2001 Chevy Tahoe power steering

LEWSTONER

MEMBER
2001 CHEVROLET TAHOE
V8
4WD
AUTOMATIC
144,000 MILES

When idling and the vehicle not moving - attempt to turn the steering wheel and it is very difficult to turn. Also the power steering whines and sounds like when you have the steering wheel turned all the way in one direction. I feel like I am fighting the power steering and then all of a sudden it will turn or if I give it a little gas it will turn. Does not happen all the time. When I jack the Tahoe up the steering turns very freely. I have replaced the power steering pump and that did not fix the problem. Replaced the rack and pinion, that did not fix the problem, replaced the power steering pump a second time and that did not fix the problem. After each replacement I purged all the old fluid and put in new. Bled the fluid each time. Still the same problem. Does not have hydro boost, does not have magna pure filter, has one pressure line and one return line. Has variable resistance steering. I have tried disconnecting the electrical connector and at low speeds makes no difference. Computer reads no codes of any kind. None of the lines are plugged or make a tight turn. Replacement pump I was told is rebuild Cardone 20-8748. I can not find any vaccum booster or connector to the pump, gear box or brake vaccum unit. Any ideas?

5 Replies

BMRFIXIT

MECHANIC
19,053 POSTS

Check power steering pump pulley may be positioned too far inboard on the power steering pump
inspect the Ps pump pulley for proper positioning on the PS pump shaft.
If it is determined that the pulley is not even /flush with the end of the shaft (+/_ 0.25mm 0.010in )
reposition Ps pump pulley
inspect belt and belt tensioner
good luck

TECHNICAL SERVICE BULLETIN

SERVICE INFORMATION
A recently completed analysis of returned power steering (PS) pumps that had been replaced for noise, no power assist, no or low pressure and leaking conditions has indicated a high number of "No Trouble Found" results.
Service Bulletin Number 01-02-32-004 indicates that when attempting to repair a power steering concern, the steering system analyzer should be utilized to assist the technician in a successful diagnosis. Note- Saturn ASTRA does not utilize the Power Steering System Analyzer.
In addition, extensive warranty analysis has shown that the following situations are all significant root causes of PS pump failures:
Improper pulley installation
Re-using the O-rings
Using fluid other than the OE-specified steering fluid
Failure to flush the PS system
In order to help improve customer satisfaction and reduce comebacks, GM recommends the following tips for replacing a PS pump:
Low or no pressure from the PS pump may be the results of dirty or contaminated fluid, which could cause the pressure relief valve to stop functioning. Using the proper tools, flush and bleed the PS system. Any residual contaminants will result in pump failure.
When removing the pulley, use the proper special tools. Because the pulley alignment is critical, distorting the pulley may damage bearings on the new PS pump.
Be sure to use only the new O-rings included with the PS pump. The new reservoir O-ring must be lubricated with OE-specific PS fluid prior to installation. Also make sure that the control valve O-ring is in its exact groove position and is NOT covering the pressure bypass hole.
Bleed the PS system according to the procedures/recommendations in SI.
Following these procedures and using the correct tools and fluids should help ensure that the new PS pump operates properly. Skipping steps may cost you time and trouble later.

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Friday, June 5th, 2009 AT 6:01 AM

LEWSTONER

MEMBER
8 POSTS

Checked the pulley and it seems to be exactly even with the shaft. However, I took a straight edge between the pump pulley and the alternator pulley, and also between the pump pulley and the engine pulley and the ps pulley seems to be approximately 1/4 inch further forward (towards the radiator) than the rest of the pulleys. Should I try to get the ps pump further down the shaft? Also, the first time I changed the pump I put a new belt tensioner and a new belt. When I replaced the pump each time I used the new o ring provided and put it exactly the same place the old ring was located, and I am pretty sure it does not cover any holes. I used a ps puller to remove the pulley and I used the nut and bold system provided with the ps unit to put the pulley on the shaft. The fluid I used was Valvoline MaxLife vv335. There does not seem to be any leaks in the system. All suggestions are greatly appreciated. Lew

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Saturday, June 6th, 2009 AT 9:26 AM

BMRFIXIT

MECHANIC
19,053 POSTS

Sorry I missed your replay
it should be flush /even with the end of the shaft (+/-0.010 in )
and if its off by � an IN I would think you have a wrong pump and also would suspect to see the belt to jump or uneven wear on it
good luck
let me know

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Saturday, June 13th, 2009 AT 6:55 AM

LEWSTONER

MEMBER
8 POSTS

The power steering pump Advance Auto sold me is a rebuild Cardone 20-8748. 2001 Chevy Tahoe 4 x 4 with variable resistence steering. 1 in line 1 out line. No vaccum assist or vaccum connection. No hydro boost, no magna pure filter. Does have the reservoir as part of the pump assembly. Serial # 1GNEK13T91J1743242. If you suggest a different brand that is OK. All info is greatly appreciated. Lew

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Saturday, June 13th, 2009 AT 5:49 PM

BMRFIXIT