Reddit mentions of Hayes Disc pad set, G1,G2,MX-1 - semi-metallic pr

I'm pretty sure that's a G1. I have the same on an old Jamis Diablo.

I've used these pads: https://www.amazon.com/gp/product/B001CK0IQI

Fortunately this caliper has worked flawlessly for me since ~2001 with little to no maintenance, so I've never had to try to rebuild them.

This Pinkbike post indicates a G2 rebuild kit will work on it https://www.pinkbike.com/forum/listcomments/?threadid=192349 and indeed from a search it looks like rebuild kits are generally listed for both G1 & G2 as the same kit.

I had a look at the Hayes website and a quick google around and I think the answers are as follows:

1. I believe it is a G1 caliper.
   
   
2. Looking at the images from 1, if the connector currently functions, then simply unscrewing the existing hose and pushing on a new hose would probably work. The caveat is of course, as long as Jagwire hoses have the same ID as the original hoses.
   
   
3. The rebuild instructions are available on the Hayes website, no rebuild kits are listed. The pads are readily available according to Google, same as MX 1 pads, and it looks like Chain Reaction has rebuild kits. So does Amazon
   
   
4. I would ignore all of the above and make a small aluminium spacer to allow a standard IS or Post mount adaptor to fit inside the rear triangle. It would require a little fiddling around with cardboard templates, but I think a simple rectangular spacer with some holes drilled in it (perhaps two would need to be tapped) would allow the use of a more modern brake system and probably cost you not much more than all the bits needed to make these work properly again. Rebuilding them is risky because you are assuming the inside of the calipers is still in good condition, if you open them up first and inspect you can make a better decision.
   
   I revived an old set of Avid Juicy 5 brakes, just because I could, but when you look at the price of new Shimano kits, it just isn't worth it.
   
   Good Luck