New Hydroboost issues

[C30Seenafew]

Hey All!

Installed new hydroboost unit w/master cylinder, plus new pressure lines.

I have two issues;
1) bleeding the system: I've been using the PDF Bleed instructions from Lares. Still getting lots of foam in the power steering pump. What am I doing wrong?
2) I have little-to-no brakes.
3) Why is my dashboard "Brakes" indicator panel light remain on?

Any help in this topic is welcome.
Thanks!
Wayne

[VileZambonie]

Why did you replace it? Is it the same issue you were having prior to replacement? Is it plumbed correctly? Is the power steering pump working and belt tight? Did you use the correct fluid? Explain the process you used to bleed? The brake warning lamp will be on if the pressure differential valve is not centered or if the park brake is set.

[C30Seenafew]

I've never owned a Chevy with a hydroboost. I learned to live with the extreme touchiness of the brakes. I never had a full pedal from the moment I bought the truck, but the brakes worked.
Then I started having trouble steering when making a turn. I was told by a mechanic, the hydroboost unit was bad.
The power steering pump, and gearbox, was replaced after I had an accident, and the brakes adjusted but no joy.

As far as I know, the lines are in stock locations.
One line is pointed 45ş towards the passenger side of the truck. It is connected to the power steering gearbox, (the larger of the two ports).

The other hose is point 90ş counter-clockwise from the first, and is connected to the power steering pump.
The third line must be a low-pressure return line that tees into a return line from the gearbox, back to the pump.

When I replaced the hydroboost unit, I used the original lines. They were leaking because when I fired up the truck, the two high-pressure lines were spraying fluid around the tube nuts. I replaced those two lines and there is no leaking. (some progress, anyway). I have assumed the pump works from that object lesson.

Here's the process I used to bleed:
1. Jack the vehicle up so the front wheels are off the ground.
2. Make sure the steering wheel is centered, then start the engine.
3. SLOWLY turn the steering wheel to the right 1/2" from center, then turn left the same amount.
4. Continue to do this SLOWLY, increasing the amount you turn the wheel 1/2" at a time. Do this until you are lock-to-lock.
5. If you get small bubbles appearing in the fluid, shut off the engine and wait for them to disappear.
6. Keep doing this until no bubbles appear.
7. Once you have gone through this process, the steering and brakes should work.
(From the Lares Corporation website)

What pressure differential valve? Is that the same as the proportioning valve?
My original master cylinder did not have a proportioning valve. Not in the traditional location, (attached to the master cylinder), anyway.

The parking brake is off.

Maybe my avatar should say this; "I know just enough to keep professional mechanics employed."

 

[VileZambonie]

Fill oil reservoir to proper level and let oil remain undisturbed for at least two minutes.

Start engine and run only for about two seconds.

Add oil if necessary.

Repeat above procedure until oil level remains constant after running engine.

Raise front end of vehicle so that wheels are off the ground.

Increase engine speed to approximately 1500 rpm.

Turn the wheels (off ground) right and left, lightly contacting the wheel stops.

Add oil if necessary.

Lower the vehicle and turn wheels right and left on the ground.

Check oil level and refill as required.

If oil is extremely foamy, allow vehicle to stand a few minutes with engine off and repeat above procedure.

Check belt tightness and check for a bent or loose pulley. (Pulley should not wobble with engine running).

Check to make sure hoses are not touching any other parts of the truck, particularly sheet metal except where design calls for a clamp.

Check oil level, filling to proper level if necessary, following operations 1 through 10. This step and Step d are extremely important as low oil level and/or air in the oil are the most frequent causes of objectional pump noise.

[C30Seenafew]

Once I lower the front end and the wheels are back on the ground, and there are still bubbles in the pump, how far back up the procedure list do I go? Do I have to jack the truck up again, or do I go from the point with wheels on the ground? Thanks!

[VileZambonie]

As long as the pump is working and fluid is correct, like you didn't put brake fluid in there or something, then it will just bleed itself by turning lock to lock and then letting it rest.