bugle6x606
Member
Hi all,
Long time lurker, first time posting.
I first off want to thank a lot of guys on here that have helped me troubleshoot my dads 8N. Dell, Soundguy, Bruce, Zane, there are others too I cant think of, but I really appreciate all the help.
Working on my uncles 8N. Two weeks ago we did my Dads 8N. It had the normal piston leak, and lift would not go all the way up. Replaced the cam follower pin, and a new NAA piston fixed it right up. My uncle mentioned his lift was weak too. It will lift all the way up but with a wood splitter on it, you have to crank the rpms to get it to lift, and once it is all the way up if you press the clutch it drops to the ground in seconds. He mentioned it came on quickly, was not a gradual issue that got worse over time.
Heres what Ive checked so far:
1. Hydraulic lift cylinder is not leaking. He converted it to a NAA style a few years ago.
2. No leaks from the top plate or anywhere up high. Top cover gasket is not leaking.
3. Pressure relief valve does not appear to be leaking by. It is not original, it has multiple holes in the sides. But when the pump is running I cannot feel any fluid coming out of it. There is no obvious movement in the oil.
4. On thing I did notice was a layer of foam on top of the oil. The oil itself was not creamy looking so water didnt appear to be an issue.
At this point I figured it was in the pump or I was hoping the bottom gasket was blown near the tube perhaps. The pump was moving, nothing appeared to be broken.
Today first thing I did was remove the relief valve and double check it to see if it had dirt in it. Appeared to be fine.
Next we drained oil and dropped the pump. The bottom gasket was old, but didnt show an obvious bad spot.
We took the pump apart, cleaned all the sludge out and put new gaskets on the valve chambers. The old gaskets didnt appear to be bad.
The valve seats did have some wear. I wonder if this is our issue, but will keep going here.
The pistons are worn. One in particular had a big groove in it, as did the housing in the valve chamber. Must have had something get in it at some point.
Reassembled everything and put new oil in it, traveller all mineral sae90.
Fired it up and pretty much have the same issue. Heres where I need help. When its running I see no bubbles or air in the oil, but as soon as I turn the key off, it starts to roll foamy oil up in the upper right corner near the transmission. Not around the tube more against the transmission housing. And nothing in the center of the pump near the pistons. Is it possible the valve seat are not holding and due to one of the pistons being scarred, its somehow getting air in the oil? This is where Im not sure and I havent seen a similar issue posted. Before we pull the trigger on a complete rebuild kit I wanted to ask the 8N experts. The tube doesnt appear to be split, I would think it would be blowing out oil while running, not after shutting down. Same result with a cracked housing I suspect.
I am going to try to post a picture of the foamy oil coming up after we shut it off. I also have a video of it, not sure if I can post it. The iPhone can really see what is going on in there, pretty handy.
Thank you for any insight anyone may have!
Donnie
Long time lurker, first time posting.
I first off want to thank a lot of guys on here that have helped me troubleshoot my dads 8N. Dell, Soundguy, Bruce, Zane, there are others too I cant think of, but I really appreciate all the help.
Working on my uncles 8N. Two weeks ago we did my Dads 8N. It had the normal piston leak, and lift would not go all the way up. Replaced the cam follower pin, and a new NAA piston fixed it right up. My uncle mentioned his lift was weak too. It will lift all the way up but with a wood splitter on it, you have to crank the rpms to get it to lift, and once it is all the way up if you press the clutch it drops to the ground in seconds. He mentioned it came on quickly, was not a gradual issue that got worse over time.
Heres what Ive checked so far:
1. Hydraulic lift cylinder is not leaking. He converted it to a NAA style a few years ago.
2. No leaks from the top plate or anywhere up high. Top cover gasket is not leaking.
3. Pressure relief valve does not appear to be leaking by. It is not original, it has multiple holes in the sides. But when the pump is running I cannot feel any fluid coming out of it. There is no obvious movement in the oil.
4. On thing I did notice was a layer of foam on top of the oil. The oil itself was not creamy looking so water didnt appear to be an issue.
At this point I figured it was in the pump or I was hoping the bottom gasket was blown near the tube perhaps. The pump was moving, nothing appeared to be broken.
Today first thing I did was remove the relief valve and double check it to see if it had dirt in it. Appeared to be fine.
Next we drained oil and dropped the pump. The bottom gasket was old, but didnt show an obvious bad spot.
We took the pump apart, cleaned all the sludge out and put new gaskets on the valve chambers. The old gaskets didnt appear to be bad.
The valve seats did have some wear. I wonder if this is our issue, but will keep going here.
The pistons are worn. One in particular had a big groove in it, as did the housing in the valve chamber. Must have had something get in it at some point.
Reassembled everything and put new oil in it, traveller all mineral sae90.
Fired it up and pretty much have the same issue. Heres where I need help. When its running I see no bubbles or air in the oil, but as soon as I turn the key off, it starts to roll foamy oil up in the upper right corner near the transmission. Not around the tube more against the transmission housing. And nothing in the center of the pump near the pistons. Is it possible the valve seat are not holding and due to one of the pistons being scarred, its somehow getting air in the oil? This is where Im not sure and I havent seen a similar issue posted. Before we pull the trigger on a complete rebuild kit I wanted to ask the 8N experts. The tube doesnt appear to be split, I would think it would be blowing out oil while running, not after shutting down. Same result with a cracked housing I suspect.
I am going to try to post a picture of the foamy oil coming up after we shut it off. I also have a video of it, not sure if I can post it. The iPhone can really see what is going on in there, pretty handy.
Thank you for any insight anyone may have!
Donnie