A question about proportioning valves

[junkyardjeff]

I am converting my 66 F250 to a 1/2 ton using the front suspension from a 76 F150,I have a proportioning valve from a F350 but should I grab the one from the donor truck or are they all the same.

[wayne petty]

might as well...
just to have it.. it will probably be needed..

it contains the safety switch

it depends if it has a proportioning valve in it to reduce pressure to the rear tires...

braking forces on disc drum cars are usually 2/3rds on the front and 1/3 on the rear..

are you dropping from the 3/4 ton rear end to the 1/2 ton rear end??? so you keep the brake bias somewhat equal..

does the 66 rear end use 11 inch brakes or does it have the 12 inch #357 style shoes. on a full floating dana 60 type housing???

the later F150 will probably have a 9" ford rear end with semi floating axles..   bearings pressed onto the axle shafts...
if you get much later than that it may have a ford 8.8" with axles that slip into the bearings and ride directly on the rollers against the axle shaft surface..   you may want to think about an adjustable prop valve for the rear brake system.. so you can get the front and the rears to lock up at the same time with no load.. and a half tank of gas..  which may be an average weight of the truck in operation..

just make sure to convert the brake system to a true DUAL SYSTEM.. so front and rear are separated..  as the 66 is a single system..  where a single failure will result in a no pedal situation..

[junkyardjeff]

I plumbed one in and using a 76 master cylinder,I drove it around the block a couple times before going back in the garage to change the Dana 60 for a 9 inch,thought I had a center section with 2.75 gears but must have sold it so time to find another and a set of 5 lug rims which I am having a hard time finding a complete set.