Frame - is it straight?
 

I inherited a 29 Phaeton which originated from Brazil.


Looking at the car, I assume it had a harsh live and little care.



One of the big things, that bother me is the frame. The car must have had at least one accident as the crossmembers in the front have been reinforced and welded as ugly as possible...


Then, to transport the car in a container away from Brazil the frame was cut in halve and welded together again.



So you might understand that my trust in my frame isnt the best.



I've now found a guy who has frames at sale.

But I need a way to check that the frame that I will buy is as straight as possible. I dont have the tools nor the time to straighten it myself.





Can anybody give a advice or a manual on how to check a frame on its straightness?





And, have there been differences in the frames? Have all models the same frame? Must I only look for a 28/29 frame for me?
thanks a lot,

Re: Frame - is it straight?
 

I'm sure someone will post a plan of the chassis with dimensions for you. As for the m all being the same, no they are not. The difference is most obvious at the front cross member. The "pad" on which the radiator sits is lower on the 30/31 chassis than the earlier ones. If you have one of each side by side, you will see what I mean or maybe someone will post a picture of that too.
The most likely place for the chassis to bend is a sag at the rear engine mounts. I clamp a 1/2" thick piece of wood to the rail at the front X member and the other end near the middle X member and stretch a string between them. If there is any sag, it will show as a smaller gap under the string at the engine mounts.
FWIW, The chassis under my Phaeton is bent there and I'm hoping to straighten it without taking everything apart.
With all of that said, I wouldn't trust your welded chassis - replace it. At least a "new" chassis is possible over there.

Re: Frame - is it straight?
 

Clamp a string onto the front and the back of each frame rail and pull the string taunt. You will see really quickly if it is bent. Also check the measurements diagonally to verify that the measurement is the same in an 'X' pattern.

Plenty of information how to heat shrink a frame back to being straight here in the archives.

Re: Frame - is it straight?
 

28/29 is different than 30/31 You can check for straightness with a tape measure and a long straight edge or long level [ 8']or a string line.

Bill

Re: Frame - is it straight?
 

Here are a couple of pictures of a bent frame with a string used to show how bent the frame was. The upper picture is the driver side and there is a slight sag around the rear motor mount. The second picture is the passenger side which has a very large bend from the rear motor mount to the front of the car. The frame should be perfectly flat from the back all the way to the front where the front fender support attaches to the frame.


Bob


http://www.modelahouse.com/images/bent-frame01.jpg

Re: Frame - is it straight?
 

so all 28/29 Modal As have the same frame? no matter of their body style?


Do I understand correct, that the red stings will show me if it is straight on the length (like in Bobs pics) but also not tilting to the left or right.


Brent, how do you do diagonal check? I assume it's hard to check if the left and right is twisted


ps, hope you dont mind me using your pic Brent, was one of the first which popped in the search.

Re: Frame - is it straight?
 

This may be helpful.

Re: Frame - is it straight?
 

Although it's implied, it's not specifically stated. The frame needs to be perfectly flat from the front crossmember all the way to the rear crossmember., the full length of the red line on the photo above in post 6.

Re: Frame - is it straight?
 

Endeavor to purchase a perfect frame,however its not entirely critical to driveability and in some cases body alignment can correct issues.

Re: Frame - is it straight?
 

I made some wood blocks and ‘strung’ my AA frame. The rails were level, no sag but about an eight of an inch off side to side. I talked to the owner at a local frame/body shop and he chuckled, said that’s as close as they try to get one they straighten.

Re: Frame - is it straight?
 

...or it may not. Compared to some factory prints, there are some measurement discrepancies.

Re: Frame - is it straight?
 

Hudson32700... That's a useful drawing. You wouldn't happen to have a similar one for the 30/31 frame, would you?

Re: Frame - is it straight?
 

MACDONGE
Go to plucks329s.org for info about mode A frames.
See frame dimensions at: www.wescottauto.com
and click on "tech information".

Re: Frame - is it straight?
 

too add on the string idea.
I use a string tied to two 1 gallon jugs to do my alignments. its a good way to put a straight line in the air next to something

also when im picking out boards. i look down them the long way it becomes easy to see a wow in there.

Re: Frame - is it straight?
 

Agreed. Quick and dirty way to tell

Re: Frame - is it straight?
 

reading trough the previous post and for those like me seeking information


the http://www.wescottsauto.com/SubIndexes/Techindex.html has interesting information on it.
there is a detailed explanation about how to frame inspection on straightness


Thanks to Wescotts!

Re: Frame - is it straight?
 

I see this thread is over a year old. Did you ever get a frame? And how about some pictures of your car?

Re: Frame - is it straight?
 

My frame was bent

When I bought my A, the left fender was lower than the right. I made the mistake in thinking it was the fender bracket, but it was the frame. 1/2" to the right and 1/2" down with the usual sag at the rear motor mounts.

I took measurement from ever single rivet and hole in the frame. The fact that the right side is a mirror image of the left makes measuring simple, but time consuming. I measured every thing in an x pattern starting at the front corner then to every hole and rivet on the opposite side. Once I knew where it was bent, I un riveted the front cross member and I used chains, railroad ties and a porta-power do get the job done right. I got the frame within 1/32" at any point except at the rear motor mound sag area. There I bent it upwards of 1/16" positive. Over time, the known sag area will be perfectly level.

This takes time and patients, and it was well worth it. After the frame was straightened, I took it to get sandblasted, powder coated black, the shot with a couple coats clear of Polyurethane. The spot were the VIN is, has not been powder coated, but has the clear shot over it. The Vin is clearly visible with the appearance of raw metal.

Regards
Bill

Re: Frame - is it straight?
 

3 quick checks that you can do

measure corner to corner called cross measuring if its within 1/8-1/4" its ok

lay a straight pipe or 2x4 across the front and one across the rear, then stand at the front or back and sight down it to see if the plane of the 2x4s are parallel, if those lines are parallel then there is no twist.

the third thing is harder but you can run a string along the top of the frame end to end and check for sag.

if those three measurements are good the frame is likely ok.


old posting
but maybe this will help.