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Discussion Starter · #1 ·
I got a old hydro boost and rebuilt it and put it in the truck and now my brakes aren't working like they should. There is not anymore bubbles coming from the power steering reservoir so I believe I got all the air out. I did also drain the power steering pump and replace the lines going from the power steering pump to the hydro boost. It steers fine but when I press the brakes they feel firm but just don't want to stop. When the truck is off and you have pressure on the brakes when you start it up the pedal will go to the floor, but once you let the pedal come up the brakes firms up. I also bled the brakes, I'm thinking maybe my hydro boost is bad since it isn't the one that was on my truck.
 

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I have my old leaky one laying in the garage yet that is meant for an LBZ, wanna try and rebuild that one?
 

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Discussion Starter · #3 ·
OK I had my dad check it out and the brakes are better after flushing everything, but when we accelerated from a a stop it seems the brakes might be grabbing. When the truck is at a dead stand still the steering is like manual (no power). I think it may be the pump because it was low on fluid when the issue started. I think I may buy a pump but hate to spend the money if it is something else.
 

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I bought a delco replacement off of ebay for half dealer cost if you go that route,
 

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OK I had my dad check it out and the brakes are better after flushing everything, but when we accelerated from a a stop it seems the brakes might be grabbing. When the truck is at a dead stand still the steering is like manual (no power). I think it may be the pump because it was low on fluid when the issue started. I think I may buy a pump but hate to spend the money if it is something else.
In your first post you said the steering was OK?

How did this all start? Was the old hydro unit leaking?
 

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Discussion Starter · #6 ·
Yes it was leaking and I replaced it. I thought this was the cause of my steering not wanting to turn while the truck is still. Also while braking my truck would randomly lose pressure in the brakes for a few seconds but it would only happen like once a week.
 

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Can you increase engine speed & regain power assist? If so....Most likely a worn pump or stuck regulator.
 

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Discussion Starter · #8 ·
Yes as soon as I move forward it will turn
 

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Discussion Starter · #9 ·
My grandfather says he thinks its the steering box
 

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Discussion Starter · #10 ·
Well I've replaced the hydro boost, power steering pump, and gear box and the brakes aren't working right, it's like there's still air in the lines but there's no bubbles in the reservoir. Any ideas?
 

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The unit you rebuilt, was it from the same year truck with a diesel, i think the gas and diesel versions are different, also the push rod length can be different, causing issues. What all did you rebuild on the unit?

Sent from AutoGuide.com Free App
 

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Discussion Starter · #12 ·
It came from a friends duramax. I just replaced all the seals.
 

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When you bled your brakes did you accidentally get the reservoir too low and suck some air? You may have air trapped in the cylinder and need to bench bleed the master cylinder before bleeding each caliper. You will also need to be able to activate the ABS to get any air out of that module as well.
 

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Discussion Starter · #14 ·
I haven't messed with the brakes just the hydro boost gear box and powersteering pump
 

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Your first post says you bled the brakes so that is what made me think possible air entrapment in the master cylinder or the ABS module.
 

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Discussion Starter · #16 ·
Sorry about that. Yes I did bleed the brakes just because I couldn't think of anything else but I'm sure no air got in the lines I only bled maybe few ounces worth and no air was coming out so I stopped. I also filled the reservoir to the top before bleeding them so I'm pretty sure I didn't get any air in there.
 

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Discussion Starter · #17 ·
Is there a certain way I should have bled the power steering system? Right now the brakes are really firm and don't want to stop the truck but then if I turn the wheel a little the brake pedal will go to the floor but once I lift it up its firm again. It's like it has a mind of its own.
 

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When I put new seals in my hydroboost unit I referenced the instructions from piratejack.net.

This is what they say to do to bleed it:

BLEEDING HYDRO BOOST
1. Fill Power steering reservoir.
2. Crank engine for several revolutions (do not allow engine to start)
3. Check reservoir level. Add fluid if necessary
4. Start engine. Turn steering wheel to left stop, then to right stop.
5. Shut off engine and discharge accumulator. Depress pedal. Repeat 4 or 5 times.
6. Repeat Step 4
7. If fluid is foaming, shut engine off and wait for one hour.
8. Repeat Step 4
9. Check reservoir. Add fluid if necessary.

Other than that, just be sure you assembled the unit properly. As you know since seeing the inside of it, there are numerous springs and valves and pistons. Reference the pictures in this write-up.
 

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I just replaced all my brake lines to SS and bled them very well but braking was still shitty. A friend of mine hooked it up to a scanner and cycled the abs module several times. 100% awsomer! Give that a try.

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Discussion Starter · #20 ·
When I put new seals in my hydroboost unit I referenced the instructions from piratejack.net.

This is what they say to do to bleed it:

BLEEDING HYDRO BOOST
1. Fill Power steering reservoir.
2. Crank engine for several revolutions (do not allow engine to start)
3. Check reservoir level. Add fluid if necessary
4. Start engine. Turn steering wheel to left stop, then to right stop.
5. Shut off engine and discharge accumulator. Depress pedal. Repeat 4 or 5 times.
6. Repeat Step 4
7. If fluid is foaming, shut engine off and wait for one hour.
8. Repeat Step 4
9. Check reservoir. Add fluid if necessary.

Other than that, just be sure you assembled the unit properly. As you know since seeing the inside of it, there are numerous springs and valves and pistons. Reference the pictures in this write-up.
What does it mean discharge the accumulator? How do I do this?
 
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