b7800 front drive shaft replacement

sixdogs · Mar 6, 2019

I had no idea this was so difficult. Anyone with a shop manual know how Kubota suggests it be done?

Kioti Dave · Mar 6, 2019

Kubota will split tractor. At least $1500 in labour. I know because I already had it done. Cutting an access hole from top will save a lot of money.

Kioti Dave · Mar 6, 2019

Leejohn said:
I used a hole saw and no I did not weld back in. Blow the picture up and you can see three screws hold it in. It is flush with the deck.

Ok see that. Thanks for the photos. They are VERY helpful. Will probably use a cutoff tool and cover with a thin plate. Will post photos as well.

rtrent · Nov 26, 2020

I have discovered similar problem with my B7500HST; I found the rear u-Joint at the transmission end of the front wheel drive prop shaft is really loose/sloppy; just a matter of time I think; middle u-joint seems fine; I guess no zerks for lubrication on these u-Joints?? Not that you can get to them; at least this describes a possible way of replacing without splitting the tractor. But as stated above, you need to remove the loader frame first; I tried sliding the plastic cover back on the middle u-Joint, but the loader frame has a steel brace that crosses there and is too tight against the cover to allow it to slide back.

rtrent · Apr 25, 2022

Leejohn said:
1st off if you have a loader the sub frame has to come off and there is 28 bolts holding it on. That is the hardest part of the job. The sub frame is heavy and if can get help do it. I'm 78 and did it myself but it was all I could do.
When I split my 7800 to replace the throw out bearing I went ahead and drilled a 3 1/2" hole over the rear joints. Now I get at both roll pins and can line back up easy when going back on. I wouldn't want to split the tractor at the trans, that looks like a real job.
Here are some pictures of where I put the hole and the cover I made for it. See if that helps. If you do this make sure the pilot drill isn't to long and go slow.

Hey Leejohn!! This is exactly what I saw on my B7500; my rear universal on the shaft for the front drive is getting bad and saw that in order to get at it you need to remove the loader frame; on top of that, I have a Woods backhoe sub-frame that also attaches to the loader frame; so this hole would make access a lot easier; my question though is can you get the rear universal off the splines without removing the front universal first?? Does it just slide forward when you take the pins out?? Hope you get this message and are able to respond; thank you in advance!!!

Leejohn · Apr 25, 2022

If I remember right, after the front pin is out it well move fwd enough to get the rear off after the pin is out at the rear. I well go back and look at my pictures and see if that helps me to remember.

Update: There is a coupler at front of the main drive shaft. The cover over shaft comes apart after you remove the small screws . I hope we are talking about the same shaft. I can't find the pictures I wanted of me splitting the tractor. If you think I can help anymore and want to call me I give you my phone #.