Rear Wheel Bearing Replacement

[joselvelez]

Hello everyone,

I've been searching through all of the posts to see if I can figure out a vibration that I have on my 02 Boxster S. At first I thought it was a bad front engine mount but the problem is that the vibration does not go way if I let the car roll in neutral. I usually let the car coast when I am pulling off of the highway (average speed is 65 mph). The vibration stays the same.

I am beginning to think that the problem is with the real wheel bearings. Does anyone have any info on diagnosing a bad rear wheel bearing and replacing them?

I did not find too much on the net about this so if I do the work I want to take pictures and post it up here for others as well.

The vibration sounds like it is very much dependent on the speed of the car and not on RPMs - when I let the car coast in neutral I still get the same noise.

Anyone have any other suggestions?

Thanks!

[Glyn]

Wheel bearing drone is quite easy to identify, the drone will increase as loads are put on the wheel and go quiet when load is taken off.

Drive the car along a road that is clear of traffic, get up to speed then drop the car in neutral (assume you have a manual and this is only a method of reducing the engine noise to make the drone more easy to hear) then sway the car from left to right, you will notice the drone will increase and decrease according to the direction of your steer - for instance if you turn to the right reasonable sharply and the noise increases then the bearing fault will be on the left side of the car - this is because the load - weight - will increase on the bearings as the weight of the car transfers to the left, of course if you turn to the right and the drone gets quieter - ie the load is lifted from the right hand side of the car you will be able to identify the right hand side.

Of course you need to determine if its front or back - If its the front wheel you will be able to feel the drone and vibration in the steering wheel, and again this will increase or decrease according to the direction you sway the car in.

The wheel bearings on Porsche are made from Bon Bons - utter rubish - the replacements never seem to fail again.

If you intend to tackle the wheel bearings on the rear yourself i have a photo file of the whole job, just pm me and i will e-mail the file, Its just over the file size limit to post here

Edited August 7, 2009 by Glyn

[ericinboca]

+1 on Glyn's method.

I have a 986 track car - I burn up a bunch of wheel bearings (especially left front) and can pick out the noise and corner reliably now just from experience. :o To add to Glyn's diagnosis...if you can easily lift the car, then:

* remove the wheel

* remove the caliper

* remove the rotor

You will be staring at the wheel hub, the part the goes into the inner part of the wheel bearing, which is housed in the wheel carrier. Assuming you are working on the corner with the bad bearing, if you spin the wheel hub by hand, you can hear the bad wheel bearing drone as Glyn describes. Also, often, while this sounds counter intuitive, the wheel hub will spin freely, easily, when in fact, there should be slight resistance.

If the bearing is really in bad shape, you might even be able to wiggle the hub, but usually you hear the noise under a load like Glyn describes first.

[larez2]

to check a wheel bearing jack up the corner that you think is bad and wiggled the tire/rim. There shouldn't be any play in the hub.

I think you need your tires balanced. If they are older tires that are not worn evenly then you may need a new tires even if there is a lot of tread left.

[joselvelez]

I just put new tires on a few weeks ago so I might take it back to make sure they properly balanced it. I'll also inspect to see if there is any play in the suspect hub.

Thanks all and I'll report back with what I find out.

[juniinc]

How old are those rear tires?

a worn out / damaged side wall tire can also cause.

even out of balance,,,,

make sure they perform a dynamic balancing , make sure they get it to 0,0 on both side.

Edited August 7, 2009 by juniinc

[Keither32]

Hello everyone,

I've been searching through all of the posts to see if I can figure out a vibration that I have on my 02 Boxster S. At first I thought it was a bad front engine mount but the problem is that the vibration does not go way if I let the car roll in neutral. I usually let the car coast when I am pulling off of the highway (average speed is 65 mph). The vibration stays the same.

I am beginning to think that the problem is with the real wheel bearings. Does anyone have any info on diagnosing a bad rear wheel bearing and replacing them?

I did not find too much on the net about this so if I do the work I want to take pictures and post it up here for others as well.

The vibration sounds like it is very much dependent on the speed of the car and not on RPMs - when I let the car coast in neutral I still get the same noise.

Anyone have any other suggestions?

Thanks!

Believe it or not you may be able to diagnose it by hand. You'll need to get both back wheels off the ground for this. If a bearing is making that much vibration you should be able to feel it in your finger. You'll need to compare one side with the other. And if both bearings are bad, well, umm, comparison won't work.

With one hand rotate the wheel in it's normal forward direction, and with the other hand, place your finger on the spring around the shock. Compare one side with the other to determine which bearing is bad. Obviously the side with the most vibration (singing) has the bad bearing. This worked for me on my 2002 Boxster S. You can move your finger around like a stethoscope and see what you can find or feel.

On my car, I thought it was the tires at first, it needed new ones. So I put on tires (Ps2's), and well it was better for a bit (200 miles) then the vibration came back. Which turned out to be the passenger rear bearing.

Good Luck!

Keith

Edited August 8, 2009 by Keither32

[gnetwerker]

On my car, I thought it was the tires at first, it needed new ones. ... turned out to be the passenger rear bearing.

Same story with me. At about 20k miles, my '01 S started with what I thought was bad tire noise. Took it to the tire shop, and while it was on the rack I tried to see if it was the bearing (left, rear), but I couldn't detect any jitter or rattle. The tires didn't solve the problem, though, and when I next went to my (very good) mechanic, they diagnosed it and replaced it. The very odd thing was that the right rear did the same thing about 500 miles later.

[bscrivener]

I don't have a Boxster, but I may have a wheel bearing issue with my 2000 996 C2 tip (stock intake and exhaust).

I hear a medium to high pitched drone when in 4th or 5th gear at approx 40mph under very light throttle. If I let off the throttle, the drone goes away. If I speed up some it goes away.

Do you think this is a bearing issue? In any case, Glyn I'd like to get your DIY. I PM'd you my email address.

[986fan]

Last year, I had a droan in the back that I attributed to a possible bad belt in a rear tire.

When new tires did not take it away, I found it to be a right rear wheel bearing that the grease

had dried up into what looked like a little bit of dirt (01 986S with only 12,000 miles).

I had both rear wheel bearings replaced ($600.00). No more problem.

[Glyn]

I don't have a Boxster, but I may have a wheel bearing issue with my 2000 996 C2 tip (stock intake and exhaust).

I hear a medium to high pitched drone when in 4th or 5th gear at approx 40mph under very light throttle. If I let off the throttle, the drone goes away. If I speed up some it goes away.

Do you think this is a bearing issue? In any case, Glyn I'd like to get your DIY. I PM'd you my email address.

Wheel bearing file sent to you.

Your case doesnt sound like a wheel bearing - what you describe sounds like a gearbox or final drive bearing issue - dont panic - its not that serious, usually the whine you describe is simply a slight misalignment of the differential gears in the final drive - and if this is indeed the problem the car will run quite happily like that for years and years, try changing the gearbox oil first - there are quite a few all synthetic gear oils available which are specifically marketed for wear issues

[shihman]

hi guys, i am not sure if i have the same problem but i am not sure where to ask either. i pull out of the garage yesterday and heard a real sharp high pitch grinding noise came from my rear right wheel. i know it is not the engine or the break because the noise only starts when car is moving. i am planning on taking it to the shop because i have absolutely no clue what happened or what to inspect/look for. i am even afraid to drive it. please help and give me some idea what may be wrong with it. it is a MY00 boxster s. thanks whole bunch.

[1schoir]

hi guys, i am not sure if i have the same problem but i am not sure where to ask either. i pull out of the garage yesterday and heard a real sharp high pitch grinding noise came from my rear right wheel. i know it is not the engine or the break because the noise only starts when car is moving. i am planning on taking it to the shop because i have absolutely no clue what happened or what to inspect/look for. i am even afraid to drive it. please help and give me some idea what may be wrong with it. it is a MY00 boxster s. thanks whole bunch.

shihman:

If it's making a loud, high pitched, grinding noise as soon as the car starts moving, it's unlikely to be caused by a bad wheel bearing, unless your wheel bearing has completely fallen apart (again, unlikely).

Start by checking something much simpler: possibility that a small rock or other debris got caught up between your brake rotor and the backing plate or got wedged in near one of the edges of the caliper. Jack up the car, take off the wheel, and inspect the rotor etc...

Costs nothing. Worth a look.

Regards, Maurice.

[shihman]

thanks maurice. once again you have come to the rescue. i'll take the wheel off and take a look.

oh one other info i should have included is that when i make a left turn, the noise will reduce. it is like the weight of the car is lifted off of the right wheel.

[shihman]

UGG, FRUSTRATION!!! why do they make the lug nuts so tight that you can't take the tires off!!! what happens if i get a flat in the middle of no where!!!

ok maurice, i tried. i tried for over an hour to take the lug nuts off and i can only mange to get 3 out of the 5. i had the same problem when i replaced my AOS. but i jacked up the car anyway to look underneath. of course there is not much you can see with the wheel still in tact. i cleaned off any residue or debris that i can see, which is not much.

what else can i do now? please help?

[Ross1]

UGG, FRUSTRATION!!! why do they make the lug nuts so tight that you can't take the tires off!!! what happens if i get a flat in the middle of no where!!!

ok maurice, i tried. i tried for over an hour to take the lug nuts off and i can only mange to get 3 out of the 5. i had the same problem when i replaced my AOS. but i jacked up the car anyway to look underneath. of course there is not much you can see with the wheel still in tact. i cleaned off any residue or debris that i can see, which is not much.

what else can i do now? please help?

Take it to a tire shop and have them loosen the lug nuts with a pnuematic impact wrench!

[1schoir]

UGG, FRUSTRATION!!! why do they make the lug nuts so tight that you can't take the tires off!!! what happens if i get a flat in the middle of no where!!!

ok maurice, i tried. i tried for over an hour to take the lug nuts off and i can only mange to get 3 out of the 5. i had the same problem when i replaced my AOS. but i jacked up the car anyway to look underneath. of course there is not much you can see with the wheel still in tact. i cleaned off any residue or debris that i can see, which is not much.

what else can i do now? please help?

shihman:

Ross1's suggestion would definitely work. You can just have them loosen those two recalcitrant lugs with their impact wrench, and they tighten them to 96 ft/lbs yourself. When you get back home, you can then easily take the wheel off yourself. The problem usually arises when you allow a shop to use an impact wrench to re-install wheels after some service (such as getting new tires). Most of those impact guns are set on a whatever setting is high enough to get any lug bolt or nut off, and they are not too concerned about re-setting their impact wrenches to a lower setting to install the wheels.

If you want to try to remove those two lug bolts at home, you are going to have to use a half-inch drive breaker bar, and then maybe have to slip a length of pipe over it for extra leverage. Maybe spray some WD-40 or PB Blaster on those two bolts and let it sit for a while, or, use a propane torch on one lug bolt at a time to apply some heat. Either one of those methods MAY make it a little easier to get the stubborn lugs off.

The lug bolts on Porsches are pretty beefy, so I don't think you can shear the bolt off with a ton of leverage, but be careful anyway, and make sure that your socket is squarely on the bolt head (i.e., press in on the base of the breaker bar where it meets the socket with one hand, while applying leverage on the end of the pipe with the other hand. Wear gloves.

Regards, Maurice.

[shihman]

i tried WD-40 already and it still doesn't seem to work. i guess i'll take it to a tire shop. thank you both ross1 and murice.

but here lies the catch 22. the reason for doing this in the first place is to inspect the reason for the grinding noise. now that i have to drive it to get the lug nuts loosen and back. is this going to do more damage to the car/wheel or what ever the parts? that's what i am worried about. :(

[Ross1]

i tried WD-40 already and it still doesn't seem to work. i guess i'll take it to a tire shop. thank you both ross1 and murice.

but here lies the catch 22. the reason for doing this in the first place is to inspect the reason for the grinding noise. now that i have to drive it to get the lug nuts loosen and back. is this going to do more damage to the car/wheel or what ever the parts? that's what i am worried about. :(

If it is in fact a wheel bearing, you probably won't ruin anything. But, just to be safe, take Maurice's suggestion and get a breaker bar. I would probably avoid using a torch to avoid discoloration.