I thought I bled my brakes :-(

[davepl]

So today I pressure-bled my truck's brand new master, combo valve, lines and brakes. I used the Motive pressure bleeder.

I went around all four corners from nearest to master to furthest. Bled each one until there were absolutely no bubbles.

Capped everything up, went to hit the pedal (not running yet) and it was soft. After one pump it was high and hard though (no puns).

I did notice that when I took the Motive lid off the master the back reservoir (which is the front wheels) was empty or close to it. But I don't think it had uncovered any port yet.

There's also something in the shop manual about having to lock out the combination valve while bleeding, and I don't even know what that means. There's no ground present at the Brake light switch.

I've still never in my life successfully bled brakes. True, I could do the old pump and turn the screw method, but I think that would have just got me to this point more slowly.

[JointTech]

did you bench bleed the master cylinder?
i dont know what a power bleeder is but I have a vacuum bleeder that works pretty good by yourself. but if the res got low it could easily get air in it. gotta make sure its always topped off. my vacuum bleeder has an attachment that holds a bottle of new fluid above the res to keep it topped off while sucking from the wheels.

[geezer#99]

Sometimes those whiz-bang toys don't work. I've always done the pump and bleed method. A couple times by myself with the one-man bleed bottle and hose. Best part about the old way is you can closely monitor the fluid level in the master. It might take me longer but at least I don't need to do it twice.
Lock out the prop valve means this. Most have a reset button on the front covered by a little black rubber cap. You need to push the button in and keep it pushed in while you bleed. The factory uses an angle clamp they bolt on but an easier method is a big c-clamp. Leave it on until you're done bleeding.
So now go get the mother in law and have at it.

[Wrenchbender Ret]

If the pedal pumped up it is possible your shoes are not adjusted up enough.

[chopnchaneled]

What wrenchbender said ^^^^

[LockDoc]

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Actually I think you did it backwards. You are supposed to start with the longest line and end with the shortest line to bleed them....

As stated above bench bleeding the master is important....

On the drum brakes, one thing I found on mine is when you put everything back together and adjust the brake shoes you can’t just adjust them out until they start rubbing and quit. You have to adjust them out as far as they will go and you cannot turn the wheel or drum at all. This centers the whole assembly in the drum. (I even tap around the drum as I tighten them to help them center themselves) Then you back them off until the wheel just turns, and stop. If you only adjust them out until they start rubbing and quit, the first time you press on the brake pedal the brake shoe assemblies will center themselves and you will have too much clearance between the shoes and the brake drum. I also put three lug nuts on backwards to hold the drum tight against the axle on the rear.

I know it is a pain in the butt to try and hold the self adjusters off of the adjuster wheel while you back them off, but this is the only way I could get my drum brake shoes adjusted correctly.

LockDoc

[davepl]

Originally Posted by LockDoc

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Actually I think you did it backwards. You are supposed to start with the longest line and end with the shortest line to bleed them....
LockDoc

Page 5-4 of the 1972 service manual says this, bad grammar and all:

"The correct sequence of bleeding is to bleed wheel cylinder, either front or rear system, nearest master cylinder first."

I was a little worried that my power-bleeder might only feed the front reservoir, but the GM special one they picture in the shop manual -clearly- only feeds the front reservoir, so it must not matter. But I think the order is still closest to furthest.

[FirstOwner69]

I agree with LockDoc. I've always bled starting with the farthest cylinder/caliper from the master and worked toward the master. I've never read directions saying to start with the closest.

When I did my 69 last year I replaced the bleeder screws with speed bleeders (http://www.autozone.com/autozone/par...8_305221_2826_). I'd never used them before. After bleeding the master, I did the rest of the job in less than 30 minutes by myself using the old method of opening the bleeder and pumping the brakes. The speed bleeders have a check valve in them to prevent the fluid from flowing back into the brake line along with air so you don't need a helper and don't have to close the bleeder between pedal strokes. The old disc brake truck stops as well, or better, than most disc brake vehicles I've driven and has great pedal feel. The guy who did my alignment drove it pretty hard last week and said "who needs disc brakes".

[Stu Pidd]

Power bleeders work wonderfully. I used to race, and bled the race car's brakes frequently, by myself. Crack the bleed screw open, and fluid oozes out, as the master cylinder is lightly pressurized, with plenty of fluid in the power bleeder constantly refilling the master.

I always start at the farthest wheel and work towards the master cylinder.

[davepl]

Well, can't hurt I suppose, I'll try from furthest out. I have to redo it with the combo valve held anyway.

[AirSpeed]

I don't understand why you need to start at the rear then the front, aren't these circuits totally separate? Does it really matter if you do the rears first? Just curious.