What is this mechanic doing?

[Johnzoly]

When ever this one mechanic works on my car it comes back with fine black powder streaks on all four of my Fuch wheels. This powder never shows up when I've driven. I'm questioning if he does not take the parking brake off, or doing burn outs, or racing the car (1988 stock 911). The work he has done never requires wheel work.
Thanks for reading/answers.

[vesnyder]

Where does he do the test drives? I would question where he drives it, not how.

[Flojo]

picture?

powder streaks? e.g. brake dust? => hard testdriven *gg*

[LIRS6]

Suggest to ask him - and as well to note mileage before/after servicing

[Johnzoly]

Street driving. Sorry, no pics. Cleaned them up. Powder streaks running north and south, east and west from center of wheel.

[ossiblue]

It sounds like brake dust, as others have said. Question is, of course, why does it appear only after he does work on your car? Does he wash the car after each service as some shops do? If so, what you see may be a result of the water spreading the dust to the wheels as the car is driven a bit to "blow off" the excess water.

Just trying to come up with a plausible explanation. Since it's noticeable to you, you should ask the mechanic for an explanation.

[Johnzoly]

No, he does not wash car. I believe it is brake dust also. Will have to ask. I believe it's being driven hard. Thanks.

[Daugaard]

No. Brake dust never come from the center of the wheel.

(Powder streaks running north and south, east and west from center of wheel.)
I think he lube the center and nut when the wheels are of.

[Matt Monson]

He might just be blowing out the brake dust with compressed air when the car is on the lift.

[75 911s]

He was doing asbestos he can.

[Johnzoly]

Sorry, when I say center I mean where these red marks are.
And yes I did clean up the wheels with petroleum jelly. I am calling the mechanic but I am thinking he may have blown the brake dust out as part of his maintenance. (But one would think he would finish the job by cleaning it up).

[Pichu]

He's cleaning the carbon off the pistons. Free of charge.

[Quickstep192]

I'm curious to hear the mechanic's answer.

[boyt911sc]

I get similar marks after spraying brake cleaning aerosol like Brakekleen. Those deposits were probably the drip marks of the cleaning solvent (?).

Tony

[Flojo]

brake dust don't slow you down. now get out and drive!

[ant7]

+1

Originally Posted by matt monson

he might just be blowing out the brake dust with compressed air when the car is on the lift.

[Johnzoly]

Ok, still waiting for the mechanic's response. But while I was looking again at the wheels they looked a little off to me.

While waiting on the mechanic, I thought I'd ask the "Brain Trust" here on PP.

Using a straight edge from the rear body edge shows the rear driver side tire is in more.


A better view from above shows how far or close the sides are.


Is this something I should be concerned about? Normal? Something needs repair?
When I bought this 911 seller stated it was an accident free car, Carfax stated no accidents and PPI saw no signs of accident damage. As you can tell, I'm new to classic cars. I know back in the day, manufacturers were not as concerned about door and panel fit as they are today.
Thanks.

[ossiblue]

It's not unusual, from my experience, to find the body panels to be off a bit, relative to the wheel openings, side to side.

It's hard to tell from your pictures exactly what you're measuring, but I assume the top two pictures are the passenger side and the bottom two are the driver's side. My concern would be if there is a wheel alignment issue rather than a body panel issue. The bottom two pictures could be interpreted as wheel alignment, but since the straight edge is against the body, that's not a good determination to make--you need to align the wheels in reference to the suspension.

My opinion, get a four wheel alignment check and if everything's in spec, don't worry about the panel differences.

[smokintr6]

I cant tell anything from your pictures of the wood pieces, but the wheels are different sizes front to back, and it is possible to install them incorrectly. They could have both rear wheels on one side of the car (left to right), or they could have mixed up the front to rear position.

If there was no other wear on the car, tires, paint, interior etc, I wouldn't be worried about a little brake dust. streaks in that area of the wheel can also appear when the car gets rained on, so if you're storing inside and the mechanic parks outside that could be the cause. You can easily tell by visual checks on the tires if the car is being driven too hard, or being used for burnouts. I know my driving style creates dust even in my daily driver. No, the mechanic should not be abusing your car, but if he has done repair that requires a test drive, asking him to drive it with "kid gloves" on might not be reasonable. It's a sports car, and and to make sure it works correctly as such, a proper test drive might create a little brake dust. If you came to me and accused me of abusing your car with no other evidence than some brake dust, I would turn you away as a customer in the future. If your car is a museum piece that's never used as a sports car, you should probably just politely ask them not to test drive it at all. On the other hand, if he installed the wheels in the wrong position, I would find a new mechanic in the future. That's not the right level of attention to detail for working on high end vintage cars.

[Johnzoly]

And the answer is... blown out brake dust on lift. As for the rear tires' in and out he feels it's part being a hand made car and in need of a four wheel alignment. Thanks to most of you for your answers, thanks for playing! And as Flojo stated "get out there and drive"!!!