For Those Doing Disk Brakes. 60-66

[joe231]

Originally Posted by 63sbssbbw

Trouble in paradise guys
The 63 gmc xm dropped out easy,but when I went to test fit the 75 xm to see which holes I needed to modify it only went in after using 2" ratchet straps(1 ahead and 1 behind) to suck the framerails together and still needed a BFH to get it to go in
Did a raft of measurements after the body was removed and came to the conclusion that it's not tweaked,bent or twisted.
So what gives????
I'm going to do some comparing today to see where the differences are.
This has me scratching my head after every thread I've read on this subject stated that
it was a pretty easy swap.
any ideas??
Thanks,Trent

That is "normal"
when we took our cross member out to work on the frame the the rails sprung out. I would not worry about it and just keep keeping on.
the tolerances back then were quite large, so it seems every frame is different....

[63sbssbbw]

OK, I was just concerned because no one seems to have mentioned it before
I did do some comparing yesterday,the'75 xm is 3\4" narrower than the '63 xm,
that seems to be quite a bit but it will squeeze in there.
I could still strip down the 63 xm and use that ?
Will squeezing the frame that much effect its strength or integrity?
Thanks,T

[63sbssbbw]

Well, I've decided to stick with the '75 xm,mostly because of the time I've got into it,clean, sandblast and so on, and knowing that everything I'm going to bolt onto it will fit (from the same truck),also noticed the '63 xm only has 2 3\4 uca studs (the '75 has 3" studs)
T

[Nick's81]

new ? when swaping arms 64 and 79 both C-10s lower arm mounts with a "u" bolt is there some thing to center the shaft or just eye ball it

[63sbssbbw]

Yes,Nick
There should be a locating hole on the shaft and a corrosponding stud in the u-bolt saddle on the xm

[Nick's81]

thanks still in the air if i swap crossmember or just arms

[63sbssbbw]

Yay,it's in
Will start bolting stuff on today
Thanks for your support guys,this place rocks
T

[spr85gmc]

what would you guys recomend Im starting to gather parts to run the brake lines but being so new to this IM kinda lost and dont have the funds to buy a 300.00 dollar brake line kit..... could someone point me in the right direction as to what parts i need to get i already have the booster, calipers just need to figure out the lines...

[joeydirt]

is there any advantage to swapping the whole crossmember? What about if I have a c20 and I want to go to 5 lug?

[tincan1966]

I think the reason most prefer to swap out at least the complete control arm to '73-'87 parts is to gain the rubber control arm bushings, as opposed to the steel sleeve type the earlier ones have. They provide a smoother ride and are alot quieter.

I really see no advantage of swapping the complete crossmember unless you are installing it as a complete unit. But if you're going to tear everythng down, clean and rebuild, I'd personally just swap the arms and spindles.

When I did my '69 C-30 dually disc conversion, I completely cheated and bought new control arms(upper and lower) that had new ball joints, bushings installed. These are made by Dorman and available at most parts stores. The price is comparable to buying the parts and having someone replace the bushings and balljoints for you, sandblast the parts, etc. The only donor pieces I used were the spindles. I purchased the hubs/rotors, calipers, hoses and everything else new for a '74 C-30.

[joeydirt]

Originally Posted by tincan1966

I think the reason most prefer to swap out at least the complete control arm to '73-'87 parts is to gain the rubber control arm bushings, as opposed to the steel sleeve type the earlier ones have. They provide a smoother ride and are alot quieter.

I really see no advantage of swapping the complete crossmember unless you are installing it as a complete unit. But if you're going to tear everythng down, clean and rebuild, I'd personally just swap the arms and spindles.

When I did my '69 C-30 dually disc conversion, I completely cheated and bought new control arms(upper and lower) that had new ball joints, bushings installed. These are made by Dorman and available at most parts stores. The price is comparable to buying the parts and having someone replace the bushings and balljoints for you, sandblast the parts, etc. The only donor pieces I used were the spindles. I purchased the hubs/rotors, calipers, hoses and everything else new for a '74 C-30.

ok so if i get some 73-87 c10 control arms they will work with my 66c20 cross member? can rubber bushings be installed in this scenario?
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[earl84]

tincan, I like your idea. Question, though. I have a 66 C20 and want to gain disc brakes AND power steering. I have done so much reading on this, that I forget because there are so many things running around in my head.
Can I swap the arms and spindles for the Dorman products you are talking about, and just get a power steering pump, PS gearbox (and probably an adapter from CaptainFab) and connect to my existing linkage, or what else would I need to purchase to make that happen.
Thanks for your help.

[tincan1966]

Originally Posted by earl84

tincan, I like your idea. Question, though. I have a 66 C20 and want to gain disc brakes AND power steering. I have done so much reading on this, that I forget because there are so many things running around in my head.
Can I swap the arms and spindles for the Dorman products you are talking about, and just get a power steering pump, PS gearbox (and probably an adapter from CaptainFab) and connect to my existing linkage, or what else would I need to purchase to make that happen.
Thanks for your help.

I would have to recheck, but I believe the only concern with bolting the arms on MAY be the u bolts for the lower control arm, BUT that is quickly remedied by drilling out the holes in the crossmember. You'll need the donor spindles and I'd suggest the tie rods, (inner and outer)center link,idler arm and pitman arm from the same model donor. Yes you will need CaptFab's PS gearbox adapter and you'll need to drill new holes for the newer style idler arm. Other than that, it's easy! Of coarse, you need the correct master cyl/booster combo and appropriate brake lines.

[66_c10_tpi]

Originally Posted by earl84

tincan, I like your idea. Question, though. I have a 66 C20 and want to gain disc brakes AND power steering. I have done so much reading on this, that I forget because there are so many things running around in my head.
Can I swap the arms and spindles for the Dorman products you are talking about, and just get a power steering pump, PS gearbox (and probably an adapter from CaptainFab) and connect to my existing linkage, or what else would I need to purchase to make that happen.
Thanks for your help.

On my 66 c20 the lower control arms didn't use U bolts. The cross shafts were like the earlier trucks. The shaft was a cast iron unit that had 4 bolts to anchor it to the crossmember.

[tincan1966]

Originally Posted by 66_c10_tpi

On my 66 c20 the lower control arms didn't use U bolts. The cross shafts were like the earlier trucks. The shaft was a cast iron unit that had 4 bolts to anchor it to the crossmember.

I apologize for being incorrect, I thought those type LCA shafts ended in "63 -must have been confused between C10's and C 20's

[joeydirt]

Originally Posted by tincan1966

I apologize for being incorrect, I thought those type LCA shafts ended in "63 -must have been confused between C10's and C 20's

so you need the whole crossmember than right?

[Captainfab]

When changing a '63-'66 C20 to a C10 suspension, you must change the crossmember as the original C20 crossmember does not have the saddles for the round lower control arm shafts.

[joeydirt]

Originally Posted by Captainfab

When changing a '63-'66 C20 to a C10 suspension, you must change the crossmember as the original C20 crossmember does not have the saddles for the round lower control arm shafts.

what about motor mounts? I have a 292 and most 73-87 k members come from sbc trucks

[Captainfab]

Your original 292 motor mount brackets should bolt up to the later crossmember. Also, the 292 was available up thru about 1980 I believe.

Originally Posted by joeydirt

what about motor mounts? I have a 292 and most 73-87 k members come from sbc trucks

[Big E65]

Originally Posted by Mongo

It has been brought up time and time again about doing disk breaks on these 60-66 chevy trucks. So I am going to post this as a sticky in hopes that it will help everyone wanting to do the change. This will be a quick run down list. Ask questions for details.

as time allows I will sit down and edit this post and and a little more detail and then move it to the FAQ section. This thread then will have a redrect to the FAQ.

First you do not have to change the whole crossmember!!!!!
Leave the thing where it is!!!!

1.)remove the old brake lines.

2.)remove the upper and lower A-arms with the spindles attached.

3.)Get a set of arms with disk spindles attached.(72 and up)

4.)Install the newer upper and lower A-arms.

5.)install updated brake lines and hardware.


This will work for 1/2 ton 3/4 ton ect.

Thanks for the info but I have some questions? I have a 1965 gmc 3/4 pick up with 8lugs and I'm trying to convert it to 5 lug disc brakes, would I be able to use 1/2 parts to achieve this? And what year would I have to use in order to get direct bolt on without modification? Does '72 and up still apply?
Thank you

[Captainfab]

When converting a '63-'66 C20 or 30 to disc brakes either 8 lug or 5 lug, you will have to change the crossmember. This is because there are no saddles to hold the '67 and up lower control arm shafts. Yes the '71-'87 C10 front suspension will basically bolt up. I don't know about the '71-'72, but with the '73-'87 crossmember, you will have to drill one hole on each side and elongate one hole on each side.

Originally Posted by Big E65

Thanks for the info but I have some questions? I have a 1965 gmc 3/4 pick up with 8lugs and I'm trying to convert it to 5 lug disc brakes, would I be able to use 1/2 parts to achieve this? And what year would I have to use in order to get direct bolt on without modification? Does '72 and up still apply?
Thank you

[davbowen]

Captainfab, been reading a lot about this change over and drop member swap. my question is will 73-87 control arms bolt directly to my 63 cross member, other than the u-bolt size. will the newer lca fit right into my lower saddle centered up. the reason I ask is am going with cpp or ece drop spindle 6 lug kit with 73-87 bolt joints. my current truck has 50 years worth of crud on them and was going to rebuild. but after more reading and research, the 73-87 arms will be way cheaper to buy new than to rebuild my existing. I really don't what to change the x-m out or have to modify a bunch of stuff to make it fit. anyway thanks for the input.

[davbowen]

that's my 63 c-10

[suxtobu65]

I think I did mine the cheapest way possible... 83 donor. I pulled the spindles, rubber lines and steering linkage.. $60

Stock 65 upper and lower control arms, just bought 83 ball-joints ($42), installed new ball-joints, installed spindle assembly and steering linkage.. Then went to local company and had two new lines made ($34). Dual master cylinder from local parts house for a 72 ($19)..

You don't have to to swap out upper and lower control arms.. Swapping spindles is much easier and doesn't require and alignment afterwards..

$155 and I have disc brakes on a 65 C10.. Now I'm not the type of person that pinches pennies. I just wanted to see if it could be done for less, with less work than most here suggest, and it can be done..

[Big E65]

Originally Posted by suxtobu65

I think I did mine the cheapest way possible... 83 donor. I pulled the spindles, rubber lines and steering linkage.. $60

Stock 65 upper and lower control arms, just bought 83 ball-joints ($42), installed new ball-joints, installed spindle assembly and steering linkage.. Then went to local company and had two new lines made ($34). Dual master cylinder from local parts house for a 72 ($19)..

You don't have to to swap out upper and lower control arms.. Swapping spindles is much easier and doesn't require and alignment afterwards..

$155 and I have disc brakes on a 65 C10.. Now I'm not the type of person that pinches pennies. I just wanted to see if it could be done for less, with less work than most here suggest, and it can be done..

Now when you mean 83 you mean a 1/2 ton right(just clarifying)?
And thanks for the break down this was a lot of help i really didn't want to do to much work or spend to much money(on a budget) just to achieve 5 lug disc brakes.