Several postings online say that you should not chase the threads on a banjo center housing because the bolts are a special thread, designed to prevent leaking. One fella even suggested that one should take care to return each bolt to the same hole it came from because each bolt is matched to the female thread in the housing. The Green Book lists a 24329-s bolt, 3/8-24X5/8 for the axle housing. No special thread. It lists a 350522-s bolt, 3/8-24X1 drilled, for the torque tube. No special thread. Is this just an urban legend? Does anybody have documentation of special bolts for the banjo rear end?
same bolt in the same hole!! never heard that one. I've heard the special thread story, I just clean them up on a wire wheel, and if needed a thread chaser, not a tap or die
I think the hole has the tight tolerance threads, not the bolt. Same on the engine block deck. My bro and I are working on a banjo/quickchange project and I was thinking that studs might be the best answer to the leaky problem. You could glue them into the housing really nice, and then if you ever need to disassemble, just the nuts need to come off.
The issue is the CLASS of thread, not the thread size and pitch. The class determines the allowable thread tolerances and clearances, and the tighter the tolerances, the more strength the joint has, and the more torque that can be put into fastening the joint. I don't remember the class designations, but some are so loose you can throw them in the hole from across the room, and the other end of the spectrum is interference fit. That's why you shouldn't chase threads with cutting tap unless you know it's the same class as the hole. Do a quick search for 'class of thread fit'
You can still use modern technology and still stay traditional. This is what I have used on ot rears https://www.mcmaster.com/#93781A038 Sent from my iPhone using H.A.M.B.
i have never really had a problem with them leaking. i do have a can of extra bolts though, so if one looks bad or wont start by hand, just grab a different one
So many rumors out there made to scare people! Not a good idea to chase threads in housing for no reason, but Ford wasn’t that picky about housing bolts at the factory I’m sure!! Sent from my iPhone using H.A.M.B.
I'm the fellow that recommended installing the bolts in the same threaded hole they came out of. REASON: It's easy to do and just wanted to have more insurance that there would be no leaks even with sealant. The class of fit is very important also. I could not find any torque specs for those bolts. 2nd photo shows OEM safety wire configuration.
From working on antique guns I am in the habit of matching screws to the holes they came out of. Screws and holes wear together. It probably doesn’t matter so much on cars but I do it anyway if I can. Can’t hurt.
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