where to buy brake pad shims

[domiles1]

I can't find where to get the metal shims that go between the piston and the brake pad for GS calipers. I have about three different calipers I'm rebuilding for late 70s - early 80s GS 750/1000. Any ideas where I can buy in UK?
Secondly, are the shims really necessary? I can't see what they do - do they just protect the back of the pad and spread the pressure from the piston?
Cheers
Dom

[Agemax]

they are anti squeel shims, available from any suzuki dealer. not strictly necessary, just coat the rear of the pads with copper grease, does the same trick

[hampshirehog]

As Agemax says. Different shims for back and front - I've just checked Robinsons and they have the fronts, but at £5.11 each for: 59371-49000 SHIM PAD I think I'd wait until I found some secondhand or just use the copper stuff.

[domiles1]

Thanks for the explanation, I'll use the grease! The calipers are going on a bike which won't be doing a huge mileage anyway. All these bits are so expensive, it really adds up when you're rebuilding calipers with new parts.
Thanks guys.