Frame Alignment

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timberstone
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Frame Alignment

Post by timberstone » Thu Jun 11, 2020 4:45 pm

Vehicle in front backed into the MGTC, while stopped, striking the right front area of the MGTC.
The impact was sharp and knocked the MGTC backwards causing damage to the front right corner of the MGTC where the frame rail meets the front cross piece.
Upon inspection, very little sheet metal damage is apparent, but noticed cracked paint in the front splash apron so that it may have gotten bent. Also noticed, after driving about 15 miles, that the outer treads on both front tires (original unworn Dunlops), appeared to be slightly scrubbed off.
The wheel alignment had been recently set after installation of the MW Steering Box (replacement of the BC box).
During the recent frame off restoration, the values for square were within 1/8" or less.

Used measuring form to determine wheel alignment which showed the result that is pictured below.
Note that you can see some of the scrubbing off the outsides of both of the tire treads.
IMG_3149.JPG
Have not been able to find any shop in the area willing to check frame alignment. Even have difficulty finding any shop that will consider doing just a wheel alignment.
Question:
Whether the outer tread wear is normal for the camber value determined at the factory?
Or is outer tread wear caused by improper alignment?
Thinking that the frame might be 1/4" off square, would it be possible to just use a cable wench to ratchet it back into square?
Does the body tub have to be loosened off the frame to check and readjust the frame alignment?
If so, then how much to pay a specialty shop and where would such a shop be?


Octagonally yours, BOXLEY (Robert and MGTC0820)
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IMG_3148.JPG

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stephen stierman
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Re: Frame Alignment

Post by stephen stierman » Thu Jun 11, 2020 5:58 pm

I doubt very much that your collision is the cause of your tire ware in 15 miles. The combination of positive camber and toe in can cause the odd patterns that you are seeing. Has anyone owning a TC ever seen fairly even wear all the way across the tire tread, I'd be curious to know.
As far as chassis alignment, certainly a tape measure and a string, run around the four corners can tell you a great deal. Check wheelbase on both sides as a start. There are many ways to straighten a bent chassis and most would require some disassembly if not all. TC2911 suffered a side impact at some point in its life that we discovered when the chassis was on stands and by careful use of timbers and hydraulic jacks we were able to straighten things as required.

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Steve Simmons
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Re: Frame Alignment

Post by Steve Simmons » Thu Jun 11, 2020 6:43 pm

Sorry to hear about the accident. I hope they have good insurance in case this turns into a big repair. Unfortunately I can't help with alignment shops in your part of the world but hopefully someone else can.

The problem with a front end collision in a TC is that the wheels stick out farther than anything else, so unless you were really lucky, the right front wheel probably took a substantial blow. The very first thing I would do seeing that the alignment is off, would be to check the steering linkages, steering arms, rod ends, etc for damage. I would also check the wheel itself for true (straightness) both vertically and laterally. Next, I would definitely check the axle alignment, especially castor and also straightness from tip to tip to ensure the right extension isn't bent backward.

The chipping on the frame concerns me as well. Obviously the frame flexed a great deal. Or did you just mean the apron itself? I don't know the process to measure a frame on a fully built car but I sure hope it can be done. If not, then you may have an insurance battle ahead of you because that would be an incredibly expensive job to have a professional remove the body and whatever else to check and possibly align it. I just had a bare frame aligned recently and it ran about $450.

Just an aside, the tires on my TC wear very evenly. I run Dunlops (actually Ensigns now that real Dunlops are no more) and haven't noticed feathering. Maybe I haven't been looking close enough as the tires wear. Here are my current tires with several thousand miles on them...
Attachments
front-right.jpg
front-right.jpg (49.26 KiB) Viewed 1720 times
front-left.jpg
front-left.jpg (57.34 KiB) Viewed 1720 times
1949 TC8975 / XPAG 9609
1948 TC6011 / XPEG1182 (XPAG6472)
http://www.mgnuts.com

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SteveW
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Re: Frame Alignment

Post by SteveW » Fri Jun 12, 2020 1:36 am

If you think that your steering geometry has gone off as a result of the impact, the easiest thing to check would be the tie rod and drag link. If they have been bent the you will be scrubbing your tires due to excessive toe in, but as said, it would have to be something extreme to notice a change in tire wear over 15 miles unless you are running on a very soft compound.

With regard to the frame, if you can just strip enough body work off to get to the four corners then you could park on a level bit of ground, drop a plumb line from each corner, make marks on the ground, roll the car out of the way and then measure the diagonals on the ground.

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Duncan M
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Re: Frame Alignment

Post by Duncan M » Fri Jun 12, 2020 11:51 am

A textbook example of why (most) cars have bumpers...

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timberstone
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Re: Frame Alignment

Post by timberstone » Thu Jun 18, 2020 1:23 pm

Bumpers for this impact would have been no help whatsoever, because when the vehicle backed into the stopped TC, their trailer hitch was the projectile that impacted our tender foremost right frame member. The hitch and receiver were the lowest part of the SUV so it was suited perfectly to come into contact with the most likely damaged front portion of this TC.

Regarding bumpers -- a more recent thread on this forum discussed them on TC's as not really being appropriate, except for only the EXU models; not contributing any to the appearance; difficult to attach without welding or modifying essential parts and unnecessarily expensive. I would also add that bumpers would not prevent damage from most of the usual impacts which would actually involve the front tires and wings. Also, we do not know whether bumpers would have prevented any distortion of the frame.

The upshot of this encounter has been enlightening: Their property damage appraiser had no clue about how to evaluate the nature and extent of damages. We had to lead every step of the way through all the parts, suppliers, shop sub-routines, time expenses and specialized labor. They wanted references from the shops which had provided past rebuilding services for us and since we did most ourselves, they wound up with only two (2) references. Could not find any shop within 250 miles that could take on this type of work for at least a year with no guarantee how long the time in shop would be.

There was one point that I was not aware of: They could have owed me a replacement rental of a "driver" vehicle !! This was because we had actually driven BOXLEY over the months since they had been totally frame-off restored. Before the costs got astronomical, the company caved and offered a lump sum just to get out of it. So now the plan is to do some minor patch work and limp through the summer driving season, until winter when there will be time to dig deeper into the frame and alignment concerns.

In the interval we are having more fun now with just "a driver" !!

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Steve Simmons
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Re: Frame Alignment

Post by Steve Simmons » Thu Jun 18, 2020 1:55 pm

You won't get any argument from me that a driver is the most fun way to enjoy a classic car. There's something liberating about having little concern about scratches or other wear and tear type of damage. If my TC was a show car then my wife and I would have missed out on some incredible memories!
1949 TC8975 / XPAG 9609
1948 TC6011 / XPEG1182 (XPAG6472)
http://www.mgnuts.com

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timberstone
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Re: Frame Alignment

Post by timberstone » Sat Jun 20, 2020 1:47 pm

With reference to getting the TC frame back into square, we found out there is no such thing or person as a "cable wench" to ratchet the frame back into square ---
Meant to say "cable winch" as something that spools a drum to winc cable, usually driven with a ratchet handle or motor.

(Could a "table wench" be recruited to manipulate a "cable winch" on an out of square TC frame -- ) ?

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jddevel
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Re: Frame Alignment

Post by jddevel » Sun Jun 21, 2020 7:48 am

I have a set of 4 books entitled "Motor Repair and overhauling" published by George Newnes Ltd London. In volume 4 of the 9th edition (the set I own) how to check and repair a chassis is covered. This particular section was written by A.A. Baker M.I.A.E., A.M.I.M.E. As there are some 50 plus pages it is not practical for me to copy and forward this information. However perhaps a set may be available State side to assist you and others.
This are a couple of sets currently listed here in the UK.
https://www.ebay.co.uk/itm/Motor-Repair ... SwobFevOFS
https://www.ebay.co.uk/itm/Motor-Repair ... Swc59e63K-

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