Undoing brake caliper pin cap

[MarkJ]

Part 20 on here:
https://webservices.motorsportdealers.com/parts/partImages/HOM/2/14MV9M/ILLUST/MV94F/0900D.Gif

The front pads need changing on my 92 CBR, however the little caps that screw on above the pins have really chewed up heads (for a flat head screwdriver). Looks as though the last person who tried to get them off failed.

Now, how should I go about getting them off? In the past pouring boiling water over them has worked, however it still stripped the head a little and I really don't have much head to work with. Is there some sort of release agent I can use, which can soak into the thread overnight? I could maybe use an impact driver, but that might knacker the disc if I do it on the bike, and might slip if I try to do it on the floor. The final option I'm swaying towards is to use one of those screw extractors and buy two more caps. If people think this is a good idea, what kit is a good one to buy?

Opinions?

[yen_powell]

I've got the same calipers on my Africa Twin. I've used an impact driver with no disc problems on other people's bikes.

On my own I've always copperslipped them to death, now I don't even bother fitting them, they have a much more important job on the bike. They blank off the chokes on the carbs, perfect fit.
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[Walloper]

Buy a wee butane heating torch out of Halfrauds (About £6 I think.)

Heat up the plug mad hot and let them cool. They may come then.

You risk melting the calliper seals by this method.

Next way is to drill the plugs out then clean up the thread using the correct taps You will need Semi taper and a Plug.
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[stinkwheel]

My weapon of choice is an old fashioned drill brace with a screwdriver bit clamped in it. You can really press down on the end of it very hard with your shoulder and use the handle to turn the bit at the same time.

Repeated application of freeze and release spray has got me out of trouble on a few occasions. Halfords sell it.

You may even find you can tap it round using a fine punch and a hammer applied to the outside edge of the screw slot.

I've always wondered why they aren't made of plastic. They aren't in any way structural, they just keep the dust out and at least you can rive a plastic one to bits of it gets stuck.
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[DrDonnyBrago]

I've found plusgas to work well as a penetrant in these circumstances. That plus heat, plus the best fitting bit you have and lots of weight pressing down on it/impact driver.

As above though I really cant see why they aren't made from plastic/rubber. It seems total overkill to have steel ones and everyone with nissin calipers seems to have had the same problem (me included!!!).

[Kickstart]

Hi

Down side of penetrating oil on them is that some is bound to get onto the top of it and make a screw driver more likely to slip.

They are a fairly soft metal so if the worst comes to the worst they can be drilled easily.

But an impact driver would probably be my choice.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[Noxious89123]

Punch and hammer method works well I have found.

It's how I removed a brake res screw that was well and truly fucked. Kept bashing it until the punch had dug it's own goove right into the screw and then it eventually came free.
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[DrDonnyBrago]

[MarkJ]

Liking the punch idea May call in at B&Q after work tomorrow and get one. Thanks for all the ideas

I was thinking of this as a screw extractor as it should dig into the soft metal fairly easy?

I have the same sort of calipers on my hornet which I religiously coat with copaslip everytime they come off - and they still manage to sieze up again

[Kickstart]

Hi

A trick that I have heard used it to put a bit of valve grinding paste on the tip of the screw driver.

With degreasing I would be concerned that you will just remove what little lube remains on the threads.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[bacon]

I had to remove one of those on an old cb250, with the caliper off the bike i used an impact driver, worked perfect

[MarkJ]

Holy crap, how good are impact drivers?

I should have bought one of these a long time ago, one hit on the bolts and they were loose! I'd have saved myself so much faffing around in the past if I'd had one. Thanks guys

[Walloper]

[MarkJ]

Didn't know that, cheers