[kweeksdraw]

I'd been wanting to have a look at the lift piston as it lets the bush hog set down slowly after I shut down the tractor. Well I figured now's a good time to get that done, and here's what I found...There was about 1/4 to 1/2 inch of sediment in the bottom. The oil wasn't polluted with water, but who knows how old it really is or even what it is for that matter. The cylinder was scored, so was the piston and rings. I'm not sure how bad they are because it's the first one I've seen.
I've cleaned and honed out the cylinder. I didn't get the scoring completely out as I am afraid of over sizing it. Right now it measures 2.502 inches. (the pictures here are before the final passes, I'll add them later).

I debated about weather or not to use steel rings, or use the NAA piston and rings, thinking that if some of the scoring was left that it would chew up the rubber rings. I asked Derek at Just 8N's and he told me I didn't have to worry too much about getting the scoring completely gone to use the NAA piston with rubber rings, that it would last a good long time that way.

Well, I guess the painting and putting back together is put off again. Sigh. I get it done eventually! Hopefully before the snow flies!

 

[JohnW]

Derek would know... I think there are a lot of tractors out there with some scoring.

I know it seems as if you will never get it done but you will. They just do not go as fast as yo want. Been There Done That. :goodl:

 

[souNdguy]

Hone her some more.. that's deep scratches.... then use the naa piston / oring.

i hones my 8n to just outside tolerance, and oring from CNH was still a nice fat one with a tight fit.. and held up loads for DAYS after that.

don't let it bother ya.. the R&R of the lift cover and the pump can be done in 9 hours if you keep at it.

DO clean the sump out...

soundguy

 

[kweeksdraw]

Soundguy;

Boy, were you right! I mentioned that the gear oil seemed un polluted by water or sludge...boy, was I wrong! When I pulled the plug on the bottom of the hydraulics well the water ran clear before the oil came out! Oh,my gosh! And the sludge! Jeeze! Glad I took your advice!

 

[souNdguy]

yep.. btdt...

soundguy

 

[Dan]

Sounder hit on a point that should be well noted - use the CNH hydraulic o-ring - not the Tisco you will get at all aftermarket parts places. I have measured both and the CNH version is thicker. Thicker = tighter in the bore = stronger lift and better holding power - and with any honing this is essential.

If you do not have a New Holland dealer close, Derek at Just 8N's can get one for you.

HTH,
Dan

 

[kweeksdraw]

Dan;

I placed an order with J8Ns and got the NAA piston and it's rings to replace mine. Are those the CNH type? I've taken out most of the scoring in that picture above. I guess that brings the cylinder diameter to 2.542, thereabouts. I don't know what the spec.s are, but considering the cylinder was 57 years old before I started scrapping away at it, I must be getting near the top end!

Anybody out there know the numbers?

 

[Dan]

If you just placed an order with just 8ns, you got the Tisco O-ring. You would specifically need to tell Derek to pick one up from their local New Holland dealer.

Here is my comparison between the two. NH ring is on the right. The size difference is huge when put in place: