[Wufei]

hi
i've got a 78 chevy full size truck, i did a brake job(rotors,calipers,pads) on the front and when i try to bleed the brakes i keep getting air, theres no end to it, ive gone through 3 quarts of fluid trying. i would imagine that if there was a bad spot that was sucking air in that it would also push fluid out, but i've found no leaks. im at a loss and would greatly appreciate any help


thanks,
Wufei

[poncho62]

Your bleeder hose is probably letting the air in.....does the brake pedal feel spongy still?

[Wufei]

actually im not sure what the pedal feels like ,ive been the one working the bleeders but the hose is completely submerged in fluid plus ive got what they call a check valve bleeder which i understand is designed to enable one to bleed the brakes on his own and still i get bubbles, in fact today it was as bad as i have ever seen it , it resembled the head of a beer running through the hose and everyone ive talked to has never heard of such a thing. like i said i am at a loss

[oldschoolrods]

make sure the hose is completley over the bleeder. Have whoever is working the pedal push it down 3-5 times then hold it down, then open the bleeder.

[poncho62]

Did you bleed the master separately?....if you had it completely dry.

[Wufei]

i didnt bleed the master separately but it also wasnt run dry either
ive done more brake jobs then i can remember and my dad has 30 years more time with it than me and neither of us has ever experianced such a thing
my grandfather mentioned something about a proportioning valve and ive never messed with one before but he did explain the purpose , do you think this could have something to do with it? i dont really see how myself it just seems to me that if there is air getting in that i would see fluid coming out. i know my bleeder tube is sealed in my bleeder valve, its worked for me many times before, im doing everything exactly how ive always done it , but there definatly something going on and its got to be some uncommon problem because everyone that ive explained the problem to is bafled aswell

[poncho62]

The proportioning valve won't let air in, so I can't see that being the problem. Proportioning valve problems usually occur when you blow a brake line and the valve slips inside of it.

Have you tried driving it a short distance to see what the pedal feels like?

[Dusty82]

I did a complete brake job on the Dusty '82 El Camino myself, to include new rotors, calipers, pads, wheel bearings, rubber brake lines, etc...

When I bled the brakes, I got bubbles like that too. I used one of those "one man brake bleeder kits" as well. I got so frustrated with the damned thing after continually seeing bubbles in the line, I finally gave up and did it the old fashioned way - the wife in the car, and me under it yelling for her to pump the pedal. Turns out the brakes were just fine before she ever got in the car.

When I got to looking at things a bit closer, it seems the clear tubing never quite fit the bleeder screw, and air was getting into the tubing there. I took it on a limited test drive, and the brakes were perfect. The pedal wasn't spongy at all, and if I hit it hard enough, it would launch me out of my seat and anything I happened to be carrying at the time clean out of the bed. I've been driving it daily for the last 4 months, and haven't had even a hint of a brake problem. I'm betting your brakes are fine too.

Give 'em one last bleed just to make sure you have the bleeder screws tightened up, then take it for a cautious spin. If they're not 100% perfect, take the truck to a shop and have them pressure bleed the entire system. That shouldn't cost more than about $30. I'll bet they're just fine without needing that though.

[adtkart]

You might want to try bleeding it the old way.

1 ) Place a small hose over the end of the bleeder to control where the fliud and air goes.

2 ) Have an assistant push down the brake pedal one time and hold it. Do not have them pump the pedal, as that can break up large bubbles into many small ones.

3) Open the bleeder to let out the fluid/ air, then close it, while the pedal is down to the floor.

4) Have the assistant release the pedal.

Repeat as often as necessary

Many times the one man type of bleeders will allow air back in thru the threads of the bleeder valve when the pedal is released.

Start at the furthest wheel from the mastercylendar.

[Wufei]

i dont even have the wheels on it yet do to the fact that its much easier to get to the bleeders while there off and if i still get bubbles then i know that the job isnt complete
im going to try the one pump method and if that doesnt work then ill just go pay the money to have it pressure blead either way ill let you know how it goes

thanx guys for all your help

[poncho62]

Bet, when you go to drive it over to the shop, it will be fine.............Any takers???