gaazmon

2008 CLK550 coupe. When I'm reversing my vehicle at slow speeds and turning the steering wheel all the way to the left and backing up, I hear a groaning noise from the passenger side wheel area. It sometimes does it when I'm moving forward and have it turned all the way to the right, but its more common with the reversing. Also, when I am braking on a somewhat steep downhill, as the vehicle comes to a complete stop, the groaning noise can also be heard from the passenger wheel area before coming to a full stop. The strut, upper and lower control arms, and sway bar links were changed about 26k - 27k miles ago so I don't know if any of those can be the issue again. Couldn't see any leaks on the strut the last time I was at the tire shop and they had the wheel removed. I had the same issue on the last set of front tires so don't think that is a cause. I'm wondering if it could be a steering issue (steering fluid, steering pump, or steering rack) or if it is the more likely culprit of a suspension component. Anyone experience this before? My indy couldn't see anything wrong last time when I had stopped by quickly, so will try to go by again when he has time to take a longer look at it and take things apart. Thought maybe the wheel bearing is bad, but I don't hear any odd noises when going straight or on the highway.

EDIT: Also, I notice its more so when the car has been sitting for quite some time such as in the mornings. I went over the same locations and same actions after I had already driven the car about 30 miles today and it did not make any of the noises.

Rudeney

Does the noise occur only when rolling, or even when stopped with the wheel turned to the lock? If only when rolling, it's probably in the suspension. If not, then it's probably in the pump, or possibly the serpentine belt tensioner pulley.

gaazmon

I'm quite sure it has happened in both types of instances, but will try to replicate again. Also, I will check with the A/C on and off to see if that does anything. So if it is the tensioner pulley, besides changing that and the belt, is there any other part I should have them change during the work such as the idler pulley?

I just remembered, I do also get this squeaking noise when the car is sitting at idle from the engine bay, so I am beginning to think it all points to the tensioner pulley as you mentioned.

Rudeney

If it's the pulley(s), I'd replace both and the belt. On the tensioner, replace the whole thing - not just the bearing/pulley. The housing has a spring in it and it gets weak over time.

gaazmon

Thank you for the advice and help as always.

gaazmon

After inspecting the vehicle engine while its running after warm up at idle, I can hear a sort of whining/chirping noise and from what I can tell by trying to pinpoint the noise it is coming from the #4 pulley on the diagram from the manual. It shows as the power steering and I figure most likely that means the pump is on its way out. I also get a weird sort of "blockage" when making sharp turns from one side to the other at low speeds. Let's say I'm going 5-10mph and I turn the car to the left to go around an imaginary traffic cone, then I turn it sharply to the right to go around another one but from the opposite side. As I'm turning the wheel towards the right, the wheel gets hard for a split second (as if it cuts out) and I have to force it a little to re-engage.

Rudeney

I'd invest in a mechanic's stethoscope and pinpoint it. You can get one cheap at Harbor Freight. Of course you don't press it against the moving pulley, but on its bolt or part of the block next to it. You still could have a problem with the tensioner or an idler pulley. If those are dragging, then loading up the power steering pump can cause the belt to slip.

gaazmon

Thanks again. I'll get a hold of one of those and poke around. Makes perfect sense if there is any extra stress being put on other parts of the v-belt.

gaazmon

So my indy told me that the issue is with the steering rack and that bushings are shot. My question is does the whole thing have to be changed or can just the bushings be replaced (because I know for the sway bar bushings they changed it)? He states on this one the whole thing would have to be changed, but I found that a bit hard to believe. The vehicle does have the speed sensitive steering so idk if that makes a difference because I found on the W203 forum that they were able to change just the bushings on that model.

https://mbworld.org/forums/c-class-w...iy-w-pics.html

Rudeney

There may be companies the rebuild racks, but otherwise, there are no serviceable parts on it.

gaazmon

Ah noted. I was hoping just the bushings themselves could be replaced instead of the whole rack as there are no leaks or other issues with it.