Tacoma Frame Rust Repair... The right way?

[FreshSeaBass]

This MIGHT not be the "right way" by some standards, but it is at least 100% better than the OE frame.... and it is over-done if nothing else, so here goes......


A friend of mine has been using his '03 to do a bit of camping and set up his Scamper in the bed of his Tacoma. To help with the added weight of the Scamper, he has been running airbags for some time.

If we've learned anything from the last two decades, it's that the 1G Tacoma frames are at least 50% disappointment. I was initially going to weld on some of the 'rust buster' frame plates that are available for the frames of the Taco, but I lack any sort of confidence in what remains of the rear half.


The plan is to replace the rear half, which is the tapered-down portion of the frame; going down from ~2.25" x 5" boxed frame to something along ~2.25" x 3.125". By process of elimination, going to the furthest point back where the frame begins to taper.....


Crtl + Alt + Delete



What's next from here? The plan is to take a can opener to the folded down steel at the taper to check the inside of the frame. Look for scale, deep pitting, etc.

We have a complete rear half to pull some angles and drop measurements from;

- 2" x 3" .188 wall will get a pie-cut and bend then re-weld to give us the rise/run.
- Rust treatment and coating inside + Welded end caps to seal everything off.
- Fish plating at butt joints (sides and top)
- Tube bridge between bottom of old frame rail up to new frame rail.
- Welded gas tank crossmember (either round tube or box)
*Optional*
- Drill and sleeve new frame rails into existing frame.



This is the plan for now, and in my opinion feels like less work than grinding/chipping away rust and scale from an existing frame rail that measures out to be somewhere between 14ga/16ga..... Coating the frame rail caps, welding it all on, and welding on new leaf spring mounts either way. Same amount of work (in hours) BUT vastly different end result.


I think the Scamper will be a bit more solid.


Feel free to weigh in with your experiences on dealing with Tacoma frame repairs, rear-half tube conversions, frame chops, etc.... I'd like to hear from all of you that care to share your own personal do's and dont's.

 

[74FJ40]

For the connection point onto the oem rear frame ive always done a 45 angle on one or both sides (depends on frame box size vs what you can get tube stock) to merge them together then fish plate over the sides and top. It seems like a heavy debate topic on some forums to what way offers the most strength.

 

[4runner DOA]

@slander just did his frame not too long ago. Might be worth picking his brain.

Slanders TuRD

I figured I would start a build thread on here as it looks like a few of you can actually weld and build stuff and may be interested. I have owned this truck since 2005 and wheeled it IFS on 33s with dual cases until 2016 when I did the axle swap. The goal of this truck is to drive 8+hrs to the...

www.independentoffroading.com

 

[FreshSeaBass]

Off to a good start!

The way I decided to start this off was to take all of the odd curves and tapers out out the original frame rail shape to work with some clean, straight lines.

With 2.5 inches of the frame rail set into the original frame.... this is to give enough room to sink a 1.25" OD tube into the frame from top to bottom. Effectively both frame sections will be in shear with one another. This tube will be welded through all joints.

1st Gen Tacoma

-10 inches of frame rail protrusion out to a bend 160° angle (20° inner bend).


Using a large anchoring strap, a few C-clamps, and a steel biscuit, I slapped some chamfers onto the tube, wedged the gap and burned it all in. When all said and done, the angle sits at at 160° ± 0.2°. Success!





Looking forward to moving on to the other side now that I have had a chance to work out exactly what we need. The next side should move along much quicker.....

Plans (may change in some way)

- Cut rail no.2
- Open tapered box-end to determine rail placement
- Mark/cut shear-tube & hole locations
- Rust inhibitor for inside of frame rails
- Cut / weld frame rail end caps
- Set frame rails to depth
- Cut all fish plates
- Weld-in temp x-member for frame square

That's all for prep work at the moment.

That's all the pre

 

[slander]

I don't know what your overall plan is, but I had the most rust and bending/cracking issues with the stock frame down by the spring hangar. Basically hacked all that out and went a bit forward of the body mount. The gas tank cross member was a sleeper pain in the ass, holy hell that took forever.

 

[FreshSeaBass]

I don't know what your overall plan is, but I had the most rust and bending/cracking issues with the stock frame down by the spring hangar. Basically hacked all that out and went a bit forward of the body mount. The gas tank cross member was a sleeper pain in the ass, holy hell that took forever.

Fortunately, on that section the rust really hasn't taken over. There was a bit of dirt there, but after washing that area out and having a close look I don't think it will be necessary to cut any further forward...

I am almost thinking that round tube might be best for the gas tank crossmember, and for the EVAP/strap bracket I am thinking that welding on some tabs or even notching some square tube to put in place, will make the most sense in this application.

 

[FreshSeaBass]

Some Progress and getting down to the wire here. This week will be heavy with work on the taco.... I need to get through the remaining C25 in my bottle to make a trip on my way home form work and get a re-fill before the end of the week.

Both frame rails are sitting in where they will get burned together. I'll be tacking up a fixturing jig to keep things square and true; this truck will see plenty of highway miles and a bit of DD duty.



We have some fresh leaf spring hanger mounts mocked up with the stock bushings. It's looking like we should get some ARB replacements or Energy suspension bushings (whichever will show up in time for us to get some burn time over the weekend.


*Some Rust encapsulation and a long straw to hopefully live beyond my time*

SUPER stoked to be working with 50 Amps of 220V now, it's been too long.

I removed the 1/8" skin that was added to the inner face of this frame rail because it was deteriorating some. The welds also left much to be desired if I am being honest. I'll pull 3/16 in to that location to square off the box section and then fish plates to cover it all.



Look forward to seeing more either tonight or tomorrow. This has been fun so far!

 

[slander]

Fyi you can order the OEM bed mounts from Toyotapartsdeal.com, specifically that "mid" mount. I know one can make one out of square tube and a drill press, but if you want to save some time and just have something to burn right on its worth it.

 

[FreshSeaBass]

Fyi you can order the OEM bed mounts from Toyotapartsdeal.com, specifically that "mid" mount. I know one can make one out of square tube and a drill press, but if you want to save some time and just have something to burn right on its worth it.

That's some great beta. I'll have to take a look today. We are working on getting bushings, hangers, and some miscellaneous parts for setting up the fuel tank crossmember. Hopefully using some 1.75" tube will make it an easy fit up to hold against the padding on the tank itself.

I really need a drill-press....

 

[slander]

That's some great beta. I'll have to take a look today. We are working on getting bushings, hangers, and some miscellaneous parts for setting up the fuel tank crossmember. Hopefully using some 1.75" tube will make it an easy fit up to hold against the padding on the tank itself.

I really need a drill-press....

Here's how I did mine, bear in mind I'm not exactly Morgan Clarke, but my tank hasn't fallen off yet so that's a win in my book!


I welded a tab to that round tube sticking out of the square one, and used the stock pin and strap for the tank.

 

[FreshSeaBass]

@slander

Is your tank tucked some? It looks a bit to me like it may be, but it is hard to tell.

 

[slander]

@slander

Is your tank tucked some? It looks a bit to me like it may be, but it is hard to tell.

Yea I raised it 2". Basically did a home made version of eimkeiths kit. If you wheel your truck I highly recommend it while you have it out. I should have done this like 10yrs ago.

 

[FreshSeaBass]

Yea I raised it 2". Basically did a home made version of eimkeiths kit. If you wheel your truck I highly recommend it while you have it out. I should have done this like 10yrs ago.

This truck is going to be primarily a camp truck. It houses a slide-in Skamper, so I doubt it will see much wheeling during this phase of its life. Eventually a tank upgrade would be nice to run something upwards of 25 gal and closer to centered between the frame rails.


One day I could definitely see the advantages of this, but at the moment we want to try designing a really neat flatbed for long term use. This factory bed has numbered days.

 

[FreshSeaBass]

Burned a little bit of midnight oil and the rear-half is all one piece. I made my 'fixturing jig' which is just a bunch of 1" square tubing cut to length and tacked in place along the frame. Frame rails clamped and tacked to cut all ends to square.

Alternating from above to below the frame rail, I got everything to line up consistently at 41" (outside of rails); the primary crossmember is also cut and pressed-fit in place.


Making progress, time to mock up ancillary brackets and rust prep all of the additional tubes.


As a bonus we are going to try cramming some big shocks in the rear to handle some of the extra weight.

Almost the weekend!

 

[FreshSeaBass]

Here is how today began...


Shear sleeve through the frame for alignment.

 

[FreshSeaBass]

Oh man, oh man....


Is it necessary, probably not.... worth it? Who knows!

Tank placed for crossmember fit-up.





MOAR

 

[FreshSeaBass]

Tomorrow should be a pretty exciting milestone.... except its sunday, and I have about 4000 psi left in my C25 tank...


Inner'ds of the fish plate frame boxing





Outer bits

The next few steps have to happen in a sort of particular order, so it's time to think about what needs to get sealed off and in what order.

This is really coming together nicely

 

[Stairgod]

You mean 400 psi?
My main argon tank is 280 cu ft.
Backup is an 80.
Two 80s for C25. Somehow I still manage to run out in the middle of a project.

 

[FreshSeaBass]

You mean 400 psi?
My main argon tank is 280 cu ft.
Backup is an 80.
Two 80s for C25. Somehow I still manage to run out in the middle of a proj

Durr... Durr.... Late night.

Yes, 400psi! My two are 120cu one C25 and one 100Ar.

I'll get whatever I can done to seal off the new rear half, but we are currently cutting it close. We will have a stopping point here within a couple of hours.

Tomorrow night I anticipate getting this thing back on it's own weight. Currently cutting out the remaining fish plates.

 

[FreshSeaBass]

Forgot to Update! Some delays between getting parts that we want for some future and poor timing in running out of Gas/Wire. Back on it and the frame wont be coming apart anymore after last night.



Slowly but surely. Looking forward to getting it out on the road again, and having a notably stiffer chassis to see how much of a difference it could be.