Help diagnose a power steering issue on my 99' GMC

[txgp17]

The truck:
1999 GMC K-3500 (old body style), 5.7 engine, 4L80-E, with hydroboost brakes, 232,000 miles, I'm the original owner, this is the OEM power steering pump original to the truck.

Lately, if you turn the steering wheel fast while driving slowly, there's a popping sound coming from the power steering. Like whenever I'm maneuvering in a parking lot or backing into my driveway at home. High demands from the steering system, with low engine RPM. The PS pump is not whining, the fluid level is good.

I also noticed, while sitting still and not touching the steering wheel, that if I press the brake pedal lightly, there is no sound. But if I press the brake pedal firmly, the popping sounds start. The firmer I press the brake, the louder the popping sound becomes, and you can feel pulsations in the pedal at the same pace as the popping sound.

Does anyone have a suggestion on what the problem is? Thanks in advance.....

 

[GoToGuy]

I believe since it happens, popping noise with brake application or steering input. This is a pump problem. Hydro boost brake has no connection to steering other hydraulic. The only thing link on two different systems is the pump. And the abnormal sound when high demand requested. High pressure.
Have someone touch the pump and and simultaneously run your test again to create the sound condition. I think it's a pump that needs looking into.
Also is your pump have the EVO on the back, some 3500 series do not have EVO and rather have higher output pressure than lighter trucks. Good luck.

 

[Schurkey]

Verify the belt condition, and belt tensioner. If they're good...the pump and/or the pressure control is probably toast.

 

[weaponoffreedom]

my guess would be ABS related due to the pulsation, popping while turning? Have you ever replaced the cv axles?

 

[txgp17]

my guess would be ABS related due to the pulsation, popping while turning? Have you ever replaced the cv axles?

Yes, the CV axles were replaced a few years back. It got all new control arms because the ball joints were shot. They were replaced on both sides.

This is a good point because the pulsation seems to NOT be directly tied to engine speed. Yes, it occurs at slow engine speeds, but it does remind me of when the ABS engages. Something I usually only experience on snow or off-roading. Also, it doesn't seem to be throwing any trouble codes, or my check engine light bulb is burned out.

Also, I read a little on the EVO thing, and that GM offered a bypass kit because it wasn't needed. This is something I never knew about beforehand.

Verify the belt condition, and belt tensioner. If they're good...the pump and/or the pressure control is probably toast.

The tensioner, idler pulley, and belt were all recently replaced, along with a new thermostat.

 

[GoToGuy]

my guess would be ABS related due to the pulsation, popping while turning? Have you ever replaced the cv axles?

Tell us how the ABS relates to this condition when turning the wheel quickly at low speed, no brake application?
The sound / noise occurs at standstill with firm brake application, relates to half shafts/ cv in what way?
Try using systems knowledge. 98 service , book 2 section 5.

 

[Erik the Awful]

I'd also check the ball joints, tie rod ends, and anything else.

 

[Big T]

The truck:
1999 GMC K-3500 (old body style), 5.7 engine, 4L80-E, with hydroboost brakes, 232,000 miles, I'm the original owner, this is the OEM power steering pump original to the truck.

Lately, if you turn the steering wheel fast while driving slowly, there's a popping sound coming from the power steering. Like whenever I'm maneuvering in a parking lot or backing into my driveway at home. High demands from the steering system, with low engine RPM. The PS pump is not whining, the fluid level is good.

I also noticed, while sitting still and not touching the steering wheel, that if I press the brake pedal lightly, there is no sound. But if I press the brake pedal firmly, the popping sounds start. The firmer I press the brake, the louder the popping sound becomes, and you can feel pulsations in the pedal at the same pace as the popping sound.

Does anyone have a suggestion on what the problem is? Thanks in advance.....

Do you post on TheTruckStop.us? If not see posts 3443 and 3488 on steering box popping:

What did you do with your GMT400 today...or yesterday....

The TAN/WHT goes straight to the PCM and does not splice to anything else except the ring term ground. Be careful probing.

www.thetruckstop.us

He rebuilt the steering box out of necessity, but it sounds like an interim thing and will have to get a reman unit.

 

[62barsoom]

I had a similar occurrence on our 05 suburban. When you took off it'd occasionally do this weird stutter, shudder thing. Local shop said take it to the dealer, dealer said I needed this $800.00 steering sensor. My buddy found a anti lock wheel sensor in one front hub had rusted a bit and pushed itself out just enough to make the anti lock system weird out. Might be worth looking at.

 

[weaponoffreedom]

Tell us how the ABS relates to this condition when turning the wheel quickly at low speed, no brake application?
The sound / noise occurs at standstill with firm brake application, relates to half shafts/ cv in what way?
Try using systems knowledge. 98 service , book 2 section 5.

I see now that my post was incomplete, ever thought something and thought you said it but didnt? At the ABS portion of my post I forgot to also add Hydroboost. As in ABS\Hydroboost.

Try using systems knowledge. 98 service , book 2 section 5.

Sounds to me suspiciously like you are asserting something there, like you have the answer and yet I see no suggestion from you. I suggest, rather than arguing from a point of authority, with your "look at a book" section whatever.........add something to the conversation, and not start with your "tell us" BS. I am new here and just looking to gain knowledge, not argue. Furthermore, read the OP where they state that the pulsing is also at a standstill. "The book" says that a symptom of a bad hydroboost, is the pedal pulsing when you push the brakes. The popping sound could be the accumulator. What exactly is 98 service, book2 section 5? Is that something worth noting here? If so then why not note it, it not why bring it up?

I'm the original owner, this is the OEM power steering pump original to the truck.

Is the hydroboost original? Please look at the first parts of this reply, including my reply to @GoToGuy as I forgot to mention Hydroboost originally. Sorry. I had a similar pulsing iwth my Suburban, deleted the ABS fully (removed the whole unit and prop valve) issue went away. I did not have a popping, but my Hydroboost works well, and is original. Hope this helps.