both outlets. Like Stuart says the pedal should be real high with out the vacuum & drop down some when you start the engine.

You might look at these two troubleshooting sites from companies who sell brake kits. Might point you toward a solution.

http://www.mpbrakes.com/technical-support/troubleshooting.cfm

http://www.piratejack.net/Tech-Support/

A GM prop valve has a valve inside of it that needs to be centered whenever bleeding.

Also, what kind of brake problem are you having? Low/no pedal, hard pedal, little braking power with good pedal?
Scott

Randy thanks for the links !!! I think I just figured out whats going on with mine !

Are your shoes adjusted correctly? They need to be nearly scraping the drums. Adjust them tight (until the drum won't turn by hand) and then loosen them until the hub turns freely by hand, but you can still hear the pads drag.

What Builder said...I had the same prob. after ALL NEW, I still had to crank out the rear pads a BUNCH~!, I went from a lousy pedal to a firm pedal in abought 10 minutes of adjustin the pads out till they got hard an centered themselves an backed em off till they just drug a bit.
My 52 will stop on a dime now
Tim

Keep throwing out ideas. There are others (me) lurking out here hoping for an answer that will fit my situation on my '50 3100.

I have all new brake components including CPP front disks and master cylinder with booster. I just replumbed everything to get rid of the GM proportioning valve and plumbed in an adjustable valve and residual valves. Hasn't made a difference. I still have nothing on the front brakes. The rear drums which are 50 years old are working fine.

My only guess is I possibly cross-threaded the speed bleeders when I put them in, so now it lets air in around the bleeders. I reaching but that's all I can think of.

Well, I'm certainly happy to see that I'm not the only one having brake issues... Not so happy to see that these issues exist, if you know what I mean...

Right. I have never had to bench bleed a MC, so I don't know how to do it, but I know that my shoes are adjusted correctly. It may have been a year or 15 since I dealt with shoes, but I did remember that part.

So if I have to bench bleed, how is that accomplished? Also, I'll take off the vacuum hose like Stuart and others suggested. Oh, and to clarify, I have virtually no brake until I'm about 3" from the floor. What I have will stop me, but only if I have about .10 mile to do so.

DearthVader,

If you can pump the brakes several times and increase 'the pedal', this is usually a dead giveaway of air in the system...IF the rear shoes are indeed adjusted properly.

Having vacuum assist or not having it shouldn't make a difference in pedal travel, only the amount of leg pressure required.

Stuart