Hi So I recently revealed th swivel joint on my cat 315c because machine seemed to be losing hydraulic power when it warmed up. Mechanic said th seals were likely bad, 6200 hrs, however they looked fine. Anyway it didn't seem to make much difference and now I've lost turning power. Started out on th right track mainly forward but now both tracks either direction. Sometimes when still cold a certain direction will suddenly kick in and have normal turning power but when warmed up good it basically never will. When putting the swivel back together I had to put a lot of pressure on it to push it back together. Is that normal did they give me th wrong seals? Th machine di run fine for maybe 10 hrs after the swivel was reinstalled.
Yes its going to be a tight fit with new Orings in the swivel. I suspect it needs to be removed and checked for damaged O rings
Not what I wanted to hear but ur probably right
Check at least the pressure and ideally flow at the track motors before tearing random stuff apart.
Maybe check the return filter for obvious bits of o-rings.
That wud be th filter in th tank?
Yes, the filter sits in a well. Remove the cover, let the oil drain through filter for a few minutes. Have a clean bucket ready. Set the bypass screen and spring off to the side then pull the filter up and out and set in the bucket. Observe the outside of the filter with a strong flashlight. Look for little bits of rubber or vinyl. Place whatever you find on a clean sheet of wax paper. Post pics and guys with knowledge of your machine will try and help you narrow down the source. Then carefully feel around the ledge that the filter sets on. Be very careful. Anything you knock over the edge will directly feed your pump if it gets past the strainer. Feel around for additional rubber, vinyl, shavings etc. I don't know if your machine is equipped with a separate case drain filter, if so, I'd spin it down and pour the oil into a clean pan. Let's see what ya got. The best part, this only costs time. If there's no debris or damage, you could put those parts right back. Until you resolve the problem and perform your regular maintenance.
Ok will do that..thanks alot
Don't have any gauges..shud just buy some I guess
Gauges are a metric crap ton cheaper than the parts cannon.
Ebay, amazon ****, there's options. The challenge is to identify your test ports "style" so you're not wasting money on the wrong stuff. The most common now are the parker ones common on CAT, and Stauffs universal hydraulic test fittings. These are the best imho. They keep clean & you can connect under pressure
Been there with track issues on a 312 - those swivel joints can be a pain. They're always tight with new seals, but if you really had to force it, something might be off. Check your return filter like funwithfuel said - quickest way to spot O-ring bits. I'd bet money one of those seals got pinched during reassembly. Had a similar problem where power would come and go depending on temp - ended up being a relief valve that was sticking when hot. Worth checking before pulling that swivel apart again.
Let's back way way up. How much track sag do you have and what kind of material were you in? Have we checked pilot pressure? Have we checked pilot pressure to the spool caps. I get the idea of going after what is common to both. We can't let ourselves forget to check basics.
First off sorry about th two identical threads. I'm new on here and didn't know if my first one was at th right place. Thanks for all th replies so far. I haven't had much time to work on it lately but hoping to tomorrow. I did pull these 2 relief valves and did find a sliver of oring or something in one, hoping it cud be my problem. I cud here oil bypassing in th main valve block somewhere when it warmed up.
The relief valves I pulled are th two in th first pic, on either side of the big lines entering the main control valve. The trash was in th one on th right. Can anyone tell me which relief is for what?
Which relief valve was it?
Gonna pull the filters tomorrow. Also ordered a set of gauges off Amazon
Did you oil all the O-rings thoroughly when putting the swivel back together? Years ago a Cat mechanic told me you never install O-rings dry.
I always use Dow Corning 111 lube on the o-rings with a small hair of coconut oil on top of that. I put the liners into a Komatsu D155 bock with the o-rings installed with this lube combination and no press. They push in and I use a compothane hammer to put in the last 1/8 inch. Have not seen anything that works better yet for tight fitting o-rings. Maybe someone else has seen something better, I have not yet. Super slippery. Simon C
Yes I had everything thoroughly oiled and even rubbed some red mystic grease on still went together extremely hard. I'm wondering if they gave me th correct seals. The originals were one piece. The new ones were two pieces
What did the new seals comprise of and what were the original? If they both used O-rings maybe the new O-rings were a bigger cross section? Other thought is if the new seals use a backup ring maybe it was put on the wrong side and the O-ring rolled a bit and got pinched when putting the rotary swivel together?
Post a Serial Number for the correct OEM Part Number of the seals for the swivel. From SIS I do not see them being a 2-piece seal. EDIT: There is only one Part Number of swivel for a 315C, whatever the machine Serial Number happens to be. See the attachment. The five main seals (circled) separating the various hydraulic circuits are basically square in cross-section and are 1-piece. Sounds like wherever you got the seals from gave you the wrong ones.
Yes that looks like a sliced Oring- possibly giving you a good enough bypass that would make your turning sluggish. Also knowing the problem worsens when hot could be influenced by oils viscosity changing due to temperature- when its hot it becomes alot more water-like, meaning it can pass through tighter tolerances with much less resistance. Oil will always take the path of least resistance. I would definitely check your basic track sag and ground type first like someone previously said. Then I would move to pressures check going to each individual drives and compare with a spec unless its clearly ridiculously low. I would guess some sort of bypass interally- evidenced by the o-ring pieces, is your suspect, especially if it happened randomly and was working fine earlier.
They were twopiece..square cross section . The taller or thicker one was black the shorter one was blue. The blue piece was slightly smaller in diameter and fit nicely inside the black one so that's how I installed them. I recently revealed a hydraulic cylinder that used a similar setup so thot that was the right way but maybe not?
I got them from Cat. No way I was gonna take a chance on something that hard to redo. And now I probably gonna have to anyway.
Here's what I found on the return filter. If the pieces were blue I wud know they came from th swivel. I wud have thot the blue seals would have been th ones that were damaged as they wud be th ones th swivel was slipping past.
What Part Number did the Cat dealer sell to you.? Can you also post the machine Serial Number please.
I will do some digging and see if I can find th packages or parts invoice. Serial is CJC03144
I think i would measure track sag, check the gearboxes for oil, and check pilot pressure to my travel pedals before i tore something like that down a second time. Start at the beginning and work your way forward. Pilot pressure is gonna be crucial, BTW, do you have a straight line travel pedal? Does track power change if you boom up or arm in over relief?
Did you put one track in the air and try to move the one on the ground?
Track sag was fine, gearboxes are fine, it does not have a straight travel pedal. I just got my gauges but am waiting on a part so I can start the machine. How and where do I test pilot pressure? I never tried boom up or arm in but will when I get it running.
Not th one on th ground. When I lost power to the right track first thing I did was lift that side up. It turned fine in reverse but barely half speed in forwards.
I am not a cat guy, the cat techs will have to fill you in on that. The general idea is, from the safety solenoid, there's a line that carries pilot oil to each joystick and to each travel pedal. Each of those 4 valves should have an inlet fitting which acts as a filter. Sometimes they get jammed up with trash , rag debris , hose lining, etc. If the signal is corrupt, the control pressure to the spool caps will suffer.
That seems really odd to have one seal fit inside the other. Seems like one seal the right dimensions would work better.
If the swivel is bypassing the one in the air should move when you try to move the one on the ground
In high pressure, moving parts. It's common to use a teflon or viton outer seal with a common o-ring beneath as an expander to provide constant tension on the sealing surface.
I see..that makes sense
It appears the 2 piece seals aren't the correct seals the OP needed.
OK, so I have an update regarding the swivel seal Part Numbers. There was a service publication in 2003 announcing an the introduction of an "optional 2-piece seal" for the swivel for use in high-temperature applications. At that time the 159-7782 one piece seal in the parts listed I posted earlier was still the factory-fit part but the new 141-2163 2-piece seal was available for parts service for any customer wanting it. Over the intervening 20+ years it appears as though Cat have decided the 2-piece seal is the way to go, because both 141-2163 and 159-7782 are have been cancelled and service to a single Part Number 609-7007. The new seal is 2-piece, has increased resistance to wear and to water, and allegedly reduces friction in the swivel. Based on the above if the swivel was as difficult to assemble as you suggest I reckon you might just have cut one or more of those five seals as you were reassembling it.
Ok thanks a lot! I found the parts receipt and that part number is on there so apparently they did give me th right seals.
Any update on this project?
Yes finally had time to work on it again. So I pulled th bottom cap off th swivel thinking might see pieces of seals but found something else. The cap that goes on th end of th male part of the swivel that basically holds the two pieces from sliding apart had come loose or i had forgotten to tighten th two bolts, i think th latter, and had allowed the male part of swivel to slide up enough, i think, to allow oil to bypass seals. I'm desperately hoping that's the deal anyway and also hoping that didn't damage the seals. Haven't started and tried it yet and might be a bit , since it was down anyway decided to pull th hydraulic oil cooler since it was leaking worse and plugging th cooler. BTW never buy an older excavator unless u can afford to pay someone to work on it. They are th worst machines ro work on I've ever seen. Also pulled th main relief valve and pilot valve beside it. Main relief had some trash in it and one oring was chewd up and others were hard and square so hoping that might help. Th bad is i lost a tiny spring out of th other valve and so ordered a after market valve for 200 bucks. Thinking about just pulling th little spring out and using it in th original valve, or wud it be better just to use th aftermarket valve? Th valve from cat was 1100 bucks so a very expensive mistake.
Another update..so I was putting th two halves of th oil cooler back together and found this in one of them. Guess I get to redo th swivel after all. No other place a piece of blue seal wud hav come from is ther?