Power steering feels "lumpy/notchy" (1 Viewer)

[jockaneezer]

Joe's just called by in his '04 Rodeo pick up, complaining about the power steering feeling lumpy. The oil reservoir is filled to the level and we tightened the pump drive belt to no advantage. I need to investigate further in the daylight but I did notice that the oil level in the reservoir didn't alter as we went from lock to lock and I expected it to vary, does that sound correct or suggest that the pump's not circulating it ?
Google suggests checking the column universal joints too, but again, a job for in the daylight.

 

[Kev and Carolyn]

The steering wheel shaft is connected to the steering box via a universal joint. These can and do fail. They are sometimes under the dash transmitting the action through another shaft connected to the steering box, but quite possibly it connects to the steering box under the floor.
If you can see it..with the engine off, grab and hold the steering wheel and turn as if trying to turn left to right. If the joint has failed , often there is movement noticed in the u'j in the form of ' lift or kick '. Replace to suit.
If it does not move or flex, then it will be either the pump as stated, or most likely a worn seal in the steering cylinder.
You say the oil level is on the mark? When you raise the car off the ground, steer left to right on full lock and hold it with the engine running. Then turn opposite lock and hold it with engine running. This should remove any air in the system.
Check your level. If it has dropped, there is a leak which will need rectifying first . If the system seams dry around all moving parts, it has to be either a seal within the cylinder that may be letting oil pass by giving the judder affect. Like all things moving, wear and tear comes to all. Finally... last but not least..the pump! Even though it may be turning freely and belts etc are tensioned correctly, It could easily be allowing slippage so the pressure builds up then drops off rapidly due to wear in the pump itself. This can only be checked properly with a gauge. A dealer will have one . Some where there will be a pressure reading for the pump when in the fully pressured situation.
You have not mentioned miles covered? Suggest you try the above and eliminate to suit.
Quite possible that it is a seal rather than a major failure.

Kev

 

[Kev and Carolyn]

No bud. When the seal blows internally it only allows oil to pass from one side to the other purely seeping passed its damaged seal. You won't see it ..only feel it. The oil level will stay level in its tank because it is not possibly to leak off any where. Hence my question regarding any oil leaks visible?
The system will always work until the seal gives up totally. Basically it will function ,although poorly, until the oil seal fails entirely and allows an equalising of oil across the cylinder making assisted power steering heavy has hell!
Your description leads to two possibilities..1) Seal blown 2) Pump failure due to the oil pressure passing back from the pump So it cannot pressurise the system correctly to aid steering.

Hope this sheds some sort of light for you? Picture is purely for visual aid
Kev

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[jockaneezer]

Thanks for your input fellas. Got it up on the stands last night and greased the uj's which seemed to improve things a little, but the clincher (pun intended) was the nylon bushing through the bulkhead, a squirt of spray grease both sides loosened everything up nicely.
Thought I'd have a quick check over the track rod ends and rack cylinder rubbers on the nearside and saw that the shock absorber had seized solid and had snapped the top mounting bracket in half, good job the boy's a time served welder, and if it had been a McPherson strut setup instead of torsion bars, it would have punched a hole through the inner wing. When we got the shock off, we couldn't get it to compress at all, had them leak in the past, but never seize up.
Edit: It has a hard life on forestry tracks.