New power steering pump but still turns hard at low speed

Tiny
ELARVICK
  • MEMBER
  • 2000 GMC SIERRA
  • 5.3L
  • V8
  • 4WD
  • AUTOMATIC
  • 200,000 MILES
My truck was getting difficult to turn at low speed but mostly turning right. It also was making a "hissing" noise but only when turning to the right. I replaced the pump and bled the system correctly. A very slight improvement but basically didn't change much. Then I decided to do a flush on the system thinking that would help. Nothing changed. When I elevate the front wheels and turn the wheel with the engine off it turns with no issues or noise. I was told if the gears were bad I should be able to tell by doing this. The pump I bought was remanufactured from Autozone. What else could it be?
Friday, June 3rd, 2016 AT 4:37 PM

7 Replies

Tiny
CARADIODOC
  • MECHANIC
  • 34,330 POSTS
Which steering gear do you have? A rack and pinion assembly or a gear box? I am betting you have a rack and pinion.
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Friday, June 3rd, 2016 AT 6:14 PM
Tiny
ELARVICK
  • MEMBER
  • 5 POSTS
I just checked, it has a gearbox
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Friday, June 3rd, 2016 AT 6:58 PM
Tiny
CARADIODOC
  • MECHANIC
  • 34,330 POSTS
Rats. Your symptoms are very typical for a rack and pinion assembly, but I suppose a gear box could cause this too. The glaring clue is the difference in turning effort between the two directions. A weak pump will cause hard steering both ways, never just one way.

There is a way an improper alignment can cause hard steering one way, but that will not change over time by itself. That symptom will appear right after the alignment was done. If any repairs were made to the front suspension system, an alignment is the first thing to consider.

The next step is to use a flow gauge to measure the volume of power steering fluid flow while turning each way. If the volume is higher when turning to the right, internal leakage is taking place in the gear box. Again, that is not common with that style steering gear because a single piston is used and only the control valve can have something different for each direction. In the rack and pinion assembly, leakage in the spool valve is real common. In fact, GM had a huge problem with that in their 1980's front-wheel-drive cars. Their fix was to replace the spool valve in hopes that would make it out of the 50,000 mile warranty, then the proper repair, replacing the entire steering gear, became the owner's responsibility.
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Friday, June 3rd, 2016 AT 7:15 PM
Tiny
ELARVICK
  • MEMBER
  • 5 POSTS
Well, it sounds like its the gearbox. I can get a re-manufactured one for about $140.00 online. It does not sound like too big of a job. Thanks for the help.
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Saturday, June 4th, 2016 AT 4:50 AM
Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
One other thing check your tire pressure.
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Saturday, June 4th, 2016 AT 6:55 AM
Tiny
ELARVICK
  • MEMBER
  • 5 POSTS
I did do that and they were about 10 lbs low. Inflating them did help, but its still hard to turn at low speeds to the right.
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Saturday, June 4th, 2016 AT 8:18 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
Hey ELARVICK,

We just had this problem in the shop the box is bad, here is a video on how to change it. You will need to rent a puller from an auto parts store or get one from amazon.

https://youtu.be/KKeFqHLuRQ0

Let me know how it goes,

Best, Ken

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Saturday, June 4th, 2016 AT 8:40 AM

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