By David Major
I set out on this adventure due to the fact that all-drum brake systems now days have to many problems due to the decline of quality brake shoes. I just could never get the "pulling" ,left then right, out of the brakes no matter how many "adjustments" I made.
Plus , how many of those pressure-differential valve's still function ?!
I wanted to maintain maximum stopping power so I went with the dual piston set-up.
I notice upon visual research at the junk yards that the single piston calipers are in the back of the spindle and have the bracket for the caliper and the tie-rod connection all part of the spindle. Well in the truck the tie-rod bolt is going down in to the spindle. In the van the tie-rod bolt goes up. Try to go around that stuff and you mess with the front-end geometry. Where as the dual piston caliper bracket models bolt "on" the spindle, leaving the tie-rod connection's alone! . Doesn't mess with the alignment at all.
I own a 1972 Ford E300. Here is a list of the parts that I used for the conversion:
1973 Ford F250 Dual Piston Caliper bracket's. (2)(unbolts from the spindle)
1973 Ford F250 Dual Piston Calipers (2)rebuilt w/pads
1973 Ford F250 Master Cylinder (1 in. bore)
1973 Ford F250 proportioning Valve
Rotors (2) 8 Lug
New wheel bearings (same number!)
New straight brake lines. (ranging from 18" to 36")
A double flare tool (for brake lines) plus line bender!
A large assortment of different sizes of brakeline ends and couplers.
A left side flexible brake line (to the calipers)
A right side flexible brake line
I purchased from the "donor" truck in a Pick-a-part the caliper bracket's, prop valve,
and if you find decent rotor's get those..I chose to purchase new. You might get the calipers for trade in value for rebuilt's.
1.Jack up vehicle, set jack stands
2.Pull off the tires.
3.Remove drums and backing plates,disconnect brake lines.
4.Save those backing plate bolts!
5.Remove the master cylinder
6.Remove the pressure differential valve
7.Install the caliper brackets onto the spindle's (yup, they bolt right up)
8.Install the rotor's with bearings.(grease of �course)
9.Install the "right" and "left" calipers w/pad's.
10.Install the master cylinder.
When I comes to the brake line's ..I reused the one that goes to the right front,
and both of the ones that go to the master cylinder. There are couplers at the frame
that I installed new lines on that go to the proportioning valve. So in other words you won't have to make all new lines that go from the master cyl to the prop valve.
All others are short. I.E.- Left front and the one going to the rear brakes.
One thing I learned about double flaring, it takes practice and lot's of it. You will not be able to duplicate a "machined" flare! You'll have to "play" around with the flare kit awhile to "know" what the best placement is for the line in the tool will be. I started off with some "ugly" bent double flares till I "learned" the right time to STOP the squeeze down with the adapter. I practiced with new line,(so I threw away 3 buck's). This is the most important and serious thing that you will do! They cannot leak. (After I was done with the project I checked those line connections for a week!)
Get all the "ends" you can when you get the proportioning valve you'll need them. They are all different sizes. You might have to search for a valve that doesn't leak. I even got one from an 83' van, never did find out if they are different in operation but it will have to be one for dual piston calipers.
One important note!!!!!! Make sure you KNOW which line goes from the right front into the prop valve and the left front into the prop valve, it makes a difference! Just as the lines from the master cylinder.
To install the two lines from the couplers (near the frame up front) to the propvalve you can use pretty straight line (except the easy curves at the ends) I secured those lines by using a short piece of vacuum line so they don't rub on the frame holes while going to the prop-valve. The left front brake line was easy,(nice a short). I also used the original mount for the flexible brake line to the calipers. (Although the flex hoses are kinda long)
I also left the old lines where they were.
Once I got all the line's hooked up to all the wheel's , the master cyl, and the prop-valve, I used a strip of steel, bent it to bolt into the frame and then the prop-valve.
Your next step is the bleeding part. Of course I bleed the Master cyl first without the lines hooked up. Then it's that slow process of getting the fluid to all the caliper's . I sped everything up by using a Mity-Vac. It really help's getting rid of all the air. I did finish the job by doing the Ol' "pump" them up and hold it routine. You might hear about "pulling " out and holding the bleed rod in the prop-valve but I Didn't and it bled fine.
I was really surprised by the straight path I took once I "got" on the binders. I stopped straight with no wandering. You will have to wait for good stopping power because of break-in of the pads to the rotor's.
You now have a Van as good as a '75 or better!
It will be more fun once you are done as always.
"There is never enough time to do it right...
"But always enough time to do it over!