Stray plug

[Bill Everly]

I'm in the process of changing tranny/hydraulic fluid on 1951 TO-20. When I pulled the hydraulic system drain plug, a square headed 1/2" plug came out with the oil.Is a plug such as this used inside the hydraulic unit? Everything was working OK.

 

[Jerry/MT]

There is a part no 181 072 M1, "Plug, Base Drain" that shows up in the hydraulic pump parts list along with a gasket(part no 29 930 X, "Gasket, Drain Plug). Could be what you"ve found. It"s located near the rt front corner of the front face of the pump near the bottom. You can maybe get at it from the rt side access hatch. Otherwise, you"ll have to pull the pto shaft and drop the pump.

 

[AussieDoc]

(quoted from post at 06:02:28 05/23/08) I'm in the process of changing tranny/hydraulic fluid on 1951 TO-20. When I pulled the hydraulic system drain plug, a square headed 1/2" plug came out with the oil.Is a plug such as this used inside the hydraulic unit? Everything was working OK.

Square headed bolts are used to hold the gear selectors in position. They also have a small hole drilled through the head to be security wired. However they are in the transmission area. I can't see how they could make their way to the hydraulic section.

However. Is it possible that you drained the transmission oil and hydraulic/pto,diff section oil into the same container? Thanks what I usually do.

If it is one of the gear selector bolts and you have not had any shift problems then it could be that a previous "mechanic" dropped the bolt inside by mistake and had since replaced it.

I put some photos in the parts and pieces gallergy a few weeks ago. May be worth a look. Photos of hydraulic pump, transmission etc. It's for a TEA20 but it will give you some idea.

 

[AussieDoc]

Partly ignore what I just said. But look at the photo of the hydraulic pump. Can you see the 4 square head bolts/plugs.?
Is that what it looks like?

If so then you may be able to go by feel and re-fit your found one if you have small hands by removing the dip stick cover and or pto engage lever cover. Otherwise you'll need to remove the pump which is not too difficult.

 

[Jerry/MT]

Great pictures of the pump, Doc! But I don"t se any "plug" on the pump where the parts drawing indicates there is one.

 

[AussieDoc]

The photo is for a TEA20. But I assume the TO20 has the same pump.

One of the pictures shows 4 x square head bolts. They look to be half inch. I don't know what they do. I never stripped the pump down.

They're the only square head bolts that I can see in that area.

Are they plugs? I don't know. But it may be the thing Bill is looking for.

 

[John (UK)]

The only square headed plugs used on the hydraulic system are on the side chambers and if one was out the hydraulics would not work on one cylinder of the Pump so it would be jerking when lifting, it will most likely be one that someone has dropped and couldn't find again. As long as it is out it wont do any harm.If you look at the pump you will see two of these plugs on the front and same on the back on each side, just check if one is missing before you fasten it all up again...John

 

[Jeff-oh]

Am I missing something? I do not see a picture or ref. in either the modern or classic view.

 

[Jerry/MT]

It"s in the Parts and Pieces, Jeff

 

[Bill Everly]

After looking at the pictures and pulling the side covers, I have decided the plug was inadvertently left behind or dropped into the unit the last time someone worked on it. The plug is a 1/2" pipe plug and I don't see any place on the inside where a plug this size is used.
I would like to thank everyone for their help.