disc brakes on a 1970 longhorn

[bronze 72 super]

Just bought a '70 Longhorn with factory disc brakes!! This is not a '71 model. VIN on this is as follows: ce240z120631. This truck come out of southern Idaho. I live in North central Oregon. Brakes were not put on as a upgrade. Still have factory rivets on upper ball joints. Has anyone ever come across early setup like this? Truck will be parted out next year. Also come with a after market canopy for a 8 1/2 foot bed!! It's going on my project '71 longhorn. Any insight into this would be great.

[lolife99]

Welcome to the board.
Factory rivets only mean the upper ball joints haven't been changed in those a-arms.
The entire suspension could have still been swapped out with 71-72 parts.
42 years is a long time to not have anything done.
I was converting these old trucks to disc brakes back in the late 80's.

Please post up some pics when you get a chance.

[too much stuff]

I have to agree with keith that the front was changed at some point. Discs came out in 71.
And yeah, lets see some pics...

[68Gold/white]

Many parts books list disc as an option, in 1970, seen s few 70's w/ disc.......

[SS Tim]

Originally Posted by 68Gold/white

Many parts books list disc as an option, in 1970, seen s few 70's w/ disc.......

Have to agree. That VIN is fairly high out of Freemont and its possible. Would be interested in the build date and if the frame numbers match. Need to dig out my '70 truck data book and see if there is anything there. But in all likelyhood it is a transplant.

[tmorton]

I too have a 70 with disc up front; it has not been switched. Late 70's had disc up front as did the 71 & 72's.
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[too much stuff]

I will stick with the disc brakes coming out on the 71 models (9-70) Some of the books do list discs as an option, but i think that is on the elcamino. If it was an option in 70, wouldn't it be listed on the spid? That would also mean it would be 5 lug stuff in 1970? Until i see otherwise...

[SS Tim]

I remember that truck. It had a Cummins swap done to it so anything is possible. The SPID was painted over so its hard to know how it was optioned. However it is a light GVW truck and badged Custom Camper 20. The cap per the story was custom made for the previous owner.

[bronze 72 super]

This reply is specifically for Tim. How do you know about this truck? The pic of the metal data plate is correct. As is the none factory green paint. I bought this as a parts truck. No front clip, no motor or tranny, no steering box or seat. It did have some Custom Camper 20 emblems that where left in it. I bought this for the Dana 60, to swap out the Eaton with 4:10 gears in mine. The Dana has 3:54 gears. Anyone want a 4:10 Eaton cheap? I'll try to post some pics. of the disc brake set up soon. Looks factory to me. Any thing is possable with these trucks.

[WIDESIDE72]

What size are the lug bolts front and rear? Do they match in size front to rear? My understanding is the drum brake trucks had one size (I forget, 1/2"?) and when GM went to disc brakes in the front, the lugs were upgraded as well (9/16"?) I have a 70 Longhorn with 4 wheel drums. I was thinking of swapping a 72 disc brake front crossmember into it and when I was looking at it, I realized hat the lugs on the 72 disc rotors were larger than the lugs on the 70 drums. I didn't want to have two different size lug nuts. Not too big of a deal , though as I also have a Dana 60 out of a 72 C20.

I already have a similar situation with my 79 Malibu (originally English standard thread lugs). I swapped in a larger 8.5" rear out of a 80's 442 which had metric lugs. I could swap the rotors, but I have actually been saving up to buy the spindles necessary to perform a B body (Caprice) spindle swap and Camaro 1LE rotors. for the time being I have to watch the tire monkeys if I go to hav etires mounted, etc and remind them not to mix up the lug nuts, and let them know they will need a different size socket front to rear.

[SS Tim]

Originally Posted by bronze 72 super

This reply is specifically for Tim. How do you know about this truck? The pic of the metal data plate is correct. As is the none factory green paint. I bought this as a parts truck. No front clip, no motor or tranny, no steering box or seat. It did have some Custom Camper 20 emblems that where left in it. I bought this for the Dana 60, to swap out the Eaton with 4:10 gears in mine. The Dana has 3:54 gears. Anyone want a 4:10 Eaton cheap? I'll try to post some pics. of the disc brake set up soon. Looks factory to me. Any thing is possable with these trucks.

It was on Portland CL back in April. Talked with both the seller who lived in Eastern OR. and the his parents in Western OR. where the truck was stored. He had bought the truck specifically for the Cummins that had been swapped into it. The truck was offered complete save for the engine and trans.. I don't remember if it ever ran with the diesel but it had been unlicensed about five years. Signed over Idaho title didn't thrill me nor the peeled and painted SPID. It simply was not worth the money to bring it down here a thousand miles. I had hoped it was a factory dark green CST but the pictures confirmed the color change as well as its C20 load rating. Here are some pictures. If you PM me an email address I will forward a copy of my file on the on the truck.

[SS Tim]

Just received a message from bronze 72 super with the pictures of the front brakes. The truck was being converted to a Cummins but I don't think it had been completed. Any ideas on how to tell if they are factory '70 disc brakes or not? Maybe the hard lines or brackets like a Camaro. The frame VIN and door plate apparently match for a '70 Fremont "Z" built truck. The number does seem low for a mid-year change. There are days I really wish I had full set of service news bulletins.

bronze 72 super... "Took some pics. of the disc brakes on my parts truck, 1970 Longhorn. Setup looks factory to me. Rotor and rubber brake line are replacement items, found old repair receipt for this. Judging by the old grease build up, and parts, it looks factory to me. What do other people think?"

[SS Tim]

Last one.

[c10srule]

kind off looks like he smaller drum brake master cylinder, hard to get a good look at it

[bronze 72 super]

The vacuum booster and master cyclinder I think where thrown in the truck. The kid I bought it from, put a bunch of scrape parts in the back of the truck, this was part of that. He used a bunch of parts on his own truck, that's where the front sheet metal went. One person did reply earlier if this had two size lug nuts, it does. My project '71 Longhorn also has two different size lug nuts, as well as the spare Dana 60 in the back of my Longhorn. Any thought on this? Why did G.M. use two different sizes?

[Mayo]

I would think this is a conversion. 67-70 used 1/2 inch studs while 71-72 used 9/16 inch studs. I know that disc brakes widened the track width, and from your pictures it almost appears to me as if the front tires are out further than the rears are. I would think if it was disc brakes from the factory, it would have the wider rear end to match the front. Plus, seeing as it has been repainted and had an engine swap, somebody was already doing work to this truck so they could have upgraded to discs while they were at it.
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[68gmsee]

As I have mentioned before, these old vehicles were being messed with by mechanics many years ago -probably more so than now. In the old days cars and trucks had more interchangeable parts than they do now with everything computerized.

I've been swapping things out on old cars and trucks since I was 18 years old back in the 60's. We converted a truck to discs back in 1980. That's over 30 years ago. Lots of dirt and grime accumulates on them in a short time.

[WIDESIDE72]

Originally Posted by Mayo

I would think this is a conversion. 67-70 used 1/2 inch studs while 71-72 used 9/16 inch studs. I know that disc brakes widened the track width, and from your pictures it almost appears to me as if the front tires are out further than the rears are. I would think if it was disc brakes from the factory, it would have the wider rear end to match the front. Plus, seeing as it has been repainted and had an engine swap, somebody was already doing work to this truck so they could have upgraded to discs while they were at it.
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X2

As I stated above --------------------------------------------------------------------------------

What size are the lug bolts front and rear? Do they match in size front to rear? My understanding is the drum brake trucks had one size (I forget, 1/2"?) and when GM went to disc brakes in the front, the lugs were upgraded as well (9/16"?)

[WIDESIDE72]

Originally Posted by 68gmsee

As I have mentioned before, these old vehicles were being messed with by mechanics many years ago -probably more so than now. In the old days cars and trucks had more interchangeable parts than they do now with everything computerized.

I've been swapping things out on old cars and trucks since I was 18 years old back in the 60's. We converted a truck to discs back in 1980. That's over 30 years ago. Lots of dirt and grime accumulates on them in a short time.

x2 In the mid 80's, my brothers and I swapped a whole fornt crossmember andrear axle from a wrecked 72 C10 under a 70 C10, grease and all!

[68gmsee]

Originally Posted by WIDESIDE72

x2 In the mid 80's, my brothers and I swapped a whole fornt crossmember andrear axle from a wrecked 72 C10 under a 70 C10, grease and all!

Yeah, I don't remember ever cleaning and painting before or after swapping either. Just swap and go!

[Dieselwrencher]

I wouldn't say any of this is impossible. I once owned a 70 Camaro that was produced 5/69. But clearly was stated as a 70. Go figure.

[SS Tim]

Originally Posted by Dieselwrencher

I wouldn't say any of this is impossible. I once owned a 70 Camaro that was produced 5/69. But clearly was stated as a 70. Go figure.

Interesting, was it VIN numbered as a '70? They had a lot of issues with the late '69 production run. Most people know the story of the strikes causing the late run but in fact it was the drawing dies Fisher Body made for the quarter panels, they didn't work! The cars were made through November of '69 and still being made in the calender year were legal as '69s and MSOed as such but a number of people have them titled as '70s.

[SS Tim]

Originally Posted by Mayo

I would think this is a conversion. 67-70 used 1/2 inch studs while 71-72 used 9/16 inch studs. I know that disc brakes widened the track width, and from your pictures it almost appears to me as if the front tires are out further than the rears are. I would think if it was disc brakes from the factory, it would have the wider rear end to match the front. Plus, seeing as it has been repainted and had an engine swap, somebody was already doing work to this truck so they could have upgraded to discs while they were at it.
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A lot of good points are coming up. Often parts were swapped to upgrade or repair a vehicle and I think we are all guilty of at some point bolting on and going with the intention of cleaning things up later. If you look at the M/C picture I posted it shows a lot of activity in that area. But then an engine swap is often pretty invasive, just ask dieselwrencher.

But something I am seeing here is the rear axle width question. Its established fact that the 1/2 tons had a running change as a current post so graphicly shows. But did the large C20 or C30 trucks have a running change as well? Maybe the hubs or housings but that seems like a lot of expense. So can anyone nail down a documented track width change?