Randomly under accel. and braking, I'll hear a cross between a clicking and a knocking sound coming distinctly from the right rear of the car. More pronounced at lower speeds, and the harder I accelerate, the louder the sound is, under coasting, the sound completely goes away. I don't know if it is coincidence, but it seemed to start when the average weather here got much colder.

I'd say about 15% of the time I get in my car in the morning, the sound will show up. Again, much more pronounced at lower speeds. I can barely hear it at 50mph, and it seems after a few minutes of highway travel and then returning to a stop, the sound disappears.

Also, the frequency of the clicking/knocking is based on speed, not rpm (doesn't slow down and progress with engine speed).

Can anyone point me to a place to start looking to fix this problem?

Thanks in advance

 

Sounds like your CV joints are dried up.

You should remove the rear axles, take apart the CVs and degrease them to check for scoring. You'll probably have a bad one in the bunch. First to go out is usually the driver side tranny CV due to the heat from the exhaust pipe.

Replace the bad one with a new Löbro CV, repack the good ones with fresh moly grease, and you should be good to go.

Relatively easy job to DIY. Just messy!

 

Cool, I did notice the right rear boot has some play and looks really old. Are there any good online instructions for repacking or replacing the boots? Do I need to drop the tranny, or just pull the boot from the hub/rotor/etc. side?

 

Don't need to drop the tranny. You will have to put the rear of the car up on jack stands, just high enough so you have enough room to work. If you have a Haynes manual, the process is pretty well explained there. I've also posted some write ups in the past.

To remove the CVs and boots you will need an 8mm triple square bit. Kind of like a torx, but with 12 points. You can find a set with 6, 8, 10 and 12mm bits from Lisle for around $15 at your local auto parts chain store. Use the bits with a 1/2" socket.

To get the bolts out, it's a good idea to presoak them with some solvent, like brake cleaner. Use an old toothbrush to clean out the heads so the triple square will fit squarely when you attempt to remove the bolts. It helps to give the bit a good whack with a hammer to get the most grip on each bolt. Turn the bolts carefully, because you don't want any to snap.

Have fun!

 

Haynes manual + 8mm triple square bit...check. If anyone has any other tips/advice/personal experience with this, please feel free to post!

 

Well, here are a couple more tips:

When removing the inner CV retaining ring off the axle shaft with channel lock pliers (see pic in Haynes), take note of its position. I put it on backwards when reassembling the axle and spent 30 min hammering the CV to no avail until I realized this mistake.

Have a good supply of degreaser on hand. It's a very messy job. Put down newspaper, etc. Clean the CVs with the degreaser and make sure to take note of how they go together so you can reassemble the good ones later. They need to flex when mounted onto the axle.

Tighten the triple square bolts to the specified torque with a reliable torque wrench, or they can and will back out!

 

Suggestion;
Throw away the triple square bolts. I bought hardened allen head bolts and lock washers from a local bolt supplier for around $1.00 each. Repacking the CV's has now become a faster and trouble free job because I can use an air ratchet to remove/reinstall them without the normal worries of stripping out the heads.

 

Words to live by. Triple-square bolts are the biggest PITA. I have taken off many an axle, and I can't confidently say I have had a single one that didn't decide to round out at least one of the bolt's heads.

If that happens, grab a pair of vice grips and clamp down as hard as you can to twist those suckers out. If you are in the NoVA area now and want some help tearing down the CV joint, I happen to have a spare set of CV ***** and the tools to do it. I might even have some spare bolts lying around.

If you the ***** didn't heat up and mess up the inner CV ring (not hard to notice... there will be burned lines and chips out of it) get a good quality Moly grease (synthetic or blended) and just pack the boot back up about 3/4 of the way and rebuild the joint. You'll only need snap-ring pliers to disassemble the CV joints... that and newspapers on the ground and latex gloves

 

I've heard of this before, but as I understand it, Porsche chose to fit triple square bolts on the CVs for 2 reasons:

1st they're not as easy to round out as allen headed bolts -if you round out an allen headed bolt, no amount of pounding the allen bit into it will get it to grip.

2nd the triple square are more suitable for high torque applications, such as the clutch.

If you don't like dealing with the old bolts, the best option is to replace them with new triple square bolts in 10.9 hardness grade.

YMMV

 

If you dissasemble the CVs, be sure to mark the pieces so you can assemble them exactly the same way, including the *****. I would also install any you don't replace so they are turning the opposite direction. I have done them twice and never had any issues with the triple squares (AKA cheeseheads). New joints from Porsche came with new bolts and a thin wallet. I keep reading they are also a VW part for half the price.

Lou

 

If one CV has gone bad you may want to go ahead and replace all of them. I had the same symptom, changed out one CV, then ended up needing to replace another one shortly thereafter. For the money and the time you should seriously consider buying new axles with CV's already installed. That is what I ended up doing, it really simplifies the install, and the cost is only slightly different than 2 new CV's per axle.

my .02

 

Specifically, they're the same CVs that VW used for the Vanagon. I've put these on my 83 with good results. They are, however, about 1mm thinner than the original equipment CV and don't come with the boot.

 

I have to disagree, Luis. I've done these many times and when the bolts in question have had continuous torque applied to them for over a hundred thousand miles (yes, many cars have never had theirs touched), they don't want to come out. The allen head bolts are better from what I've had to take off, and they certainly don't round easier than triple-squares. The only allen heads I ever have problems with are very small ones that were over-torqued or ones that are rusted on. That applies to just about all bolt heads I'd say, however.

The triple-squares are great in larger sizes and yes, they do very well on their applications and don't round as easily as the smaller triple-squares.

Anyways... choose your poison. Like ya said, bud, YMMV

 

I can't belive this! I logged on to Rennlist to post this exact question. My 951 is making exactly the same noise in the same conditions. It just started Fri morning. Spooky.

Maybe Santa will bring me some moly grease and latex gloves.

 

I hope that's ALL Santa has to bring ME

I'll be tearing it down as soon as the temperature breaks freezing...