b7800 front drive shaft replacement

[Kioti Dave]

Has anyone replaced the front drive shaft on a B7800 without splitting the tractor? My 7800 shaft broke at the u-joint right at the transmission. Want to replace, but don't want to split the tractor. Can this be done, or am I in for a big time job?

 

[mikester]

Most tractors have the front drive shaft in 2 pieces in a tube from the tranny to the front diff. The shaft is splined and joined with a sliding collar. You dont need to split the tractor in this case.

If you see a u-joint then you definitely wont need to split the tractor. Simply split the yolk at the spider.

In any case you could at worst remove the front diff without needing to split the tractor.

It shouldnt be a huge job. I imagine you may need to replace the seals and bearings while you are at it.

 

[orezok]

Here is a cut section of the front wheel drive (6). Did the shaft break on the transmission side of the U joint or the front side?

 

[Ken]

Look at the parts picture and slide back the rubber cover on lower universal joint there is a pin holding the joint on shaft .tap out the pin slide the coupler back and lower to the floor then slide shaft from shaft at rear.
Question did this break from lack of grease. about only way to damage the upper shaft
unless the front pinion or gears in front drive. lock up
ken

 

[Kioti Dave]

U-joint broke right in middle. Some parts left on transmission shaft, some on driveshaft. I read somewhere, that you can drill a hole in top of frame to get at double spring pins. If I can do that, I can remove broken piece and install new parts from bottom. Probably pretty tricky, but if it can be done, would be better than splitting the tractor. Will look at it once it warms up.

 

[orezok]

No need to split the tractor to replace universal joint. All is accessible from below.

Part # is 6C040-57500. About $118 at Messicks.

From service manual. This is for the front universal, but rear is similar.

 

[Tomtint]

I just split my sisters b7510 to replace a motor. Made the mistake of not installing the front driveshaft as we bolted the motor to the bell housing. There is a metal cross member under the motor that makes it virtually impossible to do after the fact. Not sure if yours is the same..

 

[Leejohn]

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.

 

[Kioti Dave]

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.

That is exactly what I plan to do. What did you use to make the hole? Will make the job much quicker and easier. You tack welded the piece back in as well correct?

 

[Leejohn]

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.