loud road noise

[sleepy]

While sitting here waiting for the service manager to return my call, figured I'd see if anybody else has had a similar experience. I have an '00 S that's been making a very loud roaring road noise that I thought was worn tires. Replaced the tires and the car is still making the noise. The noise drowns out the engine note above 35mph, increases with speed, and remains present when turning left or right or dipping the clutch/coasting. Also, when driving near a wall or fence, I can here the echo of a metallic ticking noise on the right side (this might not be related)

I was thinking bearings, but jacked the car up and the wheel seems stable. I also noticed a tear in the inner CV joint boot, which is pretty well covered in grease. Will worn CV joints make a loud constant noise? Regardless of whether it's the cause, can the joint be repacked? And most importantly, does anybody know if these parts (bearings, joints, driveshafts, etc) are covered under the CPO warranty!

I did a search and came across 1 or 2 similar posts, but they didn't follow through to the cause. Any tips for diagnosis would be appreciated. Years of dealing with VW dealerships have made me skeptical, so I like to go into the shop knowing as much as possible beforehand. Thanks

Edited November 10, 2004 by sleepy

[mrmickeymouse]

CV joints can sound similar to a bearing going out, due to them both being on the same shaft. The shaft telegraphs the sound. I believe you being such a good detective probably resolved your issue.

Once your CV joint/boot grease is gone you then have a metal on metal sound.

Scott

[sleepy]

So, finally talked to the service manager, and turns out none of the parts are covered under CPO. Remote chance at good will coverage since I had taken the car in 6 months ago (and 2 weeks before going out of new car warr.) because I thought I was hearing the bearing starting to go, but at the time, they told me it was tire noise and sent me on my way.

I find out what's wrong Tuesday, but unless the cost is somehow miraculously covered, I'll do the work myself. I've pulled the hubs off cars before to have a machine shop press in bearings, so I'm not too worried if that's the problem. I'll just need somebody to post the torque values for all the bolts, if possible, and any tips would be appreciated.

But what about the CV joint? Actually, my first dumb question is, is the joint on the gearbox side of the driveshaft even called a CV joint? And please tell me it's a separate, replaceable part, because I saw a parts sheet for the driveshaft that only showed the outer CV joint as separate. And will it definitely have to be replaced, or is it possible replacing the boot and repacking the grease might take care of it?

[doughep]

And will it definitely have to be replaced, or is it possible replacing the boot and repacking the grease might take care of it?

<{POST_SNAPBACK}>

While I've never done it on a Porsche, I've replaced CV joint boots on several vehicles after having sustained a tear resulting in lose of grease and ultimately metal-on-metal noise like you describe.

It can be a pain in the butt, but replacing the boot can be done on most cars. I've even used a tongue-in-groove type split boot that gets sealed around the shaft and CV joint with a solvent that 'melts' the boot closed (like acetone). This is cheaper and worlds easier, since you don't have to pull the hub, but I wouldn't do it that way on my Boxster. I'd pull the hub and replace the boot the old-fashioned way.

Oh, and make sure you get the right grease - there are a couple of different kinds and using the wrong one can be problematic as I recall.

Having said all that, as always, I defer to the experts around here . . .

Good luck - I look forward to hearing how it turns out.

- Pete

[ar38070]

It is possible to remove the drive shaft without removing the hub (wheel carrier). After jacking up the car you remove the flat strut that runs at a diagonal from the side of the car towards the back. After undoing the axle nut and the bolts to the transmission you can then slide the drive shaft out.

You do need a 350 ft-lb torque wrench to retorque the axle nut.

[sleepy]

Thanks for the help so far, especially to ar308070, who posted all the torque values I'll need in a different thread. After looking at a parts diagram, I've got 3 questions about pulling the hub/wheel carrier - 1) any tool suggestions for separating the ball joints other than a pickle fork, 2) how is the strut connected to the carrier, and is it difficult to separate and 3) what needs to be marked to try to save the alignment?

As for the CV joint, I've never done that kind of work before, so more help would be greatly appreciated.

[sleepy]

All right - took the car to the shop and it turns out one bad bearing and 2(!) torn inner CV boots.

So I'm in the garage tearing the car apart right now, but I'm stuck. All the bolts are off the hub carrier and the strut is free at the top, but I can't get enough room to slide the strut out from it's mount. The lower control arm wedges against the bottom strut support, so I can't push the whole assembly down far enough to get the top of the strut out (need about another inch). The strut also seems to be pretty well stuck in the carrier, so I can't separate those two parts, either. Anybody have any ideas?

Edited November 17, 2004 by sleepy

[ar38070]

Have you disconnected the drive shaft from the transmission (6 hex bolts)? Did you disconnect the sway bar? Also did you remember to loosen the axle nut first? Once you undo the transmission bolts you should be able to depress the control arm enough to take out the strut and wheel carrier.

Once the strut and wheel carrier are out then the strut should slide right out of the carrier.

[sleepy]

Loosened the axle nut, tie rod, driveshaft and sway bar, and of course the lower ball joint nut, and I've used generous amounts of PB Blaster.

I'm considering taking off the support strut that runs at a diagonal underneath everything, because then I'm pretty sure I can push the assembly down far enough to get the strut out. But I don't see that getting me enough room to get the driveshaft out (header's in the way), and as long as the outer CV joint is in place, I can't get a clear shot to bang the lower ball joint out (say, with a torx bit, ratchet extension, and hammer).

Does anybody know if there is a special tool available for separating the lower control arm from the wheel carrier? Any problems with me taking the lower support strut out (alignment)? What are the torque values on those bolts?

Edited November 18, 2004 by sleepy

[sleepy]

All right, I give up...for now. I've put a torch to this thing and banged on it with a brass hammer, but the lower ball joint refuses to pop out.

I asked the local service manager and he said they use a $400 tool in the back, and somebody on this board mentioned a $80 tool from Performance Products. Anybody have info on either? At this point, I'm willing to pay for either tool, since it would still be cheaper, and since I'll probably have to do this job in another 30K miles...

[ar38070]

The tool is available from performance products for $100. If you are a PCA member then you can get a 20% discount. The tool is well worth the money. (I just checked the catalog and I do not see the tool there. Hopefully they still carry it. )

The torque for the nuts on the diagonal strut is 48 ft-lbs. You should not have to remove this.

The sequence for removal of the strut is:

1)Take off the wheel

2) Remove the stabilizer

3) Loosen the drive shaft from the transmission

4) Pop the toe control arm and control arm ball joints with the porsche tool

5) Take off the brake caliper. You do not have to take the rotor off but taking it off makes lifting the wheel carrier/strut/drive shaft easier.

6) Take off the three nuts holding the top of the strut to the body

7) Push/pull down on the control arm sufficicently so that you can swing the top of the strut out. You have to push/pull hard as you need to compress the bushings. This is usually a two person job. One to push/pull the other to hold onto the strut as it swings out.

8) With the top clear you can now lift the carrier/drive shaft, strut off of the control arm ball joint.

9) Depending on how you disconnected the sway bar you may have to undo the bolt that holds it to the wheel carrier as this bolt also clamps the strut into the wheel carrier.

Actually you said you have to replace a wheel bearing. That means you have to take off the rotor. You do need to have the right tools to get the bearing out. Heating the wheel carrier with a propane torch helps. Sir Tools (www.sirtools.com) makes a tool to R&R the bearing ($150). Theoretically this tool works without having to remove the wheel carrier from the car. When I did it I could not figure out how to do it on the car (though in retrospect I think I know what I did wrong). Anyway the tool works great for putting the new bearing in. When you put the new bearing in it helps to heat the wheel carrier with a torch and to freeze the bearing. If you do not have that tool you will need access to a some kind of press to press the new bearing in.

[doughep]

Sir Tools (www.sirtools.com)  makes a tool to R&R the bearing ($150).  Theoretically this tool works without having to remove the wheel carrier from the car.  When I did it I could not figure out how to do it on the car (though in retrospect I think I know what I did wrong).  Anyway the tool works great for putting the new bearing in.  When you put the new bearing in it helps to heat the wheel carrier with a torch and to freeze the bearing.  If you do not have that tool you will need access to a some kind of press to press the new bearing in.

<{POST_SNAPBACK}>

I have used a shop press to remove/install bearings several times, without problems. It's basically a bottle jack mounted in a frame. They can be had for well under $100 (at least in the Mid-Atlantic area), and have plenty of other uses. The downside to this method is that you have to pull the hub. If you go this route, go slow and gentle on the install making sure to drive the bearing in 'square' so as not to damage it.

Good luck.

- Pete

[sleepy]

ar - thanks for having patience and sticking with this to help me out. Again, I followed all the steps you listed, but I've had several problems executing.

-With the lower support bar in place, I can push down on the assembly only until the control arm bumps against the edge of the bar. That doesn't even let me get the strut out the tower, let alone the whell well. Turns out removing the bar didn't help entirely, but I got a lot closer, and it might have worked if I had help.

-At the same time, I see no way to slide the driveshaft out with the carrier still attached, as you mentioned in a previous post. Even with the lower support bar gone, the exhaust header/cat is in the way.

- I'm not planning on changing the bearing myself - I'll let the machine shop handle that - but they need the hub first...

- ...which is still stuck to the control arm.

Sorry if I don't sound very focused - it's just that solving any one of my 3 problems (driveshaft, strut, ball joint) gives me enough room to get the hub carrier out.

I checked Performance's website and didn't see anything about the ball joint either - I'll try calling them. Anybody else have any info on this tool?

[ar38070]

Refering to the attached drawings:

Are you saying that when you press down on the wheel carrier that forward suspension link (8 in the first drawing) is hitting the diagonal strut (1 in the second drawing)?

That is odd. On my car (though it does not have the stock suspension) at full droop there is 3 inches of clearance between the forward suspension link and the diagonal strut.

If you can, take a picture of what it looks like and post it or send it to me.

We can take this offline if you want. You can email me at eshih@pacbell.net.

[mrmickeymouse]

http://cgi.ebay.com/ebaymotors/ws/eBayISAP...&category=33728

[secretaznman4u]

Refering to the attached drawings:

Are you saying that when you press down on the wheel carrier that forward suspension link (8 in the first drawing) is hitting the diagonal strut (1 in the second drawing)?

That is odd.  On my car (though it does not have the stock suspension) at full droop there is 3 inches of clearance between the forward suspension link and the diagonal strut.

If you can, take a picture of what it looks like and post it or send it to me.

We can take this offline if you want.  You can email me at eshih@pacbell.net.

<{POST_SNAPBACK}>

The setup is much like that in my bmw, when I did the bearings on mine, I opt out on buying the bearing removal tool, and just used a dremel and cut out the inner and outer race, but becareful you do not cut into the hub. and that you can eaily press in the new bearing via hammer and wooden block, i know its ghetto, but it works

[WolfgangK]

Hi Sleepy,

I doubt that the noise you describe is caused from the CVs. They may cause the 'ticking', but IMHO not necessarily the 'road noise' which sonds like 'worn tires'.

I had very similar symptoms on my old 2.5l and tried almost everything (stabiliser, CVs, bearings...). The culprit finally was the front engine mount.

Here the rubber inside the mounting disintegrates. The result is that you have a metal-to-metal contact from the engine to the body leading to all sorts of strange noises.

It's hard to identify it while the engine mount is installed, but with a bit of luck you can feel (or see) whether the part facing the engine is centered with the part facing the body.

Before you change expensive components I propose to give it a try. I am sure you will find more on that in this forum.

Regards

Wolfgang

Stuttgart/Germany

[sleepy]

Thanks for another reply. I didn't think the CV joints would cause the noise either, but a tech did say that a bearing was bad. In my first (failed) attempt to replace it, spinning the hub by hand made a pretty noticeable grinding noise, so I'm inclinded to believe that diagnosis for now. I ordered a ball joint tool to solve my problems, and I'm looking forward to replacing the bearing and repacking the CV joint boots (you wouldn't believe the price of the grease) next week.

Like I said, I'm pretty sure the bearing needs replacing, and hopefully that's all that's wrong. If the noise persists though, thanks for giving me something else to check out.

[sleepy]

So, 2 months later and I finally fixed the problems. It's nice to have my car back to normal (now if only it would stop snowing so I could drive it) Just wanted to thank those that helped me out, especially Ed, who spent a good chunk of time helping me find the right tool to separate the lower ball joint (Porsche tool 9560).

The only other thing missing from the instructions I came across was having to loosen the lower control arm so I could push the hub down far enough to separate it from the strut (I marked the original alignment). As hard as I tried, the bushing was too stiff for me to push the assembly far enough down. Just curious if anybody else has encountered that...

[robgettings@gmail.com]

Sleepy I was having exactly the same problems in my driveway this morning that you had. My Bentley service manual has been somewhat helpful but it leaves out alot of the info contained in the threads to your post.

I just bought a 2001 Boxter S with 40k mi. I'm getting a metal-on-metal noise from the driver's side rear that increases steadily with speed. The inner and outer CV boots back there were both torn wide open. I also have a broken motor mount (one of the posts mentioned that as an alternate noise source). I'm at the stage where I've removed the inner CV joint from the trans, but cant get the outer CV joint apart. Bentley says to buy Porsche special tool 9560 to do that.

Do you remember what tools you did finally buy to complete the repair? Also, I also live in Alexandria VA, any advice on a reputable shop in case I've also got to have a new wheel bearing pressed in (or any other advice on this repair for that matter)?