The Bad Noise is Back (Now with Video)

[OsoMoore]

My SC is making a noise when under acceleration. No noise on braking or coasting. Noise comes from the rear passenger side, and ticks at the wheel's speed.

It only seems to happen when the car is pretty warm - ie. after some moderate highway speed. If I am in gear but coasting, it does not happen.

I already replaced the engine mounts last month. There isn't anything bumping around in the engine compartment. The CV boots don't have any tears or weird bulges, and there is no evidence of escaped grease.

My only idea remaining is that one of the passenger-side CV joints has something bad going on inside the joint. When the grease is cool, it sufficiently lubricates. After a lot of driving, the grease thins out and the joint becomes noisy when under torque. But that's just an idea.

First video.
Porsche Clicking #1 - YouTube

Second Video. Still being cropped by youtube, so you will need to wait a few seconds until the wind noise dies and you can hear the clicking.
Porsche Clicking #2 - YouTube

[szyzygy]

I'd go with CV joints like you said. But wouldn't they make noise when coasting? The wheels are still turning and rotating the axle, right?
I replaced mine in May and it was similar sounding to yours. I had no evidence of escaped grease, either. No noise when cool, but after it got warmed up it was hella loud and shook my whole car. If you jack up the car and spin the tires in neutral, does it make the noise still (while still hot)? I could feel mine bind up when I did this.

[OsoMoore]

Originally Posted by szyzygy

I'd go with CV joints like you said. But wouldn't they make noise when coasting? The wheels are still turning and rotating the axle, right?
I replaced mine in May and it was similar sounding to yours. I had no evidence of escaped grease, either. No noise when cool, but after it got warmed up it was hella loud and shook my whole car. If you jack up the car and spin the tires in neutral, does it make the noise still (while still hot)? I could feel mine bind up when I did this.

I have a theory for why it clicks only under acceleration. When coasting, there is no torque being applied through the joint.

I put the car up on jacks and tried to replicate the sound, but for whatever reason by the time I found an extension cord for my impact wrench and got the wheels off it wasn't doing it anymore. I'm hesitant to take it for another long drive just to heat up the joint.

Right now my plan is to pull off the half-axle tomorrow after work. At least there's no cat on that side!

[Tidybuoy]

I had a similar issue - car would only make noise when under a load and not all the time. When I changed my rear axle (whole piece - two cv's and the axle), not only did the noise go away but the transmission also got quieter.

I also had a similar noise in my 944 however, in this case, it turned out to be the emergency brake which had a broken spring.

It's hard to tell from your video but my bet is on the CV's. Check to see if you have a torn boot. It doesn't take long for dirt to get in there and ruin the joint. Also, depending on the mileage, it might need new cv's anyway.

[neilschelly]

I'd echo support for the CV. They can make noise constantly if they are bad enough. In this case, just coasting or under engine deceleration, they probably aren't loading the right surfaces inside the joint.
-N

[kodioneill]

Broken spring/cable on the emergency brake shoe would be my guess. As the previous poster said.

[Bob Kontak]

Originally Posted by kodioneill

Broken spring/cable on the emergency brake shoe would be my guess. As the previous poster said.

That's a good thought but the noise would not go away, I don't think

One thought is to swap ends of the one shaft on the side making the noise. If the noise goes away or the click/squeak frequency changes, you got the problem isolated. You swap ends and the thrust surfaces are reoriented to unused surfaces.

Now, I have only read about this trick but never tried it. Bummer is, for the same amount of work, you could have a new "turnkey" shaft installed.

If you have a pnuematic ratchet with a hex drive, the task would not be too bad.

[theiceman]

Get a grease, cun , atach a piece of copper pipe.. hammer it down almmost flat at the end ... stick it in the small end of the boot and squirt some CV grease in. if it goes away you have found your problem , then either leave it or rebuild CV joint..

[kodioneill]

Originally Posted by Bob Kontak

That's a good thought but the noise would not go away, I don't think

One thought is to swap ends of the one shaft on the side making the noise. If the noise goes away or the click/squeak frequency changes, you got the problem isolated. You swap ends and the thrust surfaces are reoriented to unused surfaces.

Now, I have only read about this trick but never tried it. Bummer is, for the same amount of work, you could have a new "turnkey" shaft installed.

If you have a pnuematic ratchet with a hex drive, the task would not be too bad.

I had a 76 turbo that made that noise only after I drove it about 5 or 6 miles. I found that the emergency shoe would heat up
and tighten up on the inside of the rotor. Took of the rotor found the broken v clip inside replaced it problem solved.

[OsoMoore]

Originally Posted by kodioneill

I had a 76 turbo that made that noise only after I drove it about 5 or 6 miles. I found that the emergency shoe would heat up
and tighten up on the inside of the rotor. Took of the rotor found the broken v clip inside replaced it problem solved.

Did it make the noise non-stop after it heated up? I'm only getting the noise when I apply torque during acceleration.

[Bob Kontak]

Originally Posted by kodioneill

I had a 76 turbo that made that noise only after I drove it about 5 or 6 miles. I found that the emergency shoe would heat up
and tighten up on the inside of the rotor. Took of the rotor found the broken v clip inside replaced it problem solved.

If you heard the noise and it's similar, then it is a viable thing to look at.

I bet it's the CV joints though, a couple of badly cooked thrust surfaces that are thirsty.

[OsoMoore]

Originally Posted by Bob Kontak

That's a good thought but the noise would not go away, I don't think

One thought is to swap ends of the one shaft on the side making the noise. If the noise goes away or the click/squeak frequency changes, you got the problem isolated. You swap ends and the thrust surfaces are reoriented to unused surfaces.

Now, I have only read about this trick but never tried it. Bummer is, for the same amount of work, you could have a new "turnkey" shaft installed.

If you have a pnuematic ratchet with a hex drive, the task would not be too bad.

I've taken the CV on and off on the other side, so I am familiar with the task. Greasy! I may try that tonight.

[OsoMoore]

I pulled out the joint - much faster your 2nd time.
The bolts on the inside joint had grey grease all over them when I removed them.
The bolts on the outside joint were dry and slightly gritty. Bad news!

There is also this amber junk on the ends - some kind of other grease? I'll tear the joints down later tonight or tomorrow and see what's going on inside.

[OsoMoore]

I removed and disassembled the passenger-side half-axle, both joints. I'll refer to the joints as inner (transmission side) and outer (wheel side).

First off, the bolts were a mess of lengths and threads. On top of that, the inner joint bolts were definitely not to torque - they came off way too easily.


Second, the holes in the cage for the inner joint were an extremely tight fit for the balls, I was barely able to work them out. On the outer joint, the balls easily dropped through the holes. For comparison, when I did the driver's side outer a month ago, the balls passed through that cage easily.
I thought both joints should be identical, but they clearly aren't quite.



Off to the races! On the inner joint, there was a single mid-sized pit on inside race, and a small pit on the outside race. Not super-bad, but not perfect either.




The outer joint was a real mess. The inside race had significant pitting on 5 of the 6 surfaces. The outside race scarring on several surfaces as well.




And, to top it all off, the outer joint (which had all the race scarring) was significantly discolored.
Two pics of outer joint. Note the dark discoloration all around the joint.



A pic of the inner joint for comparison. No dark wavy lines here.


Oh, and there were metal shavings all over my cleaning rag for the outer joint


Interestingly, all the balls seemed in good shape from both joints.

I presume this means I will need to replace the badly scarred joint entirely, and possibly the other joint as well. Dare I even keep the boot from the outer joint? I fear it will have nasty metal bits in it that I won't really be able to clean out.

Thanks for looking at all the pics and helping out!

[porterdog]

Originally Posted by OsoMoore

And, to top it all off, the outer joint (which had all the race scarring) was significantly discolored.
Two pics of outer joint. Note the dark discoloration all around the joint.

Could just be that this particular part was induction hardened vs. some other method.

[OsoMoore]

Interesting, I didn't realize there were different methods of hardening. Would that cause the curved lines that follow the race's channels?

On the issue of different sized bearings - I got out my English micrometer.
All the balls were 0.75" diameter.
The outer joint's cage holes' diameters was 0.75", while the inner joint's were 0.748". That is what caused the balls to not fit through the hole easily.
On the outer joint, the diameter inner race was 2.159, while the inner joint's was 2.202
The diameter of the outer joint cage was 2.651, while the inner joint's was 2.6405.
This is surprising, because I thought both joints were supposed to be identical. I'm not sure if this is significant at all.

My question for all you CV bearing experts out there is this - should I replace both? Or is a little light scarring on the one joint OK, or I can just re-grease that one buy one and replace the other?

[Josh D]

If it were me, I'd replace all four knowing that I would not have to worry about them again for several decades.

[theiceman]

Originally Posted by Josh D

If it were me, I'd replace all four knowing that I would not have to worry about them again for several decades.

this......

i found exactly what you did and replaced them all, even new bolts . my inner is a cool paperweight.

retourque bolts at 500 ,1000 and 2000 miles.

they have been known to back out

research Belleville washers or schnorr washers.

[OsoMoore]

Thanks guys, new joints are on order. I'm getting bolts from McMaster Carr - very beautiful bolts and I hope to be on the road this weekend or Monday.

[Leland Pate]

Looks like you got it sorted out. From watching the video, I would have guessed it was a torsion bar making that noise.

This car has to be one of the most documented and loved cars on Pelican.