Drive shaft connection

[Karl]

Hawk owners with Jag rear,
after driving 1500 km now, (nearly 1000 miles), speed on the Autobahn 190 km/h (nearly 120 MPH, it will do more, but still too frightend), many secondary roads and hard acceleration and braking, I started to experience some knocks from the rear. Found out that all nuts, connecting brake disc and drive shaft to
the diff-flange, had worked loose. Anybody had the same problem? Do you need to torque them up after the disc has been warmed up and cooled down a few times? Your comments, please!
Karl

[Roger King]

Have you used the correct Jag nuts?
IIRC, they are a crimped-style metallic locknut, not a normal Nyloc.
SNG Barrett list them as:

Brake disc nut NV607041J, 8 needed.

Never had this problem with mine, so this may be your answer.
Also, it's important that they can't come loose - the bolt head doesn't have to move back far before it will lock in the diff casing, which could lock the drive shaft with incredibly nasty results.

Roger

[Cotton Mouth]

I have just had my rear end done and the supplied nuts have a special sort of metal collar that only works once on tightening. Ed at Jagaxles has these and recommends torquing at 55lbs ft. Jagaxles easily found on the net and Ed is very helpful. Hope this might be of assistance.

[Karl]

Thanks guys, I have the correct nuts, as supplied by Ed. I have a rebuild axle from him. Maybe they were not torqued up correct, as I cannot reach there with my
torque wrench. I used the correct size ring spanner with extension pipe (1 meter) now. The bolts were not loose, just the shaft had a little play (forward-backward, only under load).
Maybe my engine has too much torque? (340ftlbs)

[Roger King]

Thanks guys, I have the correct nuts, as supplied by Ed. I have a rebuild axle from him. Maybe they were not torqued up correct, as I cannot reach there with my
torque wrench. I used the correct size ring spanner with extension pipe (1 meter) now. The bolts were not loose, just the shaft had a little play (forward-backward, only under load).
Maybe my engine has too much torque? (340ftlbs)

Don't understand - if the bolts weren't loose, where was the movement? In the splines? You'd need a lot more than 340ftlbs to damage those, unless already worn.

[Karl]

Roger, the bolts and nuts connect the drive shaft and the brake disc to the diff - output flange. Now the nuts were not that loose, you could not move the bolts by hand. There was just that little play that you have in the boltholes. You could only hear it whilst accelerating and decelerating, just one knock. I only found out about it, when I put the car stationary in first gear and had another person rocking it forward and backward. Then, lying underneath, I could just feel that tiny little movement. When I put the spanner on the nut they were no tight, just turned easily. Hope this helps!
Karl

[Roger King]

Roger, the bolts and nuts connect the drive shaft and the brake disc to the diff - output flange. Now the nuts were not that loose, you could not move the bolts by hand. There was just that little play that you have in the boltholes. You could only hear it whilst accelerating and decelerating, just one knock. I only found out about it, when I put the car stationary in first gear and had another person rocking it forward and backward. Then, lying underneath, I could just feel that tiny little movement. When I put the spanner on the nut they were no tight, just turned easily. Hope this helps!
Karl

Ah, so the nuts were loose, just not excessively so.
I'm surprised there was room for movement as the setscrews should not allow much movement at all.
You won't get a torque wrench on these. I seem to remember the figure is 55lbs.ft. torque (check that!). The best way to do this is to find another nut somewhere on the car that has a higher torque setting than this, fit your torque wrench, set at 55lbs.ft., and hold it at about the same distance from the nut as your open-end spanner would allow. Pull it till it clicks, maybe a few times. Now put your spanner on the output shaft nut and pull with the same force you were just using on the torque wrench. This should give a pretty close approximation to 55lbs.ft.
Did you clean all the paint off the drive shaft flange etc? This will crush after a while and 'loosen' the nut.

[Karl]

The movement was very, very small. I used a ring spanner with pipe extension to get to the length of the torque wrench. I actually used the axle as delivered by
Ed. This connections were left loose up to the end to allow for camber setting with the shim plates. I think if they stay tight after the next 500km the problem is solved.
Not much time for testing now, weather is bad and the next jobs are waiting.
Thanks Karl

[andyg]

Hi Karl,

Finished my FIA (except for a few minor things - and the paint!) in May this year and have now completed 1200 fun miles. Have a Jag rear end, and after about 1000 miles, started to get a single knock when accelerating from standstill/low speed. Have had a quick look and nothing obviously loose - maybe I have the same problem! Will check it out - thanks for the post.

Andy

[andyg]

Karl,

Checked my nuts today(!) and found them all slightly loose. Some turned very easily with ordinary spanner others a bit tighter. All now done up to 55lbs/ft torque. Car is off road for winter however, so road test will have to wait.

Thanks again,

Andy.