Brake bleeding, no fluid comes out the two rear calipers?

[massimofinance]

Bleeding the brakes on my older car. Using a vacuum pump type device. I cant get a good flow coming out of any of the brakes. When I just crack the bleeders, the fronts bleed by gravity but nothing comes out the rears, even when I remove the bleeders completely. The bleeders aren’t blocked. Is this systematic of a bigger issue with the booster or the lines? Thanks guys...

 

[Harritwo]

What type of car? DOes it have ABS, Rear ABS?

 

[massimofinance]

Its an old FIAT; no ABS.

 

[MTboatguy]

Do you have a person that can push the brake pedal while you have the bleeder open to see if it will push fluid out under pressure? My wife and I have done so many over the years, I can bleed brakes on just about anything in 10 minutes with her help.

 

[GA_Boater]

The master cylinder didn't run dry while bleeding the front, did it?

 

[massimofinance]

no, the master cylinder didn't run dry; the reservoir was always topped off. I did have someone press the pedal and nothing comes out of the rears.

 

[Harritwo]

Proportioning Valve stuck? Seen that a few times when moisture got in

 

[Scott Danforth]

If you have rear abs, you need to hotwire the abs pump to blead the rears

 

[Tim Frank]

You could try going old school.

Get a length of clear plastic hose that will fit snugly on to the bleed nipple, and a jar. ...about a 13 oz. jam jar is fine.
Put about 2" of brake fluid in the jar and put the free end of the hose which you attache to the bleed nipple farthest from Master Cyl;. into the jar....end must ALWAYS be submerged.

Have an assistant press brake pedal and hold down. Loosen nipple 1/2 turn and watch for bubbles escaping from hose.
Tighten bleed nipple to seat. Tell/ask assistant to release brake pedal.
Repeat until no more air comes from that nipple.
Move to either 1) next furthest point if the Fiat is old enough to be single feed system i.e. not 2 circuits. ~ OR ~ 2) to other wheel on the same circuit if dual circuit system.

If you are not getting air you will never get fluid either and you have either a blockage in a line or a master cylinder issue.

Make sure that you monitor the master cylinder reservoir for level....if it goes drry you must start again on the circuit being bled.

 

[harringtondav]

If everything is good, you should get some gravity bleed. I returned two calipers to Advance before I realized I had a bad brake hose. It wouldn't gravity bleed, but would with a helper on the pedal. The bad hose held pressure and fried the pads.