'68 - '74 Power Steering Pump Pulley Lock Nut

[HouseOfCadillacs]

I recently ordered a rebuilt PS pump for the ’70 and unlike the ’75 it has a lock nut on the pulley shaft (’75 on have a press-on pulley). Unfortunately one of the previous owners had cross-threaded the old nut onto the shaft and once I got it off, it turned out the threads of the nut were rendered unusable.

The FSM says it’s a 9/16-18 lock nut and I was able to source one locally from a specialized fastener store but they only had the regular style and not the low-profile style like the original. The problem with that is that the pulley shaft is not long enough for the new nut to completely fit on it. In fact the nylon insert doesn’t even touch the shaft threads preventing it from locking the nut in place. I guess I could just use Loctite thread lock on it but the nut also sticks out a bit. Does anybody know any sources for the original style nut?

Thanks,
Stephan

[Dave Shepherd]

In a pinch a machine shop could turn it down then rethread it if necessary  and locktite it.

[HouseOfCadillacs]

That might be my only option if I can't find a new correct one. Thanks.

[TJ Hopland]

If it has ever run loose I doubt you are going to be able to keep it tight.  I have had several cars where that had been loose and even with the replacement pump they would not stay tight.  I suspect it was due to wear in the pulley.   I think I ended up switching to a later pressed on pump.   Now when I do see a car with that style that nut gets checked with every oil change.