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Oct 4, 2012

65-66 Mustang and Shelby Disc Brake Proportioning Valves

NOS Ford 65-66 Mustang Disc Brake Proportioning Valve.  Image ©Virginia Classic Mustang Inc.
I am re-posting this Blog post that was originally published in December of 2010.  It was one of our more popular posts, and I've sent it to several people just this week.

If you are really into the detail end of the 65-66 Mustang and Shelbys, you may find this post interesting.  A Kelsey Hayes disc brake proportioning valve was originally installed on the 65-66 Mustangs with factory front disc brakes.

Rather than discuss the function of this part, this post is more about the detail and restoration.  There seems to be a widely held thought that this valve was originally a bluish-gray color.  All of the New Old Stock / Ford Service parts that I have seen are certainly this color, and perhaps some of the ones originally installed on the assembly line were also this color.

Original Black Paint Finish shown on Disc Brake Proportioning Valve from a June '65 Production San Jose Mustang (Early '66 GT350)     Image ©Virginia Classic Mustang Inc
Original Black Paint Finish shown on Disc Brake Proportioning Valve from a very late Production San Jose Mustang (Very Late Production '66 GT350).  Image ©Virginia Classic Mustang Inc
I do have evidence though, that at least some of these valves were originally finished in black paint.  I have seen several other original examples that were black, including the one on an early '66 GT350 (SFM6S033).  This GT350 will be featured here on our Virginia Classic Mustang Blog soon.  I have also seen a black one on a much later production '66 GT350 (near the very end of the '66 GT350 production.)

The "end discs" on these valves are dated. The numbers indicate the day of the year along with the year.

End Disc stamped "81-5."  This is the 81st day of 1965, which is March 22, 1965.  This disc was clear zinc plated for restoration.  Image ©Virginia Classic Mustang Inc

Disassembled Proportioning Valve with Zinc DiChromate Plated Nut and Clear Zinc Plated Adjusting Stud and End Disc.  Image ©Virginia Classic Mustang Inc

Valve has been Cleaned, Glass Beaded and then Epoxy Primed before sending out for Brass Sleeving and Rebuild.  Image ©Virginia Classic Mustang Inc

Rebuilt valve reassembled with the newly plated original parts and  refinished with black paint.  Image ©Virginia Classic Mustang Inc
Jeremy at Maple Hill Restoration did the paint work on this.  He also does the restoration work on the 1965 Mustang 289 HiPo convertible that is featured on our Blog.  He will soon start on our Carryover 1966 GT350 Shelby.  You can contact Jeremy by going to his web site at

 Image ©Virginia Classic Mustang Inc

Dated end disc.  Image ©Virginia Classic Mustang Inc


Jeannie said...

What is the value of one of these NOS proportioning valve?

Confused: why are you rebuilding a NOS part?

Virginia Classic Mustang Inc said...

I'm not really sure of the value on the NOS proportioning valve.
The units that were rebuilt here were not the NOS units. The valves that were rebuilt were used, original valves.