Leaving the caps off your car for a prolonged eriod of time will cause the end thread to corrode.

Though this in itself is not an issue, if you have to do some work in that area

(eg, change a wheel bearing) this could cause a problem not only getting the various bits off but more importantly, putting them back on again.

If you have to replace this thread, it's a new drive shaft which is probably a couple of hundred quid or so.
