127 Trunion Shaft Removal
 

Replacing pump shaft and trunion shaft seals this afternoon. I've studied the manual pretty thoroughly and believe I have a good understanding of everything I'll need to do with one exception. The manual is a bit cryptic on driving the spring pins that secure the swash plate to the trunion shaft. There are no photos for clarity. Are the holes in the swash plate blind?>and if so how in the heck would you ever get the pins out of the shaft and back into the swash plate to secure the assembly? The manual seemingly alludes that some swash plates are drilled through and some are blind. Any experiences and guidance would be greatly appreciated.

Are the trunion shaft seals leaking?

Yes the left side is making a mess :(

Just to clarify, left as you are sitting on the seat?

Yes, same side as the controls.

I feel really dumb. After thinking about this for a while I answered my own question. The pin is driven to centerpoint in the shaft. Remove the shaft then remove the pins from the shaft for reinstallation from the front of the swash plate into the reinstalled shaft. sheesh I feel like a dummy.

Alright. Yeah, disassembly is required for that seal. Too bad. Make sure to clean the housing off really well and get you a very clean place to work on it. DO NOT use a cloth rag on the internal parts. Not even to set the pieces on. Get you a roll of blue shop "paper" towels. Yes, that pin can be driven all the way through. Make sure when you split the two housings that the plungers stay in their bores. Some people will say that this isn't important. I disagree. I have had many piston style pumps apart, and that is like rule #2. (Rule #1 is there is no such thing as being too clean when working on these.) As added advice, there is no reason to remove the opposite side pin. That seal can be changed without taking it out. As long as you keep everything clean, don't wash the internal parts. Just clean the case gasket face and put the internals back in. If cleaning is necessary, lube with hy-tran on reassembly. If you want read through this write up in the technical section. Hydro's: How they work.

Don't feel so bad. Any time we gain knowledge we gain advantage for the next adventure. Most times I myself open my mouth before engaging the brain. Happens to all of us. Glad you got it figured out.

Thanks for the great advice. What's the best way to remove seals with the shafts still in place?

Go get a small wood screw that is long. Drill two small holes in the seal opposite each other. (Just large enough to help start the screw.) Run the screw in, being careful not to bottom it on the alum housing. Then, take a pair of needle nose pliers, grip the screw right at the seal and pry against the housing. Alternate sides. Sometimes, you don't even need two screws. They usually just pop out! Every now and again, this method doesn't work. But you'll have it apart, so if you have to you can pull the pin. I've changed the seal on the right side like this many times. Good luck!

If they are just an oil seal they arejust a thin metal circle holding a rubber seal. Last evening I removed just such a seal from a creeper. I used a flat bladed thin screw driver and basically removed the metal out to the rim and then tapped the edge in and it popped right out. Just be careful not to nick the edge of where the seal fits into.

Successfully completed the hydro seal replacement for my 127. The combination of reading and understanding the manual and the practical real world advice here made it happen. As others said surgical cleanliness is mandatory but the actual work was relatively easy. I will say my 127 had the blind swash plate holes so I'm glad I had already thought through that scenario. Thanks to everyone for your solid advice.

Great to hear! Yours did have the blind hole huh.... I've not had one apart that did. I knew some did, just hadn't seen one yet. Pull it with a screw? Please share for future "lookers". :ThumbsUp:

Glad you got it fixed! :beerchug:

Since the control side trunion had to come out anyway I removed both trunions and the pump shaft. Used a traditional seal puller at that point.

No, how did you pull the pin on the trunion shaft if it had a blind hole?

Simple really;the manual says mark your punch at exactly 15/32 with tape. Drive the pin that far and no further. This centers the pin in the shaft allowing you to extract the shaft. Then knock the pin out of the removed shaft and insert from the front on reassembly.

I knew that.

I knew you knew that LOL

Yeah I took out a trunion shaft I had removed a few months ago and looked at it yesterday and there was the pin stuck directly in the center of the shaft.

Ok, not trying to be a pain here..... but I'm not following you. You said the swashplate had a blind hole. That would mean it doesn't go all the way through. Just so I'm clear, you drove the pin into the shaft, removed the shaft. (The pin is short enough to fit inside the shaft?) Then, drove the pin out of that, and reinstalled through the front. Is that correct? Because all of them I've had apart, you could just drive the pin straight through the shaft and the swashplate and out the back.

That is correct, the pin is short enough to be contained completely within the shaft. The only potential issue is driving the pin too far causing it to hang on the blind side of the swash plate making removal a pain.

:ThumbsUp: