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Old 05-30-2019, 10:05 PM   #1
bigtexasrob
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Getting to the pinch weld?

My custom control arms have finally arrived! I am very excited! S#!+, now I have to figure out the details!

Truck is going on air. 1.5” pancaked crossmember, 3” drop spindles are next, 325/35R22’s going on all six wheels measure 31” tall. I know, the great and powerful google is my friend, but I’m having some hard time finding some of these answers. I accept both links to articles and explanations.

1) How are people adapting bag brackets to the stock crossmember? I saw something about trimming the edge of the crossmember around the spring pocket to clear the control arms, do I need to do this to put the rails on the ground?

2) How far do I need to body drop a ‘74 C30 to put the pinch welds on the ground? I’d measure it but it’s over gravel/excuses/already dropped too far for me to accurately measure. Do I cut the firewall above or below the column, and what problems does this present?

3) damnit what brakes do I have
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1974 C30 Dually Longbed
Diesel swap- Not finished
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Old 05-31-2019, 09:53 AM   #2
Ziegelsteinfaust
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Re: Getting to the pinch weld?

C10's who do it get a 2x4 3/16 walled box tube. They they cut it to match the upper curves of the frame, and weld it to the top inside of the C-channel frame.

Being a C30 I think the frames are taller then C10's.

So what you need to do it clamp a straight edge across the bottom of you frame, and measure the difference to the pinch weld. This will tell you how much you have to remove. You can see if you can find box tube in the size you need. Or you can trace out the cut line, and cut the bottom of the frame off. The over lap it back on to the frame, and weld back on. Then get some flat 3/16th metal to box the frame to restore the frames strength. Then you will have to fab a trans cross member.

Everyone who does it removes the body, and engine to make it fast + easy. Also they usually have to raise the engine, and trans in the frame. Then cut the body to match. This is easy to do once the frame is on the ground. Just mark where the engine was so you can reposition it once the mounts are gone.

Lastly for the last detail. When you Z the front of the truck to lay frame. Also Z the back of the bed to remove the ugly step notch. Then cut the inner sides of the bed to drop the bed to match the cab. This gives you the cleanest look plus loads of accessibility to fix things under the truck, and mount a blazer tank behind the axle. You rear Z has to take this into account too.
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Old 05-31-2019, 10:04 AM   #3
Ziegelsteinfaust
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Re: Getting to the pinch weld?

For the front cross member most people cut it to the desired height, and make a removable plate to mount the air bag too. How much depends on bag style, and the A arm mods below.

The lower air arm they can do 1 of 2 things.

Cup the lower a arm with a section of pipe that clears the bag by a 1/2 all around.

Or plate the a arm after cutting out the spring pocket.

Like I said above if you Z the rear frame too this make mount a 4 link much easier, and give plenty of room.

Bags are mounted at static no pressure height to start. What I like to do is build my mount 1 inch higher so I can use aluminum plates to trim my ride comfort. Along with shock valving or adjustments. Your first plates can be wood for testing to determine desired height.
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Old 05-31-2019, 12:49 PM   #4
bigtexasrob
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Re: Getting to the pinch weld?

maybe if I phrase this differently...

C30 owners who have done only the sectioned crossmember, bags and spindles, how far did you body drop?

C30 owners on bags, do your control arms clear the sides of your crossmember?

C30 owners on bags, do you have pictures of your upper bag mounts?
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Old 05-31-2019, 06:51 PM   #5
Ziegelsteinfaust
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Re: Getting to the pinch weld?

I have never built a truck for myself or others to lay out.

I have bagged 1 truck, and Z'd about 4 others. 2 both front, and back. That is as close as I got.

To lay pinch weld. Throwback 2x4 across the frame, and get a measurement. From there you have to decide the best way to tackle it. There are no bolt in options for less then 20K.
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Old 06-01-2019, 04:58 PM   #6
bigtexasrob
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Re: Getting to the pinch weld?

I previously mentioned that I cannot measure the truck where it is and that I am not doing a Z or bolt on. I am looking for information about a traditional body drop only.
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Old 06-01-2019, 08:52 PM   #7
Ziegelsteinfaust
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Re: Getting to the pinch weld?

What I described is often referred to as a stock floor body drop, and the one nearly every home guy does on this series of trucks. Plus what aftermarket frames effectively due.

The CK series past 73 do not lend them selves to a traditional body drop like let's say a 50's truck.

You still need to measure it to find out how much to remove. Then cut your body by that amount to remove a lets say a 3" strip of metal from both the fire wall, and back of cab. You just cut the floor off along the rocker panels about a inch in from where the door sits fully closed. Them you square everything back up, and weld it shut. Make filler panels for the door edge or step as it would be then. Then you do the same to the bed to match. The CK series beds in bolt, and I would consider working on it in pieces. Then tack weld back quickly, and reassemble to verify everything is still true. Make a filler panel for the back of the bed. Construct drop brackets for the front, and rear bumpers. Section the same amount as previously out of the core support so the front sheet metal drops down. Cut you column down at the slip joint, and put in 2 universal joints to reconnect it to the steering box. Modify your bench seat or buckets to lower them to match. Or as some do fabricate most of the floor pan to make seat installs easier. Tweak the break lines to allow for the body drop. Most of the wiring should be easy enough to zip tie up, and gives a couple more inches of play for a nice routing job. For the heater/AC depending on level of trim you have. You have to cut around the lower end of the box or go to a aftermarket system. Most due aftermarket if they have ac since the tires now have a tendency to hit the box. You either need use slosh tubs, trailer fenders, and or expensive surgery to fix you factory wheel wells. Or just toss them if your not planning to drive in the rain.

Now you may think I am a old idiot, and want to channel your body to show me up. Which is the third way it can be done. This usually looks like a abortion, and the channel is stupidly annoying to work around for cab interior fitment.
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Old 06-02-2019, 04:35 PM   #8
bigtexasrob
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Re: Getting to the pinch weld?

Quote:
Originally Posted by Ziegelsteinfaust View Post
What I described is often referred to as a stock floor body drop, and the one nearly every home guy does on this series of trucks. Plus what aftermarket frames effectively due.
I have already specified that I am asking about a different type of body drop.

Quote:
Originally Posted by Ziegelsteinfaust View Post
You still need to measure it to find out how much to remove.
I have already specified that I am currently unable to measure the truck.

Please stop replying to this thread.
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Airbags- Not finished
Rust- Extensive and ongoing
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