Can't Get Brakes Bled!!!

[tracterman2]

Okay, I'm going to drive the truck that I've started working on today...it hasn't been driven in 15 years...and I'm so close its not even funny. I run into a problem yesterday. My brakes won't bleed. I have put new wheel cylinders on, new rubber lines on, and a few new metal lines that I destructed on their ways off. So there isn't any fluid in the system itself and of course the wheel cylinders are empty also. I bench bled the master cylinder as to instructions...and I get fluid down to the rubber lines...do I just need to keep going...does it really take this long to bleed the brakes when there is nothing in the system....we tried for a LONG time...but I don't get anything...what are my options?? It won't gravity bleed..I've done that before and thats the by far best way to bleed brakes...anyone run into this?? By the way...drums all the way around...C/10...nothing special...I left the shoes and springs alone besides taking it all off and clean...they are in great shape...44,000 original miles on the truck...I know there isn't a blockage because I've seen fluid all the way to the new equipment...nice clean new fluid...any ideas?? need help!! thank!!

[cdowns]

if you have a combinaton valvwe you need to clamp the pin in

[tracterman2]

okay not knowing what your talking about? is that the same as a proportioning valve?? are you talking about the junction just under the master cylinder?? what pin are you talking about?? I really figured the bleeding would go better...I must be missing something. The pedal also comes back up each time you push it...sure because of air in the lines....

[Bus Ted Knuckle]

Tracterman, you have drum brakes right? If so you don't have a reset on your prop valve, and I don't even think it is called a proportion valve. Anyhoo..

What order are bleeding the brakes in? You should start with the one that is the furthest away from the master cylinder ie the rear pass side, then rear driver, then front pass, then front driver. If you don;t do it in that order you can suck air back into one of the longer lines.

Now...You have to make absolutely sure that you don't let the Master cylinder run dry. If you do you will have to start from square one on the end that you let run dry (dual res. right?).

Does this help any, or is this stuff you are already doing?

PS how's them wheels?

[tracterman2]

yeah drums...doing that...did not go in that order, thats a good idea about the order...didn't think of that....I did know about the master cylinder not running dry. the wheels are great...I had them bead blasted and they are now painted....I will get pics on here for you to see...they turned out really well...will be getting rubber on them today

[Richard H.]

Originally Posted by Bus Ted Knuckle

Tracterman, you have drum brakes right? If so you don't have a reset on your prop valve, and I don't even think it is called a proportion valve. Anyhoo..

What order are bleeding the brakes in? You should start with the one that is the furthest away from the master cylinder ie the rear pass side, then rear driver, then front pass, then front driver. If you don;t do it in that order you can suck air back into one of the longer lines.

Now...You have to make absolutely sure that you don't let the Master cylinder run dry. If you do you will have to start from square one on the end that you let run dry (dual res. right?).

Does this help any, or is this stuff you are already doing?

PS how's them wheels?

Not really the passenger side , after ripping my truck apart , C 10 it dawned on me that the rear line goes accross the cross member to pass side down the frame to a t on the axle and then over to the drivers side rear making it the farthest away

[Bus Ted Knuckle]

Originally Posted by Richard H.

Not really the passenger side , after ripping my truck apart , C 10 it dawned on me that the rear line goes accross the cross member to pass side down the frame to a t on the axle and then over to the drivers side rear making it the farthest away

Good call Richard, I forgot that, I think you would be splitting hairs though. Never gave it much thought.

The rubber hose comes down just a few inches to the right of the pumkin, and then splits to run along the axle, so the difference would be about 12 inches (depending on how many curly-q's the PO put in the replacement line

[jhow66]

This should help: (pin is on the end) Scroll down
http://www.classicperform.com/TechBo...t.htm#testprop

[jkaylor68gmc]

It can take a while!

[Rokcrln]

I assume you are doing it with the tires off and on jack stands right? If so I just learned a trick because last week I had the same problem. Turns out with the front suspention dropped the lines will not bleed right because their is more air in the line then the master can push out and it keeps creeping back up. You need to jack up the "A arms" so the bleeder is as high as possible then take a piece of wire and tie the rubber line down to the lower "a arm" so the air will travel up tot he bleeder and not back up to the frame. Try th esame with the rear end. I have been doing brakes for over 18yrs and have never heard of this untill I could not get my system to bleed and a brake shop told me this. I did not think it would do any good but I was at a loss so I tried it and 15 minutes later I was done with the best pedal I have ever felt in an old vehical. Does you combination valve have a single wire going to it? If it does turn you key on and see if the brake lite is lit up. You may have poped the valve. Here is my thread from last week it may shed some light on the problem.
http://67-72chevytrucks.com/vboard/s...d.php?t=241722

Good luck

Kevin
LFD Inc.