Discovery Caliper bolt size

You're approaching this the wrong way!

Corrosion could result in a hex. size anything between what it was and something much, much smaller. The only sensible way to do this is to have a handful of sockets at hand and use that which has the tightest fit (slightly hammered on tight is suggested).

Remember that if you mess up the bolt head you will have a major problem on your hands. Get it right first time and be prepared to replace the bolts when you put it back together.

Either buy several sockets, a mixture of imperial and metric even Whitworth, or borrow some. Don't use the borrowed socket as a gauge, go out and buy a similar sized one and use that. It's almost guaranteed to be the poor fit.

Thanks for the reply Dougal.

The heads are not badly corroded, and there is no way a 15mm socket would hammer on, so before I go and get any new sockets, metric or A/F, I was just trying to find out what the satrting point was. It may just be that my 16mm is knackered!!

Reagrds Jeff

The old hex headed ones were 5/8" A/F and the later ones 12pt 14mm A/F I think.

Don't get hung up on whether it should be imperial, metric or Whitworth - just make sure that it's tight! If that means a 'metric' socket on an 'imperial' bolt so be it.

5/8", 3/8" Whit/BSF(Current series), 19/32", and 15mm would be starters for the 5/8" hex. 14mm, 5/16" Whit/BSF(Current series) and 13mm would be starters for the 12pt.

Your 16mm was too big for anything but you get the idea, a worn undersize socket may be just what you need.

Thanks Dougal

5/8" A/F sounds like the size, that would account for why 16mm is not a tight fit. It looks like a new 5/8" socket is the staring point (my 15mm isn't that worn!!)

Reagrds Jeff

On or around 1 Sep 2006 07:25:53 -0700, "Jeff" enlightened us thusly:

if 16mm doesn't fit right, they're possibly 5/8" AF. some of the disco rear calipers were UNF bolts, not metric.

On or around 1 Sep 2006 08:34:55 -0700, "Jeff" enlightened us thusly:

yep.

metric ones tend to be 12-point 13mm anyway.

Why do caliper and supension bolts often seem to be AF?

On my saab, everything is metric except for the shock nuts, caliper bolts and some of the axle fittings.