1995 Z71 4WD brake issue.

[Aerovette]

The truck is my dad's. It has disc / drum combo brakes.

It has new:
Brake booster
Master cylinder
Wheel cylinders
Calipers
Pads and shoes

The ABS unit does NOT work.

I bled the master cylinder, then cracked the lines into the ABS and bled, then cracked the lines out of the ABS and bled. Then I bled the little valve at the side of the ABS unit. Then went to the furthest wheel and worked back to the closest wheel. Everything bled air out and as ONLY shooting fluid EXCEPT the driver's side rear wheel. It will not bleed out. It spits air no matter how many times I bleed it. I went to the T above the differential and there was no air. I went to the inlet connection at the wheel cylinder, there was no air. The bleeder...AIR.

Am I correct in diagnosing that the new wheel cylinder is defective and drawing in air? Have I over looked anything?

I am trying to talk him in to doing an ABS delete with a 75/25 proportioning valve and get rid of that mess even though I don't think it is the problem in this particular case.

[Rodnok1]

Did you replace any lines. Th e new ones are junk I found th e hard way.
Only way i got rid of that problem on a 2k jimmy was to use copper flare washers. Could be the wheel cylinder is not perfect and line isn't sealing. Granger about only place to get them and th ey had to order mine. My only suggestion is flare washer on that one cylinder.
Also outside shot the bleeder is not sealing but i bet the line connection is the problem.

After all that only way i got pedal back hard was scanner with abs bleed functions.

[Aerovette]

Did you replace any lines. Th e new ones are junk I found th e hard way.
Only way i got rid of that problem on a 2k jimmy was to use copper flare washers. Could be the wheel cylinder is not perfect and line isn't sealing. Granger about only place to get them and th ey had to order mine. My only suggestion is flare washer on that one cylinder.
Also outside shot the bleeder is not sealing but i bet the line connection is the problem.

After all that only way i got pedal back hard was scanner with abs bleed functions.

Flare washer at the line inlet? I don't think I've seen a flare washer.

As for the scanner, I think that's too expensive for me to buy for a single use tool. Is there any way to trick those motors in to activation? Jumping pins or something?

[Rodnok1]

https://www.grainger.com/product/5WRW0?gucid=N:N:FPL:Free:GGL:CSM-1946:tew63h3:20501231

Local parts stores may have in stock if get lucky.
I ended up using 5 or 6 of those just due to shitty lines and fittings(every thing was new frt to back).
I couldn't get the air out of th e back brakes. What's stupid is you'd think there would be a leak of fluid.

Depends on model, since that truck has abs bleeders probably don't need a tool but i haven't done that yr/model so you'd have to look it up if don't have a good pedal after bleeding.
Some vehicles it's absolutely needed or never get pedal right again. I didn't want to spend the money either but 125/150 vs taking somewhere just to bleed the pump.

[Mike Mercury]

After all that only way i got pedal back hard was scanner with abs bleed functions.

yep, that is almost a must for ABS air removal.

[Rodnok1]

yep, that is almost a must for ABS air removal.

Just depends on the year and model. My caddies don't require any special bleeding nor tools. Easiest cars I've ever bled brakes on.

[Grey Ghost]

Did you 'trip' the proportioning valve during bleed? Try resetting it.

[Aerovette]

Did you 'trip' the proportioning valve during bleed? Try resetting it.

There is no proportioning valve. I assume the ABS handles that task.

[Aerovette]

yep, that is almost a must for ABS air removal.

At $400.00 dollars, I'll delete the ABS first.

[GTOguy]

To do the job properly, you will need a scanner and to follow manufacturer's bleeding sequence instructions. Or, as you stated, you can delete the ABS and install an adjustable proportioning valve and be on your way.

[Don Rickles]

For your dads safety, (no insult this time), I'd get a certified mechanic to fix his brakes.....:yesnod::seasix: