72 K30 Build

[Dieselwrencher]

Great work, those black parts look sweet! Nothing wrong with smoothing the grind marks out. That'll just make it a better job done in the end!

[7dee2]

Thanks guys I appreciate it.

Our little booth is full up with the rails in there! And all done, it took about 1.5 gallons and into a second spray can so far to get to this point.

[Dieselwrencher]

Looking nice!

[JJorgensen52]

It's amazing how just a little time in the spray booth can make SO MUCH difference in how far along your project looks and feels. I better get busy catching up!

[7dee2]

Thanks guys so used to looking at the old fugly, greasy frames for so long it is a bit of a shock!

Paint booth is gone and starting assembly, putting in all of the cross members finger tight so we don’t have to fight them.

[7dee2]

We used a ½” impact gun to tighten all the bolts from the center of the frame working outward. Here are some pics of the hangers & bump stops installed.

Still need to add a couple more small brackets (front shock, front & rear brake line), braces (gas tank mount) and the frame will be done.

[rgunlock]

Frame is looking really nice Brett. I like that you know its also rust-free and painted behind the brackets.

[Dieselwrencher]

That is some nice work! It looks very nice.

[7dee2]

Thanks Rick & DW! When bolting the frame together the flange bolts did tear into the paint layer and the bolts have no corrosion protection. Thought we better put a coat of paint on all the bolts followed by a coat of satin clear over the whole frame. Here are some pics after clearing, looks dusty but it is just overspray dust that comes right off.

[mjensen]

Originally Posted by 7dee2

Thanks Rick & DW! When bolting the frame together the flange bolts did tear into the paint layer and the bolts have no corrosion protection. Thought we better put a coat of paint on all the bolts followed by a coat of satin clear over the whole frame. Here are some pics after clearing, looks dusty but it is just overspray dust that comes right off.

This is looking killer Brett!

You'll be happy to know I'm actually going to make some more progress this weekend as well! I'm now considering switching over to the NP205 TCase because I don't want to deal with this T-221 and reworking the exhaust.

[72MARIO]

I am trying to get all my parts together to build my 1968 longhorn frame I bought what I believe to be a 1981 1 1/4 ton military frame. The rear spring hangers look diffirent than yours any idea what the differences are in years ? I also looked at a 1972 2500 4X4 and yours look so much taller.What year was your dually chassis ?

[JJorgensen52]

Originally Posted by 72MARIO

I am trying to get all my parts together to build my 1968 longhorn frame I bought what I believe to be a 1981 1 1/4 ton military frame. The rear spring hangers look diffirent than yours any idea what the differences are in years ? I also looked at a 1972 2500 4X4 and yours look so much taller.What year was your dually chassis ?

The high GVWR military trucks are an animal all to themselves, so there is not a lot of commonality with what Brett is doing here.

The major reason for the height difference is the axles themselves - the 2500 series trucks used a Dana 44HD front axle, while the 3500 series trucks used a Dana 60 - the axle is larger and taller in every respect, making the front of the truck sit up higher.

[Zane M]

I don't know how I missed this thread previously.
You are doing a fantastic job! Looking forward to further progress.

[71blksuper4x4]

Looking good Brett!

[7dee2]

Originally Posted by mjensen

This is looking killer Brett!

You'll be happy to know I'm actually going to make some more progress this weekend as well! I'm now considering switching over to the NP205 TCase because I don't want to deal with this T-221 and reworking the exhaust.

Thanks Mike, glad to see the forward progress happening on your project. You get your truck running again and it’ll motivate you finish I’m sure of it!

Originally Posted by 72MARIO

I am trying to get all my parts together to build my 1968 longhorn frame I bought what I believe to be a 1981 1 1/4 ton military frame. The rear spring hangers look diffirent than yours any idea what the differences are in years ? I also looked at a 1972 2500 4X4 and yours look so much taller.What year was your dually chassis ?

Originally Posted by JJorgensen52

The high GVWR military trucks are an animal all to themselves, so there is not a lot of commonality with what Brett is doing here.

The major reason for the height difference is the axles themselves - the 2500 series trucks used a Dana 44HD front axle, while the 3500 series trucks used a Dana 60 - the axle is larger and taller in every respect, making the front of the truck sit up higher.

72Mario, Jim is spot on with the Dana 60 info and his 72 GMC K3500 build has been a huge help and inspiration for this project, so if you have not yet make sure to check his build out. http://67-72chevytrucks.com/vboard/s...d.php?t=573671

My donor was a 1984 GMC K3500 3+3 (D60F/T400/NP205/14BFF DRW C&C) we are using the axles, transfer case and various other bits & pieces. Everything in our suspension is 71-72 K20 except the rear, rear position spring hangers and the rear spring packs (9/1) which are refurbed from the 84 K3500. These rear hangers measure just barely over 8” from the top of the bracket to the center of the inner eyelet. Sorry not the best pic holding the tape and camera at the same time but you get the idea.

We got all of our K20 stuff from forum vendor DLTruck1973, Tom & Thomas they are great to work with and I’m sure could help with any square body parts as well.

Originally Posted by Zane M

I don't know how I missed this thread previously.
You are doing a fantastic job! Looking forward to further progress.

Thanks Zane M, me too!

Originally Posted by 71blksuper4x4

Looking good Brett!

Thanks Trevor, I like the new avatar looks great!

[7dee2]

So the boy & I are thinking of going in a new direction?

[flashed]

Now that there is an uptown rig .

[7dee2]

Yep, still waiting for somebody to pass us the gray poop on!


Back to the build, it's time to do something with the diffs. Started on the 14b and found it needs a little more than I originally thought. Drums are to be discarded @ 13.09" ours are both about 13.125". Also on closer inspection decided we should speedi-sleeve both hub seal areas both have multiple grooves.

[JJorgensen52]

Originally Posted by 7dee2

Yep, still waiting for somebody to pass us the gray poop on!


Back to the build, it's time to do something with the diffs. Started on the 14b and found it needs a little more than I originally thought. Drums are to be discarded @ 13.09 ours are both about 13.125. Also on closer inspection decided we should speedi-sleeve both hub seal areas both have multiple grooves.

Seems like it might almost be easier just to pick up an axle in better shape?? Rebuilding the axles was one of my favorite parts of the K3500 build.

[7dee2]

Ha, my donor was no low mileage cream puff for sure! But I’m like you Jim rebuilding them is a big part of the fun and when done you know what you have and can count on.

After documenting the location of the remaining shock mount we removed it. With the narrow c&c 14b our mounts were centered @ 10.25” in from the brake backing plate mounting surface. For reference it also looks to be fairly in line horizontally with the housing and backing plate mounting bracket. That will not make much difference though our new ones are shaped more like the original GM ones.

[7dee2]

I’ve been on the fence about re-gearing the truck for a long time. It’s currently 4.56 and I’m thinking a 4.10/4.11 might be better for our application but with the carrier breaks between the two ratios that’s a big $$ commitment. I know I don’t want the rear to remain open so a new carrier is going to be needed, and no a locker is not an option for this build. Leaning towards a Truetrac carrier Eaton has a spiffy video here http://www.eaton.com/Eaton/ProductsS...dex.htm#tabs-5

Did find just a little bit of metal fragments hiding behind the left adjuster and tube don’t know if you can see it in the picture. Everything looks pretty good and that’s the only place I found it so may have been left over from an earlier problem.

[DWilbur]

For a daily driver I would say away from a locker or posy up front. My friend Pat had Detroit locker in the rear and posy in front in a 1972 K20 and it was slide ways in the iced up roads in the winter.

[JJorgensen52]

Originally Posted by DWilbur

For a daily driver I would say away from a locker or posy up front. My friend Pat had Detroit locker in the rear and posy in front in a 1972 K20 and it was slide ways in the iced up roads in the winter.

I've actually had this problem in a truck with an open front and locked rear - most people I know who drive in snow and ice prefer posi in the rear for that reason.

[7dee2]

Originally Posted by DWilbur

For a daily driver I would say away from a locker or posy up front. My friend Pat had Detroit locker in the rear and posy in front in a 1972 K20 and it was slide ways in the iced up roads in the winter.

I’ve heard that same thing from several sources as well and you’re probably right, but I think I’m going to give it try and see firsthand how the helical-gear style carrier works out. Our off road plans do include pulling a lite weight 5th wheel and I want the extra pull when needed. We can always switch it back to an open and use this carrier elsewhere if it really doesn’t work out.


The front gear set seemed noticeably looser than the rear.

[7dee2]

First wave of axle stuff has shown up and the shock mounts are ready to be welded on. Found way too much travel in the rear springs, if we leave them like that it would possibly over extend our new shocks and could possibly bend or break the top leafs. We are going to have to limit the travel some.