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Discussion Starter · #1 ·
Hey guys,

Didn't think I'd be posting so soon with an issue but unfortunately my 2010 Cayman S is pulling to the right slightly.

Backstory: I purchased the car CPO from a not-so-local dealer (apx 500km away) with just over 30000km on it. It had a clean bill of health (no prior issues, accidents, etc) according to dealer and carfax, and as part of the process they fitted a brand new set of Michelin Pilot Super Sports.

I've only put about 3000kms on the car so far (as it spent a few months in the garage while I waited out winter) but I've been noticing a slight pull to the right in recent weeks. After fiddling with the slightly uneven tire pressure from its winter slumber I had to accept it was likely an alignment issue.

I took it in this morning to my local dealer (not the one who sold the car) and had them perform an alignment. They pulled a few numbers into the Porsche specified range, as well as noticed that the front right caster is at the low end of the specified limit. The technician that drove (briefly) the car noticed the same slight pull that I did, which was still present after I picked it up. Without further diagnosis they're not sure what's causing it, and have offered to do a ride-along with me to chat about the issue and potential investigative/corrective measures.

Before I start throwing more money at it I was hoping someone might be able to provide insight or point me in the right direction. In case it helps, here are the alignment numbers they recorded:

Text Font Line Parallel


The service technician also advised that the caster is at a non-adjustable angle. I asked if it was a potential cause for the pull and he said its highly unlikely that the caster would affect alignment like this.

Anyone have any similar issues, and/or an inkling of what might be causing the pull? It's not severe enough as to pose a danger, and is only noticeable on straights - but obviously I'd prefer to not have my car pulling at all. It's a bit annoying and I worry that it will cause uneven tire wear in the longterm, if not something worse.

Appreciate any and all advice/recommendations!

Thanks fellow enthusiasts,
Caydan
 

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caster difference can cause pull to the side.
right caster lower by almost 3/4 degr -> right side wants "less" to keep it straight = possible explanation why your car pulls to the right.

caster is not adjustable - so it has to be something in the suspension.

basicaly it's defined by the 2 arms (#3 and #6) and the shock strut:

 
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Discussion Starter · #4 ·
Thanks for the replies guys!

If I'm understanding this correctly, the caster is potentially the issue despite what the technician said, but because it's not adjustable I'll need to have someone investigate the suspension itself and see what can be done to offset any disparity caused by the caster?
 

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Discussion Starter · #6 ·
That's a good idea actually, I hadn't though of swapping the wheels simply because they should be relatively fresh (just over 3200 kms/1900 miles); but it might be worth a shot. I'll need to get a jack and try swapping them myself.

Not sure on the right brake rotor; is it something I can discern with a visual check?
 

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Discussion Starter · #7 ·
caster difference can cause pull to the side.
right caster lower by almost 3/4 degr -> right side wants "less" to keep it straight = possible explanation why your car pulls to the right.

caster is not adjustable - so it has to be something in the suspension.

basicaly it's defined by the 2 arms (#3 and #6) and the shock strut:

Any idea how the caster would have ended up lower given that they're non-adjustable? Just wear and tear over the car's life?
 

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When you have the right front wheel safely removed see if the rotor spins freely. If it doesn't you might have a caliper piston that isn't retracting. When was the last time you replaced the brake fluid? Porsche wants it replaced every two years regardless of mileage. Good luck.

You may have wear and tear on #3 & #6 from a pothole or curb contact.
 
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That's a good idea actually, I hadn't though of swapping the wheels simply because they should be relatively fresh (just over 3200 kms/1900 miles); but it might be worth a shot. I'll need to get a jack and try swapping them myself.

Not sure on the right brake rotor; is it something I can discern with a visual check?
You can't just swap the wheel from left to right as the tires are usually directional in rotation which means swapping would have both tires rotating in the wrong direction. You would need to have the tires removed from the wheels and then switched to the opposite side.
 

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just for the test drive there is no problem to install the tires in opposite direction.
just don't drive 150mph for 6 month like this :hilarious:.

why caster changes?
i can see only either geometry of the parts involved (arms, strut, chassis, etc) or some bushings wear.
but after 30,000 km i would expect bushings to be OK.

wheel/tire balance and air pressure were checked?
 

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Discussion Starter · #11 ·
Tire Pressure is good (fronts and rears identical 33/33 - 34/34 cold.) I'll admit I don't have the knowledge or means to check the tire balance, but I'll check with the dealership that I bought the car from when I visit next friday.

It's a bit of a hike normally, but I happen to be going by their location so I booked an appointment to have them look at the car (thus giving me a second opinion).

In the meantime I don't yet have the tools or means to remove the wheels and check the brake calipers. I did notice when I took it out for a quick drive (-20 mins) yesterday that the car may also experience the slight pull when applying brake pressure. If I was genuinely feeling it, it further leads me to suspect Rob's theory of it being a possible brake caliper issue. Or at least that the brake caliper may be involved.

On an unrelated note I finally located what I believe to be a source of a weird burning smell while the car is running...Somehow a plastic bag or wrap got stuck on the left exhaust pipe where it sits next to the rear left wheel. It's partially melted/grafted to the pipe now and will clearly remain as such until it fully burns away or I find a way to remove it. Here's a picture I just took: Auto part Vehicle brake Tire Disc brake Brake


Anyone ever encounter anything like this? Just wondering how much of a fire hazard it is; and how to safely remove it without damaging the exhaust itself.
 

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A short test drive with tires swapped will not cause a problem. You might want to check the date code on the front tires to see if they are the same. Seems like a long shot, but if one was substantially older than the other maybe that could cause an issue due to the condition of the rubber.

A quick and easy crude check of whether a brake is dragging is to feel the calipers after a test drive, preferably after limited brake usage (I'm envisioning a 15 minute drive on an interstate then coasting into a rest area). If one is substantially hotter than the other it is likely dragging. Back in the old days I occasionally had rusty caliper pistons stick and the calipers would get smoking hot.
 

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At this point the melted plastic on the exhaust is probably not a fire hazard. I'd certainly want to get it off though, if only to get rid of the smell!

I think your best bet would be a putty knife, and scrape off the plastic at a shallow angle, like you were removing old peeling paint from a board.
 

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I think your best bet would be a putty knife, and scrape off the plastic at a shallow angle, like you were removing old peeling paint from a board.
I would put a wire brush wheel on your variable speed drill - that should remove it cleanly.
 
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