CV Joint Nut

This is more of a curiosity question. Having replaced the CV joints and boots I was wondering why the 308 uses “flex top” nuts on the CV joint bolts? Why not just use a good quality Nylon insert lock nut?

 

My guess and it's only a guess is that the axles can get really hot and the nylon can soften and not hold.

I have often wondered the same thing.

 

that could be but a good quality Nyloc nut is good to 250 F. does it get hotter than that at the CV joint?

 

I don't believe CV joints get that hot. Maybe Nyloc's didn't exist in the early 80s? In fact, I can't ever remember seeing Nyloc nuts fitted to cars by any OEMs?

 

Lotus was using nylon locknuts in the '60s.

 

There are many nyloc nuts on the car, many in much hotter places than the CV nuts, I always wondered how they can withstand the heat. I can only presume the CV bolt torque is so high that it needed a stronger mechanical lock, I think they are very vibration resistant, the suspension movement must create alot of vibration.

 

My 1961 Lotus Elite uses an all mtal "Flex top" nut on its inner u-joint -- because there is an inboard brake disk sandwiched between. It uses nuts with lock washers most everywhere else.
Mike Flanagan

 

Heat (both convective and radiant) from the (glowing ) exhaust manifold near the inboard CV joints probably played a role in their selecting an all metal locknut (rather then a Nylon insert locknut).