hydroboost

[Boonie]

ok, I'm replacing the kingpins on my k30, and noticed the brake lines should also be replaced. always a hidden surprise. lol. anyway, I have searched how to bleed the brakes on a hydroboost, and if I'm understanding what I keep finding, this system should self bleed by turning the steering wheel back and forth? this seems to easy, is this actually correct? thanks in advance for any help

 

[Blue Ox]

That sounds like the procedure for bleeding the power steering. Hydroboost brakes bleed the same as regular brakes.

 

[highdesertrange]

that's for bleeding the hydraulic side of the booster. for bleeding the brakes it's the same as any other brake system. many have their own preference on how to bleed brakes. basically they all will work if done right. highdesertranger

 

[Boonie]

ok. that's what I thought, but somehow kept twisting the two around. thanks again

 

[MOguy]

You bleed the hydraulic different then the vacuum. One you have to bench bleed the other you don't. I can't remember which is which but the one that needs bench bleeding should come with a couple little nipples and little hoses so when you bench bleed it you can run the little hoses back into the reservoir and not waste your brake fluid.

 

[Frankenchevy]

You bench bleed the master cylinder. No vacuum involved. As said before, the brake system bleeds just the same as any hydraulic brake system. Once you’ve bled the master cylinder, start at the closest wheel to the master cylinder and work your way to the furthest. I’m weird and like to go through twice.

If you don’t open any lines pertaining to the power steering or hydroboost, you don’t need to worry about that. Even if you did, you just go lock to lock repeatedly making sure the power steering reservoir stays topped up.

 

[Snoots]

Here's what I used . . .

GM’s bleeding procedure from their service manual.

If equipped with hydro-boost, fully charge the hydro-boost accumulator using the following procedure:

Start the engine.
Firmly apply the brake pedal 10–15 times.
Turn the engine OFF.

Raise the vehicle until the front wheels are off the ground. Refer to Lifting and Jacking the Vehicle.
Key on, engine OFF, turn the steering wheel from stop to stop 12 times.

Vehicles equipped with hydro-boost systems or longer length power steering hoses may require turns up to 15 to 20 stop to stops.

Verify power steering fluid level per operating specification. Refer to Checking and Adding Power Steering Fluid.

Start the engine. Rotate steering wheel from left to right. Check for signs of cavitation or fluid aeration (pump noise/whining).

Verify the power steering fluid level. Repeat the bleed procedure, if necessary.

Bleed the BRAKE FLUID lines as you would any other brake system.


NOTE:

One item that everyone should pay attention to is, use POWER STEERING FLUID ONLY with a Hydroboost system.
Save the ATF for your tranny (if it's an automatic).

ATF in a Hydroboost system tends to foam/froth that causes unwanted headaches.

If your power steering fluid foams up it is likely contaminated and the system should be flushed with fresh PS fluid.

Hydroboost systems should use a cooler.

I've noticed one heck of a lot of threads by people having problems with hydroboost. In the end their problem was because they used ATF as their power steering fluid.

Once they flushed and changed fluid from ATF to PS fluid their problems were solved.

 

[Blue Ox]

X2 on the power steering fluid.

It took us three Hydroboost units before we figured out that ATF makes them leak ATF into the cab. Put power steering fluid in the third one and it's still in the truck. BTW, the manual recommended ATF.

 

[cmoore]

Good info, never heard that about ATF

 

[PrairieDrifter]

I believe your supposed to start from the farthest wheel away from the master cylinder, at least as long as I’ve known and been told.

Right rear, left rear, right front, left front.