3/4 ton 8 lug front disc conversion

[HeavyMetalChevy]

Please chime in... What all is needed and is it easier (with a competent body man/welder I might add to just hack the whole front end off a 71 C-20 custom deluxe bb to a 70CST20 Long Horn??? I am asking this for a friend...I do not plan on converting mine for a LONG while... Need a jump start into this overhaul. I am sure the big block to small block front end will create some unique issues as well correct??? Let me know please.

Thanks,
"DWANIAC"

[MADMIKE]

Originally Posted by HeavyMetalChevy

Let me know please.

Thanks,
"DWANIAC"

If you want to just add the disc brake spindles its actually pretty simple.
I am currently helping out my neighbor with installing '84 2500 8 lug discs on his '70 2500 GMC. You can follow my pain, anguish and relief over on 1970 GMC 2500 2WD 8 Lug disc brake conversion.

TL;DR
You will need the front spindles off a 2500 with the rotors.
We are using a '70 'Caprice' MC. It should cross over as the same MC used on a '72 C10(bolt on but verify pushrod depth, adjust if need be) but there have been discrepancies. Front brake hoses from donor truck. We are currently going to try the 75mm calipers, but have the 80mm versions as well. Rear wheel cylinders on a leaf sprung 2500 need to be changed from the stock 1-1/8" WCs to the smaller bore 1" MCs found on '68 Cadillac Fleetwoods(bolt on).

Quickie parts list.
'70 Caprice MC w/disc brakes
'68 Fleetwood rear wheel cylinders (Verify 1" bore)
Spindles/rotors/calipers/inner-sleeve-outer tierod, from donor truck.
Correct BJs for spindle, if not replacing the FUCA/FLCA.
Lug nuts are one size larger on the later disc brake trucks so you will need 16 lug nuts.

No need for 'special' or 'custom' parts. Don't waste nearly $1000 on some 'kit'. It's all horse hockey from those clowns. Find a '73-'87 truck and get the spindles.

[HeavyMetalChevy]

well played sir...well played... cracking up at "horse hockey" lol

[383longhorn]

i have a 70 longhorn that i just converted to front disk brakes about a month ago. it was a pretty simple swap took me about 5 hrs. i got the front end from a 72 gmc 3/4 ton i found at a pick a part junk yard. i just un bolted the whole front end from the frame. i think its only 16 bolts and it all drops out in one peice. the only issue i ran into when installing the front end into my longhorn was two bolt holes have to be enlogated. the front bolts directly behind the top A arm one on each side. you can just drill the hole a little bigger and it will bolt in easy. also the disk brake wheel studs are 9/16 and the drum are 1/2in so you will need 16 lug nuts

for the brake system you will need...
a disk brake booster
disk brake mater cylinder
disk brake proportioning valve
front brake lines from the calipers to the master cylinder
rear brake line from the master cylinder to the next fitting witch is in the frame rail right about where the fender and cab meet. you will need this because the fittings are diffrent between drum and disk proportioning valves but the same on the frame rail fitting.

i think thats everything you need to do the swap. the easiest way is to fined a 71-72 with disks and youll get every thing you need but it is hard to come by one.

if you get the front end from a small block truck and yours is a big block truck just remove the coil springs from your drum front end and put them in the disk front end. i think it will go right in.

hope this helps. josh

[383longhorn]

[HeavyMetalChevy]

Originally Posted by 383longhorn

Attachment 817604

Attachment 817605

Attachment 817606

Attachment 817607

Attachment 817608

YOU GUYS ROCK!!!! Now that I know this...I will prob keep the front off the 71 and put it on my 70 C-20...YEAH BUDDY!!!!! Awesome stuff...

[Cuttyman9]

So what is needed to perform this same swap on a 66 3/4 ton?
Posted via Mobile Device