key tips from 986 S drive axle replacement

Have been meaning to write up a few key points that I learned from my drive axle replacement job on a 2001 S a few weeks back. First a big thanks to Pedro for his great write-up, and several folks from the board for answering a few questions as I tackled this; it was of great help.

Here are a few comments that others might find useful if they attempt this job themselves:
- Not huge trouble getting the axle nut off...found a nice 4-ft cheater bar and it came off with expected force.
- I opted for the ball joint removal approach - didn't want to mess with the header bolts and exhaust lowering, but perhaps this might have been easier. I wanted to learn about the suspension approach anyway.
- Toe arm joint was easy to break and relatively straightforward to remove by hand.
- Control arm ball joint was the major headache....my ball joint tool was too thick to get in far enough to get onto the nut to break. Solution was two-fold: I got the cheapie $19.99 Harbor Freight joint breaker which was much thinner, and in combination with wedging a 2x4 to hold the back side of the wheel carrier out several inches, there was room to get the cheapie HF tool in and break the joint. A loud pop when it let's loose...
- Axle was indeed tight in the wheel carrier.....but nothing that a brass drift and a sledge couldn't handle.
- Getting the control arm free of the wheel carrier (once joint was popped) proved challenging. Pedro apparently has been able to do this w/o releasing the eccentric bolt, but despite many approaches/attempts, I ended up having to mark/loosen the eccentric. I would love to see someone get that out w/o loosening the eccentric just for entertainment value!
- Reassembly was easier, with exception of one step. Once the control arm is back in the wheel carrier there are two issues: First, it was necessary to counter hold the ball joint with a T40 bit, but there is almost no room, and as the nut is tightened there is progressively less room for the T40 bit. I ended up getting a cheapie HF T40 bit and ground a quarter inch or so off of the end to get the required clearance, and holding the bit with a small vise grip. Secondly, there is a torque spec for that nut, but no way to get a socket on in for the torque wrench, so the torque had to be estimated ("really tight" with my 18mm combination wrench!).
- The skid cover was an exceptional pain to reinstall....I'll leave it at that. Not sure why Porsche needed to have this fit so ridiculously tensioned....in fact next time I take this off I'll probably enlarge the holes unless someone has a good reason not to.
- I ended up opting for replacement axles (one inner CV needed to be replaced, and I was going to do the pair) as opposed to the additional tasks/mess to replace the 2 inner CVs and cleaning/repacking/rebooting. I still have the old axles with only 32K miles and the outer CVs are fine, so may rebuild them someday to have a replacement set ready. (or may post as parts in case someone else wants to reboot...PM me if anyone interested in these...still have boxes to ship.)

My only remaining decision is whether or not I really need to fork out the $ for an alignment. With only the rear control arm eccentric released and subsequently reset to the pre-marked position, it seems that I should be OK. My tire wear has been perfect (before this job), but I just put on a new set of Pilot Super Sports and will probably have this done just to be safe. Interested in what others think re need for alignment or not. (Park Place and Autoscope are close here in Dallas...)

Thanks again to everyone - this board and it's predecessor have been invaluable and I really appreciate the insight. Hopefully some of these points will help someone else down the road....Cheers, Mike

keep things where they ought to be.

I would not enlarge the holes. Chances are it will not have to come off again for a long time. Keep an eye on those nuts, though. At over 150K miles and having had the panel off only once (when the RMS was done and this was done at the dealer) I found 2 nuts had vibrated loose and fallen away.

My understanding is if the panel is removed and the car is not moved any the panel can be reattached and the alignment is unaffected. (When my Boxster was in for an RMS while the car was partially disassembled the car was lowered to the ground and rolled out of the way to free up a lift for other cars while parts were on order. When I got the car back no one advised me about this and I drove the car and found the alignment was terrible. Inner edges of the rear tires wore down to the belts very quickly. Yet before the work the tires with around 25K miles on them looked nearly new.)

Anyhow, the need for alignment or not I think relies upon also the car being supported by its tires/wheels, not its body lifting points. By lifting the car by these the suspension droops and the alignment may change. In fact this may have accounted for the difficulty you had in reinstalling the panel. (If I'm right then an alignment is almost a given.)

Since you just put on a set of new tires my advice would be to play it safe and at least check with a knowledgeable shop (dealer service department or an indy) to see what is recommended.

Or to just have an alignment done. If you have it done where other work on these cars is done (dealer service department or even an indy) maybe someone there will share with you the secret on how to access/tighten the fastener for the control arm, if you ask.

Sincerely,

MarcW.

Thanks Marc....hard to believe that that thin piece of sheet metal has anything to do with alignment?! My thinking was that I marked, loosened, and then replaced the eccentric bolt to the same position all while in the air (supported by jack stands on the lifting points), so my assumption is that the alignment is OK. Certainly could be something I'm overlooking....but I'm with you in thinking it better to play it safe. After all, $199 for alignment is considerably cheaper than a 4 digit set of tires.....

... with Marc regarding the aluminum plate.
It doesn't really do anything to "keep things where they ought to be".
That's why AX cars need the TechnoBrace or similar. The aluminum plate deforms and bends.
The keeping things where they ought to be is done by the diagonal braces.
The aluminum plate is just there for protection and for channeling air to the tranny.
If you moved the eccentric, your alignment is off.
It is practically impossible to dial it back to where it was.
Happy Boxstering,
Pedro

Pedro Bonilla
1998 Boxster 986 - 311,000+ miles: [www.PedrosGarage.com]
PCA National Club Racing Scrutineer - PCA National HPDE Instructor - PCA Technical Committee (Boxster/Cayman)

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Racecar spelled backwards is Racecar

"Racing is life. Anything before or after is just waiting" ... Steve McQueen as Michael Delaney in "LeMans"

"If you wait, all that happens is that you get older"... Mario Andretti

"Being second is to be the first of the ones who lose" ... Ayrton Senna

Warning!
Risk of damage!
Only place the vehicle on its wheels or push it after the rear-axle support, the sheet metal brace, and both the diagonal braces have been installed.

Kind of reads to me the sheet metal brace thing has some bracing/stiffener aspect to it.

Sincerely,

MarcW.

It says that because if the diagonal braces are loose and you load the suspension by placing the car on the ground, the whole rear alignment will be out of whack.
They mention the "sheetmetal brace", because the "sheetmetal brace" is mounted first, then the diagonal braces and finally the nuts that secure it.

I'm surprised they don't have more CYA sayings such as:
Warning!
Risk of damage!
Only place the vehicle on the ground after the wheels have been installed.

Happy Porscheing,
Pedro

Pedro Bonilla
1998 Boxster 986 - 311,000+ miles: [www.PedrosGarage.com]
PCA National Club Racing Scrutineer - PCA National HPDE Instructor - PCA Technical Committee (Boxster/Cayman)

---

Racecar spelled backwards is Racecar

"Racing is life. Anything before or after is just waiting" ... Steve McQueen as Michael Delaney in "LeMans"

"If you wait, all that happens is that you get older"... Mario Andretti

"Being second is to be the first of the ones who lose" ... Ayrton Senna

That was my thinking....the diagonal braces are substantial enough to be structural but the center plate is too thin/weak to be a brace.

I'm puzzled as to why one can't reset the eccentric to matching location to maintain camber.....the entire eccentric adjustment range can't be more than a few degrees at the wheel, and one should be able to mark and return the eccentric bolt to within a few degrees of the eccentric bolt's rotation. But I'll take your word for it....just can't follow why it's not possible...

..... is just not precise enough.
I tried to see how precise some time ago by setting magnetic laser pointers on the rear rotor before the work was done.
Then I carefully marked the eccentric.
The work was performed.
I placed the eccentric back to my markings and went to see the lasers.
They were both (vertical and horizontal) by a substantial margin.
I then reset by the laser pointers and looked at the eccentric and it was off by 1.5 marks.
It simply doesn't allow repeatability.
You will be close enough to be able to drive the car to the alignment shop but not much further if you like your tires.
Happy Boxstering
Pedro

Pedro Bonilla
1998 Boxster 986 - 311,000+ miles: [www.PedrosGarage.com]
PCA National Club Racing Scrutineer - PCA National HPDE Instructor - PCA Technical Committee (Boxster/Cayman)

---

Racecar spelled backwards is Racecar

"Racing is life. Anything before or after is just waiting" ... Steve McQueen as Michael Delaney in "LeMans"

"If you wait, all that happens is that you get older"... Mario Andretti

"Being second is to be the first of the ones who lose" ... Ayrton Senna