Who broke my wheel hub?(5 Posts)
Took my car to Mechanic A, a long established local garage with a good reputation for honesty. Have used them before and am very fond of them. They did a service which included checking the tres, the wheel hubs and the brakes.
They told me that one of my tyres needed replacing as it had a slash all the way through the tread in one place. They didn't have the right tyre (not really a tyre place) and advised me to get it replaced before I drove much further than home.
I took the car to Mechanic B, a well known chain. The kid who changed the tyre was about 16. He undid the nuts, changed the tyre, went to put the wheel back on the car and then called the boss over. As I went over I heard the kid say "But if you torque it up to 100 then you know it's OK whatever, don't you?" and the other mechanics saying "shh shh" and shaking their heads.
They told me that my previous Mechanic must have used an airgun and damaged both the thread of two of the four nuts, and the hub itself. They said that the evidence of this was that there was liquid copper seal on all of the nuts. In the end they took out one of the nuts from my other wheel (solemnly pointing out the copper seal on those nuts too) and torqued them up so that now two of my wheels have 3 nuts out of 4.
I am inclined to think that the kid broke the nuts rather than my previous mechanic because
(a) I do not for a moment believe that my mechanics would have let me drive away in a car with only two nuts fully torqued and the other two loose, and I also think I would have heard the loose nuts rattling in the wheel.
(b) The kid unscrewed all of the nuts in the usual way - I saw him do it and none of them were loose, they all had to be fully unscrewed. It was only when he tried to put them back on that it happened.
(c) the torque setting for my car is 86, although I did not check that until afterwards, so if the kid had the wrench set to 100 then that was definitely too high.
(D) copper seal doesn't seem to be anything that would hold in a loose wheelnut?
Before I kick up a fuss, I would quite like to know who to kick up a fuss with. Views?
Did Mechanic A use an airgun to put the wheel back on?
Is the '86' setting for your car in Newtons metres or pound feet? Is the '100' referred to in Nm or lb.ft?
It was probably copaslip they were talking about - it's a high temperature/pressure grease used to prevent nuts/bolts seizing. There is a school of thought that it shouldn't be used on wheel nuts/bolts (and other torque-sensitive fastening) because as a lubricant, it makes the nuts/bolts get tightened easier, meaning that a torque wrench will create a greater clamping force between the two surfaces than if the grease hadn't have been used. If Mechanic A put copaslip and used an impact wrench (airgun) then I imagine it would be very easy to damage the threads.
Meant to say, the problem would not have been that the nuts were too loose; loose nuts aren't going to damage threads. Also, you wouldn't hear loose nuts rattling.
Ah, OK. That makes quite a lot of sense. I don't have the answer to the torque questions but it explains what they meant about the copaslip. I will have to have a chat with Mechanic A, plainly sigh. Thanks very much for this!
Just to echo what's been said about copper grease. No way should it be on threads of wheel nuts/bolts. I'd go fucking apeshit if I found a mechanic had put it on my wheel bolts.
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