I just shortened my driveshaft ,it has no weights and no vibration ,it runs out at .032 ,can I run it as is ???
Try it, but if it ends up giving you a buzz at a certain rpm plan to get it out of there before it takes itself out. Been there and done that, had to replace a exhaust system and rear pinion yoke because of the thrash everything got when it failed at speed.. If it does give you a vibe, try unbolting the u-joint from the rear yoke and turning the shaft 180° and bolting the joint back to the yoke.....there may be some offsetting runout from the pinion yoke itself, factory issue yoke can be off quite a bit, I checked a half a dozen for less than .040" from a GM 10-bolt yoke before I found one. If that doesn't help your out of luck with that shaft.
The weights are generally used to try and balance a ****py drive shaft build. At .032 you are way closer than a lot of OE shafts. If it has no vibration, run it.
Agreed with the others. If it isn't vibrating at any speed, run it. Balancing it is to get rid of vibration. If it doesn't vibrate, don't worry about it. Congratulations, you did good.
If it shakes , a hose clamp around the shaft and keep slowly turning it until you get it as smooth as possible .
I’ve cut a few. Never checked anything other than lining things up as good as I could and welded. Just hammerd the **** out of the last one no issues
I understand that you guys have had success in shortening drivelines at home. Just because it works, doesn’t mean it’s right. I worked in a driveline shop and built drivelines from 1-1/2” diameter PTO shafts to 4-1/2” diameter monsters for extreme duty applications. Our specifications for runout, measured at each end was .005” or less. When building a brand new driveline, they were never balanced and they ran as smooth as a gravy sandwich. The driveline I just had made for Papaw was 55-3/8” long, 3-1/2” X .083” DOM tube with new weld yokes, new U-Joints, all ****er Parts was $489.
This would be reasonable for someone building driveshafts for the general public considering lawsuits and all.
I would take it to a driveline shop, I use Plaza Fleet Parts/Truckpro in St. Louis, there might be a shop in The Cape, but I’m not sure. There is a lot more science to this than people realize.
Nearly 40k miles on a home cut non balanced shaft. Both ends on a 2 piece. but the local drive shaft shop will do the “customer” ones. got 3 home cut shafts in personal rides.
I shortened the driveshaft on my 61 Impala 35 years and 60,000 miles ago. One time I drove most of the way from Oklahoma to Mn at between 100 and 120 miles per hour. I had a good reason, don't ask.... does not shake one little bit
I've shortened several by hand, most worked fine but one did shake pretty bad and ended up in the s**** bin.
PEM racing in St Clair, MO builds drive shafts and will also balance or repair your drive shaft if you end up with a vibration issue.
Just because you have a build doesn’t mean that it is done right. I have seen a few out of a local professional driveshaft spe******t to me built as much as .190” out of round so all I can say is “your results may vary”.
I cut the old weld on a big lathe after s****ing a line down it knock out the end . Cut the shaft in The lathe so it's true and bevel the edge slightly and drive in the end aligning the line I previously made and reweld it . Not sure how what is basically a press in fit end is going to be out of round or what I'd do to correct it even if I could. Never had a issue. Last one I had made the ends were out of index but about 20 degrees and I had to have then redo it .
I had a trained mechanic do exactly that on my OT work truck recently. When I queried it, I was told I was wrong !
That shaft has pulled over 12k across the scales, pulled stumps and yanked old cars out of the weeds. That’s all I know
End runout is usually the yoke not being perfectly square to the tube. Since you have already built the driveshaft ,you can heat-shrink the weld and pull it straight. Just heat the "High Side" approx 1/4 to 1/3 cir***ference. 32 thou should be easy to shrink out If you ***k that up, you should do what @Truckdoctor Andy suggested $500 is cheap to prevent a driveshaft spinning at 3500 rpm + from coming through your floor.
According to one of the very old Chrysler factory service manuals, an out of round end of a driveshaft should be at the transmission end. The transmission mount will reduce vibration that may be felt. They also do not give an out of round spec, for either end (but it does have a spec on the straightness of the tube). The factory manual does include the "home balancing process" with the hose clamp, and even offers a method of balance using 2 hose clamps if needed to eliminate the out of balance. The ability to feel a vibration , or not, was the sole determination (outside of as bent tube) of a good drive shaft or a bad drive shaft. A company bragging about the specific amount of an out of round tolerance for a drive shaft is the company trying to make themselves appear to be more important.
I have shortened several. Three things I do is 1. Grind off the weld flash on the inside of the tube seam so the end will seat concentrically with the tube. 2. Use white tipped pushrods to align the ends through the bearing bosses. This works surprisingly accurately. 3. Put a chamfer on the end so full penetration will be guaranteed. Oh, and don't use one of these
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