jslarks Posted June 21, 2017 Share Posted June 21, 2017 Long time reader, first time poster... I have been upgrading my R50 (by necessity and by desire to make it more offload ready) and have come across an issue that I can't figure out. I had a steering rack leak and ran out of fluid to the point of squeezing / whining a couple of times. I replaced the rack and the rack and it no longer leaks, but the pump groans when under load - i.e., not moving and cranking the wheel or at the far ends of tight turns. In addition to the steering rack I have replaced all suspension, control arms, tie rod ends, strut mounts, ball joints, etc. - but not all at once. All along I have had a shimmy I could feel at the steering wheel and kept thinking "oh, this is going to fix that" as I upgraded and replaced things, but still have a shimmy that is not consistent. I even replaced the power steering belt thinking it was worn or glazed, this solved the issue for a few days, but the shimmy is back. Is it possible that the pump was damaged and now causes a "surging" in pressure that can be felt at the wheel?? I guess I think of a bad pump as a leaky pump, but it does not leak. Tires have been balanced twice, alignment is good and tracks fine, but the shimmy comes and goes to varying degrees and the pump still groans under load or when hot. My vehicle has really come to life and drives great with with exception - THE SHIMMY!! Link to comment Share on other sites More sharing options...
Exorpmtech Posted June 28, 2017 Share Posted June 28, 2017 Noisy pumps are usually caused by two things. Either a bad pump or the system is sucking air, generally the line from the reservoir to the pump is sucking air. If the fluid isn't aerated(full of micro bubbles) then it's probably just a noisy pump, which can happen if you run the system low. As far as the 'shimmy' in the wheel I would check a c few things. Check for a bent wheel or out-of-round tire. You'd need to get it in the air or have a tire place carefully check each wheel on the balancer. From there it could brake rotors but usually you'd notice quite a bit more vibration under braking. The last thing is front wheel bearing loose or very worn out CV shafts will cause a shimmy. Let us know what you find. 1 Link to comment Share on other sites More sharing options...
jslarks Posted June 28, 2017 Author Share Posted June 28, 2017 Wheels, tires, suspension, ball joints, linkage, CV shafts, steering rack, etc. are all new and the shimmy was there before and after these items were installed. It's not the brake rotors since it only happens at higher speeds with no change when braking. I did find one wheel bearing loose and adjusted with no improvements. For a few days I thought I had it fixed when I replaced the power steering belt after thinking the old one was worn or glazed. The shimmy came back a few days later which led me to think that it's the pump, but I don't know enough about the internals of the pump to know if it could surge and cause shimmy at the wheel and not the whole vehicle. I only feel it at the steering wheel. Link to comment Share on other sites More sharing options...
Slartibartfast Posted June 29, 2017 Share Posted June 29, 2017 All I can think of (and keep in mind, this is just a guess) is that maybe the pump has a tight spot, so it catches as it goes around, making the belt slip just a little each time. Each time the pump binds, and the belt slips, the power steering system pressure falls, and the varying pressure is what's giving you the shimmy. The new belt would've forced it past this tight spot, for a while, until the strain made it glaze like the last one and it started slipping again. If you take the belt off and turn the pump by hand, does it turn freely all the way around, or does it feel like it's binding? I'm not familiar with belt routing on the R50s, but if the PS pump has its own belt, I'd try removing the belt and driving it around the block without power steering. If it still has a shimmy, it's not the pump. If the shimmy is gone, then yeah, my money's on the pump. In any case, it does sound like your steering pump is damaged, and replacing it wouldn't be a bad idea. If it eats itself, all those metal fragments are headed into the rack you just replaced. Link to comment Share on other sites More sharing options...
jslarks Posted August 7, 2017 Author Share Posted August 7, 2017 Well, a new remanufactured power steering pump took care of the issue. I have about 1200 miles (combined on and off road) on the new pump and haven't felt any shimmy at the steering wheel. I found a rebuilt pump for around $100 and spent about 2 hours installing - everything is good after the swap. I cracked open the old pump to see what might be the problem, but didn't see anything dramatic. The vanes seemed stickier than what I think they should be, but really do not have point of reference - no major scoring, no discoloration, no detectable slop, but it sure pumps better. Mystery solved, case closed. J 5 Link to comment Share on other sites More sharing options...
Citron Posted August 8, 2017 Share Posted August 8, 2017 Thanks for the update. Link to comment Share on other sites More sharing options...
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