77 Kc 620

[slodat]

Are you aware that you can't just bolt on the '78-'79 disc brakes on a '72-'77 king pin truck? You will have to adjust the issue of the control arm not putting the wheel in the right place. Megga camber, it won't align.

[Rubberman]

Are you aware that you can't just bolt on the '78-'79 disc brakes on a '72-'77 king pin truck? You will have to adjust the issue of the control arm not putting the wheel in the right place. Megga camber, it won't align.

 

Fab work, it'll work. Hell of alot cheaper than the other way.

[Bandit240]

You still want that auto trans? Ill have the wagon 100% ready for some driving next week.

[Rubberman]

You still want that auto trans? Ill have the wagon 100% ready for some driving next week.

 

Yep, sent you a pm.

[Rubberman]

Are you aware that you can't just bolt on the '78-'79 disc brakes on a '72-'77 king pin truck? You will have to adjust the issue of the control arm not putting the wheel in the right place. Megga camber, it won't align.

 

I did some measuring today and what's the problem slodat? How are the frames different from 72-77 to 78-79?

[Rubberman]

Took off the drivers side A frames and hub and bolted up the 78 disc set up. I'll get some pics up later. 78 lower A frame wider by a 1/2 inch, not a problem, making a peice to remendy that. Bar going to the middle of frame for adjusting front end, 1/2 inch to long, no problem, cut weld back with rap around metal for strength. Two rubber stopper mounts for top A frame not ligning up, cut reweld in correct spots. Other than that I don't see any problems. The tie rod ends and center link look fine. I'll get deeper into that when I do the final mounting of the 78 set up, if any problems, That's what a welder is for, make them longer or shorter with the right adjusters on them to work correctly.

[yello620]

I think that if you swap sides with the upper arms that it will help out your caster numbers. If you install them how they came off of the 78/79 you will get very negative caster, but if you swap sides they actually produce an acceptable positive caster. Camber is a whole different story, 78/79 upper arms are a little too short to work well, result is negative camber. The arms need to be about a 1/2" longer to work well.

 

If you look at the upper arm mounts on the frames, you will see the obvious difference. the angle of the mount. Now you may understand the need to swap sides with the upper control arms.

 

You will also find that the upper arms mount to the frame with different size bolts. 12mm vs. 14mm

[Rubberman]

Thanks yello620, I'll do some more checking and try what you suggested on the upper arms to see how that works. On the camber problem, I'll either cut the upper A arms in half and add that 1/2 inch or it might be easier to move the upper mount on the frame. The challenge is on, I'm gonna make this work.

Edited February 8, 2009 by Rubberman

[ezcruiser]

Effin smooth man, you want your stock wheels back so you can paint em orange and put the dog dish on?

[Rubberman]

Effin smooth man, you want your stock wheels back so you can paint em orange and put the dog dish on?

 

Gonna go with some different rims. I finally got the 78 disc brake set up figured out. Four cuts and four welds and she'll work just fine. They had me freakin on here for a bit. It's pretty simple remendy to get everything right. I'll get pics up as I go.

[yello620]

Thanks yello620, I'll do some more checking and try what you suggested on the upper arms to see how that works. On the camber problem, I'll either cut the upper A arms in half and add that 1/2 inch or it might be easier to move the upper mount on the frame. The challenge is on, I'm gonna make this work.

 

If you have the proper skills to do that, then why dont you make a custom tube arm? Use your stock uppers as a guide to make a jig. You can get the right size DOM steel and even use the stock upper control arm bushings.

Something like this.

These are on my 620, made for doing the same swap you are doing.

[Rubberman]

Yello620, that looks good. I may do that. I had finally came to the point that I was going to move the angle of the A frame mount on the frame. Angleing it like the 78-79 would take care of the problem, but I do like your idea also. Did you have to do anything to the two bars (can't think of their technical name) that raise and lower the front?