- Correct bearing tightening instructions
- Brakes work again, even when turning
- No wheel wobble at high speeds
- Greatly reduced chances of dying
I strongly believe in the value of fudging values from time to time. 5 ft/lbs? Finger tight! 0.05mm tolerance? Finger tight! 32 PSI? Yup, finger tight!! Please note that I am not an accountant, and do not work in the finance industry (where a lot of 'value fudging' goes on as well, I imagine...).
Unfortunately this does not always work. Bearings, for example, are an example of one of these situations. I learned that this week when the brakes on my XJS stopped working every time I made a hard left or right.
I recently changed the bearings on the XJS, but followed my usual method of tightening the end nut: finger tight plus a turn of the wrench. Generally that's good enough (as it seems to be for the MG). Tightening too much leads to premature wear of the bearings, and that lovely grinding noise you sometimes hear on old cars. Too loose has never been much of a problem, so I didn't think too much of it.
Well, I was wrong. Turns out the XJS needs a full 25 ft/lbs on the end nut (as pictured above, on the MGB, before pin removal), backed off one flat (and more if necessary to fit the pin back in). After adjusting this the brakes returned to normal, and high-speed driving stabilised a bit. Turns out the nut was loose enough to let the rotors move around enough to push back the brake pads, but only when the wheels were turning. So really the brakes were working fine, it's just that they had to be reset each time I made a turn.
So:
Here are my general bearings instructions (for the MGB and most cars that aren't Jaguars):
- Tighten the end nut to 5 ft/lbs while turning the wheel. If you hear grinding or anything like that your bearings may be bad, or some dirt may have entered the hub. Clean the hub and make sure you pack it with (clean) grease.
- Loosen if necessary to enter holding pin
- Reassemble the wheel (keep it jacked up).
- Check for wobble by holding the wheel on the top and bottom and try to make it wobble. Then hold the wheel on the left and right, and do the same. If you feel any wobble or anything that seems too loose, tighten the end nut a bit, and recheck.
- If everything seems right, take your MG out for a ride. If you do not notice the same or better performance, something is wrong (duh, this counts for anything I guess...). The best speed, in my opinion, to find problems is around 70 mph. Good luck.
Mind you, despite the bad braking and wheel wobble I still did a 400 mile road trip at 80+ mph speeds....
