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GMC 1 Ton Disc Brake Conversion

Doing a disc brake conversion on a half ton truck is easy, as many suppliers offer kits for
this, but on a heaver truck one must come up with their own kit. I'm going to install front
disc brakes on my 1965 GMC one ton dual wheel truck. This page will cover what I'm doing.
So far I have only collected the major needed parts to compleate this task. GM Started
using disk brakes in their truck in 1971, so you need to find a truck that is a 1971 or
newer for you donor. you mite also consitter using the rear axle from the same truck.
I would guess this would also work for 3/4 & 1/2 ton trucks as well, but you will need
to check this out yourself as I don't know for sure, & I'm not going to research it as
I don't plan on changing over my 1966 GMC 3/4 ton, & don't own a 1/2 ton.

You will need to change the master cylinder & if you don't have power brakes, now is a good
time to add them. My truck has the power booster, so I just need to Change to a dual master
cylinder, I have one fron a 1972 GMC 3/4 ton pickup. Also you will need to replace some
brake fluid lines & add a proportioning valve (small valve seen on new master cylinder).

To do this conversion the way I am, you need to change the parts from the ball joints out
under the truck, some have changed the entire front cross-member with a newer assembly but
why go to more work than you need to. You will want to use new ball joints & tie rod ends.

For starters, you need to find the front assemblies off a newer truck, mine came from a 1972
Chevrolet one ton. They were removed at the ball joints with the wheels still attached.
The wheels were stuck on by rust to the hubs, so I guess that is why they left them on &
removed the entire spindle assembly. Here is the right side as I took it down, the wheels
were stuck to the hubs, so I held them up with a forklift & use some Mistic Metal Mover
to eat through the rust. This is some good stuff & works well. I let them sit for a about
an hour, then by knocking out the lug studs, the wheels came off.

I got the assembly on a bench, & used the stuff on all the bolts & about 30 minutes later took
it down the rest of the way. As you can see, there is not a lot to doing this, to this point.
Sandblasting took a bit more time.

I have the hub & rotor assembly apart, these are the parts you really need to do this swap.
The front hub, which is a one piece hub & rotor, spindle, backing plate, brake caliper, all
the small parts to put them together. Use new brake pads & bearing if yours are not in good
shape. Be sure to inspect every thing really good & if it looks bad, replace it. The parts I
got were rusted bad, but once I got them apart, I sandblasted them & will be painting them.
These are the parts for the left side.

Also now would be a good time to think of changing to one piece wheels if you have split rims. I have
a 1994 GMC Dually & the wheels off it will fit this truck with the new disc set up. The old drum
brakes had half inch studs & the disc has 9/16. You can get used wheels from a wrecking yard or
buy new ones, like a set of custom chrome wheels. I'm going to stick with newer stock wheels myself.

I will be updating this page as I move forward in this project, so far I'm working on getting
all the parts rounded up & ready to install.

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