Excavator tracks weak turning

[diggerjoe]

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.

 

[BluewaterLa]

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

 

[diggerjoe]

Not what I wanted to hear but ur probably right

 

[IceHole]

Check at least the pressure and ideally flow at the track motors before tearing random stuff apart.

 

[funwithfuel]

Maybe check the return filter for obvious bits of o-rings.

 

[diggerjoe]

Maybe check the return filter for obvious bits of o-rings.

That wud be th filter in th tank?

 

[funwithfuel]

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.

 

[diggerjoe]

Ok will do that..thanks alot

 

[diggerjoe]

Check at least the pressure and ideally flow at the track motors before tearing random stuff apart.

Don't have any gauges..shud just buy some I guess

 

[92U 3406]

Gauges are a metric crap ton cheaper than the parts cannon.

 

[funwithfuel]

Don't have any gauges..shud just buy some I guess

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

 

[David_Johnson]

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.

 

[funwithfuel]

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.

 

[diggerjoe]

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.

 

[diggerjoe]

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?

 

[diggerjoe]

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.

Which relief valve was it?

 

[diggerjoe]

Gonna pull the filters tomorrow. Also ordered a set of gauges off Amazon

 

[Welder Dave]

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.

 

[Simon C]

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

 

[diggerjoe]

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