1987 XJ-S V12 coupe with stock starfish wheels. I periodically go out with the torque wrench to make sure they are all tight. Yesterday I discovered one on the right rear that wouldn't stop turning. It offers some resistance, but it doesn't go in any further, nor will it come out any further. There is no grinding or particular spots of resistance. I can't turn it either way by hand, but it turns easily with a lug wrench. It's sticking out about 5mm from the rest of the nuts. If I recall correctly from the last time I was under the car (and I hope I'm wrong on this) that even if it were lifted I wouldn't be able to see anything.

Thoughts on how to remove it, or at least to see what the problem is?

Thanks,

John

 

Well, that sucks! I wonder if the stud is turning in the hub. Your 87 still has inboard brakes, you may be able to have someone look from behind the wheel while turning the nut. If the stud is indeed turning, I would try to hammer it outward (probably will need a long, sturdy punch) , then try to unscrew the lug nut. I wonder if the nut did not get cross threaded, and never got tightened.

 

Try taking the other lug nuts off, then while pulling on the wheel/tire combo put force outward on the nut. Use an impact gun in reverse on the nut and try that.

​​​​​​If that fails, this might be your only option.

 

Had a chance to do some investigating today. The photo shows what appears to be a weld right behind where the stud for that nut in question would be.

I found that I can stick a finger into one of the starfish wheel holes and can feel the weld. When I use my other hand to turn the lug nut, I don't feel anything moving. I also don't see any holes where any other wheel studs should be.

Does anyone have an exploded view/drawing of how this area is assembled?

Thanks,

John

 

Thanks JAL1234. I'll give your suggestion a try. I did try and pull the nut off with vice grips, but the wheel hole for the nut is so small I can't get a good grip on the nut. Luckily I do have a 1/2 inch 10 amp drill so if push comes to shove I'll use the method presented in the video.

Cheers,

John

 

The stud is a press-fit splined item screwed into the rear hub disc. I am pretty sure that you have a stud which has stripped threads at a certain point, so the wheel nut cannot either be done or undone. Cutting or drilling it off somehow is definitely your best option.
https://www.ebay.co.uk/itm/JAGUAR-DA...-/124121907577

 

Are they? I thought so too but now I’m not sure. I went looking at pictures on SNG Barratt’s website. They show a splined stud for the front hub but a threaded stud for the rear stud. Now I’m confused. I thought all the studs on my car are splined, but it’s been a few months since I worked on the rear end so I can’t be sure.

 

Apologies to all, You are quite right. The rears are theaded in. Part number C13365, still available from Jaguar too.
https://www.ebay.co.uk/itm/JAGUAR-DA...-/124121907577

 

Lol,,, I need some NEW and IMPROVED drill bits.
Mine NEVER cut like that...
Get what ya pay for, I hear...

 

Cobalt drill bits. Worth their weight in gold. Expensive, but they work. Forget high speed, titanium, etc.

 

Here's a picture of the backside of the hub flange showing the stud head. As you can see, it's got slots on it. If that's not turning when you turn the nut, the stud or nut is so stripped that threads can't engage either forward or reverse. Sometimes with pressure outwards on the nut, they will engage enough to allow you to get the nut off. Oil the nut seat in the wheel so friction from the impact gun spinning the nut won't damage the wheel. Apply as much pressure outwards as you can, preferably with a friend's help. If that doesn't work, drilling is likely your only option.

 

Here's a picture of the backside of the hub flange showing the stud head. As you can see, it's got slots on it. If that's not turning when you turn the nut, the stud or nut is so stripped that threads can't engage either forward or reverse. Sometimes with pressure outwards on the nut, they will engage enough to allow you to get the nut off. Oil the nut seat in the wheel so friction from the impact gun spinning the nut won't damage the wheel. Apply as much pressure outwards as you can, preferably with a friend's help. If that doesn't work, drilling is likely your only option.

 

I just drilled it out. Wasn't that hard and didn't take that long.

Question is, since the threads are damaged I'm going to have to drill a larger hole and tap it for a slightly larger stud....or...get a new, and same sized stud, and weld it in from the back. Or..., or what???

Are the studs made of weldable steel?

Other suggestions?

Thanks,

John

 

Yikes. That couldn't have been fun.

If it were me I might be considering spending 100-150$smakers on a used rear hub. But that's just me. Then, and I'm sure Greg can help with this, what does it take to rightly size up the replacement of the hub... considering spacers, end floats and stuff that is way beyond anything I've done on the rear carrier.

I think it might be a struggle to safely recover that...?
Sourcing a new lug bolt that fits, takes the same sized lug nut and be secure seems like a tough set of needs on something as important. I guess you could find a longish bolt that takes the correct lug nut, enlargen the hole on the hub and just push it thru the hub and wheel and tighten it up? What about balance at speed in that?

I dunno. Super interested in what happens next. Often I find myself in situations like this big and small in working in my machines. Figuring it out is a part O the fun of it.

​​​​​

 

John
What about a Helicoil? They are made just for this type of repair.
Mike

 

That's what I was thinking.

 

My feeling is that it would be far easier and FAR safer to swap out the hub as a unit. The easiest way to do that is to undo the driveshaft flange at the inboard end, unbolt the lower pivot on the hub (that joins it to the lower wishbone), and remove the driveshaft and hub as a unit. Buy the same from a breaker and bolt it back on. 2 hours max and job done.
I would never want to trust a helicoiled wheelstud, or some sort of bodged up welded/rethreaded repair.

 

+1
Dont take risks on this safety critical item. You should be able to get a used hub from a breaker. What you've shown us is what Charlie Allthumbs gets up when he works on cars !

 

Deferring to the knowledge of those who have more experience/education than I have on these matters, safety seems to dictate that the hub be replaced. Understood. Apparently welding the stud in is a poor option per Palm et. al. (possible cracks, distortions and the like).

Greg, why is it that I shouldn't just replace the hub proper in lieu of replacing the hub and driveshaft as a unit? It seems that by pulling out the hub and driveshaft that there are all sorts of bits (bearings, spacers, seals, rings...) that have an opportunity to "go out of line" if I pull the entire drive shaft out. Not suggesting yours is bad advice, but just trying to grasp the implications of this vs. just replacing the hub.

Thanks!

John

 

A good used hub would work too.
Properly installed Helicoils are used in many critical applications including aerospace and manufacturer has wheel stud repair kits. Stanley Engineered Fastener catalog link is attached. Give them a call if a Helicoil repair is of interest.
https://www.stanleyengineeredfasteni...02-revkweb.pdf