Techno Duck

Noticed a new sound last night while making a slow speed u-turn in a large open lot. Its sounds like something is rubbing, makes a faint grinding thump. Hard to explain really. Its dependent on speed, my first guess was the brake pad dragging on the brake disc a bit, but the sound does not go away with the brake pedal depressed. So my next guess is the wheel bearing. History on them is unknown as the hubs are from a 968.

I took the wheels off and the pads out (so the rotors spin freely) and can here a clicking sound once every rotation, this happened on both front wheels. Does this sound like bad bearings?

I am going to repack the bearings in my old hubs and swap the old hubs onto the car next weekend. Was wondering if anyone has ideas as to anything else it could possibly be..everything else looked fine when i went over it.

I have no vibrations or undue sounds around town or at highway speeds..only get it while doingthe low speed u-turns. Its hard to diagnose this because my car is so damn loud..

fork_included

since there is nothing else at the front of the car! :P

another way to check is go on the highway and slowly shift the weight left to right, you can be 100% certain its the bearings if the sound changes pitch.

Techno Duck

If anyone has a new wheel bearing handy i would appreciate it if you can check this for me. Is it normal to have some minor side to side play between the inner and outter portions of the bearing? What i mean is if you are holding the outter diameter of the bearing on its side, can you move the inside portion side to side? All four of the bearings i took out have this and i assume its normal. Ive handled new bearings a few months back..but honestly cant remember. These are the bearings out of the spare hubs.



They have about 75k miles on them before i took them out. Waiting on the inner seal before i repack them and swap the hubs.

KuHL 951

Even new bearings have some play in them. When they heat up they would bind if they were too snug in the cage. The most important thing to look for after you've flushed them is galling or heat discoloration anywhere in the assembly including the race.

Techno Duck

Thanks Steve.. i am guessing the bearings are still good and plan to reuse these.

I took the wheel off and there is defenetley no play at all with the wheel on or rocking the rotor.

Took a 25 mile ride back to school and no noises or anything strange to report. Before i left i did a few quick u-turns and it feels okay still..but i do notice cornering to the left is defenetley louder than the right (refering to the strange sound).

krahmlow

Well, if you're still looking for other possibilities, I once had a trained, experienced mechanic mis-diagnose bad motor mounts as a bad wheel bearing. (He insisted that the mounts "looked great"--because I specifically asked about them; but I'd better not get started). I assume you checked to see if the tire was rubbing anywhere. I don't think you should be hearing any "clicking" on rotation, though. And I believe you should have a minimal amount of lateral play if everything is adjusted correctly, but you'll probably only be able to feel it with the wheel on; it's hard to get enough leverage just pulling on the hub. Any chance the noise could be in the power steering pump?

Z-man

A tell tale sign of a wheel bearing going bad is vibration in the spring:

- Lift the wheel off the ground.
- Place your finger on the spring behind the wheel.
- Give the wheel a good spin.
- If you feel vibration through the spring, you definately have a bad wheel bearing.

-Zoltan.