Pioneer T-6600 reel to reel problems

I've got a Pioneer T-6600 reel to reel with a couple problems.

The belts failed due to age related cracking. Where can I get new belts?

The stock reel brakes don't work so good which leaves the sound a little muffled during playback.

From what I've read online there was a mod for better reel brakes, but mine never got that mod.

How do I fix the brakes?

Also is there anything else I should do to this unit before putting it back into regular service?

I plan on using it to play a tape someone recorded that runs slightly fast by altering the AC input frequency to the reel to reel using a variable frequency AC supply.

I currently do that using my AKAI GX-255 for the playback and supply reel with an AKAI Terecorder being the drive unit and take up reel, but that requires work to set it up right as I have to remove the capstan roller off the GX-255 and I have to start playback on both units at the same time. The Pioneer has an AC motor so I can just lower the frequency to achieve the same thing.