99 4R-Rust holes on frame rail fix?

[hawkcharmer]

Hello,

I have a few rust holes on frame rail near muffler section and on bottom section of frame inside the rear trailing arm mount and where the trailing arm mount connects to frame.
Most of these holes I poked through with a screw driver on my own. The frame rail on the other side, front and back are ok. Ive been coating it with por15 for years, but now it's time to fix these bad sections.

What's the most cost effective way to do this?
Buy the pre-made steel sections or weld plate on my own?
What thickness of plate should be used?
The flat surfaces are easy to get to, but inside and above the trailing arm mount, seems to be tough.
I would need to remove the trailing arm section to weld bottom of frame section in that area?

Also, this is worth fixing right? The rest of my rig is in great shape.

Any feedback is greatly appreciated

 

[hawkcharmer]

I hope its worth fixing

 

[brillo_76]

I fixed a lot worse. I make my own plates out of 1/8 steel and I plate the inside of the frame.

Some folks prefer the safe-T weld over plates.

You can see several examples through my build threads on my method.

I like to cut out the bad clean the frame out. Then weld in new steel and then seal out the holes by welding them shut. Then I coat the inside extremely heavy with fluid film so it can creep all around inside the frame.

That's my preferred method.


As these rust from the inside out. Thus why I went to this method of cleaning out the frame. Then fixing it. Because if you don't treat the inside of the frame. It will continue to rust away from the inside. Well this is what I observed anyways.

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[hawkcharmer]

I fixed a lot worse. I make my own plates out of 1/8 steel and I plate the inside of the frame.

Some folks prefer the safe-T weld over plates.

You can see several examples through my build threads on my method.

I like to cut out the bad clean the frame out. Then weld in new steel and then seal out the holes by welding them shut. Then I coat the inside extremely heavy with fluid film so it can creep all around inside the frame.

That's my preferred method.


As these rust from the inside out. Thus why I went to this method of cleaning out the frame. Then fixing it. Because if you don't treat the inside of the frame. It will continue to rust away from the inside. Well this is what I observed anyways.

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Thanks for the reply!
Your welding job looks like it will last a very very long time. Im wondering if the safe-T weld over plates are a much quicker option? I know its more cost

 

[brillo_76]

Thanks for the reply!

Your welding job looks like it will last a very very long time. Im wondering if the safe-T weld over plates are a much quicker option? I know its more cost

They are. I would definitely do something with inside o the frame. If nothing else, keep the inside coated with something, or it will just rust the safety t weld over covers too. Plus the welds like to rust as well.


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[jsnppp]

Nice truck. Worth saving.

I had similar rust on my '02. I chose to cut out the rusty holes and create a direct fit patch panel, then butt weld. Prior to this I cleaned all external surfaces to bare metal, used OSPHO to convert, clean thoroughly, etc. After patch panel welded in I primed and painted.

I'm not a fan of the metal over rust approach and didn't feel it was required to go into the internal boxing metal that Brillo does, much as how I like it. His post has an amazing amount of content.

I'm in Texas and so don't have to fight it down here (truck came from Indiana originally).

Jason

 

[brillo_76]

Nice truck. Worth saving.



I had similar rust on my '02. I chose to cut out the rusty holes and create a direct fit patch panel, then butt weld. Prior to this I cleaned all external surfaces to bare metal, used OSPHO to convert, clean thoroughly, etc. After patch panel welded in I primed and painted.



I'm not a fan of the metal over rust approach and didn't feel it was required to go into the internal boxing metal that Brillo does, much as how I like it. His post has an amazing amount of content.



I'm in Texas and so don't have to fight it down here (truck came from Indiana originally).



Jason

I can understand that folks not liking or doing the internal plating.

For me it's a 2 prone attack. As you are eliminating ways for the water salt and crap to get inside your frame. As well as fix your rusty hole issue.

The plating over the rot is one of the worst things you can do in the rust belt.

As I did that on Tetanus 1 in 2015. No coating no painting nothing as an experiment. Needless to say in 5 to 7 years you are redoing it.

Hence why I changed my ways.

Cutting out the rot and butt plating is alot better in the long run the plating over rot. As in 2015 I couldn't weld very good yet.

It's like anything else. The more you do it the better you get at it.

As I can now even rebuild thin rusty steel in brackets etc. You can see how I rebuilt the rusty brackets on the rear axle housing I redid and put under Tetanus 1. All those brackets were curved and anyone can do this. It just takes practice and time.

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[hawkcharmer]

How does one achieve welding the inner plating fully in place?

Is the bottom section of frame doubled up 1/8” plate?
This seems to be where most of the support is.

Should I cut out bad sections, back plate the cut out sections on inside of frame and then butt weld plate in specific section I cut out?

Or cut out bad section, butt weld in new plate and then another plate over that section?

 

[brillo_76]

How does one achieve welding the inner plating fully in place?

You cut sections out and weld them back in.
I have held plates with self tapping screws and C Clamps.

Is the bottom section of frame doubled up 1/8” plate?
This seems to be where most of the support is.

You can a lot of times, it in the better sections. I cut the bottom out and
then cut weld windows in the sides to weld the plates in. It seems to be easier though to cut the inner frame well out and then weld the plates in. Then reseal the inner frame rail. As I have done them both ways.
You have to slice with either cutting torches, cutting wheels or a plasma cutter.

Should I cut out bad sections, back plate the cut out sections on inside of frame and then butt weld plate in specific section I cut out?

You can I do that a lot of the times. I just did that on tetanus 1. Except I skipped the but plate on the section I cut out.

Or cut out bad section, butt weld in new plate and then another plate over that section?

You can if you wish. Its entirely up to you.


Our rear lower control arms are nortious for coming off the frame.

So you really have 2 options:

Buy a saftey T plate and weld it on..

Or make your own plates to fix the issue.

As you have to fix 2 sections. You have to strengthen the frame
and you have to strength that control arm bracket.

If it were me, I would cut out the inside of the arch. Then clean it all out and
assess the inside of the frame in that area. Clean it all take out the rust chunks etc.

Then weld a plate on the inside of the outer rail. Check and see how back the bottom of the frame is as mostly they are rotted out. You can plate it shut the bottom or leave it open so crap cant build up in that arch anymore.

Then weld a plate on the inside of the inner rail. I always burn through and weld the lower control arm bracket to both the outter rail and the inner rail. So its welded to all 3 pieces of steel securely. Then you can plate the outside to smooth it up and hide your repairs.

You notice that the outer C is on thickness of steel while the inner is thinner...Another reason why they rust out faster.


Then you can plate over the lower control bracket to give it some strength back....Or you can cut it off and put on a non rusted one. Its harder to put the plate in the inner bracket as you have to make sure you don't interfere with the bolt area of the lower control arm.

I have one frame that someone did all external plating on before I got a hold of it. I plan to leave it alone and they outer plated both of those lower control arm brackets. So I can probably send you pictures of how they did it.

Is it just the sides of that lower control arm bracket with holes in it? As you can outer plate it or inner plate that bracket. Its not as critical as the water and crap just fall out. Inside of laying inside the frame rusting it out.


Then make sure you after all the welding down that you super coat the inside of the frame with rust inhibiting solutions like Fluid Flim, Transmssion fuild etc. Then paint the outside of the frame over those areas as they will rust especially where you welded.

Hope this helps.

 

[19963.4lsr5]

When I welded my drivers side rear lower control arm mount onto the frame I cut the dead metal from the frame and used a flapper sanding disk to clean up the inside of the frame. Then I sprayed the inside of the frame with a encapsulating paint.


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[jross20]

Make sure you clean off the rust and then prime it all with like weld through primer or something. Gotta make sure you don't get rust between the plates.

I'm sure someone else has a better method for doing so

 

[masondr04]

I think worse has been fixed before, definitely don't give up on it!