Power Disc Brake Bracket & Booster Questions

[fasttech]

I am about to start a brake conversion from all drums to 4 wheel disc. My current setup is manual and I have some questions about power brake brackets and booster. I purchased a set of used brackets from one of the members and a new brake booster. See attached pics. The new booster has a threaded type rod that is actually for a late 70s Camaro / Chevelle. I got it cheap so I went for it. From my research the 11" boosters are all the same and only the rods are different. To adapt my new booster to match the old booster I plan to shorten the rod, add some threads, and install a heim rod-end.

Now for the questions... The used brackets I purchased has some included levers. Are these levers standard on all 1/2 trucks with power brakes or just 3/4 and 1 ton trucks? Are these levers for proper alignment with the brake pedal or is it there to create a mechanical advantage of some type? I am trying to figure out if I can eliminate the levers and extend the rod directly from the booster to the brake pedal before I shorten and add treads to the new booster rod.

Also any info on which way the brackets are supposed to be mounted would be helpful since I don't have a starting reference from my manual setup.

Thanks for everyone's help in advance.

[AusTx68]

I'm gonna take a crack a this question since it's Christmas Eve and it's been sitting out here with no responses for 4 hrs My 1/2 ton came with the levers and they were needed to get the proper alignment so I'm guessing they are standard. Perhaps if you didn't use the stock brackets you could make a custom setup that went direct.

[Mike C]

Pull the actuator rod out of the old booster and install in the new one using all of the brackets that you acquired. They are needed for clearance/geometry.

[fasttech]

Thanks AusTx68, now I don't feel so bad about posting questions on x-mas eve I figured the levers were on 1/2 ton trucks but there is no way to tell by just looking at pictures of other trucks. I got some additional support brackets that go between the brake booster bracket and attach to the firewall. Does your truck have these installed? I don't see them on all trucks.

[AusTx68]

Originally Posted by fasttech

Thanks AusTx68, now I don't feel so bad about posting questions on x-mas eve I figured the levers were on 1/2 ton trucks but there is no way to tell by just looking at pictures of other trucks. I got some additional support brackets that go between the brake booster bracket and attach to the firewall. Does your truck have these installed? I don't see them on all trucks.

No problem I only had the bracket and levers as shown in your first photo.

[fasttech]

Mike C, as far as I know the rod in the booster can't be removed without disassembling the booster. Boosters are spring loaded and are dangerous to take apart. If you know a safe way to remove the rod please let me know because I would rather use the old rod.

Thanks.

[68 TT]

The lever type brackets are needed on the truck so you can reduce the pedal input force with the conversion to power brakes. On the cars they tilted the booster up in the front to lower the attachment point on the brake pedal to achieve the same reduced pedal input with the power brake conversion.

It makes the brakes less touchy. More pedal travel needed for the same amount of hydraulic pressure.

I don't know why they approached the power brake vs manual brake problem in different ways with the cars & trucks. It might have something to do with clearance as I think the under steering column mounted 67-68 style lever type parking brake mechanism may not leave room to lower the brake pedal rod.

[AustinScott]

here are some pictures of the booster off my truck for reference (68 1/2ton)

Original & new replacement

in the first picture, you can see I measured the original pedal rod length.
I traced out the eye center to eye center length on the cardboard in between the boosters
(blue sharpie 9 1/8 - 3/16)









If you need any other pics to help you get the info you need, please let me know I'm glad to help in any way I can.

Scott

[fasttech]

Thanks Scott, your pics will be a big help when get to installing mine.

[fasttech]

Finally got around to making some progress on my disc brake conversion. Got the booster rod cut down to the right length and treaded. Also got all the brackets and levers repainted. If I had to do it all over again I would just buy a chrome booster made for my 67. It was a lot of work to get the rod threaded that close to the booster housing while keeping it from spinning. I hope these pics help the next person who has to put all the levers and brackets back together. Pay close attention to the notches at the top of the lever and make sure they are facing the booster. I believe this allows for more travel to fully actuate the booster. I have seen some pics with these installed backward.

[v62go]

does anyone know the length of the rod going to the brake pedal from middle of the eye to eye?

[fasttech]

Would like to here from some folks ho have it installed myself. The rod in my picture measures 9" eye to eye. It's adjustable and have not installed it yet so it could end up being a little different.