Brake Bleeding Issue

[dubyehnel]

Just did a rear axle job and went to bleed the brakes. I can't get any fluid to come out of the rear calipers. I've poked around and the only thing I can think of is rusted/plugged up bleeder screws. I'm going to go get some new ones tomorrow, but in the meantime I wanted to check if anyone had any ideas of any other issues that might be causing this.

I'm using a vacuum pump to bleed the system and what makes me think its a plugged screw is that when I loosen the screw, the pressure in the line does not drop at all. I also installed the slee brake lines(just the calipers ones so far) so I could have put those in wrong somehow, but i don't think so. I can get fluid out of the LSVP and the front calipers. Could other brake lines have collapsed in the rear?

 

[skiater]

I had the same problem the other day on the rear DS bleed screw.
Actually thought that it was a defective bleed screw, when I removed it I could not see any port.
Turns out it was totaly rusted/plugged up.
Used a paper clip and dug out the rust, reinstalled and was able to bleed that caliper.
The other bleed screws were all good, flowing freely.
Might be as you suspect, strange that all four are plugged up though.

 

[fourtrax]

i had the same problem when i purchased my 15 year old 80 with 230k on it... most people never even think they need to change the brake fluid let alone do it. brake fuild will pick up moisture and hydrolics will generally push it to the bottom or the end of the brake line.

 

[dubyehnel]

It was the rusted bleeder screws!!! Just took a minute to take them out and cleaned them out with a paperclip. I'm still going to go pickup some new ones tomorrow.

 

[fourtrax]

don't forget to bleed the LOAD SENSING PROPORTIONING VALVE (LSPV) in front of the rear drivers tire as well.

 

[madbomber]

Had the same issue with both rear caliper bleeders. Took them out and cleaned them. This past week I changed out the rear rotors and pads and got to looking at the calipers and thought about how much they were clogged up and the contamination that came out the lines. So I took off my rear calipers and took them apart to see if their condition inside. As I suspected, they had a lot of contamination and corrosion behind the pistons. I cleaned them up, but have since ordered replacements. Just some info to think about, maybe your calipers have the same issue as well.

 

[wxm]

Rusted bleeder. Lots of us had that. Just take it out and clean it with brush wire and compressed air. Make sure bleeding it well when reinstalling it.

 

[dubyehnel]

Bleeders cleaned. Ordered 4 new ones for whenever I do the front axle job in the near future. Now bleeding is a problem. Vacuum bleeder gets some fluid put all around. Most comes from the LSPV(lots of bubbles). Two person method yields a pretty weak stream but not many bubbles. Just going to keep bleeding and see where it gets me.

 

[excessive]

I;ve heard you are supposed to bleed the LSPV last ( after rear calipers) but that doesn't really make sense....

 

[lt1fire]

You are supposed to bleed the lspv third. Start furthest away from the MC. PR, DR, LSPV, PF, DF in that order