Front Caster Is WAY off

[awdconnor]

Hey There, Over the past few weeks I have been dealing with a weird caster situation and was wondering if anyone else has seen/had the problem.



As you can tell by the photo, the car is about 2 degrees off on the driver side. Not only can you visually see the problem, but ive had the car aligned twice (once by an indy shop, then at the dealer) to confirm.
When I had the car on the rack at the first shop, the mechanic and I were going over the underside of the car. Nothing looks wrong or out of place. Both side suspension setups look identical in terms of age and use. No bushings are shot, I hear no sounds while driving.
The car doesn't pull, the Camber and Toe are in spec and perfectly fine.

The car spent about a week at Audi. They tech first put it on the alignment rack, preformed a normal wheel alignment, and confirmed that the caster is 2 degrees off. He too, agreed that the car doesn't look like anything is bent or out of the ordinary. No scrapes on the belly pans, very light scratching on the lower control arm, but "didn't look like that could be the problem. He recommended me to go to a body shop and check to make sure the frame was straight. Now, im feeling discouraged with the car. While visually on the outside I can tell no body panels have been replaced to indicate that maybe there was an accident that wasn't on the CarFax. Im a BIT OCD so when I look at the car I can visually see the problem, and I worry that in the future with a wider wheel and tire setup, that the scrub radius could be affected and would cause rubbing.

My assumption, the previous owner Hit a curb in a parking lot, or a parking block and bent something so slightly that it caused the caster to shift, or possibly even the subframe shifted upon "impact".

The main questions:
What would you do? I bought the car about 2 months ago.

I know that B8s had a subframe alignment tool that could shift the subframe for an alignment, but I was told by the audi guys that that was only for camber, but I believe it can help with caster too.

Would 034 Upper control arms adjust caster like the SPC arms claim to do. I wouldn't worry if it were less than a degree off, but 2 is a bit much for me..

Any insight, thoughts, or opinions would be greatly appreciated.

[BaggedB9S4]

That really does sound like something is bent. Was the car ever in an accident?

[dak656]

FWIW - my car was aligned when it was brand new… has been part of the sales deal for me for all new cars we’ve bought, and of the five vehicles we’ve bought this way… all five needed alignment when they were brand new. Good way to eat factory tires if the alignment isn’t right.

Anyway, it was 4.51 driver side, and 4.75 pass side. Hope that helps.

Any pothole damage on the wheel, or does that wheel look like it’s been replaced?

[awdconnor]

That really does sound like something is bent. Was the car ever in an accident?

FWIW - my car was aligned when it was brand new… has been part of the sales deal for me for all new cars we’ve bought, and of the five vehicles we’ve bought this way… all five needed alignment when they were brand new. Good way to eat factory tires if the alignment isn’t right.

Anyway, it was 4.51 driver side, and 4.75 pass side. Hope that helps.

Any pothole damage on the wheel, or does that wheel look like it’s been replaced?

@baggedb9s4
The CarFax claims that there was "minor front end damage, cosmetic. The belly pans show no sign of impact, the lower control arm has slight scratching. But doesn't look like enough to bend since these lowers are quite beefy.

@Dak656
Thats my assumption that someone hit a pothole at some point because on the CarFax, it states 2 front tires replaced. Interesting. so it seems like both sides are incorrect on caster spec. The more I research the more it screams subframe to me. Wheel doesn't look to be replaced. Shows the previous wheel weight adhesive as the passenger side. If it were new, there would be 3 total strip lines. (OEM set, Replacement set as per the CarFax, and the new contis I just got.)

[sbruno624]

I slammed my A3 into a curb, same situation, nothing looked broken and on the rack everything seemed fine. Car never drove straight again despite constantly having alignments done.


Sent from my iPhone using Audizine

[awdconnor]

I slammed my A3 into a curb, same situation, nothing looked broken and on the rack everything seemed fine. Car never drove straight again despite constantly having alignments done.


Sent from my iPhone using Audizine

I see, I ordered upper control arms to see if that would do anything. Next plan of attack would be to try a new lower control arm, then try to get under the car and shift the subframe myself since audi is too scared to do so... My car drives straight which is the oddest thing

[RoverJoe]

You would have the shift the subframe front/back to adjust caster, which would screw with all the other angles too. You can even out the camber by shifting left/right, but the total will remain the same.

Also, if it drives straight, what's the issue? Caster can cause a pull, but wont' affect tire wear. If it drives straight, leave it alone.

[awdconnor]

You would have the shift the subframe front/back to adjust caster, which would screw with all the other angles too. You can even out the camber by shifting left/right, but the total will remain the same.

Also, if it drives straight, what's the issue? Caster can cause a pull, but wont' affect tire wear. If it drives straight, leave it alone.

Thats where im at with the subframe.

Main reason for this whole debacle, is I will be bagging the car. And when the time comes for wider wheels, the wheel will sit very awkwardly in the arch, not to mention the scrub radius is all jacked up now to.

[RoverJoe]

Then you probably need to replace the arms and knuckle. I see plenty of bent knuckles on newer cars where there is no visible damage but the alignment is out of spec.

Caster doesn't affect how the wheel sits in the wheelwell. You have to do a caster sweep so it can measure it, it's not a static angle, it's only present on turning. Yes your scrub radius will be uneven, but so what? You won't be tracking the car on bags.

[awdconnor]

Then you probably need to replace the arms and knuckle. I see plenty of bent knuckles on newer cars where there is no visible damage but the alignment is out of spec.

Caster doesn't affect how the wheel sits in the wheelwell. You have to do a caster sweep so it can measure it, it's not a static angle, it's only present on turning. Yes your scrub radius will be uneven, but so what? You won't be tracking the car on bags.

Caster absolutely can depict where the wheel sits in the wheel well. Either way, track or not it’s still something I will be addressing


Sent from my iPhone using Tapatalk

[awdconnor]

Tried to replace the upper arms this morning, they made no change. Onto the next...

[deviantspeed]

How much deeper are you willing to go into this?

Caster angle would be something most likely fore to aft Since you replaced the upper links, I'd suspect the two lower links. But maybe something with the spring/strut assembly kinda stands out. Think like if you were able to grab the top of the strut mount and move it, fore and aft, caster angle will change and with everything else static, wouldn't affect anything else greatly.

Being that camber and toe were in spec, I'd just throw a wrench at it. Left and right side are the same springs/struts, so I'd just R&R the assemblies by swapping sides, and see if things change. That's not for everyone though. That's where I'd start in this puzzle.

If the body was damaged, I would almost certainly expect to see a change in either toe and/or camber with caster. But it's just caster that's off. Quite odd and frustrating, especially when you may notice this a lot more when bagged. That's about all I got right now, but good luck!

[awdconnor]

How much deeper are you willing to go into this?

Caster angle would be something most likely fore to aft Since you replaced the upper links, I'd suspect the two lower links. But maybe something with the spring/strut assembly kinda stands out. Think like if you were able to grab the top of the strut mount and move it, fore and aft, caster angle will change and with everything else static, wouldn't affect anything else greatly.

Being that camber and toe were in spec, I'd just throw a wrench at it. Left and right side are the same springs/struts, so I'd just R&R the assemblies by swapping sides, and see if things change. That's not for everyone though. That's where I'd start in this puzzle.


If the body was damaged, I would almost certainly expect to see a change in either toe and/or camber with caster. But it's just caster that's off. Quite odd and frustrating, especially when you may notice this a lot more when bagged. That's about all I got right now, but good luck!

Thanks for the reply!

The same thought crossed my mind yesterday as I was replacing the uppers. I tried to stand back and look at the shock but its hard with just the eye. My air ride kit should be coming in soon, and at that point I can pin point it down to the strut. Ive been under the car 3 times now and really cant see anything that would be bent. Im gonna take it to a local euro shop and see if WE can throw it on the alignment rack, try to unbolt the subframe and shift it slightly. Ill go as deep as possible to get it resolved as I plan to keep the car for a very long time.

[RoverJoe]

The strut does not affect alignment angles, it's the arms and their attachement points. In a Mcpherson setup yes, but in our multi-link system, it's the knuckle and arms, which are not interchangeable.

A digital inclinometer might be of use, but you would have to check very carefully to see something that is setting the camber off by such a small amount. You could measure the arm mounting points from a relative point on the subframe, there was a fixture and measurement specs for this type of process at MB when I worked there, not sure if Audi has the same. But if you did the uppers and it didn't change, then your lowers or knuckle is bent, or the left side of your subframe is moved (unlikely to be the case with the other angles ok).

[awdconnor]

UPDATE:

Turns out the reward lower control arm was bent. Replaced and caster is back to 4.4/4.7.


Sent from my iPhone using Tapatalk

[RoverJoe]

Good find, glad you got it fixed!