Alignment

I am looking at a 512TR, left hand drive. Private sale, friend of a friend. Vendor tells me car had damage along one side when he hit the barrier on the side of a road years back. Since then, it has been serviced at main dealers/specialists regularly. PPI is all fine; alignment check is all well within specifications with the exception of one measurement (front, left, lead) which is 5 degrees 50 minutes where specification is between 5.15 and 5.45.

That's what it was adjusted to during the test & correction. Right is 5.31.

My question, not knowing about these things, is: is that OK? Am I being paranoid? Everything else fine and the inspecting dealer says fine. Thanks for any thoughts.

 

I would not worry about it. You will not be able to tell the difference between what it is now and in specification. More than likely the measurement error (5 minutes) is greater than the error you are concerned about. If you redo the measurement, you have a 50/50 chance of it being in specification next time without changing anything.

For background, more lead or caster will make the steering heavier at low speeds and less likely to follow the grooves in the road at high speed i.e. freeway speeds. Less lead or caster will do the opposite. If there is over 30 minutes to a degree difference side to side then there is a risk it could pull to one side at speed. However, if it does pull to the side check the tire pressure first. It is more likely to be the cause then the lead.

Cheers Jim

 

Caster or lead may have been intentionally set mismatched to deal with the crown in your roads. Which side having more positive caster will depend on whether you drive on the left or right side of the road. Either way that small difference won't be noticed and the most important thing is that little discrepancy is not likely due to the accident. There are other things to be measured to make sure the chassis and body are correct. You don't do that at an alignment shop. You do that at a body shop who has the right tools to check the multiple reference points along the chassis for proper relative position in 3D space.

 

Got it. So chassis alignment doesn't necessarily have anything to do with wheel alignment. Thank you.

 

If you want to do a simple chassis alignment check to get comfortable with the purchase, you can use a plumb bob and a marker. Hang the plumb bob off the bolt were the suspension bolts to the frame and mark the ground where the plumb bob points to. Note you must use exactly the same procedure and location on each side of the car. It is very easy to make errors that will affect your results. Once you have points for each front wheel and each rear wheel, then you need to measure each side (front to rear) and diagonally (left front to right rear and right front to left rear). If everything is good the side measurements and the diagonal ones should be within a 1/4 inch of each other. If they are 1/4 to 1/2 inch off it is a little bit of a grey area if it is an issue, anything over a 1/2 inch is clearly a problem.

Cheers Jim

 

Thanks Jim, appreciated. I'll take a look again.
Darius