1981 CJ7 - I have just done a complete brake job, replacing drums, piston, rear shoes, front pads, rotor, and calipers. Before the brake job I couldn't get a good pedal when bleeding the brakes and I still have the same problem. When I bleed the brakes there appears to be no air coming out of each wheel?

Does anyone know whether I just can't get all air out of the system or have a small hole somewhere in the system?

Please give your suggestions.

If you don't have any air coming out when you bleed it, and you have checked to make sure there are NO external leaks of brake fluid when you repeatedly activate the brakes, it sounds like you have a bad brake master cylinder.

They're not that expensive, but make sure that you follow the master cylinder bleeding procedure before you even install it on the vehicle, and then bleed the entire sustem after you've installed it.

Harvey the calipers are marked left and right! You describe the results of installing them backwards!!! It is a common firstimer problem.
Check again the air relief should be at the zact TOP of each caliper.. If installed on the wrong side there is air ABOVE the relief that cannot be purged..
Big JIm <img src="/forums/images/graemlins/pfft.gif" alt="" />

Good catch, BJ. I forgot all about Murphey's Law! <img src="/forums/images/graemlins/lol.gif" alt="" />

The calipers were installed correctly, any ideas on how to check for a leak in the system? Will a small leak allowing air to enter the system cause the problem, if so, how do you check for the leak.

Have thought about making or buying a vaccum bleeder like the one shown at:

http://www.jeephorizons.com/tech/brake_bleed.html

to ensure no air is in the system, does anyone have experience with these, I have hear that brake bleeder valve when open sometime allows air to enter the system via the threads, therefore the vacuum systems can be problematic, anyone had experience with these systems. Helpful Ideas welcome. <img src="/forums/images/graemlins/scared.gif" alt="" />

I have never had a brake system that, if air was being leaked into the system, would also not leak out brake fluid if the brake pedal was depressed vigorously (with engine running) if power brakes) several times. Pump the hell out of rhe brakes, and then religiously check every part of the brake system for visible signs of leaking.

As I noted before, if you're not leaking fluid, and you can't get adquate pedal by bleeding the system, chances are you have a bad master cylinder. If the piston(s) in the master cylinder are worn and letting fluid get past them when applying the brakes, the symptms will be exsactly as you describe.

Harvey, have you checked the rubber lines? They may get soft with age and swell when you apply the brakes.

I had this same problem as well and couldn't figure it out for the life of me. Mainly because I could not find any brake fluid leaking anywhere. Until, my brother the mechanic told me to stick my head under the dash and look where the master cylnder is connected to the fire wall. He told me it would be soaked with brake fluid. It was replaced master cylnder. Worked great. word of advice bench bleed your master cylinder first it will save a load of headaches.
<img src="/forums/images/graemlins/patriot.gif" alt="" /> <img src="/forums/images/graemlins/cheers.gif" alt="" />

Thanks for all the suggestions.

Still having troubles, I replaced the master cyclinder (which I think was bad as the brake fluid was froathing, like beer coming out of the bleeder valve, before I replaced it).

But, I still can't seem to get a pedal, only after three pumps. There is no air coming out of the bleeder valves just a nice steady stream of brake fluid? I have also pumped the hell at the brakes with the engine on and can't seem to find a leak?

What about the proportioning valve on the 81 cj7? The book is a little confusing on whether you should bleed the brakes with the valve in, valve out, or if it matters? It looks like the valve is last thing the that I haven't replaced!!! Any Sugesstions?

<img src="/forums/images/graemlins/scared.gif" alt="" /> <img src="/forums/images/graemlins/scared.gif" alt="" /> <img src="/forums/images/graemlins/scared.gif" alt="" /> <img src="/forums/images/graemlins/scared.gif" alt="" /> <img src="/forums/images/graemlins/scared.gif" alt="" /> <img src="/forums/images/graemlins/scared.gif" alt="" /> <img src="/forums/images/graemlins/scared.gif" alt="" /> <img src="/forums/images/graemlins/scared.gif" alt="" /> <img src="/forums/images/graemlins/scared.gif" alt="" /> <img src="/forums/images/graemlins/scared.gif" alt="" /> <img src="/forums/images/graemlins/scared.gif" alt="" /> <img src="/forums/images/graemlins/scared.gif" alt="" />

You sure making an EXCELLENT description of the calipers being on the WRONG side.. Please do yourself a favor and look to see if the bleeder is at the ZACT highest point of them..
Big JIm <img src="/forums/images/graemlins/pfft.gif" alt="" />