so my 84 Z28 came with the factory rear disc brakes, the pedal is soft and was going to bleed the system, I went to loosen the bleeders and them are seized, big surprise I know, and everyone wants an arm and a leg for manufactured rear calipers. So I was wondering if anyone had a trick to getting the bleeders loose again without breaking them off.

 

You can always shoot it with penetrating oil multiple times and see if it loosens up the rust

 

penetrating oil (pb blaster) and a breaker bar. I'd be skeptical of applying heat to a caliper. those calipers are expensive, I think I paid $250 for two new rear calipers when I bought the car/

 

Apply PB Blaster to the outside and inside of the bleed screw, then immediately strike the bleed screw (Moderately) w/ a hammer. Hitting STRAIGHT DOWN, as if it's a nail your driving. BUT NOT THAT HARD!! Goal is to shock the threads to loosen and draw in the fluid.

This should be done several times a day, for a few days. I have had veh's on my lift for a week or more, doing other work and repeated this quick procedure dozens of times, before attempting to loosen. Depend on time constraints.

I have heated iron calipers, not aluminium. Get it red then remove the heat. This destroys the rust . Too much heat and the screw will melt, of the hose might (in extream cases) burst. (WEAR goggles, of course)

When ready to remove, I prefer a six point, tight fitting socket and an impact wrench. I find it works better than twisting w/ a hand ratchet.

Good luck, some are just gonna break, no matter what. But the more time and effort, improves odds.

 

ps If it breaks and you want to drill it out, get left hand drill bits!

 

Remanufactured rear calipers aren't too bad. They run about $55 apiece at most part stores with a $20 core charge. Part number 18-4164.

 

.

 

Use a new-good pair of small vise-grips. Then clamp them on the bleeder very tight, and hit the vise-grip with a hammer. I've had very good luck with that.