Re: The action of the rear wheels when trying to spin one with the other on the ground….

Hey folks - have an '00 Boxster, 5 speed. I have had some noises coming from somewhere in the back (just coasting thru a parking lot w/o in gear can hear it if just have modest bumps in road surface).

Anyway, today I thought I would jack up the car (I only have the jack that came w/ the car - so 1 rear wheel @ a time is all I can do). My plan was to get the tire off ground and then basically see if when i jiggled the whole wheel up/down I could hear anything odd. I didn't really get much out of that - there was some noise when pushing down hard on the wheel when it was off the ground - as the shock fully extended. But I don't think w/ the normal range of travel in the shock that would be heard. So, in the end, I couldn't find the noise I was looking for.

But.......I did notice when trying to spin the wheel...........if I spun it in the reverse direction, it would spin pretty well/easily. But when trying to spin the wheel in the forward direction (way car normally travels), it was much more resistant. Yes, it would spin, but w/ a lot more effort. Is this normal? Why would this be? I found same w/ both rear wheels.

Thanks

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bb1
Hey folks - have an '00 Boxster, 5 speed. I have had some noises coming from somewhere in the back (just coasting thru a parking lot w/o in gear can hear it if just have modest bumps in road surface).

Anyway, today I thought I would jack up the car (I only have the jack that came w/ the car - so 1 rear wheel @ a time is all I can do). My plan was to get the tire off ground and then basically see if when i jiggled the whole wheel up/down I could hear anything odd. I didn't really get much out of that - there was some noise when pushing down hard on the wheel when it was off the ground - as the shock fully extended. But I don't think w/ the normal range of travel in the shock that would be heard. So, in the end, I couldn't find the noise I was looking for.

But.......I did notice when trying to spin the wheel...........if I spun it in the reverse direction, it would spin pretty well/easily. But when trying to spin the wheel in the forward direction (way car normally travels), it was much more resistant. Yes, it would spin, but w/ a lot more effort. Is this normal? Why would this be? I found same w/ both rear wheels.

Thanks

is normal, I think, though I'm having a problem coming up with a reasonable explanation.

However, you have no issues with the diff while the car is on the road and the car moving, you are interested in the noises.

Better than just jacking up one side at a time is to back the car up on ramps. While the wheels/tires of course won't spin you can get under the car and with a bright light check for any looseness at the various places the rear suspension and drivetrain connect. You can trap various links and rods and sway bar links and such and give them a shake. You can maybe even give the shocks a test to see if you can detect any movement or play.

If you do not spot anything then you might want to get both wheels/tires in the air. While some like to jack/raise the car using other points other than the sanctioned lift points, I do not. The few times I have needed to raise both wheels/tires of an axle I used a 2nd scissors jack one on each side and worked one then the other to bring both wheels/tires off the ground.

Last but not least, my local dealer's service would put the car in the air if I went in with a noise or suspicion of a problem and have a tech help me check for a problem. If you have any kind of relationship with your dealer or indy shop it should do this for you. (I even had a local BMW dealer service lift my car and help me inspect it when I hit some debris on the freeway near the dealer. And the BMW dealer refused any payment for this.)

Thanks. Yeah mainly I opened this post just about the extra friction when spinning the wheels.

As to the noises I'd been hearing in the car - yes, I have had a shop check, w/ me standing around trying to help, and they weren't able to find anything loose or that made the kind of sound that can be hear (when banging/jiggling around on stuff under the car). It's frustrating, especially when I know forums like this are so poweful w/ so many people who love their cars. I would think has to be common enough w/ so many folks w/ high mileage cars by now w/ these older Boxsters.

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bb1
Thanks. Yeah mainly I opened this post just about the extra friction when spinning the wheels.

As to the noises I'd been hearing in the car - yes, I have had a shop check, w/ me standing around trying to help, and they weren't able to find anything loose or that made the kind of sound that can be hear (when banging/jiggling around on stuff under the car). It's frustrating, especially when I know forums like this are so poweful w/ so many people who love their cars. I would think has to be common enough w/ so many folks w/ high mileage cars by now w/ these older Boxsters.

with the differential. Differentials are funny devices in they have to allow the two rear wheels the ability to rotate at different speeds -- when turning the car -- and yet transmit power from the engine/tranny to the rear wheels. They must do this over and over again with no driver intervention whatsoever. They must do this quietly. And with a minimum of attention. (90K mile fluid changes IIRC. Hardly a high maintenance item.)

In talking with techs about differential problems, and dealing with these -- via replacement -- the few that they have replaced have been done based on noise complaint by the owner and confirmed by the tech.

Absent any abnormal noises when going down the road, turning corners, I have to offer the WAG the behavior you report is normal.

As for the noises you hear from the back of the car over modest bumps on the road surface the noises can be a loose or worn or broken suspension or drivetrain component, including a shock or a spring, or a part of the exhaust system, or a loose engine/exhaust heat shield. It can even be some line or hose that has come loose from its restraining tie and is flopping about when the car encounters these bumps.

My impression is noises of this type are rather uncommon with these cars based on what I read on various forums and based on my direct experience. All I have had with my car in this area -- noise from the back of the car -- arose from a loose "brick" in a converter housing. The thing would produce a distant faint dull knocking sound upon cold start and later a higher pitched buzzing noise that had me thinking a sheet metal heat shield was the source of the noise.

Banging or pounding on the hardware may not uncover the source of the noise, if the noise is from a heavier loaded suspension or drivetrain component.

With this possibility one has to grab the various hardware and push and pull with considerable force to try to get any abnormal movement.

Another technique is with the car supported on the lift by its tires/wheels to grab something under the car or make like Atlas lifting the world and push up and pull down over and over again to get the car bouncing up and down and listening and having a co-worker listen for any abnormal sounds. I have watched a tech vigorously do this to both of my cars -- while on the alignment rack -- to help "settle" the car's steering and suspension and to check for any worn or loose hardware during an alignment.

These things eat control arms. The noise, if a clunk, manifests itself mostly while driving slowly through parking lots with undulating surfaces. You would think hard bumps do it, but you really only ear it when road noise is really low. Common, no big deal and pretty easy to replace yourself. The issue really is positive ID of the bad control arm but it is most likely that lateral arm. My links were always fine, it was the control arm for me.

It is probably the lateral arm going front-to-back. You can not tell with the car jacked as it takes quite a bit of force, a car load, to make it move.

Peace
Bruce in Philly



Edited 1 time(s). Last edit at 09/22/2014 05:41PM by Bruce In Philly (2000 S Boxster, now '09 C2S). (view changes)

I contend it's one or more of these causing it:
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