Front x-member repair: pros & cons

[Seppi72]

My '72 is all sandblasted and epoxy primed and rust repair is underway.:classic: I know what's ahead of me for the next few weeks, but I'd like the opinions of those who have "gone before me" on one aspect. That is what to do when repairing the rust damage on the front crossmember. A photo of the current situation is attached.

While it's not blatantly obvious from the photo, there is rust-through on the backside of the x-member between the oval openings. It is worse between some than between others. Numbering the ovals 1-6 from L to R, there is no apparent rust between 1-2 and the worst is between 3-4. I think you can see the extent on the others.

My thought is to (1) remove the entire back "wall" of the x-member, (2) treat the inside surfaces with sandblasting, Ospho and an appropriate coating (POR-15 ?), and (3) weld in a solid wall piece.

I frankly don't understand the purpose of the factory openings and I don't see what harm would attach to eliminating them in my rebuild. There are plenty of drainage openings on the underside of the x-member and I could always create more. Besides, I could always create a template and paint black ovals on the new solid piece to give the OEM effect.

Let me state that I am NOT going for a restoration here and this car will NEVER see winter driving while I own it although it will likely see some rain.

So, if any of you have insight into what Datsun was thinking regarding the design of this piece, I'd like to know. And, certainly, I want to know what you think of my proposed fix - pro, con or ambivalent.

[doradox]

The openings are probably just for weight reduction.

Steve

[geezer]

The openings are probably just for weight reduction.

Steve

Yes, weight reduction and an increase of strength that is gained from the pieced being stamped. When spot-welded together with the front portion which is also stamped into shape, the assembly becomes very rigid but light. I don't think there is any problem fixing it the way described if you aren't looking for total originality. In that case I might even be tempted to just cut, notch, bend and weld up a piece of thin walled square tubing.

Edited August 24, 2008 by geezer

[Big sam]

my 260's was full of rust, so i removed the whole inner portion.I've since made a replacement with round holes, i just turned up a simple press tool on a lathe at work.I havent fitted it as yet so i can send photo's if you like.