hydroboost idle issues

[jp0863]

Just installed hydroboost on my suburban. aside from the pulley removal and install everything went smoothly. While trying to bleed the system anytime I apply the brakes it damn near kills the engine at idle. I can't imagine this is normal... did I do something wrong? Its a new pump..

 

[Larry]

Just installed hydroboost on my suburban. aside from the pulley removal and install everything went smoothly. While trying to bleed the system anytime I apply the brakes it damn near kills the engine at idle. I can't imagine this is normal... did I do something wrong? Its a new pump..

Did you remember to plug the vacuum port when you removed the vacuum booster? An item that is worth mentioning is the proper way to bleed power steering and hydroboost. Pretty much 90% of people think just starting the engine and turning the steering wheel back and forth is the proper method to bleed the system. The actual correct way to bleed the system according to steering engineers I work with is to lift the front wheels off the ground, start the engine and turn the steering wheel lock to lock 2 or 3 times then, turn off the engine, exit the vehicle and turn the wheels lock to lock about a dozen times by using the actual tire/wheel. The difference is the motion and pressures inside the box initiated by the movement of the pitman side of the gear box instead of the selector shaft side (steering wheel side). When it was explained to me it made perfect sense but I don’t recall all of the details but has something to do with creating high and low pressures inside the box to push the bubbles out. That procedure works great the first time, every time....

 

[sweetk30]

getting air out of system on p/s and hydro boost is most of the time done wrong. your NOT to do it with the engine running and letting air get n the system .

I have and other have posted up on bleading out p/s system before .

 

[jp0863]

Ive always done it with the engine running, ill try without when I get home... and yes I plugged the vacuum port at the manifold.. would air in the lines cause the excessive load which almost kills engine?

 

[jp0863]

Here's the latest.. Although it no longer places an excessive load on the engine, the steering is difficult at best, unless I rev the engine slightly. Does this mean I still have air in the lines? I have tried moving the tire back and forth, steering wheel back and forth, it's just pushing fluid without air in it... Any thoughts? Do I need to start over? If so is it best to drain the fluid from one of the return lines or somewhere else?

 

[beags86]

Rebleed. Most likely air. Jack up the front and cycle 20-25 times. Yes that many, it can take that much.

Edit: I found that making sure you use a quality oil matters to. Some cheaper oils could foam up.

 

[ashman]

Mine took a long time to bleed too. I'd guess that is the issue. Make sure you aren't running low on fluid too.

 

[1-ton]

If there is air still in the system, your fluid will be frothy. Check to make sure your lines are not hooked up backwards. Sometimes people modify their steering pumps by drilling the pressure valve out to a larger size. I am not saying this has been done to yours, but if it has, this modification does not play nice with Hydroboost.

 

[jp0863]

Everything is hooked up properly and there is no frothy fluid, I guess I'll start over and see what happens... I've cycled the steering about 100 times, even had my daughter help.

 

[ashman]

Here's the latest.. Although it no longer places an excessive load on the engine, the steering is difficult at best, unless I rev the engine slightly.

Just spit-balling here, but is it possible your pump is just worn out, or maybe your pulley is too big?

If everything is fine if the pump is spinning faster maybe a better pump or smaller pulley would solve the problem.

 

[mrk5]

Here's the process I follow:

How to Bleed

1. Do not start the engine until the system is fully bled. Doing so may cause damage to the power steering components. Pump internals are metal on metal. Any air in the system can cause metal to metal contact and damage.
2. Raise the front wheels off the ground, or remove the pitman arm or tie rod.
3. Turn steering wheel fully to the left.
4. Fill fluid reservoir to “full cold” level. Leave cap off.
5. With an assistant checking the fluid level and condition, turn the steering wheel slowly and smoothly lock to lock until fluid level drops in pump reservoir. If fluid level has not dropped, no fluid has moved through the system. This normally indicates a large bubble in the reservoir or pump. Until this bubble passes, no fluid will circulate through the system.
   
   — On systems with coolers, winches, or Rock Ram assist you may need to cycle in excess of 40 times.
   — Do not turn the steering wheel fast as this will cause the fluid to overflow the reservoir. Trapped air may cause fluid to overflow. Thoroughly clean any spilled fluid to allow for leak check.​
6. Check fluid constantly to ensure proper level and that no bubbles exist.
   
   — If you see any signs of bubbles, recheck all connections then repeat the steps above.
   — Fluid level should be steady (Rock Ram’s level will vary slightly).​
7. Disable engine from starting. (Non Hydro Boost Brake Systems)
   
   — Crank engine several revolutions. If fluid level drops, there is compressed air trapped in the system. Repeat above steps until fluid level is stable.
   — If fluid foams while cranking, wait 10 minutes or more until dispersed air has time to accumulate and purge through the reservoir.​
8. Continue above steps until fluid level remains constant and no air bubbles are visible.
9. If you have a hydro boost brake system continue, if not skip to Step 11.
10. Hydro Boost Systems Only
    
    — Discharge the Hydro Boost brake unit by performing three full presses on the brake pedal.
    — Watch power steering reservoir for any bubbling, foaming or burping.
    — Once foam clears, crank engine until it just catches and shut off.
    — Discharge Hydro Boost unit with three full presses of the brake pedal.
    — Repeat these steps until no air or foam is seen in the reservoir.
    — If brake pedal feels soft, spongy or funny, system is not fully bled.
    — Repeat above steps.​
11. Enable engine to start. With engine idling, maintain fluid level.
12. Reinstall reservoir cap.
13. Return wheels to center.
14. Lower front wheels to ground or reinstall pitman arm or tie rod if removed in Step 2.
15. Run engine for two minutes. Turn steering wheel in both directions.
16. Do not hold steering wheel against the stops.
17. Verify the following conditions:
    
    — Smooth power assist
    — Noiseless operation
    — Proper fluid level
    — No system leaks
    — Proper fluid condition
    — No bubbles, foam, or discoloration​

If all conditions are satisfied, the bleeding procedure is complete.
If any problem exists, turn off engine and see Special Conditions below.