Detailing a ZF and have a few technical questions:
1- Did the factory use any thread locking agent on either the in board or out board portions of the 10mm and 8mm studs for the axle carriers and rear cover respectively?
2- II in the case the factory didn't use a thread locking agent, would it be prudent to do so in reassembly?
3- Is thoroughly cleaning and spraying these threaded studs with a self etching primer not recommended for any reason
4-What are the torque specs. for these fasteners?
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I can't answer whether the factory put thread locker on the studs. However in my experience, there isn't any and gear oil tends to weep thru the studs. Last year I re-sealed (for the second time) my ZF to reduce weeping and leaks. It worked great and now I don't have an actively leaking ZF. I used high-temp thread sealant instead of PTFE paste or tape on the side cover studs. It seems to be working great.
I'm not sure on the self-etching primer.
Torque specs vary with the part. I will look but the manual is available to download if you're a POCA member.
A very knowledgeable transmission technician recommended the use of Loctite 518. What was it that you used?
I used a high temp thread sealant. You can get it at an auto parts store. I haven't ever used Loctite 518 for this application.
Regardless of the Lock-Tite part number, their reps say that Red Lock-tites will need heat (typically, a few seconds from a torch) to loosen. Blue Lock-tites can be disassembled with a good wrench and no heat. And Green Lock-tite (used to fill larger gaps) unfastens even easier than the blue stuff. So if you don't plan on removing something, use Red. If the thing will need to come off now 'n then, use the Blue.
@bosswrench posted:Regardless of the Lock-Tite part number, their reps say that Red Lock-tites will need heat (typically, a few seconds from a torch) to loosen. Blue Lock-tites can be disassembled with a good wrench and no heat. And Green Lock-tite (used to fill larger gaps) unfastens even easier than the blue stuff. So if you don't plan on removing something, use Red. If the thing will need to come off now 'n then, use the Blue.
I'm sure in an aerospace (or racing) application we might consider something like Loctite blue or red. However on a street car that isn't going to be subject to extreme vibration, I'd rather have the threads sealed and rely on the torque setting of the nut/stud assembly.
