72 K30 Build

[JJorgensen52]

Originally Posted by DWilbur

Do you think it would still work lengthening the rod and using the factor hole.

You can do it that way, many folks do. When I did it (and I think what 7dee2 is after as well) I chose to modify the pedal so that the hydroboost was a 100% bolt on - that way, should I have to replace it later, I could just buy one off the shelf.

[7dee2]

Yep our thoughts exactly and now is a good time to bring this up, I really liked Jim's approach on his 72 GMC (4x conversion) build. The entire truck is built with either a '72 C3500 or a '87 Sierra V3500. All the service parts are one or the other and bolt on with no or very little modifications required.


Put a steering column in place and finished the HB mounting plate mods. Also tested the rest of the trans shift linkage and there’s no problems. Thought I would do a quick check on the fan shroud as the new core support bushings were thicker. Gets a little close with this 18” fan but it fits well enough no worries.

[JJorgensen52]

Originally Posted by 7dee2

Gets a little close with this 18” fan but it fits well enough no worries.

What, no clutch fan?? That is my single favorite mod to do on these trucks, makes them SOO much quieter at cruising speeds. My '72 sounded like a turboprop on the freeway

[7dee2]

I know, I know I've got lots of history (bad) with non clutch fans I could tell ya!

While waiting for some parts to arrive guess what day it is, hump day? No that was yesterday but if you guessed it’s tubing time you’d be correct.

What you see is a pile of (crap) C30 & K35 bits and pieces, let’s see what fits. Started right off with the K35 brake lines once we figured out which ones were them. Another member (could it be Jim?) posted that they fit pretty well and I was pleasantly surprised he was not kidding! I’d hoped perhaps the fronts might land were the frame alignment holes are and they do sweet! We will order new lines but wanted to make sure that using the K35 style brake lines was a good idea first.

We also have started looking at a parking brake solution as we will probably try and use the same vendor (inline tube) for both and combine the order if possible.

[JJorgensen52]

Originally Posted by 7dee2

What you see is a pile of (crap) C30 & K35 bits and pieces, let’s see what fits. Started right off with the K35 brake lines once we figured out which ones were them. Another member (could it be Jim?) posted that they fit pretty well and I was pleasantly surprised he was not kidding! I’d hoped perhaps the fronts might land were the frame alignment holes are and they do sweet! We will order new lines but wanted to make sure that using the K35 style brake lines was a good idea first.

We also have started looking at a parking brake solution as we will probably try and use the same vendor (inline tube) for both and combine the order if possible.

I'm probably not the only one to say it, but I definitely did in my build thread! The only trouble I had was with the rear axle, nobody seems to have a pattern for the narrow 14FF rear, so they need to be reshaped a bit.

I ended up using the later truck style equalizer for my parking brakes, which is #12 and #13, two brackets that hold the cables (inside the red circle). A whole HECK of a lot easier to integrate, then it was just a matter of, in my case, making a longer center cable section, or if you got Inline to make you a new front cable to length that would work well too. I mounted the front cable end to the forward cab mount using just a piece of angle iron, GM did it that way on the later trucks.

[7dee2]

Our setup is the one just below the one you circled RV(03-43), that must equate to crew cab limo! Can’t quite fit the L-bracket closest to the diff in the same K35 location on ours because the K20 front position rear hanger interferes with the cable routing. Thinking we can do something very similar though it’ll be inboard mounting to the frame section a little higher up.

[First c10]

Hey Brett, look like your coming along nicely that thing is going to be a beast. Looks great. On my sons truck I put rear disc's so no off the shelf piece would fit easily. So I used the stock front e brake section and made a new intermediate and rear cables. I had them made by www.controlcables.com Ed miller is the guy I worked with. Him and I emailed pictures back and forth until we had a solution even down to the correct clevises. They are in Southern California with like 3 day turn around. I changed the routing from stock by running the cables to the driver side inboard of the frame. I can try and get another picture if you want. I did have to make the cross bracket (2 cables to 1) as I didn't have the room for most I found and didn't want to spend 50$ for a fancy anodized piece of metal.
Hope this helps.

[First c10]

I still need to brace the passenger side brake cable but I am waiting till the exhaust is installed.

[7dee2]

Thanks, I’ve really liked watching your chassis come together you guys are doing a great job. I am trying to make off the shelf work as much as possible but this one is going to get us. We could use a good pic of the front brake cable frame bracket don’t have one of those and will probably need to fab something up.

Our donor K35 setup does have the same 2 into one going forward which I like but has some extra bracketry that in our case makes the right side not engage as well as I think it should. Both rear cables have different ends on the front or intermediate cable side (right is threaded, left is not). So far I’m thinking stock 1972 front cable like you guys and then custom from there. Good chance we might be able to use a stock K35 right rear cable but we will see, going to think on this for now.


Here’s some new and rebuilt stuff that showed up.

[First c10]

Attached is a picture of the end of the from cable and its mount. This is a stock 70 k20 bracket. I had to turn it so that the front cable would be inline with the rear cables.

The tank is the same tank I have a 31 gallon one with internal high pressure pump. Is that what you have there? Minus the HP pump? It fit well just needed to lower the full tube.

[7dee2]

Thank you sir, yep it is the 31 gallon thought about the 40 but then decided 31 was a better fit for us, ha pun intended! I know that was dumb.

Talk about fit our rebuilt K35 box did not fit right off and needed a little clearance. First few pics it wouldn’t clear last few it fits like a glove.

[7dee2]

We needed a later steering coupler for the later steering box as it has a smaller 17 spline input. Mated right up to the old 72 column and its shiny is the good news. Bad news is I had one but gave it away on the column we sold earlier, oops!

Plumbing the hydroboost is pretty straight forward using the mated steering box. The return line from the box needed a 90 degree bend to clear the inner fender we also rolled the inner fender lip a little in that area.

[JJorgensen52]

Originally Posted by 7dee2

We needed a later steering coupler for the later steering box as it has a smaller 17 spline input. Mated right up to the old 72 column and its shiny is the good news. Bad news is I had one but gave it away on the column we sold earlier, oops!

If you want to do away with the rag joint, '97+ Jeep Cherokee (old square style) should have the right ends on it and they're plenty long

Good progress!!

[7dee2]

Thanks Jim but we’ll stick with the shiny part since we have it now.

Here are the pics of the rest of the HB plumbing. So to adapt the old pump we just needed to add a tee in the return line to get the fluid back to the reservoir. We also changed out the pressure fitting from the pump to the old style inverted flare to accommodate the old pump. Jim did recommend an alternative pump in this thread for those not wanting the tee in their plumbing. http://67-72chevytrucks.com/vboard/s...&postcount=373

[DWilbur]

Why did you use the old pump. My friends 1987 1 ton had factory HB system.

[7dee2]

Our donor truck did come with the small block style HB pump reservoir but would have put the fill right into the bottom or just to the right (inboard) of the alternator with our alternator bracket setup. The later big block remote reservoir fill location also goes straight up into alternator territory so regardless even if we have to replace the pump later the old style big block reservoir is what we have and I wanted for this project.

I borrowed this pic posted from forum member Tx Firefighter to give a visual of how sharp the angle needs to be to accommodate this fill set up. I really like the fill on the fender of these old trucks, its cool!

While on this topic our thoughts are still to restore the factory a/c as well as running all the original 72 C30 402 accessory stuff, exhaust manifolds, etc. that we have. Engine (454 or 496?) should look a lot like a stock L72 or LS6 out of a Chevelle or Corvette but with all the truck bracketry when done. The 2nd pic is from an earlier project, 66 Impala SS w/air that’s close to what I’ve got in mind again for this truck. Dressed like a 427 it’s actually a solid lifter 454 LS6 crate engine we had acquired in another project car.

[7dee2]

Here's how the brake pedal mod turned out, sorry for the bad pic but by the time I checked we’d removed the cab again.

[7dee2]

Did a quick rear brake inspection to get the rest of the brake cable length measurement and to see what we have going on in there. Both drums did come right off without having to back off the shoes, sweet! Not really surprised that we have more brake material on the right side versus the left. Pretty sure the right parking brake was not engaging and if this side was not adjusted as tight we would see this wear difference (2 – 3 32nds). We still need to measure the drum material when we get back into this axle but there was no lip so I’m hopeful we can run them again. Inner seal area is showing a little wear (left was worse and may require a speedi-sleeve) but all looked pretty good.

[JJorgensen52]

That's the 14FF out of the K30 donor truck, right?

[7dee2]

Yes that's our new 14FF out of the 84 K3500 donor. We do have a little FF collection going on though 1 HO52 & 2 HO72's counting the one in my daily that will all be outta here once this truck is built.

Kept the rear ride height brake proportioning valve from our donor also. Thought about setting one up for this truck for about a minute but after doing some research doesn’t seem like such a great idea any more. Thinking we'll use the bracket and lose the rest. Got the brake cable mounted to the brake distribution block in the pic and that routing was just some earlier brain storming.

[7dee2]

The K30 is back down to a bare frame we have just a few more things that need fab/mockup/weld which will be much easier without all the weight on the frame.

[7dee2]

Time to fit the gas tank started making room by removing the rear most crossmember. We needed to remove these frame rail tabs for clearance also.

[7dee2]

So the tank fits in there now. We want the flatbed to sit as low as it can so using a piece of 2x6 as a guide for the bottom rail of the bed we have about 2” of clearance for the fill tube & vent. This is the lowest the tank would sit in the frame and the highest without having to notch the bed rail so that’s our target position. It does look like the straps I ordered will be just long enough in this position also.

[RedRoad]

Tank looks great! Where did it and the straps come from?

[7dee2]

Hey RedRoad thanks they came from RockAuto, here’s the manufacturer and part#s.

DORMAN 576312 {GM#14050684} Steel Fuel Tank (31 Gallon, large fill neck & external pump)
SPECTRA PREMIUM ST11 Set (for 31 Gallon Tank)

So this tank gets close side to side and front to back as mounted but it clears, I’m thinking we’ll probably get some kind of stick on gas tank insulator for the areas that will touch (top of tank). The original rear lower c-channel braces mounted up under the upper frame lip will space the tank down perfectly. Had a little left over angle iron for the front strap mount and we will use the rear crossmember for the back strap mount.