brake bleed problem

Topic: brake bleed problem (Read 1347 times) previous topic - next topic

brake bleed problem

May 04, 2009, 12:47:02 PM

I CANNOT get the rear brakes bled on my 88 sport. I pulled the whole thing out a month ago so a friend could rebuild the blown chunk. I replaced it this weekend and i sat at the rear wheels for an hour with my vacuum pump, but i can even get fluid to the bleed ports. I replaced the copper grommets on the distro block, thinking it might be sucking vacuum there, and looked for dents in the lines but nothing. The fronts bled fine so what the hell. The pedal is complete mush(engine off). Anything i missed besides some patience?

brake bleed problem

Reply #1 – May 04, 2009, 01:25:07 PM

Time for a new master cylinder??? Crud in it? Maybe a seal dried out in the calipers? Bleed ports plugged with gunk... Lots of possibles. I'd say recruit an assistant, start at the mc port loosening connections while asst pumps the pedal. You're looking for 'leaks' at each junction as you loosen. Follow the fluid back until the pressure won't blow any fluid out. Be careful loosening the connections, easy to break them. PBlaster is mandatory.

The pedal on my 86 remained complete mush until all 4 corners bled good.

brake bleed problem

Reply #2 – May 04, 2009, 04:07:47 PM

take the line loose infront of the block that goes to the rear end and see if you can manually pull fluid though the line. if not your M/C is most likely bad.

brake bleed problem

Reply #3 – May 04, 2009, 04:31:32 PM

rog thanks. hopefully i can get to it this week.

brake bleed problem

Reply #4 – May 04, 2009, 09:50:05 PM

if the line blew, it could be that Darn proportionong valve..... im pretty sure if a line blows, the valve "shuts off" fluis from that line, or in youre case the rear,.... this exact situation happened to me a while ago...... after a new M/C, and booster, i replaced it and they were fine..... correct me if im wrong!!!

brake bleed problem

Reply #5 – May 05, 2009, 09:55:26 AM

My 86 had the same problem. New master fixed it.

brake bleed problem

Reply #6 – May 07, 2009, 08:42:58 PM

okay, i think i've narrowed it down to the prop valve. I tried compressed air to blow it out and i am soaking it with brake cleaner but nothing so far. When you say "blow a line" what do you mean exactly? Is there a valve that shuts off the rear and thats what's not letting the fluid thru?
Just so you know what i did,i pulled the flexible line off the rearend and hooked my mityvac up to the hardline and pumped the line up to 25 inches and it held. I then loosened the rear brake line at the prop valve and it released the pressure. I then cracked open the line on top of the prop valve for the rear brakes and had my assistant press the brake and fluid shot out.

brake bleed problem

Reply #7 – May 07, 2009, 08:49:10 PM

My passenger side line blew apart after the car was sitting for a year...... i stepped on the brake and it went to the floor....im guessing the excessive amount of fluid tripped the valve, and blocked off the rear lines... unless it was just clogged... i did this before i was a member here, so thats all i can think of... like i said, i replaced everything!!! and it didnt work, but once i replaced that valve.... i actually got fluid from the rear...

brake bleed problem

Reply #8 – May 07, 2009, 08:51:10 PM

rog...is that a junkyard part?

brake bleed problem

Reply #9 – May 08, 2009, 06:31:21 PM

FIXED, i removed the prop valve and put it on the bench. I then used a 3/4" wrench to take the end off. Be careful as it's spring loaded and has a rubber grommet on the end of the spring. Pull the red rod and spring out and clean THOROUGHLY with air and brake cleaner. Hope it helps someone else.

brake bleed problem

Reply #10 – May 08, 2009, 11:50:34 PM

helps me!!!!! my brakes havent been the same since....(spongy)... and yea j/y part..