I have one particularly squeaky brake that has new pads and a rotor in pretty good shape. The squeak goes away when the brakes have a chance to warm up so I'm thinking there is something wrong with the caliper. My guess is binding on the guide pins. If its a pretty tight fit, what would the consequences of cleaning them up with a fine grit sandpaper be? Assuming I'm lubricating them when reinstalling, will it have any negative side effects not having a smooth surface?

Also, the gooey stuff you put on to eliminate sound, where does it go on front brakes? On the rear I can put it on between pad and shim however on the front the pad clips directly to the piston.

Cheers

 

That stuff goes on the backside of the pad, use that, it will stop squeaking. Don't sand and then put a lubricant on the brake pad, that's basically reversing the brake pads job.

 

To clarify, I meant sanding the guide pin to help eliminate binding/seizing.

Also with regards to front brake pads, the only part of the caliper that comes into contact with the pad is the piston. There aren't any shims so I'd be getting the goo all over the piston on that side of the caliper. That seems wrong. Or am I missing something entirely?

 

No need to use silicone grease on the front pads. Squealing is coming from the back and you need to apply that stuff like Gilber33 suggested. Here are DIY instructions

 

Rear are easy enough however my squeal is front. So you are basically saying anti-squeal stuff will not work on front brakes?

So back to guide pin question. Can any build up be sanded down without consequence? Replacing on this side of the world is not as easy as it should be.

 

I have read many squealing posts and they were all rear break squealing. In my case I used silicone grease and "half shims" and it helped.
As for guide pins they should be cleaned and greased not sanded down. And here is link that shows to use that silicone grease (gooey stuff) on the back of the front pads

 

Clean the guide pins really well with brake cleaner, clean the guide holes really well too. If there is rust or scale on the pins they should be replaced. I have used emery cloth to shine them up a bit and have use a drill bit that just fits inside the hole (turned by hand, not on a drill) to dig out the old grease. Re-grease and re-install.

As for the anti-squeal stuff, spread a little on the back side of the pad wherever the pad comes into contact with the caliper bracket and it is OK if that happens to be the piston on the caliper.