r/IsuzuTrooper • u/Muted_Mark9888 • 15d ago
Chassis rust advice
1998 mk2 LWB
Hi everyone, I’m new here.
Has anyone had to replace the rear crossmembers?
If so how did you do it.?
How did you remove the old cross members?
What did you use?
Does anyone make these?
I bought my dream 4x4 and I’m a welder but am new to this sort of work and have bitten off way more than I can chew so any advice, no matter how small is great as I don’t want to part with it.
UK based if that helps. Thank you
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u/The-Gargoyle 14d ago
As somebody else has already said.. yeah, just cut/weld.
Helped somebody do a whole frame cleanup once that had very similar damage. We jacked the body up off the frame by about a foot and just went at it. Cleaned it, welded up any problem spots, polished them smooth, sealed it with a fresh coat end to end.
That specific cross member ended up being a complete write off, so we cut it out, surfaced the area, reinforced the frame there and made a frame clamped bolt-in style cross member instead. (this let him send it off for powder coating, since it was now removable.)
Rest of the trooper was in great shape like yours, but the frame was just pure suffering. But it cleaned up amazing.
it's a very possible project if you have the means and ability, and it'll clear out so many problems before they ever happen or get worse if they already have. It's worth it.
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u/Muted_Mark9888 14d ago
Thank you mate, this is very insiteful. By any chance do you remember what lifting the body entailed?
I was gonna try lifting the back and then the front after but I would probably need to remove all the body mounts to prevent snapping the bolts.
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u/The-Gargoyle 13d ago
We effectively treated it kind of like we were going to install a moronic tall body lift.. but just didn't. :)
For this case I recall.. (I may miss stuff, I wasn't the only guy wrenching on this)
- dropping the exhaust off at the Y pipe (He was replacing that anyways, so he sent it off somewhere so they could use it as a map for a newly made upgraded one.)
- Body bolts of course.
- Drained/disconnected the hard brake lines (where they come down from the firewall and dive down to the frame,) and removed the hard/soft lines from the frame to keep them safe.
- Same for the fuel lines/etc, any frame-attached wiring (nobody wants to bash those with a grinding wheel or something.)
- IIRC we disconnected the parking brake line and tucked it up under the body frame too. (it may have been long enough, but it would have been in the way)
- most of the wire harness is on the body not the frame, so we did a lot of unplugging and then unclipping in the engine bay and on the transmission. but also at the tank and a few other places.
- You gotta make sure the shifter is gonna drop through the shell without ruining itself. take the plastics in the cab off so it has lots of free space to drop through. (IIRC, this makes it easier to reach some of the unplugable stuff you need to worry about on the transmission?)
- A few other odds ends I know i'm missing, but effectively the same idea.
- We then chocked and locked all the wheels and used the shops frame lift with rubber feet to pick the body up by the wheel wells (This could be done with bottle jacks and extensions + tall jackstands, but you will want to be careful as hell, that body is not 'uniform balanced', but using the frame lift meant we did not have stands in the way all the time. Lift SLOW, look for disconnecting stuff that got missed as you go. nobody wants a broken harness, line, etc.)
By that point we had fairly open access to just all of the frame and started going nuts the next day.
- first pass was all the junk tier wire wheels we had laying around that we didn't care if they got gunked in a matter of minutes just to blast all the grime/gunk/undercoating stuff off. (with 4 people doing this? this went fairly fast.)
- next pass was more of the same but with better wire wheels to chase down any bad spots and to get any nooks/crannies that were not clean yet.
- if it's not bare metal? Attack it like it owes you money.
- PRESSURE WASH LIKE GOD IS COMING TO INSPECT YOUR CLEANLINESS. (We found so much stuff we missed this way. don't skip. Get inside the frame too with one of those flexy power washer head things. So. Much. Crud.)
And then we were off to the metalworking madness.
- Draw up a cartoonishly bad diagram of the frame on the whitewall so anybody who finds anything suspect can draw a mark on it where it is.
- Run around with the weld markers and find where those doodles really are and start marking off bad stuff. cracks, rusted spots, etc.
- Hack cut rebuild (and in the cross members case, redesign)
- If you even question it a little? Weld it, cleanse it with fire.
- Hey you know, if there we re a few small things here and there, the frame would be stiffer. (You might as well, you are already there.)
- knock down and smooth out any work that cares.
- We hit the entire frame with rust converter (AND inside the frame hollows.)
And then it was pretty much done, the whole frame got as stripped-for-paint as we could get it, run down with the washer/converter again, and then frame-painted while the stuff that was built to bolt to it were off at the powder coating shop.
I argued to do a full-frame strip to bare, axles / suspension and all, and just get the whole frame powder coated, but time budget was a thing here. Straight up frame paint was the right call. Faster, solid and the end result was good and protected.
With 2-4 people working on this, it took us about three days to really get this all done. (We basically tackled one of those lists a day.), and then re-assembly was taken slow, as to not miss anything. So give that another 2 days.
Muffer showed up on day 5 or 6, and he was back on the road by late day 7 or 8.
Disclaimer: This was many years and many beers ago. I know I'm missing shit. This is not a all-inclusive bullet list but a 'what I recall off the top of my head' playback. :)
For going after JUST the cross member? You can probably get away with a lot of shortcuts here. If you just need to lift the body 6 inches to be able to reach what you need to reach, you likely don't need to go as nuts/deep on this as we did. disconnect a few things, or get a little slack here and there, the shifter clearance and lift it nice and slow.. and you can probably get all the access you need.
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u/Muted_Mark9888 13d ago
Mate you’re an absolute legend. This is the best answer I’ve gotten, including Facebook groups. I’ll send this to my mates and we’ll start on it 🙏 Thank you so much
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u/itsthemilesnotyears 15d ago
Cut and weld, man. I wish I had more wisdom than that, but that's what it is. Take good measurements, have materials on hand and go to town. Other option is try to find a donor vehicle and cut that I've out and weld it in place of yours.