Boom Cylinder Lip Seal Direction

[peakbagger]

My SEE has had a persistent hydraulic leak out around one of the boom cylinders since I got it. It has always worked but has been a housekeeping issue as it leaks 365 days a year even when sitting all winter. Lately I have been doing some "hardcore" digging in the local rocky soil and noticed its leaking more when I am using it. I had bought seal kits from Foxkits.com several years ago in anticipation of needing to do a rebuild.

I did the tear down yesterday and while replacing the various seals, in general they looked real good, I was expecting far worse. When I got the internal lip seal #6 on the drawing, the lip definitely is pointing out towards the rod end. The lips larger diameter is facing right on the parts sketch below. This really does not make sense to me. as the return pressure on the cylinder is on the left. In theory the pressure int he cylinder would push on the lip and push it outwards making the seal against the rod yet this cylinder on the See has it facing the other direction and it looks like its never been touched.

The question is does anyone know which was the lip seal should be facing?. My guess is someone long ago put the seal in facing the wrong direction and since the SEE has minimal hours and worked despite the leak, that the military just didnt mess with it.

I really do not want to re-assemble and have to take apart again.

 

[Gastrap]

Yes, the lip should be the other direction so pressure expands it, the only one facing the rod end is the wiper (4). Also a good idea to put red loctite on the piston bolt.

 

[peakbagger]

Yes, the lip should be the other direction so pressure expands it, the only one facing the rod end is the wiper (4). Also a good idea to put red loctite on the piston bolt.

Thanks, you confirmed my research. I just got it back together again. I had made up my mind to flip it and then found a You Tube video on a rebuild a very similar Case loader that made up my mind. I used Loctite blue on the threads of the big screw. I am glad I had long threaded rod in stock, getting the "plug" off the rod and back on again was the biggest hassle. I got 8 hours into it over two days. I could cut a couple of hours but really do not want the practice . Given that the seals all looked real nice, some folks said plan to rebuild the one on the other side but, I can hope I will be lucky.

Everything looks like it came from Case like this with the seal flipped as I was breaking lots of joints sealed with CARC paint. Mien had 43 hours on it when I got it and was not recapped so

The Foxkits guy said he sells a lot of these kits for this size cylinder. I posted a link to him back in 2017 and had the parts in my spares since then. I wonder if mine is the only one out there with a seal reversed?.

 

[peakbagger]

Thanks, you confirmed my research. I just got it back together again. I had made up my mind to flip it and then found a You Tube video on a rebuild a very similar Case loader that made up my mind. I used Loctite blue on the threads of the big screw. I am glad I had long threaded rod in stock, getting the "plug" off the rod and back on again was the biggest hassle. I got 8 hours into it over two days. I could cut a couple of hours but really do not want the practice . Given that the seals all looked real nice, some folks said plan to rebuild the one on the other side but, I can hope I will be lucky.

Everything looks like it came from Case like this with the seal flipped as I was breaking lots of joints sealed with CARC paint. Mien had 43 hours on it when I got it and was not recapped so

The Foxkits guy said he sells a lot of these kits for this size cylinder. I posted a link to him back in 2017 and had the parts in my spares since then. I wonder if mine is the only one out there with a seal reversed?.

BTW, He now stocks the Schmidt front end loader seals, I ordered a set.

 

[The FLU farm]

Given that the seals all looked real nice, some folks said plan to rebuild the one on the other side but, I can hope I will be lucky.

I'd say there's a good chance you will be lucky.

My first SEE sprung a major leak on one not long after I got it. Got it fixed and left the other one alone. That was six or seven years ago.

 

[peakbagger]

I'd say there's a good chance you will be lucky.

My first SEE sprung a major leak on one not long after I got it. Got it fixed and left the other one alone. That was six or seven years ago.

Thanks for the confirmation from a fellow SEE owner. Unlike most worn out old equipment most of our SEEs have little or no hours and something like a seal is probably going to last a long time before they wear out. I thought the wiper seal which is exposed to the outside would be shot but its a teflon bushing type seal rather than a lip seal so unless it cracks, I expect it has a long life.