I remember reading an article online rebuilding the pontiac cone type posi. Anybody have any links about this? I read that the halves need to be machined to tighten up the slack caused by the cones wearing. At the same time ,machine off a few thousands from the end of the cone to allow it to slide deeper into the socket.
Mine is about down to a single wheel peel. i have to pull it out soon as i believe sombody didnt set it up correctly ;-) me.LOL It was running nice and quiet, until last week. I got on it hard a few times , then i noticed @ cruise it whines. So i'll need to pull the differential out and reshim. i figured while its out i can tighten it back up to a more solid posi.
If the cones and the taper in the case are severely scored and worn and shiny your pretty much out of luck and a new diff is needed. A true old school machinist should be able to fix these things but the cost may outshine a new diff.
The 2nd article is the attached PDF that I saved as a web page off the net some time back. It shows how the cones and carrier wear out. I don't quite agree with his strong opinion that all 64-70 BOP posis are junk, but it has good pictures.
If I didn't think that you would use extreme caution using this source, I wouldn't mention it.
YouTube has some incredible how-to videos. But you need to be [censored] careful when using such videos as guidance. All you have to do is find some type of repair you know about, take a look at some of the video advice, and you will see what I mean.
My 12 posi and rear springs will be the last of last, of planned repairs. It might happen next winter, but I have to get this last winter's project done.
My game plan is to hybreed the information sources. I'll start with tried and true, credible, hard copy technical publications, and I will combine it with videos, milking the cream from the crap. (Actually, I have seen some pretty badass dudes doing videos, and I would feel comfortable using them as an advisor.)
I swaped my cone style to an Eaton unit. Really wasn't all that expensive past the initial purchase of the unit, but all my bearings and races were mostly new. Had a local shop do the work. The only issue with the Eaton is it only compatible in one series of gears. 3.36, 3.55, 3.90 and 4.33
Don't want to hijack the thread, but are the BOP 8.2 4-pinion posi's also the cone type?
1967 FB 400, original CA car (smog), now 455, finally in Paint Jail after 19 yrs. Metal work & block sanding done. Jambs painted. Color coat on, color sanding underway 2006 Mustang V6 Pony, factory ordered, 28 K miles, future retirement cruiser and classic(?) 1994 Chevy K2500 HD 4x4, 454 TBI, goes anywhere, tows anything, current DD (Soon to be sold) Old projects, gone but not forgotten: 1980 Turbo Trans Am 1970 Mustang fastback, 351C 4Bbl, auto 1988 Mustang GT, 5 speed 1983 F-150 4x4, built 302