I have a E120B Serial# 7NF5078 it has now close to 8'500 hours on the clock. Recently the travel speed got really slow; the fast speed is as slow as the slow one normally and it also lacks power to travel uphill etc. The other operations seems to be ok, I didn't notice any lack of power for digging etc. My suspicion is the rotary joint might be leaking. I found also an older thread here with similar issues HeavyEquipmentForums I have the service manual and started looking into it; now as the machine is quiet old and I have the impression the engine doesn't rev as high up like when we got the machine first, I wanted to do a more thorough system check; like checking all the hydraulic relive valve pressures and adjusting if out of spec. The problem is that this machine has so many hydraulic circuits and components (and hydraulics is not my strong side ) it's pretty complicated. Does it make sense to go through this and check my systems? If I understand right, I basically need some pressure gauges and connect them to the taps on the pumps and pilot pump: I found this set on Amazon: https://www.amazon.com/gp/product/B0CWRT6RKY/ref=ox_sc_act_title_1?smid=ATVPDKIKX0DER&th=1 Would this work for this taps? I hope somebody has some more experience with the hydraulics on this machine and has some time to advice me. Thanks Fellows. Pat
It may do, it may not. Hard to tell from the photos. What you need to connect to those 6V-3965 test points on your machine is a 6V-4143 coupler, like this one.... New OEM CATERPILLAR 6V4143 COUPLER ASSEMBLY CAT (G1AB) | eBay It may have shelf wear or tears. The item it's self will be new, never installed or used. www.ebay.com TBH if you are experiencing mostly travel speed issues but other functions seem reasonably up to speed I would suggest that you re-seal the swivel as a first step then move on to testing from there. Do you have a Parts Manual.? If you already have the service manual and are planning on testing the hydraulic system don't forget to test the electronic side of the hydraulic controls as well. It will be in your Service Manual as SENR4804 - "Electronic System Testing & Adjusting". The first step in it, believe it or not, is the setting of the engine speed controller.
I have a parts book. I will do that and order the swivel seals; this at least is pretty easy to do. I will look at the electronic side and start with the engine speed control. Most important is the travel speed, that's what really is impairing the operation. Thank you Nige
Sooo...I finally found the time to work on this. Pulled out the swivel, which was harder than I thought it would be. But it looks like somebody sometime in the past replaced that swivel with an aftermarket. When I pulled it apart, it only had three instead of six seals inside (even though it has slots for six or even seven seals) and those seals are bigger than the ones I ordered in the replacement kit. Also on the bottom of that swivel is like a small manifold attached (which does not show at all in my parts book), which I believe goes to the the travel brakes, only those hydraulic lines are attached to it. I called the cat dealer and he also said he thinks it’s an aftermarket unit. So I googled the part numbers which are stamped into that swivel but nothing showed up. (DOX31 and D358-01400) Does anybody know what brand that is? The other problem I have is the grease in my rotary ring gear is completely liquefied. I thought that maybe the rotary joint leaked the oil inside but it’s so much that I am not sure anymore. I am concerned that maybe my swing motor leaked, but I never had any issues with the swing drive, it was always working fine. How do I get this mess out of that ring gear case so I can pack it with new grease? I thought that there will be a little drain plug on the underneath, but I did not see any. Any ideas on this? Thanks fellows.
I'll start with your last question. The grease may be simply contaminated with water that has leaked down around the swivel from above. Did you find a rubber "boot" sealing the upper part of the swivel to the revolving frame.? That boot is designed to stop water getting down below. There ought to be a drain plug or cover plate somewhere but the other alternative is to use a "suck bucket" and suck all the grease out. See this LINK for a procedure posted by @willie59 on how to make one.
First up, what is the Cat Publication reference of the Parts Manual that you are using.? I show XEBP9919. Second. were there any traces at all of o-rings inside the other 3 grooves apart from the three where you actually found rings.? Even black traces of "rubber" in the bottom of the grooves.? Your photos are not clear. Is there any sign of modifications to either the upper or lower mounting of the swivel (welded/modified brackets, extra drilled holes, etc) that may indicate the swivel currently installed is non-standard.?
Yes there is a boot. I tried to take it off from the swivel housing but somehow it is permanently fixed where the bolts mount. My liquefied grease smells from Hydraulic oil, so I don't think water got to it. I looked again, there is no drain plug; I saw a YT video of a guy with a 320D FM, he had the same problem: leaking swivel and liquefied grease bath. Just he has a drain plug. So I was thinking to drill a hole and make my own drain. Or I will follow your "suck bucket"
Yep, XEBP9919 that's the one I have. The only traces I found are these small little "balls" I found in there: they are kind of hard, so it could be rubber. But then How could 3 big o-rings disappear completely and 3 not at all??? Further, the 3 o-rings in there do not fit in the other grooves, they are to big. There is no sign of modification on the frame, everything looks standard there. The largest indicator for an aftermarket swivel is the "manifold" attached to the bottom of it, like you can see in the earlier pictures; there is nothing in the parts book about this. And the part # on the swivel appears not to be from Caterpillar. And the replacement seal kit I ordered does not fit in the swivel I have. For now I went to our local machine shop; they don't carry metric o-rings (who knows why) so they ordered them for me. I just hope the rings I get from them really fix that swivel, not that I put it back together and it still leaks. That's why I would have rather ordered an original kit from the manufacturer. Anyway, what ever gets it going again. Thank you Nige.
I got some replacement o-rings from a local supplier but they don't look right to me, they are to small. So I will have to try with another shop. Does anybody have an idea how I could find out the manufacturer of this rotary gear??? Thanks
Sorry no idea, unless you want to go trawling through images of "excavator swivel assembly" resulting from a Google search.
Oh boy If I do find some replacement o-rings, is there I way I could leak test the assembly before I put it back into the machine? I just don't want to do all this work and then it is still leaking.
Plug all the ports except one, pump it up to whatever is maximum system pressure with a portapower hand pump, and see if it leaks.?
What is the part number of the seal kit you got? I'm guessing it's 0997166 to fit a 0990476 swivel? That IS the correct number for your machine. However. There are two other serial number options for E120B. 6JF and 4XK. Of these, 6JF seems to be the most common. For a 6JF swivel, there is a serial number break at 6JF481. The early machines have the 0990476 swivel and the later machines have a 1R7905 swivel which uses a 1R7903 seal kit. I can't find any dimensions on the seals used in the 1R7905, but the 1R7903 seal kit is still available from Cat. There's no guarantee, but I'm willing to bet that this is the kit you need. I find it VERY unlikely that someone went to the trouble of installing a non-OEM swivel. Now on to your mystery manifold. This also is part of a 6JF machine. With these early MHI built machines, mistakes in the parts records were not uncommon.
Thanks Cmark. You just nailed it Yes I have the 0997166 seal kit and it is the wrong one. After Niges respond today I was looking again in my service book and saw that there are in fact the 2 different swivels illustrated. But in my parts book only one of them is broken down and has a number for the seal kit. I was going to visit our Cat dealer next week with my books on hand and show them them problem. That is an error on their side not to have both in the book. Anyway, I am glad you guys could help solve this mystery, now I know what to order. What astonishes me still, is that 5 seals dissolved without traces, and the machine kept on moving like that. Thanks again. Cheers Pat
Don't get too cranky with your dealer. According to the information they have, you were sold the correct seal kit. The problem occurred about 35 years ago when MHI put the documentation together. Probably best to count your blessings that the machine is wearing a Cat badge and you can still get parts for it off the shelf.
No no, I wasn't going to scold them, just wanted to show them were the error lies. I do appreciate being able to get parts. I know this machine was built in Japan but I was not aware that Cat outsourced it to another company and had it built to their standards and just slapped their sticker on it. I always though Caterpillar built this in Japan. A good friend once told me, the good part with Caterpillar you will always be able to get parts, no matter how old the machine. But just recently with this particular excavator I had to make the experience that a simple part like a small hydraulic t-joint is being called obsolete. Bummer I had to call him wrong on that.
Yes.....and no. To call it badge-engineering is oversimplifying it a little. Cat and Mitsubishi had been collaborating since the early 1960s. In the late 1980s, Mitsubishi's excavator line was transferred to the joint venture to replace the Cat 200 series, becoming the E series.