zx girling calipers

ralph · Post by **ralph** » 18 Apr 2005, 12:40

I've posted about these calipers before. Put the job off for a couple of weeks, now I'm struggling to remove the bolts which secure the caliper.
Some donkey has overtightened them in the past. It's an 8mm allen key head, and the bolt is recessed into the caliper body. The bolt heads have stretched so an 8mm key just turns inside them, and a 9mm is too big to hammer into the bolt head.
Has anyone suffered this before? I'm wondering if there's a Torx bit I could use which would do the job. I haven't got one that's big enough in my set.
The job's become vital as the offside caliper is now binding.

Post by **RichardW** » 18 Apr 2005, 13:43

Have you tried imperial allen keys, one might be nearly the right size. A torx bit might well work - you can buy sets for a few quid, so worth a shot. If you have access to a welder you might be able to put the 8mm in and weld it to the bolt allowing you to extract it. Is the head accessible? Could you grind it off to free the cliper and then use a pair of stilsons on the shank to get it out. Could you get the stilons on the head of the bolt? Could you weld a nut top of the bolt? There are plenty of options, but it depends on access and the size of your tool kit...

ralph · Post by **ralph** » 18 Apr 2005, 14:30

Bolt heads are recessed a couple of centimetres into the caliper body, so I'll try your imperial allen key and torx suggestions. Thanks.

Post by **RichardW** » 18 Apr 2005, 14:56

"Bolt heads are recessed a couple of centimetres into the caliper body"
Uh, not good then. You might end up having to take the hub carrier off the car to get the bolt drilled out. If possible, apply some heat to the hub carrier where the caliper bolts on to try and help things along.

Kowalski · Post by **Kowalski** » 18 Apr 2005, 15:27

You can probably drill the heads off the bolts then use a stud extractor once you've got the calipers off.

ralph · Post by **ralph** » 22 Apr 2005, 13:22

I've sorted this by cheating - I left the slider bolts in place and managed to free the caliper by walloping it.
Got it moving enough to remove the pads and disk, then lubed up the caliper sliders with penetrating oil and then copper grease under the dust boots.
If it starts seizing up again, I'll probably have to bite the bullet and drill the bolts out.
By the way, couldn't get an imperial allen key to fit the slider bolts. And a Torx 50 bit was too small, a T55 was way too big.