The bracket that the front of the differential attaches to has rusted through. It's welded to crossmember #3. I have the bracket to be welded on. Has anybody had this bracket welded back on. Any problems? 1968

 

I can't be the only one!

 

If that bracket fell off due to rust, what shape is the rest of the frame in?

 

There is to much rust on the frame for sure. This is a patch. If I had all the time, money, and facilities, I would put a new frame underneath it. The bracket didn't fall off, it broke where the rubber bushing attaches.

 

Kevin, if the bracket that the snubber attaches to has rusted through, you really need to have the rest of the frame thoroughly evaluated. This is not a common area to rust on these frames however and portends even more serious problems. A thorough evaluation of the frame will at least let you know if it is safe to drive.

The last thing you want to do is fix this only to have a more significant failure elsewhere occur while driving it that can result in an accident or unnecessary damage to the car.

Good luck... GUSTO

 

I've done quite a bit of frame welding. The problem in doing the bracket weld that you're referring to is that the crossmember that the snubber bracket welds to is actually pretty thin-walled. If the snubber bracket is rusted through, the wall thickness of the crossmember is also rusty and reduced in thickness, even if it's not rusted through. In order to do the weld, you have to grind or blast all of the rust off the crossmember in the weld joint area, and chances are good that you'll grind through the crossmember wall, or reduce the thickness so much that the weld may not be possible. If you have adequate wall thickness on the crossmember, the weld is easy enough: You cut the existing bracket off using a high speed cutoff wheel and a grinder. You then grind/remove all rust in the weld area on the crossmember, weld prep the new bracket, and weld it on. Biggest problem, if the crossmember is sound, is that you may not be able to get to the welds on the top side of the crossmember that weld the upper flanges to the top of the crossmember with the body on the frame:

Note the welds on the top, rear-slanting surface of the crossmember holding the left and right upper flanges to the crossmember. You need to take a critical look at the position of these welds to see if they can be done with the body on the frame:


If not, you'll need to weld those flanges with a fillet weld from the bottom, assuming you can get to the old welds to grind them off. It will be a bit tricky with a lot of overhead welding, which few people can do well...

A frame weld repair in process in my workshop, showing the snubber bracket welded to the crossmember:


If your snubber bracket is all rusted out on its bottom surface with the big round hole in it, and if the left and right vertical walls of the bracket are not rusted through (since they are vertical, they usually won't rust), you'd be best off just cutting the bottom surface off the bracket and fabricating a new surface with the hole in it (or cut that surface out of your new bracket) to weld back into the bracket - much less work with a much higher probability of success.

Lars

 

Gusto14, Thank you, I have, and will have the car on a lift today for the fix. There are a few other places on the frame that I hope to reinforce. I have checked the front and rear suspension and they seem to be sound. I think what finely made the mount give way, I was doing some very hard braking tests. I know that this shouldn't be an issue on a normal frame. I wanted to replace the entire #3 cross frame,,,,, but after looking in to it, OMG what a job with the body on. I still wish someone had input on replacing the #3 cross frame or just the bracket.

UPDATE: Lars,, thank you. Good info.

 

Finished getting the bracket welded on. There was enough nonrusted metal still there to weld to. It certainly is better that it was, and with paint on it.