HUP C8A: correct wheel cylinders
 

For the record, and to keep Hanno happy, based on the excellent info on this forum, I found the following wheel cylinders fit our HUP well: 9325 for the rear, complete with starwheels, and 4571 for the front.
Both are available from Rockauto for an amazing price, and fast, cheap shipping to Canada. They're sold under the Raybestos or Wagner name, same part number, but made in China. And there's not necessarily anything wrong with that!
Both fit on the backing plates perfectly.
The 9325 rear has a 1-3/8" bore instead of the spec 1-1/2" bore so a bit less braking power.
Despite being listed as having 3/8-24 threaded connection, which is for 3/16" tubing (I was prepared to deal with that), it came with a 7/16-20 connection, which matches the 1/4" stock tubing. Bonus!

The 4571 is the exact replacement of the original front cylinder.

In case you do what I did, and look for a 1-1/2" version of the 9325 and find the 3677, it's no good. Nowhere close to fitting.

Malcolm

Hi Malcolm
I saw the progress on the HUP last weekend when I was at the museum. Any chance that you could post pictures of your groups progress for the site? It is looking pretty nice so far good job.