jeff spahn

I have a vexing issue after my rack busing and oil pan gasket job.

My problem is a pull to the left. Now, yes I have had it aligned. Twice.
I have attached the alignment report as well to show where it sits.

It didn't pull at all before the rack bushing/pan gasket job.

What I did during job.

1) Took out crossmember
2) Put in OPG and derlin rack bushings cause my rubber ones were 7 years old. Rack is 7 years old. As are tie rod ends on inner and outer. They are not loose or wiggly. Ball joints are good as well.
3) Loosened passenger side Upper Control arm to cross member brace so i could get that damn horizontal bolt in and out easily. I retorqued the bolt on the Upper Control Arm to 102ft lbs like spec says. (I did this last time too and had no pull)
4) Put everything together to factory torque specs.

What I have done to attempt to remove pull:

1) put it back on stands and removed/reinstalled the LCA bushing caps.
2) put it on a drive on lift, just taken the weight off the wheels with the bottle jacks, removed LCA bushing caps and moved the LCA around then put caps back on and torqued down.
3) Had it aligned again. Numbers are all in the green.

What am I missing here? What nugget of knowledge can the group impart on me to get the pull out of the car. I can't think of what would be causing it.

I know a wheel isn't bent or anything because it didn't pull before the job, but did right after.

Bilal928S4

Did you mistakenly switch the front left & right wheels?

GlenL

I'm sure it's been checked, but how about tire pressures?

jeff spahn

Front tires are directional and they are on the proper sides. Tire pressures are exactly the same in each tire. (use a device that inflates both tires at once and balances pressures).

See what I mean. It's making me nutty(ier).

Bilal928S4

I have never personally replaced the steering rack bushings, but seen the carnage of removed bushings. Do the rack anchoring points look straight? Did the Delrin bushings sit flat and are well seated? It could be that the rack is sitting just a little crooked?

jeff spahn

Bilal. I looked at the rack mounting. Went in beautifully. Bushings are fully seated.

the flyin' scotsman

when the rack was loose (having the bushings replaced) did the steering shaft and/or wheel move?

SeanR

How are your upper A-arm ball joints? They can be aligned on the rack but you will get movement as you are driving, causing a pull one way or the other.

jeff spahn

The wheel was still pretty much centered. No different than when I started the job. It was made damn near perfect when the alignment was done.

jeff spahn

The question is why would it change only after the OPG/Bushing job. Absolutely spot on perfect tracking before. Pulls to the left now. One finger correction type pull. The kind that just is hard enough to make you crazy.

the flyin' scotsman

ok.......theres a centering pin for the rack...........was that used?

jeff spahn

I have the centering bolt. It wasn't used. But then it never has been used on any other alignments and the car has tracked perfectly. I am going to take the car in again today at 4 and give them suggestions from you guys so keep them coming.

dr bob

Jeff--

When I did the rack bushings, I got the same results plus the steering wheel was no longer centered. So obviously the rack was displaced laterally to get the steering wheel off center from where it had been. The pull to one side wasn't severe, but I'm getting really **** about the car driving perfectly so I went after the whole alignment again from scratch. I can tell you that it's incredibly important to have both sides of the car the same as far as camber and caster. Miss by more than the tiniest bit and the car pulls. It's somewhat common for techs to do a drive test, and tweak one adjustment to get it to drive straight, and call it good. That's fine if you are correcting for your slightly-crowned roads, but you need to start from symmetric readings if at all possible.

The local specialty alignment/frame shop recommended by area owners did mine twice, and proclaimed it perfect. Into the second set of P$-2 tires on their "perfect" alignment, I was still getting inside rib scrubbing. So I started out by making some fixtures to hold common laser levels so I could verify toe and camber. I found that my "perfect" camber was off a little, and toe was off a bunch. Mind you that I'd sat under the car with the alignment guy and did everything except turn the wrenches, and he'd done everything right. So I double then triple-checked my calculations and methods before adjusting anything. I don't have slip plates or turntables so it was adjust-drive-measure, then adjust-roll-measure for the last few.

Since that initial effort, I've added digital angle gauges to the mix so I can calculate and adjust caster. I used the calculation and method described in the Porsche alignment guide (copy is in the Morehouse CD set), backed up by the instructions included with a known aftermarket alignment tool-set. I've refined the toe measuring method to get fixture differences out of the variables list, generally refining to get closer to the truth. So far so good with results. Driveability is excellent, tire wear is very predictable now. Plus having the tools means I can check settings easily, less than 10 minutes to verify everything if there's any question. Adjustments are very interactive so if it needs correction, time moves out to an hour or so. I've got vernier labels wrapped around the tie rods and ends now, making toe adjustments extremely predictable. The caster and camber are still iterative loosen-bump-tighten-measure though; marking the adjustment cams doesn't give repeatable results unfortunately.

There was a good thread on DIY alignment here several years ago. Worth a read if you have any interest at all in taking a crack at it yourself. As nice as the Hunter machines are, all it takes is putting down one of their wheel assemblies a bit hard, and every subsequent user is doomed.

FredR

Jeff,

I did the delrin bushes on my rack a short while ago and had no problems whatsoever. As Dr Bob says important to have good side to side balance but I see nothing on your alignment sheet that makes me think it would cause your problem. I would go for 5 degrees on the caster and a bit more front camber- say 1 degree with a stock front wheel but whether that would change anything wrt your problem I doubt it. I would look for both these numbers to be within 0.1 of a degree. No excuse for toe not to be identical both sides and your toe settings are in the mid range.

I would also think that if something was not re-fitted correctly it would show up on the alignment if it was enough to pull to one side. Similqrly going from sloppy rack bushes to tight delrin ones should only help the system.

Apologies but I cannot think of anything more useful.

Go lluck

fred

Leon Speed

I don't have anything near as eloquent to add as dr bob did, just wanted to share that the lower control arms should be torqued down when the wheels are on the ground. Wheels in the air, tighten the bolts as much so that there is a little gap ~ few mm, then put the car n it's wheels and then torque them down.