I searched and could not find what I was looking for.

I recently discovered that my 81 rear axle is bent, I thought it was a broken spring pin but with a closer look and some disassembling it is actually a bent axle.

I now have to replace the rear axle and had a few questions. Will the 86-95 IFS rear bolt right in or will I have to do some welding? I figure if I am going to go through all that work I might as well put a wider axle under it.

And if so can I bolt my 81 third member in it so I do not have to worry about re gearing if they are different gear ratios which I will assume they are?

 

As far as bolting the third member it won't be an issure, but for your other question I'm not sure so I'll let someone else who has done it reply. Will you be adding spacers in the front or will you be adding ifs hubs? The axle is 3'' wider total.

 

Yeah I was thinking I was going to go with the IFS hubs as I don't really want to run that large of spacers, kinda worries me.

 

Has no one done this swap?

 

Have you tried searching ifs rear axle swap?

 

Spring perches are the same width, so they'll bolt up to the springs. LSPV may mount differently and require some modification, but probably not welding. The ebrake cables will be too short, a simple extension could be fabricated pretty easily, I would think, and the brake hard lines that run across the axle will be too short, unless the ifs width axle you get still has them bolted to it. Your diff will work and your wheels will work. As for the ifs hub, good way to widen the front, but seriously...no different than wheels spacers unless you're worried about the spacer lug nuts coming loose. I can tell I've never had the lug nuts come loose, and I had 1.5" spacers at all corners of my '83 to clear brakes in front and frame in rear when flexed. The spacers are not any better or worse for your trunnions, wheel bearings, steering, or anything else on the front because it spaces the wheels the same width and in the same place relative to the stock hubs wms.

If you are set on the ifs hubs, they're fairly easy to find used for possibly cheaper than spacers, though. I have a set now I'm not planning to use on my axle I build, so maybe a trade or something if you don't already have a set? This isn't the classifieds, though, just letting you know it could be cheaper even though it's more work than the spacers.

 

Thanks Jonny
That is something I did not think of I was going to go with the hubs so less stress would be on the wheel bearings but I guess you are right either way the WMS will be in the same place, I will probably go with spacers then due to ease of work, it is my DD so I cant take a week or so to do both the rear axle and the frond hub mods.

 

An 86-95 axle uses the same perches as any 79-85 truck. How do I know this? Well 79-85 front axles are the same width for 86-95 SAS.

Now I'm not sure how the brakes and such work, they might bolt up, they might not. but maybe this is a good time to put a S/S brake line in and get rid of the LSPV.

There's many LSPV removal write ups and can be done for little to no money out of pocket