I am having the same problem after I had to replace a brake line to the right front wheel. After replacing the brake line, I filled the reservoir with fluid and attempted tp bleed the air out of the replaced line. To no avail. The master cylinder wouldn't pump fluid and no fluid was coming out of the open line. I started the engine thinking possibly that the booster "might" help with filling the line with fluid. Surprisingly, when the brake pedal was pushed all the way to the floor, the engine almost stalled and white smoke emanated from the exhaust pipe. That told me that the master cylinder had a defective rear seal, so off to the parts store to buy rebuild kit or another master cylinder. Rebuild kits weren't available, so $88 later I have a brand new master cylinder (made in china). Upon removing the old one (sorry that I didn't take the old one with me) I discovered that the new on had a shorter "nose piece" that went into the vacuum booster, so back to the parts store once more (with the old one this time). I told the salesperson the problem and went to fetch the old master cylinder and when I returned, he had another one on the counter that had and 1/8" of dust on it from sitting on the shelf way too long, but it was identical to my old unit, but the cost was now $133. Yikes ! !
I returned home and pulled the rubber plugs out of the ports and put the plugs into them to prime the master cylinder, but for some reason, it wouldn't prime. So I left it on the driver's floor and turned in for the night.
The next morning, when I retrieved the master cylinder, I found the fluid level had dropped and the unit had primed itself overnight. Cleaning the brake booster area, I found about a pint of brake fluid in the vacuum are of the booster piston and syphoned all that I could out and used paper towels to finish removing any fluid in the booster. Installed the master cylinder, topped off the fluid in the same and had my wife press the brake pedal while I went to each wheel and bled each of the four (4) wheels until there was no air left in the brake system. Good pedal and everything should be alright for now.
Took the truck out for a test drive and noticed that for some reason the it felt like I had dragging brake shoe or pads because acceleration was off and I could stop just by releasing the gas pedal. Now what?
Checking the front wheels, indicated that my from calipers were hanging up. They worked perfectly before I started working on the ruptured brake line. So, I purchased rebuild kits for both front calipers (replacement calipers were $87 each) and set about removing the calipers and replacing the seals, etc. I noticed that the lower guide pins on both front calipers were seized, so I removed them and the uppers and cleaned them both up and reinstalled the front calipers. Everything should be good at this point. Right? Wrong ! !
I took the truck out for a test drive and guess what. The same problem happened again. Both from calipers weren't releasing and making the rotors hot as hell.
The only thing that I can think of is that the (new) master cylinder from china is defective, either machined wrong or the piston is not moving far enough to clear the ports to allow the fluid from the front system to release back into the reservoir.
Like I said before, other than the brake line rupturing and loosing fluid, there was not a problem with the brake system at all, until I replaced the chinese piece of crap that was supposedly machined to oem specs. Your thoughts on my situation is welcome before I throw the master cylinder through the parts store window. First one was wrong with too short of a node piece to reach the booster rod and now the exact replacement has my front calipers not releasing and burning my new pads up.
Your input would be appreciated.
Friday, July 26th, 2019 AT 4:05 PM
