I think you're on to something. After reading this post, I did the simple test of the suspension of applying weight on each corner, and then letting go. On the back right, the resultant vibration lasts at least a full cycle before being damped out. It is stiffer on the other 3 corners, however, the right front has a little more play than the left front. There is no sounds indicating looseness of any suspension parts. But when I hit bumps, I often hear squeaking, most noticeably from the rear end; so while the suspension may not be completely worn, it has seen better days.
Now here's something else I've noticed: sometimes when I hit a bump in the road, there tends to be a momentary jerk and pull to one side, usually towards the left. It's not as dramatic as the problem I described earlier, but it's perceptible. I suspected that because there is momentarily less weight on one of the front wheels when hitting a bump, the more heavily weighted wheel gets better traction for an instant and the car responds accordingly. But maybe it has something to do with momentary misalignment like Jason brought up.
The primary jerking problem, however, is related to engine speed (not car speed), so my befuddlement continues. The jerking has gotten a little worse since my left tie rod was replaced last week - that may be due to a firmer, completely slop free tie rod.
I'll have to ask the shop that did the timing belt replacement in March if they took off the power steering pump. Daniel is probably right, the pump need not be taken off to replace the timing belt.
Thanks for all the help guys. Further comments appreciated.
Mike
: > In March I had a timing belt replaced on this car. The power steering pump : > had to be taken off and put back on to do this. Soon a problem became : > evident that I had not experienced before. The car now jerks to the left : or : > right very abruptly and momentarily. The jerking is not continual - but it : > certainly seems to be related to engine speed. It will predictably jerk to : > the left on an increase in engine speed at a certain point, and will jerk : to : > the right a little less violently on falling engine speed (note: engine : > speed, not car speed.) In other respects, the car's steering works : perfectly : > normally. : >
: > I've now ruled out other suspected causes of the momentary jerking such as : > worn CV joints, poor alignment, a newly crimped hose, or obstructions in : > either of the power steering actuating mechanisms. Also, there is no : > external pump leakage. So the only reason I can think of for this problem : is : > that the mechanic inadvertently damaged the pump when putting it back on : > somehow. Probably it ran dry or partially dry for just enough time to : damage : > something. : >
: > A worn tie rod was replaced on this car last week. And the jerking's even : > worse now. : >
: > I have a Mechanical Engineering degree from 1981, and I recall learning : > about surges in compressors; but my vague recollection is that surging : > applied to equipment moving only compressible, not incompressible, fluids. : >
: > What seems sure to me is that my power steering pump's output pressure : > pulsates at a certain engine speed rather than vary smoothly like it used : to : > and should. Anyway, does anyone have any insights to offer on this? Looks : > like my only hope is to have the pump replaced. Thanks in advance. : >
: > Mike : : . Your problem sounds like worn or loose suspension to me.Under : acceleration, there is a lot of torque applied to the drive-shafts and if : there is movement in the frontstruts, this torque is causing the strut move : out of geometric position (toe, camber and/or caster), then on override, the : position reverses. : : I'm not saying it cannot be the PS,..it just seems more like a : suspension/steering problem. : : Its normal for torque-steer to occur to some extent in front-wheel drive : cars,.and in mine ('96 Camry-4 cyl) it will jerk to the left (not : dangerously so) under heavy acceleration. However I haven't experienced the : opposite when the engine backs off. : : Jason : :