I've got a Cat 235 that we picked up last winter with a blown motor, going through it now and trying to get it in shape to do some work with it. Noticed yesterday that as we were moving it a slight trail of oil was dripping along as I went. I got looking and noticed that it was coming from what looks like a hydraulic valve/pump right in the center of the machine between the tracks. I've attached a couple of pictures... it is a nice steady ooze of oil out the top of the metal ring. What am I looking at and what is the fix? Thanks guys.
That is the centre swivel that takes hydraulic oil to the track motors. It looks as though it needs resealing .......... if you want the complete instructions for disassembly & assembly PM me your machine Serial Number and your e-mail address.
PM sent. Thanks. Chris
You will likely need to rechrome the center core as they get worn under the top seal from external dirt getting in. Later Bob
How would I know if it needs re-chromed? Will it be visibly worn? Or pitted?
Should be fairly easy to see when you pull it apart. If in doubt when you have it torn down post photos here.
OK will do.. I have parts ordered and will be in tomorrow so hoping to get it pulled apart this weekend. Thanks for all the help.
Here's some pictures I took yesterday of the swivel all torn apart. How does it look guys? Thanks. Chris
Looks average, see where the top is chewed up from the dirt getting under the top plate, that same dirt usually grinds the rotor two behind upper seal causing failure, sometimes we get them recromed or we turn down in the lathe a few thou.
Do you have the face of that housing turned down a few thousandths? where it's kind of pitted in the last picture? Or the actual center core turned down a little? Just want to make sure I'm understanding you correct.
The housing should be okay. Hard for me to see the scratches on the core. If it leaked it likely cut the seals with the wear marks. The dirt getting in does it the only one that doesn't have that problem in the 215 because the swivel is mounted upside down compared to yours. Later Bob
From your photos of the centre spindle it's obvious where the seals run, the change of colour gives it away. Can you feel anything at all if you run your finger over those marks..?
I couldn't feel anything yesterday but I will check it again tonight and see. I could just see the wear marks. I'll check a lot closer tonight and report back.
See if you can get some better close-up photos of the wear marks on both the centre spindle and inside the housing. I know it's likely to be difficult to get photos in focus, especially of the inside of the housing, but it might be worth your while for the advice you get. You may end up taking 100 photos just to get one good one. Maybe try with and without a flash, and also try using a work light to illuminate the area. Something's bound to work.
If you are using a real camera (not a phone), even a point-and-shoot -- it may have a macro mode which would allow you to get much better close-up pictures. There is often a picture of a flower in the menu setting for the macro mode.
Usually the rotor is pitted and scored up around where the top seal rides, if it isn't to pitted we try to turn them, if its heavy or a big groove then it will need recrome or replacement.
I know that the photos aren't the best but I don't see any pitting anywhere where the seals run at the top end of that rotor.
Here are a few more pictures guys... I ran my fingers around the center core and couldn't feel any grooves at all. I could just see the discoloring but that's all. I hope the pictures maybe show a little better this time around.
And some more.....
More...
From the look of those photos I think that would be good with just new seals, but I'll defer to the excavator specialists if they think differently.
What condition were the seals in?
The seals didn't look that bad... the top lip seal was pretty hard and looked old.... we bought the machine with a bad motor and don't know a lot about it's maintenance history. The machine has over 20K hours on it too....
If the seal was hard that was most likely the reason why it was leaking. I guess there was a major difference in colour between the new seals and the old ones, right? New seals ae usually a cream colour, old ones are a chocolate brown.
Yes the top lip seal was a real dark brownish and the new one we got yesterday is nice and white/cream colored and much more pliable around the edges. I am thinking that was the culprit. Tomorrow night we'll start the re-assembly process. I appreciate everyone's help on here. Hopefully we won't find any more issues as we are getting the old girl in shape
Just go careful with the install, take your time and lather the news seals with lubricant as you install the rotor into the housing.
Is there a specific grade of hydraulic oil that we need to top things off or just whatever tractor hydraulic oil will work?
Any SAE 10W (or the appropriate ISO equivalent, 32 from memory but don't quote me) hydraulic oil will be fine for the hydraulic system top-off on that machine. To reassemble the swivel use some heaver oil, gear oil if you have it, engine oil if not. The small amount of oil you use to assemble the swivel won't affect the hydraulic system whatever oil you use. Just make sure it's clean oil and the swivel parts are the same way before assembly ............
Great. Thanks again. Chris
Chris use hydraulic oil additive on parts to assemble. Later Bob
Thanks Bob. Will do.
Well we have bad news guys.... got the swivel all back in the machine this weekend and tried it out.... still leaking :'(... so now what? I'm guessing there must be enough of a groove somewhere that the new O-rings aren't sealing? It's not pouring out of the swivel but definitely a decent drip....
Okay, lets check a few things. Will the machine move? If it does is the case drain line free back to the filter and into the tank? Later Bob
Bob - it moves just fine.... or seems to anyway... We move it in the shop forward and back and then had some things to fix on one of the tracks so we lifted that side of the machine and rotated the track with it off the ground.... it all seems normal. I'm not sure on the case drain line... is that the top line on the back side of the swivel unit? How would I check to see if it's free back to the filter?
It's the one going to the filter on the side of the tank over the pumps. The top of the swivel carries case drain flow back to the tank. Try with cap off of tank, if that helps check the breather relief valve. Could be a bad drive or swing motor flooding the case drain aswell. Later Bob
Check case drain flow from each travel motor maybe..? There must be a spec for it somewhere.
Make sure prints are correct and undamaged under the top.