Hi Folks!

I have read through the technical article about replacing the 78-79 Bronco single diaphram vaccume brake booster with a more efficent F-350 (2WD) dual diaphram 9" booster.

I have a 1978 F-150 4x4 and have just finished calipers, pads, shocks, metal brake lines to calipers, conversion to locking hubs from Full time Hubs, axle u-joints, drive line u-joints, and new sway bar bushings.

If I understand the technical article correctly - the 1978 F-350 booster should be a direct bolt up without need for a different actuating arm off the current brake pedal right? Can someone confirm this?

Also I understood that the current 1978 F-150 4x4 Master cylinder would bolt right upto the F-350 booster without having to replace both master cyclinder and the vaccume booster. Can someone also confirm this

I will go forward and let you know my results....if I get the confirmations. Including the look the guy gives me when I return a booster unit for core value that is the wrong size....wonder what they will say.

Let me know Experts!

Thanks for your help!

Steven

 

1.) I'm not sure about the actuating arm. I'll let someone else respond.

2.) You need the larger MC.

3.) You need to use a caliper with a larger piston area, such as the F250/F350 dual piston caliper, or the 'T-Bird' caliper. The F150 calipers will not work. The F250/F350 calipers will only work if you have at least a 16.5" wheel and a D44HD spindle to mount them on.

 

16" wheel works fine as well

 

Yes, The F350 booster attaches to the fulcrum style push rod of the brake pedal like the BB from the F150/250 does.


79 is the year that things change from a fulcrum style to a direct rod actuation.

 

Thanks Everyone For your responses. Well, I think the change to the wheels & larger calipers/spindles is going to shoot this idea in the head for me. I may just have to keep the old single style booster unit after all. You know, don't want to pitch my friends through the windsheild with a sneeze on the front brake pedal. Ha!
The spindles are right expensive here in my neck of the woods. Most everything else part's wise is dirt cheap.
Thank you again for all your "Knowledge" and help.

One more question if I may indulge.... I just replace the brake lines to new "rebuilt" calipers (single piston style) since they were the originals. The new brake lines look like they only clear the inside wall of the tire by about 2 inches. Should they be this close to the tire? I can't remember how close they were to the inside wall of the tire & of course...forgot to take a picture before I started.

Thanks again for the previous info!

Sincerely,
Steven Davey

 

Are you meaning the rubber hose lines ?

 

Yep, Those rubber hose lines. They run from the claliper up the brass portion about 4 inches long & then bend over to the clip where they connect to the metal brake lines.
They just look a little close to me for some reason.... should I put a picture in to show what I am talking about?

Thanks!
Steven

 

I'll add that 16 inch steel wheels will fit over the big brakes but 16 inch cast wheels are a no go as well as some 16.5 cast wheels .This has been a pain in the posterior for my 78 F-250.I used the shorter car bolts that take an allen wrench this gained a little but expect to grind a little metal off with wide cast wheels.
Eedvark

 

You did install the hoses so there wasn't any twist in them ...right?

The line on the hose is what you look at to make sure it isn't twisted.

I've never really noticed the closeness you asked about.

 

Hi Everyone,

Well I figured out the closeness problem with the brake lines. I fished through the trash cans and found one of the old ones that I had pulled off. The original has a 2 inch metal tube that comes from the block that mounts to the caliper and also has about a 15 degree angle bent in it to adjust it towards the axle. The replacements have about 4.5 inches of metal tube from the block with no 15 degree angle. So, a little tube bender action and check for the "Twist" that Mil1on has pointed out and I am good to go!
Thanks for your replies! Now out to use my new left hand drill bit's on that broken bolt!

Thanks again!
Steven.