Rear Brake Bleeding

[Denverdelorean]

I just installed new rotors and calipers at all four corners. I cannot get the rear brakes to bleed. I bench bled the new master cylinder with no issues. The old rears were not functioning as the pads had rusted to the calipers, but there was brake fluid in both calipers and lines. What should I check? Should I just have a shop use their vacuum bleeder? I was able to get the fronts bled so they work.

[sdg3205]

I just installed new rotors and calipers at all four corners. I cannot get the rear brakes to bleed. I bench bled the new master cylinder with no issues. The old rears were not functioning as the pads had rusted to the calipers, but there was brake fluid in both calipers and lines. What should I check? Should I just have a shop use their vacuum bleeder? I was able to get the fronts bled so they work.

You replaced the callipers, or pads? If you've got spanky new callipers you ought to get fluid.

Did you blow out the crap from the hard lines before putting everything back together?

EDIT - old brake fluid turns to sludge over time - it only takes about 5 years.

[David T]

I just installed new rotors and calipers at all four corners. I cannot get the rear brakes to bleed. I bench bled the new master cylinder with no issues. The old rears were not functioning as the pads had rusted to the calipers, but there was brake fluid in both calipers and lines. What should I check? Should I just have a shop use their vacuum bleeder? I was able to get the fronts bled so they work.

You could have a crushed brake line or both rear hoses can be bad. Disconnect things till you can get fluid to come out from the master cylinder and that will tell you where the blockage is.

[sdg3205]

You could have a crushed brake line or both rear hoses can be bad. Disconnect things till you can get fluid to come out from the master cylinder and that will tell you where the blockage is.

Indeed. Soft lines can collapse internally too, resulting in a lack of brake fluid at any calliper.

[Denverdelorean]

Indeed. Soft lines can collapse internally too, resulting in a lack of brake fluid at any calliper.

I blew out the hard lines but not the soft ones. i may have to do that to rule out blockages. I was hoping there was some 'magic bullet' common fix for this.

[Denverdelorean]

You replaced the callipers, or pads? If you've got spanky new callipers you ought to get fluid.

Did you blow out the crap from the hard lines before putting everything back together?

EDIT - old brake fluid turns to sludge over time - it only takes about 5 years.

everything is new.

[sdg3205]

everything is new.

So... does this mean you blew out the hard lines?

[Denverdelorean]

So... does this mean you blew out the hard lines?

Yes. I specified that one post earlier. Sorry. Should have just edited that one. :)

[Trstno1]

You should also change out the soft lines with new.....

Take the rear soft lines off and blow all the old fluid out. I suppose it could also be a blockage from where the rear soft line connects to the hard line that leads to the rear caliper.

[sdg3205]

if you disconnect the hard lines at all 4 callipers, you can effectively blow out all the lines - hard and soft!

I take 4 ziplock baggies and zip them around the exit point of each hard line at all the callipers. use some duct tape to seal the top of the bag and around the perimeter of the hard line. Now poke holes up around the top of the bag. You can now blow out the lines without blowing rotten fluid everywhere and it will give you a good indication of what was inside. You just use compressed air cautiously with the hard lines off the master cylinder.

[Denverdelorean]

I'll try this. Thanks!

[Henrik]

You could have a crushed brake line or both rear hoses can be bad.

That's the problem I had. And, I learned that it isn't uncommon at all:

http://dmctalk.org/showthread.php?6672-Very-interesting-discovery-while-doing-a-brake-job&p=96937&viewfull=1#post96937