Wheel cylinders for 21-23 Custom Eight models

Posted by HH56 On 2020/8/2 13:43:48

An individual has privately asked me if there are less expensive modern and locally available wheel cylinders that can be used in the 21-23 series Custom 8 sedans. The stock diameters are 1" front and 15/16 rear. I could not answer because I bought my cylinders as part of a Kanter kit.

I have found some numbers in the x-ref and on the Napa site that look like possibilities. They are:

Front with a slightly larger 1 1/16 bore, the UP13368 and UP13369. The interesting thing on that supposed pair is according to the Napa site one has a thread of 7/16-20 and the other is 3/16-24.

Another possibility with a stock 1" bore is the UP4803 and UP4804. Both have 7/16-20 threads but are considerably more expensive than the 1/16" larger bore pair. Kanter's offerings are less expensive than the Napa numbers.

For the rears at 15/16, a direct replacement would seem to be the UP 370192 and UP 370193. Both have 3/8-24 threads so would need a BK 6413307 adapter to drop the 1/4 tubing thread size down to the 3/8 of the cylinder. I believe these may similar to what Kanter is selling as my 47 cylinders came with adapters.

Another possibility for rears (and maybe fronts) is a 1" diameter UP9025 and UP9026. This pair would also need adapters and I would wonder if the larger rear bore might introduce issues if the stock 1" fronts are also in use.

I guess my question is does anyone have some known good numbers and if not, has anyone used any of these numbers and were they a direct fit. I vaguely remember some backing plates have a different diameter opening and bolt spacing. Cannot remember the model or year and exact circumstances but do remember one locally bought pair of cylinders needed to have the opening in the backing plates modified slightly so the cylinders would fit and bolt in.