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Old 05-07-2011, 01:59 AM   #1
Jacfourteen
Big Red - Now its a SWB!
 
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Join Date: Jun 2009
Location: Oroville, Ca
Posts: 1,624
How to shorten your driveshaft

Lately I've been working on converting my truck to 1/2 ton and shortening my frame down to a SWB. One of the things that I had to deal with was the driveline. I did some research online and found a site where a guy outlined the steps that he had followed to shorten many drivelines with no trouble, so I figured I'd give it a shot. Here is the link http://www.fordmuscleforums.com/tran...riveshaft.html If it ended up out of balance I figured I'd go get another from the local junk yard for $25, and if it went well I'd save about $150 for paying someone else to do it. So first I wire wheeled all of the rust and undercoating off of the driveline, I don't know how this thing wasn't out of balance to begin with because all the undercoating was on one side. Next I decided to take the 12 inches out at the splined end because there was no balance weights to mess with. Here it is after cleanup:



So I used a thin cut off wheel on my grinder to cut a shallow groove near the weld on the yoke, it only had to be about 1/16" deep to get through the shaft. Here's a pic:



After that the yoke popped right off with a few taps from a hammer:



Then I measured to see exactly how much needed to be removed, I determined that I needed to cut out 11 and 7/8". Then I clamped it into my chop saw and made sure it was square:



Then I made the cut, and cleaned it up using a file on the inside of the tube and a grinder on the outside and end. Then I had to press the yoke back in, I made a contraption out of 2 chunks of 2x4 and 2 clamps then I had to heat the tube with a propane torch and whack the block with a hammer and keep tensioning the clamps till it was seated:



Next I bolted the driveline into place a spun it and adjusted the runout of the splined section until I got just right. I didn't have a dial gauge to check runout so I rigged up a piece of wire to see how much it was wobbling:



Once satisfied I tack welded a few spots and removed the shaft. Then I welded it up good and used a grinder to knock down any high spots in the weld to help keep things balanced. Then I shot it with some flat black and threw it on.







Since I did this I have had my truck up about 75 and haven't had any vibrations from it, so I think it has been a success. If I missed anything or you have any questions let me know.
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68 3/4 ton (Project)-350 Small Block, .030 over, 10:1 comp, 3998993 heads, C3BX edelbrock intake, comp cams XE268, Holley 670 SA, long tube headers, dual flow 40's, E-fan, Alum rad, currently under the knife getting shortened and bagged build thread
41 3/4 ton (wife's)-flatbed, fully restored to original
01 Tahoe LT 4WD (my daily driver)-Magnaflow Muffler, Rollin on 22's
02 Ford Mustang Convertable (Wife's Car)-Flowmaster 50, Clear corners, Intake, sittin on 18's
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