D4 6u/7u recoil spring and track adjuster interchange

I have a D4 7u42520 with the nut style track adjusters. On one side the recoil spring bolt is broken and on the other it's bodged up with a bunch of angle iron welded in. The tracks are so worn on this thing that even with the recoil spring on the stop the track can be adjusted to have some slack (the other track can't be adjusted at all)

I have a 6u3022 parts tractor I bought for the undercarraige that has the early type hydraulic track adjusters. I'm wondering if those will fit into the 7U.

I think that's the serial number, there may be an extra digit. I can't use the engine number since that came off of a traxcavator.

When I get around to it, I plan on moving the sprockets and chains to the 7U. It would be convenient if I could just cut the recoil springs in place and drop in the 6u recoil springs and adjusters. Anyone know if that will work?

Also, any safety tips on handling the springs would be appreciated. The Cat manual is not very helpful here; it just says you can unbolt and remove them without splitting the track if the bolt isn't broken.

The 6u and 7u until 42914 use the same coil spring and make sure the bolt is't broken before the nut and remove the 2 guides and take care you could be hit

I was taught to cut both the inner and outer recoil springs in place with a torch. Burn through each coil, one at a time, one side at a time. The guy I learned this from was an experienced mechanic who once managed a Cat maintenance facility. Although destructive, his method became the local dealer protocol after a few close calls. One of these days springs will be scarce but they aren't yet. Since you have replacements, use your torch. The more interesting part of this equation is why did the inner sleeve break. We have a machine that's broken two, both on the same side. We're probably missing something but now toying with the idea of building our own and making it bulletproof.

That's what I'm planning on doing, particularly since the 6u units will slot right in. I spent 3 days freeing up that adjusting nut the other week. It will be nice to just pump them up with a grease gun.

Haven't a clue how it could have broke, but this tractor has seen its share of abuse. I replaced the rollers on one side the other year and the bearings were completely shot (like 1/4 inch clearance kind of shot).