Rear diff swap

[SPLutah]

All,
I am in process of swapping out the rear end in my '68 1600 for one out of a 2000 car (3.7 ratio). I am wondering if I can just pull the axles out of the old one and remove the third member then put back in the 2000 third member and replace the old axles. I would think that the preloads should not change on the bearings as the axles and the housing are remaining but is my logic sound there?
Thanks for any guidance you all can offer!

[Habitat.pat]

That’s my understanding. Axle location & securing are done at the outside ends of the axles.

Peace,
Pat

[theunz]

Yes you can with no problems. Be aware that you will have to disconnect your brake lines in order to slide the axles far enough to disengage them from the third member, thus necessitating a brake bleed when you are done.
Check this out.. viewtopic.php?f=10&t=35556

[SPLutah]

Sweet. Thank you @theunz and @Habitat.pat! I appreciate the reassurance and the link! Bleeding brakes isn't an issue as the lines are a mess already right now! Front brake calipers were all super pitted and need to be sleeved. Once I pull the rear axles I will take out the rears and I am sure they will need to be replaced or sleeved. The question I am still asking is if the switch to the 510 cylinders can be done effectively. There seems to be a bunch of mentions of them and the need for adapters on the forums but I don't see any pictures or hard commitments that people have done it. It seems to be that to do it you would end up having to cut off the flare on you brake lines and shorten the line up just a bit to compensate for the thread adapter?

[DAC21]

Sweet. Thank you @theunz and @Habitat.pat! I appreciate the reassurance and the link! Bleeding brakes isn't an issue as the lines are a mess already right now! Front brake calipers were all super pitted and need to be sleeved. Once I pull the rear axles I will take out the rears and I am sure they will need to be replaced or sleeved. The question I am still asking is if the switch to the 510 cylinders can be done effectively. There seems to be a bunch of mentions of them and the need for adapters on the forums but I don't see any pictures or hard commitments that people have done it. It seems to be that to do it you would end up having to cut off the flare on you brake lines and shorten the line up just a bit to compensate for the thread adapter?

I'd be interested as well in hearing if anyone has made this metric adapter work. There is a thread going back to I believe 2019 were a 311s member had tried it but the mating flares were not correct for a proper seal to the 510 cylinder.

Edit: here is the thread discussing the correct P/N for the adapter. MrWaj is the member whom has determined that the mating flares don't look right.

viewtopic.php?t=30375&start=15

[Habitat.pat]

The alternative to the adapter is to have custom brake lines made that have metric line nuts installed to replace the SAE ones on the ends that attach to the cylinders. Personally I’d feel better with this rather than the adapters. I don’t think there is enough room for the adapters,things are very tight at the wheels so I don’t see how there would’ve enough room.

Peace,
Pat

[theunz]

Good idea Pat. I had stainless flex lines made from the T mounted to the axle to the wheel cylinders in order to facilitate quicker gear changes. A local hydraulic hose shop did it for about $60 IIRC. The lines included new fittings, therefore it would be easy to have different ends on each end. No way the rigid brake lines on my 69 would have enough flex to accommodate adapters.