Driveshaft on my 129 is out-of-round....can this be adjusted?

three4rd · #1 04-19-2023, 06:38 PM

If I didn't know better I'd say I messed something up by removing the old fan and snap ring, but can't see how that could happen (?) I rotated the engine by hand a few times to access the broken fan from different angles, and then had a pliers and/or vise grip on the snap ring. so I WAS twisting that to bend it, but, could that have changed something with the shaft / hydro alignment? If so, surely not worth it just to put on this new fan.

Should you be able to grab and slightly move that whole flex coupling or is that natural for it to give a bit. I attached two pics that show how the one side is closer to the hydro than the other. I don't think it was that way before I worked with removing this broken fan. One pic was taken with the engine turned 90 degrees so as to see from both sides.

Should I adjust something to try and get better alignment? When the engine runs at low rpm, it's visibly out of round. Once higher rpm. I don't notice it. Can't be good for it running out-of-round, but maybe it WAS that way and just never noticed it. I know it surely ran that way for many years but then I seem to recall when I put a new engine in I paid attention to trying to get it as true as I could.

Loosen the whole flex coupling and adjust somehow? Loosen engine motor mounts and shift position around on that side till the shaft appears straighter? Or is it normal for these things to run a bit out-of-round due to the nature of these flex couplings?

Thanks for advice...

athomas · #2 04-19-2023, 09:31 PM

Looks normal to me , the flex coupling is made to take up any imperfections in the drive line if it's not shaking and vibrating the whole tractor I wouldn't be to concerned about it ! just my opinion !

three4rd · #3 04-19-2023, 10:16 PM

Thanks. Runs fine - no vibrations / shaking, etc. As I mentioned, it MAY have been out-of-round and I never noticed it. Very seldom have the tunnel cover off to look at the shaft and coupling all that closely, especially when running. Still worth checking the bolts on the coupling. Flex joint could also be pretty well worn. I didn't replace any of those components 4 years ago.

ironman · #4 04-20-2023, 08:53 AM

The end of the driveshaft has a tip that goes in a hole on the hydro coupler to align them.
I have seen couplers that have the holes wallowed out and the tip on the drivshaft worn away. That may be the case with yours or the tip may have broken off.

three4rd · #5 04-20-2023, 09:19 AM

Thanks for that info. Only way to know is to loosen / remove the coupling and shaft I suppose. So then I'm sort of back to where I started and probably could have just replaced broken with a traditional fan. The shaft / tip is undoubtedly worn, especially being original. I didn't replace the shaft when doing the engine work. In either case, not ideal to run it with the shaft not "straight", is it?