Hello Everyone,

It has been a while since my last post. 70 hour work weeks for last three months keep me busy. I'm still chipping away at my 1966 F250 front disk brake and power steering upgrade. My donor truck is a 74 F250. Both trucks are 2WD. It has been 4 months since I removed the proportioning valve from the 74 truck and I did not take a picture. I thought I would be finished with the project much sooner and could recall the assembly etc.

I read the technical article "Front Drum to Disc Brake Conversion Guide for 1964-1972 Ford Trucks" on this site. The article describes mounting the proportioning valve on the frame rail. On my 74 donor truck it was mounted on top of the Saginaw power steering gearbox. I've installed the 74 PS gearbox on the 66. I'm thinking that the proportioning valve should mount on top of the gearbox. Is that correct?

I'm confused about the orientation of the proportiong valve. Using the diagram from the aformentioned technical article as a reference, should the rear outlet point towards the rear of the truck or the front of the truck? The reason why I'm confused about this is because I left the front and rear inlet lines in place on the proportioning valve as they were on the 74 truck. The outlets from the master cylinder are on the drivers fender side but, if the proportioning valve is positioned with the rear outlet facing the rear of the truck the ends of the inlet lines coming from the proportioning valve end at the passenger side of the master cylinder. I hope this makes since.

Answers to my questions and / or a picture of an installed proportioning valve and master cylinder on a 65 or 66 would be much appreciated. Thanks in advance!

 

Here is a picture of my master cylinder on my power disk brake swap on a F-100. I used a 73 F-100 as my donor truck. Like the article you read the prop valve was located on the frame rail.

As for the position of the prop valve, on mine there was a large single fitting that went to the rear axle. The supply from the master cylinder came in on two lines to the top of the prop valve. I am a little forgetful of the front but it seems to me one was slightly pointed towards the top and the other was pointed straight down out of the bottom and those both ran to the front wheels. There is also a brake safety switch which comes out of the top of the prop valve.

There was a bracket that bolted to the top of the steering gear box that held the two brake lines which came from the master cylinder and run down to the prop valve.

As to the location, I am not sure it really matters. I have seen them on after market kits that bolted right to the bottom of the master cylinder. I personaly would install the valve where it will be easy to get to and easy to run brake lines to. When I did my swap I tried my best to install the parts as close to the same location as my donor truck that way I could re-use as many of the lines as I could.

Hopefully this will help you out with your swap.

Jeff

 

bigblockford_390

Thank you for the photo and the description of how you installed the proportioning valve on your truck. Your's looks nice and clean. I see that the lines go into the passenger side of your master cylinder. I'll have to look at mine again but I think the inlets for the lines on mine are on the drivers side. If so, I'll be making a trip back to the parts store. I'll look at either mounting the proportioning valve on top of the gearbox or on the frame rail. If I find a master cylinder like yours I'll try on top of the gearbox first. That would allow easy access for any future repairs.

 

There's a drawing of the lines and their positions on my web site.
f100discs
The orientation of the valve really doesn't matter. One truck I pulled parts from and ultimately copied had the prop valve mounted to the backside of the front crossmember, transverse to the rest of the truck. Works fine that way too. The only thing that matters is that the top is, well, at the top. So you can mount it pretty much anywhere that it's convenient for your application.

 

I agree with Dwight, The porp, valve can be mounted anywhere that is convenient. I have seen them on chassis rails, on top of steering gears, free hanging, all over the place.


John

 

Thanks to all for your guidance. I feel that I can proceed more confidently now. I expect to have some time to work on my project over the hoildays. I hope to have the brakes and power steering complete soon and will let you all know how things progress here.