rear wheel bearings

[Mijostyn]

Well, I have grumbling coming from the rear at wheel rotation rhythm again. 1st time it was the right rear wheel bearing so, I suppose this time it is the left one. When I got the car it had 6100 miles on it. The second owner got it at 5100 miles and tortured the car at the track for 1000 miles. He bent an rim, ripped up the plastic air dams in front of the front wheels and warped the front rotors. Now the car is spitting out wheel bearings. Are the bearings weak in these cars? It is an 06 C4S.

[JFP in PA]

. Are the bearings weak in these cars?

Not particularly.

[Loren]

I agree with JFP they are not weak.

But if he bent a wheel or slid into a curb or something - that can easily damage a wheel bearing.

I have see a car that slid into a curb do damage to the wheel wheel bearing, cv joint, and even bend the axle shaft. It is a tremendous amount of force.

[JFP in PA]

What I would consider having checked is the car's alignment, just to be sure it is going down the road straight.

[Mijostyn]

He bent the left front rim. Rears are OK. I had the car certified so, everything was fixed. Rim, brakes, tires, fluids, accessory belt, spark plugs and alignment. I suspect the Right rear bearing went first because you go around the track counter clockwise. I always thought these cars were tougher. Fortunately, the engine and tranny seem fine. I am going to send some oil off for analysis.

I have one more year left on the warranty. So, it either settles down or it gets traded on the Turbo. It is such a cool car. I bought it knowing full well that owner #2 beat the **** out of it. Technically, it should never have gotten certified. Not sure how the dealer worked it's way around that one. Ignorance is bliss.

[spiffyjiff]

my '06S has 53k on the clock with about 6k+ of that on track. i have had no issues with bearings. they will wear out eventually i'm quite sure but theyre pretty solid.

[Mijostyn]

You must have a much kinder right foot than the previous owner of my car. It is one thing to go out and enjoy driving fast and another to race like you are Ayrton Senna without regard to the welfare of your machine at all costs. From all that I have seen these machines are not intended for all out racing as they come for routine consumer use. Special versions maybe. But, not the regular street versions. I am afraid that WW has pernanently ruined the mark putting profit above all else.

[Uwon]

The PO may have aggressively used a power sprayer on the running gear which will do it to the bearings over time. Happened to a friend of mine who insisted on pulling the wheels and spraying the face and back of the rotors. His CV joints went too within two years.

[Mijostyn]

Uwon, I routinely use a power sprayer/pressure washer. This is my 6th 911. I have put over twice as many miles on previous 911s and never lost a wheel bearing and in 25 years of 911 ownership the basic design of the hub, bearing, rotor has not changed. These assemblies are designed to take water exposure. That is why the bearings are "sealed." The only explanations for my cars wheel bearing failures are abuse, poorly designed bearings, bad metallurgy, and any combination of the three. I would have hoped that properly designed and hardened bearings would have been able to handle what ever loads the car was subjected to over it's life span. That is apparently not the case.

[JFP in PA]

Uwon, I routinely use a power sprayer/pressure washer. This is my 6th 911. I have put over twice as many miles on previous 911s and never lost a wheel bearing and in 25 years of 911 ownership the basic design of the hub, bearing, rotor has not changed. These assemblies are designed to take water exposure. That is why the bearings are "sealed." The only explanations for my cars wheel bearing failures are abuse, poorly designed bearings, bad metallurgy, and any combination of the three. I would have hoped that properly designed and hardened bearings would have been able to handle what ever loads the car was subjected to over it's life span. That is apparently not the case.

I don't know about that, we have had customers actually blow the CV boots right off the car while cleaning the underside with a power washer. And, as I noted earlier, we do not see any more wheel bearing failures on 986/987/996/997 cars than we do on other makes; the bearings are pretty sturdy on these cars. And while they are designed to deal with rain and road salt, I'm reasonably sure they did not consider what would happen to them when their seals get hit with a 3,200 PSI steam of water and detergent.......

[Mijostyn]

Wow, who said anything about 3200 psi? My electric washer maxes out at 1250, more than enough to wash a car. You could not work a CV boot off even if you jammed the nozzle right up to it. These washers only produce a lot of force right at the nozzle. It drops off rapidly as you move away from the nozzle. I can comfortably hold my hand indefinitely 6 inches from the nozzle. The wheel bearings are shielded by the rotors so, you can not hit them with a direct stream. I suppose if you had a bearing out and subjected the bearing seal to a direct stream close up you might be able to work water in under the seal but in real life this does not happen. If you think about it you probably subject your car to much higher hydrostatic pressures driving through the rain at 80 mph. If you don't think so, stick your hand out the window and see how it feels! There are industrial washers, usually gasoline driven that are a lot more powerful and too dangerous for home use. They can rip your skin right off at close range. Also, you NEVER use soap in the washer. You just use the washer to rinse the car and use a wash bucket, brush and car shampoo the old fashioned way.JFP, as I am sure you are well aware in your profession, there are nit wits out there that can do just about anything. Like, blasting their CV boots off with an industrial pressure washer set at 3200 psi. That is like using a blow torch to light birthday candles. Today I pulled a 3 inch staple out of a guy's foot. He stapled 4 of his toes together with a pneumatic stapler. He was stapling the sill down in a mobile home. Instead of placing the gun and pulling the trigger this guy liked to hold the trigger down and literally bounce the gun along. As soon as the safety at the nozzle depresses the gun fires. This fellow was holding the sill in place with his foot and he bounced the gun along right into it.

One other nice thing about pressure washers. If you pay for your water, you use about 1/2 the volume rinsing your car with a pressure washer as you do with just a garden hose and nozzle. Also, the newer electric washers auto stop when you release the trigger so, you use less electricity and the pump lasts longer and when you fill your wash bucket you get the best suds!

Edited July 26, 2013 by Mijostyn

[JFP in PA]

Wow, who said anything about 3200 psi? My electric washer maxes out at 1250, more than enough to wash a car. You could not work a CV boot off even if you jammed the nozzle right up to it. These washers only produce a lot of force right at the nozzle. It drops off rapidly as you move away from the nozzle. I can comfortably hold my hand indefinitely 6 inches from the nozzle. The wheel bearings are shielded by the rotors so, you can not hit them with a direct stream. I suppose if you had a bearing out and subjected the bearing seal to a direct stream close up you might be able to work water in under the seal but in real life this does not happen. If you think about it you probably subject your car to much higher hydrostatic pressures driving through the rain at 80 mph. If you don't think so, stick your hand out the window and see how it feels! There are industrial washers, usually gasoline driven that are a lot more powerful and too dangerous for home use. They can rip your skin right off at close range. Also, you NEVER use soap in the washer. You just use the washer to rinse the car and use a wash bucket, brush and car shampoo the old fashioned way.JFP, as I am sure you are well aware in your profession, there are nit wits out there that can do just about anything. Like, blasting their CV boots off with an industrial pressure washer set at 3200 psi. That is like using a blow torch to light birthday candles. Today I pulled a 3 inch staple out of a guy's foot. He stapled 4 of his toes together with a pneumatic stapler. He was stapling the sill down in a mobile home. Instead of placing the gun and pulling the trigger this guy liked to hold the trigger down and literally bounce the gun along. As soon as the safety at the nozzle depresses the gun fires. This fellow was holding the sill in place with his foot and he bounced the gun along right into it.

One other nice thing about pressure washers. If you pay for your water, you use about 1/2 the volume rinsing your car with a pressure washer as you do with just a garden hose and nozzle. Also, the newer electric washers auto stop when you release the trigger so, you use less electricity and the pump lasts longer and when you fill your wash bucket you get the best suds!

Like all other OEM's, Porsche tries to make these cars idiot resistant as possible. Unfortunately, God seems to side with the idiots, who regularly find ways to circumvent what the engineers have done. I could easily bore you with hours of stories of what we have seen people do to these cars, sometimes destroying either the engine of even totaling the car in the process. So, blowing the CV boots off the car is just another day at the shop; I am never amazed at what we see, it seems "stupid" is a fact of life............

[Mijostyn]

JFP, Loren, are the wheel bearings in front the same as the ones in back or are they different parts? The thought occurred to me that I might be the victim of a lot of bad bearings. Two bearings going prematurely is a little more coincidence than I'd like. If they are all the same part and it turns out that I have indeed lost another one I will try to get Porsche to replace them all or at least warranty the remaining two indefinitely. The car now has 16,700 on it.

[Loren]

The bearing are the same type (angular-contact bearings) but they are different parts front and rear.

[Mijostyn]

Thanx Loren, assuming it is the left rear that is bad this time that will replace all of the like parts. Will find out for sure tomorrow AM. Grumble, grumble, grumble......

[dphatch]

Uwon, I routinely use a power sprayer/pressure washer. This is my 6th 911. I have put over twice as many miles on previous 911s and never lost a wheel bearing and in 25 years of 911 ownership the basic design of the hub, bearing, rotor has not changed. These assemblies are designed to take water exposure. That is why the bearings are "sealed." The only explanations for my cars wheel bearing failures are abuse, poorly designed bearings, bad metallurgy, and any combination of the three. I would have hoped that properly designed and hardened bearings would have been able to handle what ever loads the car was subjected to over it's life span. That is apparently not the case.

I don't know about that, we have had customers actually blow the CV boots right off the car while cleaning the underside with a power washer. And, as I noted earlier, we do not see any more wheel bearing failures on 986/987/996/997 cars than we do on other makes; the bearings are pretty sturdy on these cars. And while they are designed to deal with rain and road salt, I'm reasonably sure they did not consider what would happen to them when their seals get hit with a 3,200 PSI steam of water and detergent.......

LOL. 3200 PSI with a 10% tip will blow holes in concrete. In that context I would agree power spayers should not be used to clean your car. I haved used a 2500 PSI unit with a 40 % tip for years with no ill effect whatsoever on all my cars including three Posches.

[Mijostyn]

Finally, someone else who grew up at the water park ;-)

[Mijostyn]

I just got a call back from the dealer. It is indeed a blown left rear wheel bearing. Always go for a car you can certify.

I paid $2000 for a warranty that has cost Porsche so far...lets see...$12,000. Lets have a big round of applause for Wendelin Wiedeking. :clapping:

Edited July 29, 2013 by Mijostyn

[Mijostyn]

It gets better. The new Lt wheel bearing lasted almost three months. This time I started getting a wheel speed squeak out of the Lt rear, not the previous grumble. Now they are going to replace the bearing, the knuckle and the hub. We must be up to $15,000 in warranty repairs by now.

[JFP in PA]

It gets better. The new Lt wheel bearing lasted almost three months. This time I started getting a wheel speed squeak out of the Lt rear, not the previous grumble. Now they are going to replace the bearing, the knuckle and the hub. We must be up to $15,000 in warranty repairs by now.

Question is, "Why is the car killing wheel bearings?" Even cars that see serious track time do not have this problem.

[Mijostyn]

They checked the alignment. The car handles great. I can take my hands off the wheel at a buck twenty and it goes straight as an arrow. The tech has no idea. I think the original bearings were defective, maybe not hardened correctly. This one probably did not press in right, maybe the knuckle got dinged in the process? I think that is what they are thinking as they are going to replace the whole shooting match.

[Mijostyn]

It gets better. The new Lt wheel bearing lasted almost three months. This time I started getting a wheel speed squeak out of the Lt rear, not the previous grumble. Now they are going to replace the bearing, the knuckle and the hub. We must be up to $15,000 in warranty repairs by now.

Question is, "Why is the car killing wheel bearings?" Even cars that see serious track time do not have this problem.

Because it was tracked! I was reading the "Track" manual for my new Turbo S and discovered that Porsche instructs to replace the rear wheel bearings every 4500 miles in a tracked car and the wheel carriers every 9000! The fronts are supposed to be done every 9000.

Tracking the car gets very expensive!