Kelsey-Hayes was absorbed by LucasVariety in the '90's. In turn, LucasVariety was purchased by TRW in 1999, and continues to produce all kinds of vehicle braking systems and parts. So you may be looking for TRW parts at this point.
But, I found a complete parts list for the Hayes 1 x 1 5/8 brakes in the Bargman catalog. Here is the link for the complete catalog:
http://www.bargman.com/Brakes/index.html - look on page 21 at the bottom for your brakes. The catalog says the brake shoe kits are no longer available, but a good trailer dealer (not an RV dealer) may well be able to find an equivalent part or recommend the correct replacement brakes for your TT.
Let us know how it goes.
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'12 F250 4x4 Super Duty PowerStroke 6.7 diesel
2011 to present: '11 Cougar 326MKS
1999 to 2011: '99 Sunline T-2453
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