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Old 03-16-2015, 10:30 AM   #1
bbcmudtruck
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Rear coil spring location/c-notch help

I am finally ready to reassemble my 68 short bed frame after a year of repairs and modifications. My issue is the location of the rear driver side coil spring bolt hole. When I attempted to attach the driver side rear coil spring to the trailing arm and frame, I noticed that the bolt hole doesn't quite line up. The bolt hole in the frame is about 3/8" of an inch to far forward. When I attempt to bolt the spring up, the spring has to sort of bend to allow me to start the bolts in the retainers. I can start the bolts and then go ahead and bolt the spring down tight, however I'm worried that this will negatively affect the spring. A little back story to help you guys understand the big picture may be helpful. I had to cut out about a foot section of the frame on that side to replace a large amount of rust where the original spring was located. I replaced this piece with a rust free section from a leaf spring frame, however I was very careful to make sure every thing stayed square and true. I also cut my frame to install c-notches. They didn't quite fit exactly so I cut the pre bent c-notches into 3rds and then located them to the frame where the axle would actually swivel up into them. Once happy with the c-notch locations, I welded them in, rather than using bolts. I also replaced the original trailing arm cross member and trailing arms with an ECE package. I'm also using a tubular shock cross member from CPP I believe. With all these changes and repairs to the frame, I'm worried that I missed a measurement somewhere. The frame measures dead on square from the trailing arm cross member and forward. However I'm getting around 3/8-1/2" difference from the trailing arm cross member to the rear. The thing is, when I measure straight line, everything is completely dead on. Its only when I measure in an X pattern that I can find differences. I believe its in the rear shock cross member area. Its the only place that I cut the frame in half and had to place the location of the bolt holes, strictly off of measurements. So what do I do from here? I can elongate the shock cross member holes on the driver side to allow that to move towards the rear around 1/8" of an inch. I believe this will correct the coil spring bind. However If I do that, it will throw the rest of my measurements off. If I measure from the shock cross member in a straight line distance to any where on the frame, either to the front or the back, it measures exactly the same. Could the fact that I replaced every rivet in every single cross member with bolts that throw this measurement off? I know this is an extremely long post, I just wanted to provide as much information as possible. If you have any questions or need any pictures, please let me know what I can do to help you, help me!
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Old 03-16-2015, 12:00 PM   #2
Steve Cole
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Re: Rear coil spring location/c-notch help

First thing, paragraphs are your friend, it makes reading a long post much easier. Second, a picture is worth a thousand words, It will help us to "see what you see." There is a lot of information there, and it left me a little confused but it sounds like your measurements are good except when you measure in an "X" pattern right? That would tell me that your rear end (or something) isn't square.
I would make sure the rear end (axles)is square to the truck. You could measure from center of front wheel hub to center of rear wheel or however you choose to make sure the rear end is tracking straight. The rest of those measurements are not that critical. If one shock hole is 1/2" off, can you weld that hole up and drill another one to line the spring up better?
Like I said, a few pics would go along way to help us understand.
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Old 03-16-2015, 12:23 PM   #3
bbcmudtruck
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Re: Rear coil spring location/c-notch help

Ok thanks for the advice. To simplify, yes I could weld that coil spring hole back up and relocate it approximately 1/8" or possibly 3/16" back further. This will not affect the straightness of the axle to the frame, however it will allow the coil spring to bolt up without being in a bind. If I take the trailing arms up to the frame without anything attached to them, I can see how the frame bolt hole lines up with the trailing arm bolt hole. The passenger side is only slightly off. The driver side is around 1/4" possibly a touch further off from lining up. I would assume that the coil spring bolt hole should line up to the trailing arm coil spring bolt hole when the trailing arm is brought up to the frame. Does that make any sense? I will get you some pictures as soon as possible. Thank you for taking the time to read through that and try to make sense out of it!
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Old 03-16-2015, 12:53 PM   #4
Rod Run
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Re: Rear coil spring location/c-notch help

Pictures are definitely needed here, because something doesn't make sense... or I'm just having a hard time following your statements
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Old 03-16-2015, 01:07 PM   #5
bbcmudtruck
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Re: Rear coil spring location/c-notch help

I completely understand. Its a hard thing to put into words! Basically, I've modified the frame a lot. I've bolted on aftermarket cross members, shock towers and lowering springs. Everything from the trailing arm cross member measures out either dead on or within 1/16" of an inch. Both using X cross patterns as well as straight line. I've verified this from several different measuring points. Where it gets tricky is the rear shock cross member and back, I'm within 1/4" to almost 1/2". Again, that's using several different points of measurement. The thing is, if I simply measure along side of the frame rail, everything is dead on. Where the hell is this extra 1/4 to 1/2" coming from and how? The main issue I'm having is that the rear driver side coil spring. When I try to mount it up, I have to hold it in place towards the front of the vehicle. The rear mounting hole in the frame needs to move back around 1/4" inch for the coil spring to line up. Again, I'll get some pictures as soon as possible. Its very hard to put into words. I've measured this frame at least 50 times from all different points of reference. Stumped
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Old 03-16-2015, 03:20 PM   #6
bbcmudtruck
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Re: Rear coil spring location/c-notch help

UPDATE: I can bring the rear of the frame back into square when I unbolt the rear cross member and use a ratchet strap to pull the frame diagonally against itself. So it looks as though when I ground out all the rivets that hold the cross members into place, the frame sprung a little. I believe I can pull the frame back to square and then tighten down the bolts that I used to replace the rivets. With that said, I've isolated the problem to back behind the axle.
My concern now is relocating the bolt hole for the coil spring. I don't believe it will affect anything by moving that hole towards the rear about 1/4" will it?
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