drum to disc (again) on C20

[Olden Days]

I want to put some 79 discs on my 70 C20. (Already have the 79 donor) was wondering is it the same deal as the C10 where it is just a matter of using the 79 ball joints and tierod ends? would rather not swap entire cross member if I can help it. thanks for any help or info you can give me.....

[thecatseye66]

TTT

I asked the same question about a month ago and didn't get a definite answer about what I needed to do for the minimum work route...a lot of guys had done it but they all seemed to have used the whole crossmember. I got a few, "...should just be the lower a-arm." statements but noone said that they had actually done it.

Just to be safe I bought the entire crossmember from tire to tire along with the MC w/booster, prop valve and brake lines from a '77 for 125 bucks and drug it home on Saturday. I got the whole steering linkage from the 77 too, right down to the pitman arm.

I was planning on waiting until this fall when I do a front clip removal to change EVERYTHING over but I'll change my mind if I find out it's easier to do.

[mer316]

I did a disk upgrade on my 69 but I used the parts from a 72. Lower arms is about all that it took.

Robby

[thecatseye66]

see what I mean?

[Billy G]

I have a 70 GMC....bought a complete front end.

Through different thought patterns, ie..IMA GONNA...I tore the purchased front end down....cabinet blasted the A Arms, control arm rods...spindles...sway bar and mounts...just about anything that could be blasted...and painted. I installed new control arm bushings.....not that hard...now that Ive done it. Ive purchased new tie rod ends...inner and outer....a new idler arm, and a new master cylinder. Donor had no booster, so Im staying manual for now. I could have used the old stuff, but I figured why not go ahead and do it now.

I left the 70 GMC crossmember in place. After blasting, painting, and installing new bushings, I installed the A Arms. Wasnt hard...once I figured out how to line the pins with the holes...hold...and tighten. I then installed new ball joints with the spindles. I used the dust shields off the donor also.
I located the prop valve in the same place as the donor was...found the front brake lines lined up perfectly with 2 holes in the frame. Looks as if the hoses will work fine there with the locater nuts. I took the rear brake line off the donor...put it in place full length towards the rear...hooked up to the prop valve. All I need to do is cut the lines and install a union. If I knew for sure what size the tubing was...I'd get a stainless union from work. Looks to be 1/4"...but looks are deceiving. Im painting the calipers now...and will install rotors and calipers as soon as I get new pads. The biggest problem I see as of now is making the tubing cut..mostly cause of the limited workspace.
I pulled the radiator out to install the prop valve...but that was for ease. Allready have the grill off...there was allready one hole drilled in the crossbrace, so that's what I used. Might drill the 2nd hole in time. You'll also need to grind the rivets off the sway bar mount on the donor frame. I need to do that yet too.

All in all, it's not that bad of a job. Hardest part was getting my BELLY to cooperate with the movements I needed to make...lolol. Im also waiting on more info on using a 90 6lug rotor....whether the calipers I have now will work or not.

Dive in....you'll get mad...you'll wanna quit...you'll CURSE the day you bought it...but as you get going....you'll actually GRIN at yourself for ever doubting.

The guys here offer a VAST WEALTH of USEFUL KNOWLEDGE....use it....and in ending this NOVEL...I just wanna say THANKS to the guys here AGAIN!!!!

Thanks again....
Billy G

[Olden Days]

Originally Posted by thecatseye66

see what I mean?

Yep,, I saw your post last time and was watching it for info for myself.

Billy G you didnt mention if yours was 1/2 or 3/4 and if the donor parts was from 73 up??

Actually I wouldnt be against changing entire xmember except my donor is a step van, and I doubt that it is the same. I figured at least the spindles, rotors and calipers should be the same though. I wish I knew where the guys are that are selling xmembers for 125 bucks. Everyone around here thinks there stuff is gold or something close to it.

[thecatseye66]

Originally Posted by Olden Days

I wish I knew where the guys are that are selling xmembers for 125 bucks. Everyone around here thinks there stuff is gold or something close to it.

I got lucky there, the guy I bought it from thought it was a cool idea that I was doing a swap like that and I helped him pull the 454 out of the truck, too. He even threw in the tranny cooler. Coolest thing is he just had the brakes redone before the accident and the tires had perfectly even tread wear. The truck only had 60,000 miles and was fully drivable before we tore in to it. Originally I thought I'd have to rebuild whatever donor suspension I found, but now I think I might just use the whole thing "as is".

[Billy G]

My GMC is 1/2 ton....donor was a 76 Chev