Hot Rods Model A Chassis Question

I bought an aftermarket chassis for my model a coupe, and I still haven't driven it yet, but I noticed the rear body mounts are starting to dog ear a little.

I'm thinking that if I move the blocks more to the center of the car it would help. Just wondering if anyone else has had this issue, and what they did about it.

Thanks,
Jon

 

Weld a 1/4" steel plat on top of the mount and welded to the frame rail. Then take 1/4" off the wood block. Henry made them stronger than what you have.

 

That mount is just plain poorly engineered. I would have a person of knowledge have a look at the entire chassis system. Even the bracket
below the mount you show has welds that look marginal in quality. Have a look at the body mounts Ford used on the 1940 or so chassis and you will see how a mount should be constructed or braced to support body weight in an outrigger type configuration.

 

Looks to me like a gusset under the body mount tab would stiffen it right up.

 

Thanks guys, I like the idea of the 1/4" plate. There isn't much room for a gusset under the mount because the rear end is right there..... The poor welding on the rearend is my doing, the rest of the frame welds look real good..... just kind of worried about this one mount.

Posted using the Full Custom H.A.M.B. App!

 

Why isn't it drilled for the bolt that would hold the body and wood block in place? Bob

 

Yeah.... it is about three down on the to do list.... just wondering if anyone has seen this before?

Posted using the Full Custom H.A.M.B. App!

 

I've seen similar quality welds on production vehicles chassis, it's not the prettiest weld but it doesn't look undercut, looks to be penetration there..the mount clearly is poorly engineered. You could put a diagonal gusset underneath it for support and drill a hole through it for a grade 8 body mount bolt.

 

I'd build a new mount a little forward of that so it can be gusseted, and drill new mounting holes. i would also make a full width wood mounting block to spread the load.

 

The mount does look rather light, (most likely 10ga. left from boxing plates?). I build a lot of these frames and I use 3/16" stock and have never had one bend. Also I would check why the subrails are coming down . The subrails should be supported on the other body bolts making the last mount somewhat redundant. The last mount in reality on a Model"A" is mostly, but not entirely, an alignment mount much like the front bolts of the cowl which are mostly for adjusting the doors. This would tell me the channel on the rear of the tub was not correct causing all the weight of the body to settle on only the rear mount. Am I making sense? In other words, most of the body weight should be on the mounts under the seats. Check to see if the blocks under the middle of the car are bearing weight. If they are not holding their own then shim them and the problem will be cured or correct the channel on the rear of the car.

IMHO, the problem is not with the brackets but with the channel dimensions and the shimming, or lack thereof, in the center mounts. Looks like a nice frame otherwise. Adding a stiffer plate will only result in the sagging of the center of the body and lousy door fit over a very short period of time. I find most aftermarket frames to be way straighter than the factory frames but find very few of them that are shimmed properly, even from some very noted shops. In short you just can't drop the body on and expect it to fit right.

 

So that I don't leave this unsolved, this is what I did. I took 31Apickup's advise and made a new bracket with gusset fwd of the mount out of some 1/4" L angle. I booger welded it in place (110 volt welder pushing it's limits) and shot some paint on it. I also put a body block in the body rail right before this attachment and that took a lot of load off this point and put it right on the frame rail. Thanks for the help guys!

 

That made a lot of since and looks like it will help a lot!

 

Looks like you've got it covered.

Posted using the Full Custom H.A.M.B. App!