Basically these are the parts I used:

1968 C20 lower control arms
1990 3/4 ton Light Duty 2X4 must have (1.25" rotors) spindles
1990 1.25" thick 6 lug rotors
1990 calipers off same truck
1990 upper and lower ball joints
1990 outer tie rods
inner tie rods MOOG part #ES2020RL
1990 style tie rod coupler


The only catch is to cut 3/4" off each end of both tie rods on each side of the truck so you can have enough room to align the truck. Well at least I had to since mine is lowered 4" in the front.

The front end I bought off the 1990 truck was 5 lug. All I did was went and bought the 6 lug rotors and bolted them on. If you wanted to stay with the 5 lug, you'd save yourself about $120 bucks.

After everything is done, you will now have 14mm studs on the front. I fixed this by drilling my rear axles and pressing in 14mm studs in the rear also but you wouldn't have to do this... I plan on going to a rear disc setup using a floating rotor design and so this helps that plan also...

Good luck.

what ball joints did you use?

if you read my last reply it's says 1990 upper and lower ball joints.

Thanks for the info, FirstGen. Did you need to modify your brake line or brake line assembly at all? I've noticed some people (normally in the back) welding on new L-brackets to hold the tap between the hard line and the flex line. Did you re-use all existing fittings and lines or buy new ones?

I used the rubber lines off the 1990 truck and used the factory mount from the 1990 to secure the line to the frame. Never ran new steel lines until later when I just wanted to, it wasn't nessary to do the swap.

Re: easy disc brake swap
 

DO you know if the 68 3/4 ton Lower A-Arm is the same as the 69? Thanks in advance for the help.

Bruce

Re: easy disc brake swap
 

I'm sure it is. Call Ed at Mothertruckers and ask him, he will know for sure...

Re: easy disc brake swap
 

Ask on the main board for confirmation, but I'm pretty sure they are the same as well.

Re: easy disc brake swap
 

I wonder if you can utilize the '88-'98 3" lift spindle while doing this swap....I'd like a little lift on my '70 C-10 Sub!!

Re: easy disc brake swap
 

Did anybody else that did this swap with factory ride height have serious alignment issues like I have??? Not toe, caster / camber...

Re: easy disc brake swap
 

GMC69mnypit, did you ever get that alignment issue resolved? If so what was the cure?

thanks.

Re: easy disc brake swap
 

I got one question!

Why do you have to have the 70 3/4 ton lower control arms to make the 87 and up spindals work.

I have a 69 c10 and a 89 1500 parts truck that I am taking the trans out of.

This sounds like the way to go and I am glad I got involved in this forum.

Do I HAVE TO GET the 3/4 lower control arms?

Re: easy disc brake swap
 

Yup, for the larger ball joint in the 3/4-ton a-arm to match the larger later model lower ball joint.

Re: easy disc brake swap
 

can you put a 3/4 ton ball joint in a 1/2 ton lower control arm.

I am really enjoying these modifications. It seems that the sky is the limit with these old trucks:metal: :metal:

Re: easy disc brake swap
 

Hello
What a great post
I have a '69 3/4 custom camper, would i just need to get parts from a newer 3/4ton? Thanks!

Re: easy disc brake swap
 

to keep this alive and kickin'...Anyone know if it'll work on a 67 GMC??? Thx so much in advance!