Is there a quick way to check the rear wheel bearings?

Andy

don't you just jack up the rear and grab hold of the rear wheels and give them a jiggle?

too much juggle means too much wear.

it's what the PCA uses during tech inspection.

Do da jiggle....

What about regreasing the rear wheel bearings?

On the list of things to do is check and lube EVERYTHING on my race car.

Sealed bearings and you pretty much destroy them pulling the hub out.
Spin them to check for noise to.

Jack up the car, do the jiggle as above. You can also pry up on the wheel and see if there's slack.

Simple test....

No noise = good
Noise = bad

wouldn't the bearing cover stop the jiggle?

No .....

The stub axle installed does though.

I wasn't aware the 914 had rear wheel bearings.

The "quick" way when I was tech'ing for PCA was to place both hands on or near the top of the tire and rock the car back and forth. Listen for a click or clunk. You can always find a bad or loose bearing front or rear that way. No need to jack anything.

remove the bearing....it will be bad then.

Rich

If you don't have bearings, the wheels don't rotate.
The 914 has a double row ball bearing.

The 914 has a double row rear HUB/AXLE bearing. The only wheel bearings I know of are on the front of rear drive cars.

Bad bearing race:

A good way to test the bearings is to speed up to about 50 mph and shut the engine off and coast(DONT TURN THE KEY TO WHERE IT LOCKS THE COLUMN!!!). Rock the steering wheel from side to side slowly. Bad bearings will give you a roar or a hum when a side load is a applied.

Wouldn't the rear one piece bearing have to be completely shot to give you a "clunk"?
For the front, the jiggle makes sense as there's not much support for the two piece bearing.

In the rear, with everything assembled, one would think that a worn bearing would still sit pretty tight on the large surface.

Also, there's so much noise from the calipers and axles when turning the wheel by hand, you can't really tell unless your bearing was already in a million pieces.


Am i just doing this wrong? I'm getting some weird grinding noises from the rear when driving, but neither the jiggle nor listening while turning the wheel by hand produce any obvious results.

Andy

Have you tried putting it in neutral and coasting to see if it's in the tranny? Or as Typ2 man suggested turning in circles in neutral to see if it changes the sound?

Yes.

You can clearly hear a grinding noise from the rear. Metal to metal. Depending on how you load/unload the suspension. Even at very low speeds (think getting into the driveway at an angle) ...

I thought it might be my brake rotors hitting the calipers, but turning down the rotors didn't make a difference. And there are no wear marks on the calipers.

The sound goes with the revolution of the wheels, not the motor ... (clutch in/out makes no difference) ...

What else could it be besides the wheel bearings?
Andy

Do you have a limited slip diff?
Porsche LSD without the proper gear oil or additive can be noisy. When you turn to load the suspension one side or the other you also force the diff to work.

That said, your description does sound like wheel bearings to me and I suspect you put some hefty side loads on the rear suspension.
If you can put it up on a rack and run it in gear and listen with a stethoscope you will probably find 1 side louder that the other. This takes at least 2 people, 1 in the driver seat a 2nd to listen, if you have a 3rd to watch for safety hazards, could save you from lifting you head into a hot header or such. Of course up on a lift changes the load on the bearings and they maybe quiet the. You will also get a lot of other noise and vibration so it can be a challenge to sort out. Spin up the wheels and then put in neutral and shut off the engine and listen as the wheels coast down.
I know this does not count as an easy method and it does not even work all the time but it is something you can do short of replacing both rear bearings.

Good Luck
Jim

Andy,

Have you ever changed out the rear bearings? If not it's probably a good idea. I managed it myself with little drama... Freezing the bearing and heating the trailing arm is key to getting them in easy.

Or just use a bearing pulling and make it even easier

They should just pull right in. Then when you tighten the stub axle everything really tightens.

No LSD.

We installed new bearings at the same time the 3.6L motor went in.

I trust McMark knows how to install a wheel bearing.
Andy

I suppose it could be a defective bearing?

I second the running it on a lift. I thought I had a bad bearing and it was a bad trans!

I had my rear bearings pass the wiggle test on a lift with no problem at a tech inspection but I kept hearing some noise coming out of the left rear in turns. So I took the rotor off, turned the hubs by hand and it felt like the left bearing was full of gravel and sand. Changed them both out with a new bearings and all is right with the world.

There is an idea
remove wheel, rotor, caliper and axle.
Then turn it.

Rich

And that's "the quick way" ???
Andy

funny....I KNEW you would say that...

Seems like the fastest way to be sure.
I was thinking....

you could probably remove the inner axle and spin it by hand with the axle attached...
that would be easier.
Rich

You'll probably only need to remove the caliper. Noise loud enough to hear when driving that's coming from anything else will probably require attention anyway, and if it's on a lift it should be pretty easy to tell where it's coming from.

Five minutes, quick enough?