rust repair on 66 b-body bumper mounting body panel

removed my rear bumper to replace the brackets. encountered rust in the lower rear of the body panels that the brackets bolt to. whats the best way to repair this?

Finding a talented metal guy , best way to fix it is to cut out the rusty metal and replace i with new metal. The bad is there is little relalcement parts available for that car so it's either a non rusty parts car ... look around your area , or make all the pieces as needed , either way it's going to be $$$ .

Good luck

edit ... you should post this in the resto section

The questions would be:
What does the other side of the car look like? is it OK, or nearly as bad?

Do you want the entire panel replaced, or just the bad sections? Replacing the entire panel is likely going to revel more rust, at what point do you want to stop?

Its very likely, the rust damage involves everything that is attached to the part, in the area of the rust holes. The damage probably extends at least 3/4" to 1" on either side of the rust through. A patch can be welded in to replace just the damaged sheet metal that may last many, many years. The downfall to that is if some rust was missed, down the road 10-20 years, it may need to be addressed again. A patch would be fine for a driver, or occasional show car, but probably not OK if your going for the 100 point show car.

Like stated earlier, there are no replacement panels for this piece, its going to have to be hand formed. Replacing the entire part is going to involve the trunk floor, the trunk floor extensions, the tail light panel, the frame rails, the leaf spring reinforcement plates, and the rear end of both of the rear quarters.

Other then that, its easy, anyone can do it.....

new detailed pics, previous repairs exposed.

more pics

I'm not super familiar with '66s.

I'll tell you what I do know about '68 to '70. The overall construction is probably close, especially judging from the pics.
I've replaced that metal on my '69 within the past year. It is a pretty big repair, to really do right and not cut corners.

On 68 to 70 there is a rear crossmember, a left and right extension at each end, and two reinforcement plates where the bumper brackets bolt through.

Reinforcement plates point to the rear.

The extensions are corner filler pieces and are welded to both the X member and the trunk extensions....These are lap joint spot welds, which is a very handy and perfect place for rust to start.

The frame rails and leaf spring mounts all have tabs that the bumper bolts go through +the crossmember+the reinforcement plates.
These three layers are lapped together and spot welded, another great and perfect place for rust to start.

First thing I would do is attempt to research how different a 68 to 70 is. If there is a chance you can use a reproduction crossmember/extensions from a 69
with minor changes, I would do that as a labor saving tactic,....existing stuff can be cut out and new stuff welded in. Frame tabs are pretty easy to fabricate. The crossmember is just a piece of U-channel but has additional stampings that would be time consuming to duplicate. Gas tank strap slots may need relocated and other work may be needed for it to be useable on a '66, or it may not work at all...but it would be easier to rework a new part rather than an old one.

If the pieces that are there must be repaired and no reproduction parts from other years can be used, then you are looking at cleaning all the undercoat off, removing the spot welds from all parts, repairing all the rust, welding it all back together, then finish work.

Here are pix from Mark's 68 road runner build thread which you may find helpful if you'd like to compare the reproduction X member to the stock '66. You can see where he's welded it to the frame tabs. In these pics he has not yet installed the reinforcement plates, which look a little like a miniature guardrail.




Look it over very carefully, though.....On a '68 to '70 The trunk floor is also welded to the crossmember (more lap joints, more chances for rust). It's easiest to just cut out the trunk floor when doing this repair, rather than try to remove each individual spot weld. On mine I ended up replacing the entire trunk floor even though it was not in really bad shape, because it went along with the crossmember repair/labor savings+quality. The tail panel is involved with all this, also. To really do it right is a big job.

ok great! thanks for the info!

JOE PHILLPIS RESTORATION IN THUNDER BAY ONTARIO CANADA MAKES THIS REAR MOUNTING PANEL

That is the outside piece, its about 1/4 of the job. But at least you don't have to fabricate that part.

The parts of your car that have been patched will still be bad, but they will be hidden behind the bumper bracket. Like I asked earlier, how far do you want to go?

A driver for 10 years? Swap out the bottom 1/2 (to just above the last patch job) of the back panel and drive it. That was what the last guy did.

The Belvedere is my last Mopar after 45 years of buying,selling,racing,stripping,Dodge&plymouths starting in 1977 with a 68 Charger. am 65 and retired on SS, have a slab in front of a double wide. Its a final ride. Holding on to a little of the past.

Patch it up and drive it, or bolt it together and drive it. The back bumper is not going to fall off, and there probably wouldn't be much difference in protection in the event of a rear collision either way.

If you can't do it yourself, find someone you trust and do as they suggest.

Really, how many people are going to climb under the car to see what it looks like (except other Mopar guys) and does it really matter to you what they think? What does their 56 year old car look like?

I'd probably bolt the bumper on and drive the wheels off of it, and would enjoy every minute behind the wheel.

All things considered including the available workspace, I would also advocate not really repairing it, just because it's too big a can of worms.

Apply some kind of rust paint (rust bullet or other) with a brush, if you feel like you must do something to slow it down.