Caleb

Thank you everyone one for the help! Solution: the push rod between the master cylinder and hydrobooster ended up being 5/16 to long. I talked to a diesel mechanic in my area and they did confirmed that there ARE two different size push rods. This is due to OEM vs. Aftermarket setups. I ended up cutting my original rod down and rounding it off. AS OF THIS POINT... brakes are working as they should be. As for anyone who runs into to this problem in the future... be sure that when installing master cylinder, it goes on smoothly without any force. Failure to do so will result in the rod pushing the master cylinder in and locking up the brakes!

Thanks for the tips and diagram tractorman! Another person stated that they very possibly make a second push rod that is aprox. 5/16 shorter, looking in to that and hoping that should fix the issue. Bty, I had used the old push rod assembly in the new hydrobooster.

I have decided to replace the "new" hydrobooster. The auto parts store is going to take it back as defective. I had two issues with it that could lead back to my stuck calipers. #1 the brake pedal would hang down about 1/2 an inch when NOT being used, even when the truck is off. #2 the rod from the hydrobooster stuck out about 3/8" to far causing me to force it on the master cylinder. I believe that with the master cylinder being pushed in that small amount, it was enough to not allow fluid back into the master. This in turn caused the calipers to stick. I'll give an update in a couple days once I receive new hydrobooster and install.

Okay, after sleeping on it last night, I came up with an idea. After we had put the new Hydro booster on, we installed the master cylinder. the master cylinder was about half an inch from contacting the hydrobooster, so we just used the nuts to push it on there the rest of the way. Now that I think about the way we did that, I think the rod from the Hydro booster is keeping the master cylinder open. If this is correct, why were we not able to push the master cylinder on completely? Or, is that correct?

Again, like I said above, I unscrewed the brake line from the master cylinder, and manually pushed the cylinder IN at caliper. And I got fluid coming out of the line that goes into the master cylinder. Wouldn't this mean that the brake lines are clear going both directions? I'm guessing the problem is something very simple, I just need to figure it out. Is there possibly a fuse that could be causing this issue?

Thanks, I'll try that tomorrow and get back to you if it works. On a side note, is there a chance that the aluminum box where the break lines and electrical wires go into bad? Could it possibly be clogged or anything? What is it and what does it do? ABS?

Thanks for the reply! Brake lines are what I WAS leaning towards on the next thing to replace, but I unscrewed the rear brake line on the master cylinder and then manually pushed the caliper cylinder in and got break fluid where I unscrewed it at. That leads me to believe that the break lines are still good. Yes, I did bench bleed MC according to directions that came with it. When I have both calipers off I can push one cylinder in and it pushes the other side out. BUT, I can not get BOTH cylinders to push in at the same time.

Ok, so I recently bought a 99 24 valve Cummins. When we purchased it, it needed front brakes rotors and calipers. Also, the rear axle seals were leaking so we change those and the rear drum brakes and drums. When we got all done putting the brakes on front and back, we bled the system properly. When we took it out for a test drive, the brakes were extremely spongy and I could press them almost all the way down to the floor. After doing some research, we ended up replacing the master cylinder. That did not fix the issue, so we also replaced the hydro booster. After bleeding both the power steering and the brake system, we took it out for another test run. At first we were sure we had fixed the problem. But after a few minutes of stopping and braking, the brakes started to get extremely hot and we lost breaking abilities. We got it back on the lift, and realized that the front calipers got stuck in the open position , causing the brakes to rub. At this point, we don't know what to do. Any and all advice would be helpful at this point! I gave as much detail as possible but might of forgot something.