• If you currently own, previously owned or want to own an Avalanche, we welcome you to become a member today. Membership is FREE, register now!

Intermittent Loss of Power Steering

Schick

New Member
Joined
May 22, 2019
Messages
7
Location
Ellicott City, MD
I've been searching for answers to this for a few months... and now I'm just plain so frustrated that I need some other thoughts...

It all started with a power steering fluid leak. Popped the hood looked around couldn't find it or tell where it was coming from... Changed out the Power Steering Pump, and the cooler because is was well rusted and ready to go while I was in there. Bled the system as best I could and suddenly I started losing power steering until I popped the brake pedal. Bled everything again, many many many more times twisting the steering wheel back and forth. Next thing the seal on the steering gear box failed. Brought the truck to the shop and had them change out the steering box.

Still had the occasional bump in power steering loss, but it was pretty intermittent. Suddenly my ABS light is on and now I seem to be having more and more episodes of losing power steering until I bump the brake pedal... :E: :E: :E: :E: :E:

:help: PLEASE tell me someone here has a new place for me to look! I love my truck, but this has be to the point of frustration that I'm considering the unthinkable and getting ready to drive it off a cliff! :help:

:B:Schick :B:
 
Sounds like a vacuum leak. Does the steering system hold a vacuum?  https://mechanics.stackexchange.com/questions/25133/how-is-a-power-steering-pump-vacuum-leak-test-performed
 
Your truck has power brakes where the power is suplied fro mthe power steering pump.

So this hydraulic brake booster could be bad.
 
Sorry for not replying sooner - been out of town.

@BainMan There's no vacuum... it's a hydroboost setup.

@ygmn - would the bad brake booster also cause the steering to drop out randomly? Could this also be caused by a bad ABS controller (yet another expense issue I need to deal with)?

Typically when the steering drops, it feels like it's only bad in one direction... if I start to turn the opposite way it also seems to free up, (assuming I'm going slow enough to move it that way). Is it possible there's air getting into the booster? I would think the loss of steering would come from a pilot valve sticking, or something but the whole gearbox is brand new.

Bottom line it's a pair of relatively simple hydraulic systems, but finding this problem is so painful!!
 
2 simple hydraulic systems operated by a single pump.
SO yes it is possible if one fails it effects the other..

Now I have a 2002 so the hydro-boost is not in my wheel house only what I read on here...
 
Schick said:
@BainMan There's no vacuum... it's a hydroboost setup.

Oh, didn't realize that, thanks! You mentioned an ABS light, what code are you getting with a scan tool?

Are there bubbles or aerated fluid seen in the reservoir when turning the wheel from lock to lock? 

edit: Is your belt-tensioner and belt in good shape?
 
After chasing this around and around... and for whatever reason I'm hoping this is true...

rims were shot which was causing tires to not hold pressure. hydraulic system must just have barely enough power to handle the job, because new tires seem to have eliminated the issue. :eek:

Thank you everyone for the support!!
 
When you got a hydro boost power brake system you have to keep in mind, the boost comes from the power steering pump. I just replaced mine and had to bleed the system and flush it as best I could. I learned that when flushing the booster it returns fluid to the pump when the brake pedal is released (that's when fluid came out of the disconnected return hose on the booster) I got the old fluid out and went to flush the gear box and fluid shot all over the place so I figure it's flushed... the pump was nearly empty! After refilling the pump I turned the wheel (not the steering wheel) not quit stop to stop several times until I no longer heard the air in the system (engine was off) this was with all hoses reconnected, topped off the fluid in the pump and did the brake pumping again to get rid of air in the booster, then shut it off and repeated everything 2 more times keeping the pump full (prolly over kill but I got the air out!) Oh yeah, have the front wheels off the ground while you do this unless you got a RED "S" on your chest!
 
Back
Top