The Ford Barn

64steve · 03-29-2026, 06:15 PM

Hi everyone!
I have a 64 F100 and my master cylinder is slowly going bad , i wanted to upgrade to a dual bowl style but having slight issues , issue number one is i bought a 67 289 mustang master cylinder part number #MC36222 and fits but the rod is too long (look at attached image) so i checked and saw that it’s suppose to be a 68-70 big block master cylinder so now i have found dorman M73323 and was wondering if this is the right one i need or which one would i need that the pedal rod is the right length? do i have to run an adjustable rod? is it worth switching to dual or just put a oem one back in there? any advice would be appreciated!

miker98038 · 03-29-2026, 08:50 PM

This is kind of like “what oil should I use?”

First, the master needs to be the same bore size as the oem one. Then did it have (or does the new one have) residual pressure valves. Presuming drum brakes, probably 10# units. Then, can you flare or buy the necessary brake lines to replumb the rears from the front.

I’m a believer in dual masters, having lost brakes with and without them. Scary. Sometimes you toss one in and it works, and sometimes it’s a disaster. Brakes are not where you want a disaster.

Might try the ford truck sites, and see if there’s one that works. If you’ve already done that, just shorten the rod or use an adjustable one. Pay attention to the free travel. I screwed that up once, and the brakes locked up when the underhood heat came up.

sugarmaker · 04-18-2026, 08:29 AM

64Steve,
Yes as mentioned by miker98038, the Ford Truck Enthusiest forum FTE is a good resource for getting information on your brake conversion. Also just basic truck info too.
Your doing the right thing on changing to the dual master cylinder. For peace of mind and safety if needed.
I replaced the single MC on our 65 Comet and went with front disc also. I used a company in NY called Leed. Everything worked well on that change over.
You can't use your old rod??

Regards,
Chris and Cheryl

Jim.UT · 04-19-2026, 10:28 AM

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I can't speak to your specific application but when I converted my 65 Ranchero to front disk and upgraded the MC to dual bowl, I used a 74 Maverick master cylinder but used the original Falcon pushrod. It worked perfectly.

03-29-2026, 08:50 PM	#2
miker98038 Senior Member Join Date: Mar 2013 Location: Kent, WA. Tucson, AZ Posts: 1,765	Re: 64 F100 master cylinder conversion This is kind of like “what oil should I use?” First, the master needs to be the same bore size as the oem one. Then did it have (or does the new one have) residual pressure valves. Presuming drum brakes, probably 10# units. Then, can you flare or buy the necessary brake lines to replumb the rears from the front. I’m a believer in dual masters, having lost brakes with and without them. Scary. Sometimes you toss one in and it works, and sometimes it’s a disaster. Brakes are not where you want a disaster. Might try the ford truck sites, and see if there’s one that works. If you’ve already done that, just shorten the rod or use an adjustable one. Pay attention to the free travel. I screwed that up once, and the brakes locked up when the underhood heat came up.

04-18-2026, 08:29 AM	#3
sugarmaker Senior Member Join Date: Dec 2016 Location: Albion PA Posts: 1,861	Re: 64 F100 master cylinder conversion 64Steve, Yes as mentioned by miker98038, the Ford Truck Enthusiest forum FTE is a good resource for getting information on your brake conversion. Also just basic truck info too. Your doing the right thing on changing to the dual master cylinder. For peace of mind and safety if needed. I replaced the single MC on our 65 Comet and went with front disc also. I used a company in NY called Leed. Everything worked well on that change over. You can't use your old rod?? Regards, Chris and Cheryl __________________ 1932 AAB Truck 1953 Ford Jubilee 1965 Mercury Comet Caliente 1966 Ford F100 2015 Ford F250 SuperCrew Lots of Allis tractors Some Cub Cadets

04-19-2026, 10:28 AM	#4
Jim.UT Member Join Date: Mar 2025 Location: Washington, Utah Posts: 57	Re: 64 F100 master cylinder conversion Sponsored Links (Register now to hide all advertisements) I can't speak to your specific application but when I converted my 65 Ranchero to front disk and upgraded the MC to dual bowl, I used a 74 Maverick master cylinder but used the original Falcon pushrod. It worked perfectly.