I have a 1996 XJS.

I had been driving for a few weeks with a strange scraping sound, usually when turning, from the rear drivers side wheel.

Today I manage to take the wheel off and whoa! was that nut loose. I could push the entire wheel in by what felt like a half inch! There was barely a thread showing from the front of the nut. I ended up tightening the bolt back on, then backing it off a bit, like I did the front.

I now realize that (a) it's a one use nut and I should replace it with JZN100024 and (b) the nut should be torqued to something over 200 foot pounds.

Is that correct?

 

You really should check the factory torque spec but the XJ40 spec is 220 to 235 pound feet,

 

Rear hub bearing end float is set by use of spacers so no need to back that nut off a bit like the front hub. It should be torqued up to book spec. I believe the nuts are NOT to be reused.

 

This is typical on many application, using a "crush" type nut secures it. They don't need replacing very often, so it makes installation less complicated with less parts that need to go into assembly and repair. Throw it away.

You will probably need to setup something like a crowbar/prybar on the studs to hold the assembly in place while tightening to that torque range.

 

What I did was reinstall the wheel, without that plastic center cap installed. Then I was able to lower the car off off the jack and torque down on that nut without any problem...other than getting 230 lbs on that wrench...

Once done, I popped that cap back on and took it for a drive. Scraping is gone.

I did already order an OEM nut, so I'll do this all over again in about a week.