Brake problem – cant lock them up

[tekno62]

Im having a brake problem’s on my 72

The first one I think I have fixed. The back brakes would loose fluid and I could not find any leaks. The PO had installed dual exhaust and the passenger side was riding tight on the brake line. I think that the fluid was just being boiled out. I have bent the brake line with about 1/ 2” clearance.

The other problem is that I can’t lock up my brakes. This is the one that’s bothering me right now. I put in a new master/booster from Kragen as well at new cylinder in back and new pads all around.

Anyone have any ideas why I cant lock up my brakes - front or back

I need to pull a trailer and like to have the brakes 100%

[VDOG]

Kragen Master Cylinder, im doing the same thing. Im on my second one in 3 days, could not a full stream of fluid to the rear. Bought a new one from CPP, still have the same problem. Did you bench bleed your MC?
Also I bought a vacuum bleeder from Harbor freight, other than my problem it bleed the front in seconds.

[tekno62]

no I didnt bench bleed. really glad I didn't as the pipe connectors where different then the original I had to get adapters. I had the master cylinder for a few months with no problem ( fist time the rear reservoir has been empty )

Originally Posted by VDOG

Kragen Master Cylinder, im doing the same thing. Im on my second one in 3 days, could not a full stream of fluid to the rear. Bought a new one from CPP, still have the same problem. Did you bench bleed your MC?
Also I bought a vacuum bleeder from Harbor freight, other than my problem it bleed the front in seconds.

[VDOG]

you have to beench bleed, dont worry Kragen will still take it back. Dry it off and take it back, thats what I will be doing tomorrow. In fact the first one I got was wet.

[tekno62]

what is bench bleeding? that where you put fluid in the master cylinder before you install it? it came with the booster

[lyrikz]

Originally Posted by tekno62

what is bench bleeding? that where you put fluid in the master cylinder before you install it? it came with the booster

If you have to ask what bench bleeding is, you shouldnt be doing your brakes. Thats between life and death there you not stopping.

Basically when you buy the mastercylinder you lock it in your vise. Have someone help you and what you do is fill it full of fluid and then put your fingers over the 2 outlets. Nowhave someone push the cylinder in and before they let it back out, cover the outlet holes so that it sucks fluid down. You will do this quite a few times and eventually when you press down on the plunger you will get no air just fluid out of the outlets.. They do sell bench bleed kits that make it easier and less messy...

Do a quick google search and you will find a ton of articles to help you out. And just because you didnt bench bleed it doesnt mean its bad. It just takes that much longer to bleed the brakes. Just easier to take the MC out and bench bleed it, and reinstall and then bleed the brakes in the correct order.

[tekno62]

why cant I do that when its installed in the truck... my dad and I have bleed brakes for years, and have had no problem removing the air from the system.

Originally Posted by lyrikz

If you have to ask what bench bleeding is, you shouldnt be doing your brakes. Thats between life and death there you not stopping.

Basically when you buy the mastercylinder you lock it in your vise. Have someone help you and what you do is fill it full of fluid and then put your fingers over the 2 outlets. Nowhave someone push the cylinder in and before they let it back out, cover the outlet holes so that it sucks fluid down. You will do this quite a few times and eventually when you press down on the plunger you will get no air just fluid out of the outlets.. They do sell bench bleed kits that make it easier and less messy...

Do a quick google search and you will find a ton of articles to help you out. And just because you didnt bench bleed it doesnt mean its bad. It just takes that much longer to bleed the brakes. Just easier to take the MC out and bench bleed it, and reinstall and then bleed the brakes in the correct order.

[lyrikz]

Originally Posted by tekno62

why cant I do that when its installed in the truck... my dad and I have bleed brakes for years, and have had no problem removing the air from the system.

You absolutely can bleed it in the car. Just messy. Bolt it in place and then have someone with their foot on the pedal. Depress the pedal and then before they lift up their foot, put your fingers over teh 2 outlets and when they lift the pedal it will suck fluid into the MC...

And give the brakes 100 miles or so to break in fully and you should be able to lock them up. If you cant, then id figure you have a booster problem...

[tekno62]

no ones ever said I was afraid of making a mess.

I'll keep any eye on the brakes. may re-bleed them later this week.

Originally Posted by lyrikz

You absolutely can bleed it in the car. Just messy. Bolt it in place and then have someone with their foot on the pedal. Depress the pedal and then before they lift up their foot, put your fingers over teh 2 outlets and when they lift the pedal it will suck fluid into the MC...

And give the brakes 100 miles or so to break in fully and you should be able to lock them up. If you cant, then id figure you have a booster problem...

[cdowns]

clamp pin on combination valve to bleed brakes

[tekno62]

anyone know where to get that little tool cheap? the ones I have found on the net seem to cost alot.

[tekno62]

Also I found this link on bleeding the brakes.

http://jeepgarage.free.fr/OWN/brake%...20bleeding.pdf

[lyrikz]

Originally Posted by tekno62

Also I found this link on bleeding the brakes.

http://jeepgarage.free.fr/OWN/brake%...20bleeding.pdf

Thats on a jeep. Everyone seems to have there little different things...

What year and make is your rig.. I will get you your exact procedure.

[tekno62]

I have a stock 72 350/350 disc on front and drum on rear. the brakes are all stock and everything has been replaced.

Originally Posted by lyrikz

Thats on a jeep. Everyone seems to have there little different things...

What year and make is your rig.. I will get you your exact procedure.

[lyrikz]

Originally Posted by tekno62

I have a stock 72 350/350 disc on front and drum on rear. the brakes are all stock and everything has been replaced.

Ok, then wha tyou want to do is crimp that pin off like cdowns said and you want to bleed it like this for a 72
Now if you have a 1970-1974 the bleed procedure is.
LF, RF, LR, RR.....

Let us know how that works...

[berencam]

Assuming by some strech the master was bled, by bleeding the entire truck, you may have old rubber hoses that are ballooning up when you press the brakes, thus not giving the force to the pads.

[tekno62]

Hmm I havent changed the rubber. But with more work then I know what to do with its going to be a few weeks before I could replace them. I know.

Originally Posted by berencam

Assuming by some strech the master was bled, by bleeding the entire truck, you may have old rubber hoses that are ballooning up when you press the brakes, thus not giving the force to the pads.

[berencam]

Oh and when you buy a new master there is usually a bleed kit with it, there is two caps that go into the outlets, I never 'bench bleed' on a bench, i install the master then leave the lines unhooked, and bleed in the truck. If you have a show truck i wouldnt recommend this because it will eat the paint, but if your truck is old and rusty, just catch the fluid with a cup when you bleed it.

[69GMCLonghorn]

I hate to bring this up as it's kind of a cop out, but in a situation where the brakes are giving you problems, hunt down a good brake shop that will "power bleed" the system. Don't ask me exactly what they do. I think they hook something to all 4 wheels, open the valves and push fluid up the lines, but I'm not sure. All I know is when I had it done on my truck when I had a problem, the pedal DOUBLED in firmness. It didn't cost very much either ($30?).

[tekno62]

thanks for the idea. I'll look into it. I dont have alot of time and doing a raod trip Friday. been working 14 hour days. most of the time I have been posting at work.

Originally Posted by 69GMCLonghorn

I hate to bring this up as it's kind of a cop out, but in a situation where the brakes are giving you problems, hunt down a good brake shop that will "power bleed" the system. Don't ask me exactly what they do. I think they hook something to all 4 wheels, open the valves and push fluid up the lines, but I'm not sure. All I know is when I had it done on my truck when I had a problem, the pedal DOUBLED in firmness. It didn't cost very much either ($30?).