Trunion Shaft Seal Leak?

[Sam Mac]

What J-Mech said. No need to mess with something that is working. All you need to do is to replace the seals, O-rings and gaskets. No need to disassemble the piston assembly's.

[ol'George]

I will reiterate to be careful so as the pistons stay in the bores they are now lapped too and living in.
If they fall out, and it does happen they all are ground the same in the beginning, so the only problem you will experience will be it is more noisy then it was before you mixed them up. BTDT.
Assembly grease (trans gel or chassis grease) will keep the valve plates where you need them when reassembling.There is a your tube video with a fellow making a board jig that helps hold the unit while dis/reassembly.

When removing the pins from the shafts/swash plate pay particular attention to directions as to marking a drive pin punch and not driving it too far.
I found one that had one long pin and not 2 pins holding the shaft in the swash plate,lucky it just cleared the case when it was turned just right so the shaft would come out.
I have seen pix where a person drove the pin threw the case, that will ruin not only your day, but a good case also.
Make sure you start disassembly with a very clean case exterior it helps keep everything clean inside, just try to think of your doctor operating inside you!
Clean clean!
Have a large bench and use plastic bags to put parts in keeping them clean.
When I get one assembled, I like to pour hytrans in side so it don't start dry
on initial start up, it just makes a more happy rotating environment inside.

[Sidewinder1]

Good deal fellas! That puts my mind at ease a little bit with not having to take Everything apart. I saw the wood jig in the manual and im going to partake in that as well. I bought a bunch of plastic baggies for bolts and parts to stay clean with. I also finally noticed that i have a ported pump. But on a 129 i dont know what for... no lines to the front or a lift... did they just put those in random tractors?

Oh while im in there i want to clean the valves... they are a little sticky... work fine i guess but the button could be smoother. Regardless a good cleaning wont hurt right? Would i just use diesel and pb blaster... then lube with hytran before assembly?

Thanks guys... gunna order my kit friday, and get this party started!

Thanks

Matt

[sawdustdad]

As others have said, it's an interesting job, and you'll learn a lot about what makes the hydro work in the process.

Work meticulously and methodically, but you will not have to clean anything inside. It will probably be spotless.

Clean the exterior very well before you start. I used a large woodworking vise to help hold the hydro as I worked on it but the manual has instructions to make a wooden jig.

Follow the instructions to remove the pins in the trunnion shafts EXACTLY.

Replace all the seals while you are at it.

I've done it a couple times. It's actually a pretty neat piece of engineering and a little remarkable that the pressure of those little slippers on the angle plates transfer power so effectively.

The one trick that Sam Mac helped me with was using grease to hold the valve plates in position on reassembly.

Also, make sure you do not pinch the O ring reassembling the charge pump. BTDT.

Oh, one more suggestion. Repair the trunnion rectangle when you have the shaft out. I welded on new rectangles on the two I reworked.

[john hall]

Yep, here's that high-tech assembly board you need! Have fun! As has been mentioned, clean everything real good before you take it apart, you'll thank yourself later. My shop is a farm shop, pretty darn dirty. I cleared off the work bench and put down sheets of cardboard so I knew I had a clean area to work on. Oh if all those pistons don't stay where they belong regardless of how hard you try, join the club--I still ain't figured out how I let that happen when I was TRYING not to.

[Sidewinder1]

John - Thanks for the pic, Im going to make one of those for sure. I like the cardboard idea, and im going to clean the outside as best i can, wear gloves and all that jazz. Going to try and get everything situated in one of those big tinfoil turkey pans too that way i have something to catch misc. items if they get away from me. Only thing i guess im worried about is putting the valve plates back in appropriately, not so much switching the motor and pump plates around, but putting them in upside down or something.... granted that may not matter. Gotta find me somemore videos... the one i did see the guys wasnt using a manual and was just kinda pulling everythning out to replace a cracked case...

Thanks guys,

Matt