29 coupe frame sag?
 

After attempting to fit the hood to an otherwise sound, older restoration on which the hood was never properly fitted, it appears that the frame has sagged. What are the chances? The gap at hood/cowl widens from pinstripe going down to cowl bottom. It fits well across the cowl top and radiator shell top. The gap is even top/bottom at radiator shell sides. If sagged, it seems that it would happen at, or just ahead of the cowl. Could it be corrected on a frame machine without disassembling the car?
Thanks.

Re: 29 coupe frame sag?
 

You can shim the body blocks if it's within reason. But know moving one corner will effect others -trial and error.

Re: 29 coupe frame sag?
 

One retired body man removed the shock links and wrapped straps over the shock bodies to anchor the frame to the chassis machine before straightening.
One approach.

Re: 29 coupe frame sag?
 

Mostly error! It will take a lot of tries to get it right.

Re: 29 coupe frame sag?
 

John Hash has been straightening Model A frames with the body on for several decades. Here's a video showing his method.
https://www.youtube.com/watch?v=0YpoDS5ZyyE


Good luck,
Bruce

Re: 29 coupe frame sag?
 

Thank you all. Your input is very useful. John

Re: 29 coupe frame sag?
 

My Fordor had all the symptoms of a frame sag. I lifted the body (4 inches) to take the front fenders off for painting and found all of the rubber pads compressed to paper thin and brittle as a cracker. I replaced all the rubber shims and made some adjustments (more than one shim) to get the doors to fit correctly. While the body was lifted I put a straight edge on the top of the frame and found it was straight. Now my hood fits correctly.

By the way, all the bolts were rusted. I replaced them all with a body bolt kit from Snyder's.

Re: 29 coupe frame sag?
 

I guess I need to call John and ask questions because I have more questions after seeing that video. :D :o :o I understand how his clamping method attaches however I don't understand how the two chains can be adjusted that accurate to make both "frame gauges" be exactly the same length. Most restored vehicles have Frame Anti-Squeak glued down or they are 'stuck' to the frame (-at least from my experiences), so how do you get the "frame gauge" wires under the welt, ...especially with the curvature of the apron in the way. The same thing with the fender and/or radiator apron in the front.

Re: 29 coupe frame sag?
 

I would have reservations about any straightening by force by which the force passes "between frame component parts." My fear being loosening rivets, or even forcing a movement between riveted parts. Or even a loss of "rivet tension."

Now to set up a strongback "going the length of an element" and working to that as restraint I have done to an intact frame with the body removed. (hydraulic jacks don't work on their side - requires a "porta-power.")

To stress/force across a riveted joint may imply necessity to "re-rivet" (i.e. "tighten") the rivets - which would probably be done "cold" - not the best effect. ("tensioning" a rivet is best done in the cooling after heating.)

At least part of the key here to success is identifying EXACTLY where the bend is and addressing it most directly - a task best accomplished by removing the body and possibly the running gear.

Not what you want to hear, I'm sure.

Joe K

Re: 29 coupe frame sag?
 

Think

Re: 29 coupe frame sag?
 

My pickup has the same sag, partially due to the springs and shackles being worn out causing a lean to the drivers side. I can't fit my fingers under the shackles anymore and the truck has a bend in the frame right around the motor mount. The hood lines up fine, only giveaway I have is a stiff choke rod. I REALLY don't want to pull the body off to fix it, so I guess once I change the shackles and springs then I'll tackle the frame issue

Re: 29 coupe frame sag?
 

A person should try to check the body blocks for extra shims. Some folks shim for door fit and make other problems in the process. Other problems such as the wrong front cross member can require shimming or deshimming of the radiator on the front cross member. It all has to be checked before attempting to bend the frame. Model A frames are flat on top but the bottom flange varies in several places so a person has to think it through. As was mentioned, the frame webbing and the body blocks need scrutiny to make sure the stuff isn't rotten and missing is several spots. Gauges should attach to be flush with the frame top rail or they are won't gauge much. I think sheet metal could be formed to work as long as it will slip under the webbing.