Bill Ball

He didn't remove the rack from the u-joint. He dropped the rack from the cross-member, removed the lower A-arm from the inner mounts and removed the cross-member. Sean, Dave and Dwayne have all covered how removing the lower A-arm from the mounts introduces error in the alignment since the lower mounts are not indexed very well and even if you managed to do some position marking you are not likely to get them back to where they were before unless you are real lucky. The same thing can happen when replacing front shocks unless you manage to leave the lower A-arms untouched.

Parenthetically, I found my car and a local GTS, apparently with original racks untouched from the factory, to be a tooth off at the lower u-joint when checked with a centering bolt installed. The steering wheel was off-center, and as Dave mentioned, the steering wheel end of the shaft has 1/2 the teeth of the lower u-joint and rack shaft. No matter how I repositioned the steering wheel, it was off-center. So, I had to reposition the rack on the lower u-joint 1 tooth. In the GTS I was able to do this w/o removing the rack. Both cars were found to have had the steering wheel centered by offsetting the tie rods, which, as you indicated, is not right. In my case, the alignment tech at DEVEK found that my rack was off a tooth during the alignment and left my steering wheel off-center rather than offset the tie rods, and I corrected the problem later. Odd, but it appears the factory had committed that sin.

AO

I disagree. As long as the rack did not change it's position in relation to the crossmember, and the tie rods were not adjusted, it should in theory bolt right back up with the same geometry as before. BTW, the only thing might have changed would be the toe (more on this below). Caster and camber are affected by the eccentrics on the lower control arms which should not have been touched.

However, if your rack bushing were mush like many are and you replaced them, it is possible that the rack is in a slightly different position than before thus changing the toe.

SharkSkin

I guess we'll have to agree to disagree then. IMHO the chances of getting the lower a-arm bushings back in exactly the same position is pretty slim. The rear bushing on each a-arm in particular is not round, it's kind of a squashed shape with bulges where the crossmember and caps meet. If it is rotated in the slightest, it can move the effective pivot point in or out. Even if you do your best to line them up the same, it can shift depending on how evenly you torque down the cap bolts. If the crossmember goes in shifted 1mm to the right, you will have more negative camber on the right wheel and less on the left. If the a-arm is mounted a bit forward of where it was mounted previously, you will have different caster.

The proof one way or the other would be getting an alignment baseline check, dropping the crossmember, putting it together, and re-checking the alignment on the same machine. Until that has happened a couple of times, I think it's safe to go with the Porsche recommendation that the car be aligned after this work.

Now, if we're talking about doing nothing more than dropping the rack -- disconnecting nothing more than the hoses, the lower plate, and the 4 bolts that hold the rack in place -- then I agree that no alignment should be needed -- worst case, your wheel is a bit off-center, but toe should still be correct.

AO

Yeah... i guess we'll have to disagree. I don't see how the lower control arm can change position. Both forward and lateral positions are determined by the carriers. The only variable is the angle or rotational position of the arm and this is determined by the shock/spring. The bushing merely dampens the rotation and protects against metal on metal contact.

I agree, that perhaps your experiment would be the definitive proof, but who really wants to go through all that to prove a point.... not me. At least not today.

blandis

My car had alignment a month before Brad helped me do my mm and pg. Drove it for a few weeks after and mangled the inside of the drivers tire and put nice wear on the inside of the passanger.
Took it in and had it redone, and it was out obviously.

If its me, an alignment is cheaper than 2 tires. If you dont do an alingment keep a close eye on your front tires. It only takes a few miles to ruin them.

SeanR

I've got proof in a set of tires, it's pretty simple, you change the geometry in the suspension, you mess up the alignment. If you take the chance (like I did with the wifes car), you pay for it in new tires.

The alignment was perfect before the mm/pg job, was not good after and I took the advice of some here and didn't it redone. Stupid move on my part.

aggravation

Thanks guys. I think I'll go ahead and go for the alignment since I'd also like to adjust the ride height back to the neighborhood of factory spec.
I swear I think Beau and Luke Duke took my car to Cooters garage for the last ride height adjustment and asked for the General Lee special! I had to raise the front a touch just to avoid hitting even the smallest bumps but I've been putting off changing it anymore until I found a shop that could do the alignment correctly but I found one and they say they have the Hunter machine that you drive onto and do the work without jacking the car up...so with all that and the steering being off too it sounds like it's time!
Should I wait until I get new tires too or does that matter? How about if I go from the 17" wheels on there now to new 18" wheels and tires? Would I have to do the alignment again then? Or does it not matter as long as the over all radius stays close?
Thanks again!

Rob Edwards

I would get the ride height dialed in on the old tires ( if you want to be compulsive I suppose you could factor in the differences in remaining tread thickness and sidewall height on old vs new tires), then have the new tires installed, then drive 50-100 miles to settle, then get an alignment.

Bill Ball

Hey Andrew:

The rack is not this issue here. The lower A-arms are. There is slop in the mounts to the body, and these mounts are unfastened to get the cross-member out. So, because of the slop, the A-arm can end up in a different location when reinstalled. Now, I've heard someone was able to replace the mounts without removing the cross-member, probably by lifting the motor rather high, avoiding disturbing the A-arm mounts, but I've not tried that.

AO

Well if you guys have proof that the geometry gets out of wack, I guess I have to believe you. I've not experienced it. I also do my own alignments at home now, so it's not that big of a deal to check. That reminds me I need to finish my excel alignment calculator.

RyanPerrella

Im with andrew in that i dont really see how alignment gets out with the a-arms lowered and then replaced. the rear mount is fixed, i guess the front could change but if we agree that the rear doesnt move, then how could the front move once its all torqued to spec?

I do understand that dropping the rack can give you an alignment issue with the wheel direction due to soft rubber mounts going in in not exactly the same spot, but i dont see the a-arm removal being an issue.

all in all its never a bad idea to get an alignment, but in curious why some say its mandatory for this specific procedure?

SharkSkin

The rear mount is not fixed, it comes out with the crossmember. There are features at the crossmember/body interface that help locate the crossmember to the body but it's not perfect and the rear bushing is not positively located in its mount.

Anyway, it's your tires -- do what you like.

Mako 928

This is all very interesting. When I pulled my motor 11/07 and got it back on the road 3/08 I did not get an alignment. I then had a "obstruction" in the oil pan and had to drop the steering rack/crossmember to get to the oil pan. The only problem I encountered was not getting the steering coupler aligned exactly as before, I was one spline off which I then corected and still did not get a alignment. I do have the solid rack bushings from Carl. From then until now I have auto-crossed it and driven the hell out of it and I have even tire wear and it handles as it did before I did the work.
Now I am not disagreeing W/ the advice given here as he obviously needs this corected. I am just wondering why I have been fortunate with this.

Bill Ball

When you push the lower A-arm back up into position to reinstall it you will notice there is measurable play in the holes through which the bolts pass. Certainly the holes into which the bolts screw into the body are fixed, but the A-arm itself has slop in the bolt holes. That's all there is to it. When I have marked the position of the arm mounts prior to removal, I have had to pry the mount back into position after inserting and partially tightening the bolts. The front is worse than the rear. There is fore-aft play in the front, and the rear bushing slides into the mount, so it is easy to get fore-aft misalignment. If either are out of position from before removal, the alignment is different.

Sure, you can remove that A-arm and remount it and have it all fall right back into place. Great. But when I have marked the position before removal I've had to struggle to get it back in the same as before.

Chuck Schreiber

I'm going to concur w Dave, Sean, Bill Ball, Dwayne, and Brad (Blandis) on this.

Blandis and I did our MM and pan gaskets the same day at different places. (His w Brad Webster, mine w Sean) Both Brad's S and my GTS had recent alignments done prior to the the procedure. (Mine had about 1,500 miles on the alignment going into it)

First 2 things I noticed driving away from Sean's house. 1-my car was silky *** smoothe!!! 2-the wheel was at 1 0'clock and pulled as well.
We discussed this that night over several beers at Sean's house after both jobs were done and we were basking in our glory. Sean said several times that chances are, you both are going to need alignments. Sure enough!

I'm looking at specs (I can try to scan and post if anyone is interested) Comparing previous alignment done 1,500 miles prior (baseline) -that one was dialed in **** on.
Fast forward to post mm job. Alignment sheet specs. Front-looks like toe was thrown out, as was cross caster, and total toe.

They dialed it back in and the wheel is straight up at 12 o'clock and it tracks straight as an arrow.

I have to admit that during the job I figured that by simply unbolting and bolting everything back up, and the fact that we did NOT remove rack (from steering shaft) I would NOT need an alignment. After this job, driving the car, and looking at the align specs, I'm now preaching alignment after performing this procedure!!