CJ-5 frame work getting kicked off

[CRJeepin]

Hey guys,
Have stripped a 1979 CJ-5 down to the frame and the next step is the frame repair. I've finally got a little time AND a buddy is loaning me his plasma cutter for a couple weeks - really super! So I'm picking up a bunch of steel on Thursday and am going to try to hit it hard this weekend, think I may be able to get everything done in 2 days if I keep after it.

Could really use your guys advice as I proceed. I dragged the frame out and started working on one side last Sunday, but I'm getting ahead of myself. Here's what I need to do:

1) rebuild rotted out sides and bottom of the back 12" of frame rail, each side

2) replace several 6-8" sections of "flat" side (and probably the bottom) about the middle of the frame

3) cut out the transmission crossmember bolts - the previous owner snapped off at least 2 heads and then used a CJ-7 crossmember by welding on tabs on the outside of the frame rail. I want to go back to a CJ-5 crossmember - since I have the plasma it will be easy to open a "window", chisel out the nut, and weld the "window" back in!

I have already repaired the body mounts - but will cut holes for the mounts using the plasma, AWESOME....


So here's what I did already (yesterday):

Rear Frame Rail Section

existing condition:






I took pictures w/the dimensions indicated - and will preserve other side for reference...also have factory FSM with frame dimensions.



The top of the rail is good - plan is to rebuild both sides, one at a time, and then the bottom. I plan to cut out the old (thinned) metal, and replace it with 3/16, including 1/8" fish plates inside & out at each butt joint. Any deviations from this you would suggest?

First I cut out one section, at the welds:


Next I cut the angled piece to transition to horizontal. It is 3/16", 2x2" angle I cut one side down on:


Red is where I will fish plate, inside and out. Ignore the small holes in the plate - will plug weld them shut or cut a fish plate hole over them.



from here will transition to horizontal angle.


inside shot of the frame rail.


I will replace the bottom as one "strip" with nuts welded on the back.


Repeat for other side....all butt joints will be fish plated inside & out.


Next Step: Frame side repair:
Frame rail is thinned on the sides where circled here. I will replace both sides (inside and out) and then a strip along the bottom.





Last Step: Un-Fubar Trans Crossmember
The previous owner's "repair" is circled....I assume this is a CJ-7 crossmember as it is about 2" wider than the frame:






Any comments, suggestions - greatly appreciated.

Thanks!

Chris

[lewray]

Its a little hard to give any firm opinions without being there to see it. The pieces you have cut look good and well thought out.

I had kinda of the same junk on my FJ, and made some of the same ideas you have there.

Some years later I just cut the frame and tubed it out, more for performance on the trails, but I would use as much 2x4 structural steel as I could to keep from making a piece here and a piece there.

Where the rust makes it thin... well ... you need to think about cutting it all out, but again Im not there you are.

Nice photos

Keep us posted

[CRJeepin]

Good tip on the 2x4 structural steel, I forgot to order some of that. Will definitely get some, it will be a big help. I think I'm going to go 3/16, the stock frame is 1/8" inner and 3/16" outer....

I plan to just keep what is good - the rot will go!

What year is the FJ? I have a buddy that has been on the lookout for one for years....they get a good price now though I think he waited too long. Gotta love old trucks....can't wait to get this CJ back on the trail.

[DSW]

I'm looking at all the heavy rust on the bottom in picts 4,6 &7. My guess is theres not a lot of "good" meal there to weld to. I would look at just getting some tube the aprox dim and replacing the whole section, butt weld the seams and fish plate that. You can build the tube from scratch if its a strange size /shape. As far as the bends, I would just make angles and weld them together, unless you've got a torch big enough to heat and bend the tube.

As said its hard to tell for sure not being there. Good luck.

[Sandy]

Yeh, pic # 7 looks like you didn't go far enough back. Tough call. You work with what you've got. If you don't you've got nothing anyway.

Keep showin pics.

[CRJeepin]

Thanks for the comments guys.

You're right, on the bottom I need to go back a lot farther than I did on the side. My plan (and I've never done something like this, so I have no idea if it is a good one!) was to rebuild both sides from the top down, then flip it over and cut out the bottom out - will have to go back probably another foot from where I cut the side out. Then replace the bottom with a piece of 3/16, including nuts for the spring hangers. I mic'd the side wall where I cut it and it is 1/8", which is what it is supposed to be - so I think I'm OK with how far I cut there. If this isn't a good plan, please let me know!

The reason I am doing it "sides then bottom" is the top is the only part I am certain is in original location, the bottom could be flattened out some (but I don't think it is, this jeep was sitting and rusting, not on the road, the past 14 years). And the bottom slopes up along the wheel arch where it needs to be replaced, so I thought I would have better luck replacing it with a flat piece that I can weld & form to the new sides than with a piece of box tubing that would require a lot of angle cuts. Again, no idea if that's a bad plan though and won't get offended by criticism or comments!


Thought about replacing it with tube but don't have a tubing bender or notcher and am trying to restore this one to "resto-mod" condition, not for a show & shine but I like the look of slightly modified old jeeps and want this to look fairly stock when it's done. And with the plasma cutter it shouldn't be bad to cut pieces to fit where I need to....without it I would be hosed. I have a feeling I'm going to be looking around for a used plasma cutter after using my buddy's this weekend!

[Jolly Roger]

That poor thing looks like it got Katrina-ized. Parked under saltwater, lol. Good luck on it.

[lewray]

Originally Posted by CRJeepin

Good tip on the 2x4 structural steel, I forgot to order some of that. Will definitely get some, it will be a big help. I think I'm going to go 3/16, the stock frame is 1/8" inner and 3/16" outer....

I plan to just keep what is good - the rot will go!

What year is the FJ? I have a buddy that has been on the lookout for one for years....they get a good price now though I think he waited too long. Gotta love old trucks....can't wait to get this CJ back on the trail.

Its a 79
Mine for 15 years and it was really nice when I got it. Completely stock except the aluminum tub. Enterior perfect just a perfect truck..then

Now its been through he!! Barrel rolled, tipped, and played the role of "Red October" in one of the rivers around here


Here are some pics through the years no real order

[CRJeepin]

Good lookin rig man! Looks like a great setup....long arm and coilover rear, hell yeah. I dunno about that front bumper, would seem like the deer would make a mess in the car wash and get ripe in the summer. Probably keeps the other deer away though so maybe it's not such a bad idea....

Just goofing that's awesome you have that old photo of the rig - makes it a lot more fun when there are personal stories to go along with the machine.

[lewray]

Originally Posted by CRJeepin

Good lookin rig man! Looks like a great setup....long arm and coilover rear, hell yeah. I dunno about that front bumper, would seem like the deer would make a mess in the car wash and get ripe in the summer. Probably keeps the other deer away though so maybe it's not such a bad idea....

Just goofing that's awesome you have that old photo of the rig - makes it a lot more fun when there are personal stories to go along with the machine.

LOL That was many moons ago

that was when it was stock. Actually the deer is on a bike rack....made a great deer rack though


keep us updated and good luck w/ your project

[DSW]

I would most likely build a replacement piece from square tube then cut and weld in the new leaving the old piece in place as long a posible to maintain the locations and profile.

If you do the sides then bottom like you talked about I would work in plate rather than the chanel you showed. You can lay the original down on the plate and trace it, then cut the piece with the plasma. You could also tack the original to the plate then use it a a guide to cut with the plasma and grind the last 1/16 or so to fit. You will need to clean ll the plasma cut edges anyways.

Hope this helps, good luck.

[rustywrangler]

Just remember on this kind of repair, fish plates can help out alot with strenght. I also recomend, as said before, the box tubing.

Couple of links I have from Jeepforum.com where I mod.

Rear frame of a YJ being repaired:
http://www.jeepforum.com/forum/showthread.php?t=150584

Custom rear crossmember on a YJ frame. It deals with replacing the rusted stuff too:
http://www.jeepforum.com/forum/showthread.php?t=442274

Another rear frame repair thread:
http://www.jeepforum.com/forum/showt...t=frame+repair

[CRJeepin]

Well, pretty good weekend working on it, one side is done and the other is just about finished. Did not get to the middle sections yet. Took a lot of time to get the dimensions just right and think about how I was building it because it's got to be accurately located or the springs will be off-canter and the axle won't locate properly.

Anyway the side I got done came out good, I think. Dimensionally it's identical to the factory spec, and everything is plated on the inside. I am going to add some fish plates on the outside too, but not until I get both sides done. Then I'll burn out a bunch of fish plates at once and weld them on.

I'm not real proud of my welds, but it was good practice. It took a while to get used to the plasma cutter and the new metal took heat different than the old metal, so I had to get the hang of spending more time on the "new" and "dipping" over to the old so as not to melt it back too much. I stitched in fairly small runs, with a couple exceptions, so I could stop and check my work and make sure I wasn't getting off track or putting too much heat into one area.

One question I have, is it better to "push" or "pull" when mig welding? both produced welds that appeared pretty similar, but I found I had better control with "pulling" and did that more frequently.

Here is the finished side, this is the "inside" of the frame rail (top is "up" when in normal operation). The only thing I boogered up here was forgetting to cut the front edge of the horizontal piece at an angle....but I gapped it inside with a plate and put another piece in the void.



Cut out the other side - you can see the "gap" plate on the inside. Before closing up the outside, I welded all around the perimeter of the gap plate on the inside:





Ed taking a whack at the plasma cutter. This thing was awesome for cutting the old metal out...a bit of a pain to use for cutting new metal, but better than a cutoff wheel.


Other side of the rail welded - bottom is "up"



making the bottom strip:



bottom strip welded in:




Finished rail (except for fish plates to be done later):






I hope that the frame rail I built is as good or better than stock, it is thicker (3/16 vs. 1/8") and certainly much better than the rusted mess.....

Either way this will not be a hardcore trail jeep, just a summer cruiser kept in basically stock form. I'll also make sure to inspect the welded areas after some operating hours to see if anything cracks.


Like I said, the other side is underway (almost done) and then I've got 2 sections in the middle to address. Then it's POR-15 time.

[CRJeepin]

The board didn't let me post these in the last post, too many images...so here they are:


close-ups of some welds....comments appreciated: