Rust between tandem mount and frame

[yolner]

So it looks like my M35 developed a pretty bad case of rust under the plate that attaches the tandem assembly to the frame. Im thinking that my only option is to cut off the rivets, make a new plate, and bolt everything back together. Any thoughts or suggestions before I start cutting pieces off?

 

[V8srfun]

Honestly unless it looks worse in person that doesn’t look all that bad to me. Looks like just some surface rust that can be cleaned and treated without any disassembly.

 

[NDT]

Huh? The gusset is bowed out at least 1/4"!!! What I have done is beat on the plate, that shatters the rust, then blow it out with compressed air, repeat over and over, then when the cavity is empty, beat the plate back down and drown the cavity with zinc rich primer, and seal all around with silicone.

 

[yolner]

Yeah thats what freaked me out. Its bulged out like 1/2" and I dont want it eating at the frame in there. Good idea on hammering it to get the rust out. Might give that a shot first and see if it comes back in a few months.

 

[tobyS]

I plated my entire rear frame when I saw under it on my A3. Bad spot for any truck ran on salty winter roads.

 

[cattlerepairman]

Yolner, that definitelu s*cks. Our fine folks here would have you teeter on the edge of not being able to safety the truck when rust jacking is that evident on frame components. That means, one way or another, it has to be fixed. The method described above to get the volume of rust out appears worth a try.
If longevity of the truck is a goal, I am afraid that, at some point, the tandem assembly needs to be dropped and the frame restored before bolting everything back.

Road salt is a killer of trucks.

 

[V8srfun]

Huh? The gusset is bowed out at least 1/4"!!! What I have done is beat on the plate, that shatters the rust, then blow it out with compressed air, repeat over and over, then when the cavity is empty, beat the plate back down and drown the cavity with zinc rich primer, and seal all around with silicone.

wow I see it now and definitely agree it needs to be attended to. don’t know how I missed it the first time I looked but.

 

[Floridianson]

Huh? The gusset is bowed out at least 1/4"!!! What I have done is beat on the plate, that shatters the rust, then blow it out with compressed air, repeat over and over, then when the cavity is empty, beat the plate back down and drown the cavity with zinc rich primer, and seal all around with silicone.

I like the beat thing what about drown the cavity with Ospho with it's phosphoric acid to help eat / convert the rust. They say Coca-Cola has phosphoric acid in it but it might make the truck gain weight and get fat with all the sugar.

 

[yolner]

Thanks for the advice all. I already have the truck down to the frame so seriously considering going the extra mile and pulling the tandems. Just really dont want to drill those rivets.

 

[CMPPhil]

Hi

What is the preferred method of replacing rivets? I know how I've done it but wondering how others have handled replacing rivets on frames.

Cheers Phil

 

[yolner]

On a ranger what Ive done is grind off heads, drill holes in the center, and then knock rivets out with a punch. Then ream the hole out to the next size up with a bridge reamer and replace rivet with grade 5 bolt. Obviously on an M35 thats going to suck way more because the frame is way thicker..

 

[Jbulach]

Thanks for the advice all. I already have the truck down to the frame so seriously considering going the extra mile and pulling the tandems. Just really dont want to drill those rivets.

Yep, drill the rivets and do it right. If you have or have access to a mag drill and annular cutters, pull the center pin, center on the rivet, and start slow.

Unless you work your truck to the max, and you have 2/3 of the material remaining after blasting it clean, seal it up, and call it good.

 

[yolner]

Well the first rivet is out. Wasnt near as bad as I expected. Only 40 more to go