I checked the past posts on this but have not gotten a clear picture. I have a 65 and I am converting to power disk brakes from a 75 F150. I planned to use the 75 booster and master cylinder. It has a pivoting linkage system in the bracket between the back of the master cylinder and the firewall. The "rod" that would normally attach to the brake pedal is flat bar with a 5/8 or 3/4 inch hole drilled in it, not a round rod with formed end like the 65. The flar bar is about 1 inch longer than the 65 rod once mounted to the firewall.

So I am trying to determine if I can just re-drill the hole about an inch closer to the booster, making the 75 bar the same effective length as the 65 rod. Or do I need to reposition the receiving hole on the brake pedal? I saw someone mention this as a possible difference in effective pedal ratio or rate when you go from non power to power brakes.

Also, is the stroke length the same on the 65 compared to the 75, taking into account the pivot systen\m and all on the 75 power setup? I had planned to use the underdash bracket and single pedal from the 75, but I can't find it now and may have failed to pull it before scrapping the truck. Should I just go get one of these from the salvage yard?

Any help is appreciated.

Chris

 

i had the same sort of problem on my 66. I was using a early 70's power booster. what i ended up doing was shimming the whole bracket that conects to the firewall out about a 1/2 inch. it work great for me.

 

You will probably receive number of responses on how other members resolved the booster spacing. I purchased 1/2" alum (strong and easier to drill for mounting bolts) square stock and cut 2 about 3" long. Drilled for the mountling bolts. It works for me.

good luck,
dave

 

The pivoting linkage system is the spacer. It also raises the 9 inch booster so it doesn’t hit the valve cover. Use the brake pedal arm from the 75 and shorten the bar like you planned. I think the hole is 1/2 inch. Drilled mine with a hand drill, real PITA. A drill press would make easy work of drilling that hole. You will actually use all to the 75 system except the 65 pedal arm support. When you have the pedal support out to swap the brake pedal arm, drill a hole in the top of the support to mount the stop light switch. Adjust the switch to come on when the pedal stop moves and you are in business. Best part is this is all Ford!

 

Thanks guys.

William, I do not have the 75 brake pedal arm or underdash brackets. So I have to use the 65 pieces. I do plan on using the brake switch mounted to the pedal arm though.

I think I will try the additional 1/2 inch spacer route. Sounds pretty easy to undo if it doesn't work. Dave and Bocephus, were you using the 65 pedal and underdash bracket? Did you use the same factory hole in the pedal arm or redrill in a different location? I had seen some previous mention of a different pedal ratio with slightly different hole location (maybe for power vs. non power brakes?). Just wanted to check on that.

Thanks Again
Chris

 

I used the 65 pedal setup. Just used the 1/2" alum stock to get the spacing and mounted the booster using same holes. No drilling. Stuck with the pressure stop light switch, modifying an adapter, but understand the pedal setup is better.

Good luck,
dave

 

Chris, go the junk yard and get a pedal arm from a newer truck with power brakes. These arms swap into the 65 under-dash bracket quicker than you can drill the relocated eccentric bolt hole. Plus you get a chance to pick the best nylon bushings and add a bit of lube. I get the wide pedal (I have an automatic truck). You can swap in these later model brake arms without removing the bracket if you’re really skinny! I drop the column and slide the pedal bracket out put it in a vice and work it over. The advantage of using a later pedal arm is you get the correct pedal ratio, wider pedal pad and correct pedal height without drilling. If you decide to drill the 65 brake pedal arm, install the booster, booster bracket and the flat bar first, then eyeball the pedal height, mark your spot and drill the mounting hole for the eccentric bolt about an inch lower and half inch back than the one for the non-boosted MC. This step corrects the brake pedal ratio for boosted verses non boosted brakes. Shortening the flat rod sets the pedal height. Turning the eccentric bolt provides some fine adjustment of the pedal height. Trust me on this one the extra time in the Junk Yard to find a later model pedal arm will be worth the trouble. I have done this install at least a dozen times and you have all the best stuff to work with. Except the newer pedal arm.