2006 CAT242B - Chain Case Leak Around Drive Motor

When we bought our 2006 CAT 242B skid steer (SN - BXM03117) 3 years ago, there was some catch up maintenance and repairs required that I have been addressing the past few years.

After repairing a pilot valve leak (detailed in another thread), we still had an oil leak that needed fixing. It turned out that the mounting bolts on the Left Hydraulic Drive Motor had loosened slightly, resulting in a leak of lub oil from the Left Drive Chain Case, past the sealant around the Left Hydraulic Drive Motor, into the belly pan and on to the floor under the 242B.

I was able to reduce the leak by tightening up the 10 Drive Motor mounting bolts, but over time, the lub oil leak has increased again, and more prescriptive repair measures are required. It is still just a nuisance leak with perhaps 1 to 2 tablespoons of lub oil ending up under the machine after each use, but I am getting tired of putting a drip pan under it … and even more tired of the leak when I forget to pull out the drip pan and run it over!

My plans include removing the Left Drive Motor, replace the Drive Motor mounting bolts (10 pieces), washers and lock nuts and then reinstall the Drive Motor with new flange sealant. That’s the Reader’s Digest version.

Does anyone have experience with pulling and reinstalling a drive motor on this type of skid steer?

Are there any suggestions, do’s or don’ts that I should be aware of?

Can anyone provide a repair procedure that I can review before proceeding?

Thank you and Regards, 3CW

Pretty straightforward. You'll need to jack up the machine and support it safely. Then loosen off the 8 nuts on both the axle stubs on the side you're working on in order to de-tension the drive chains (slotted holes, front/rear axle stubs will slide towards each other). Drain the oil out of the chain case, then pull the access cover on the chain case between the wheels and then remove the bolt(s) holding the sprocket to the motor shaft (wear heavy gloves, chains can get very sharp). Then its just a matter of removing the motor. Good opportunity to give the bottom of the case a good cleaning too as just changing the oil seems to leave a fair amount of wear debris behind.

Tensioning the chains is a bit of a pain without the tool but I've been able to do it with a large prybar and a 2nd set of hands to tighten the axle nuts. There is a spec for chain tension, its a measurement of free rotation of the tire.

Sorry but I cannot provide anything in the way of torque specs or chain tension specs as I don't have SIS access.

Thanks for the feedback 92U 3406 ... those are some good tips.

The Drive Chains Tension specs are in my Operation and Maintenance Manual ... total chain free play should not exceed 15 mm (7.5 mm up and down) or 15 mm movement measured at the outer tire diameter.

I haven't pulled a drive motor before, but was thinking that a steel bar across the loader arms might be a good way to lift the 100 lb motor ... or find another lifting point on the tilted cab.

I am also planning to replace any the Face Seal "O" Ring's that I open when I remove the motor. $2 "O" ring sound like cheap insurance compared to a future hydraulic leak. I have also ordered some more steel hydraulic service caps and plugs for the expected sizes of hydraulic fittings I might encounter (looks like 9/16, 11/16, 7/8 and 1-3/16" from the parts diagrams I reviewed).

I think most of those drive motors use a large o-ring to seal them to the case, not sealant.

Definitely plug the lines with steel plugs. The case drain will leak until the tank empties.

The parts diagram does not show an O Ring seal to the case. As per the photo that I attached of my Drive Motor, there is evidence of excess sealant squeezed between the motor and the case. So I'm pretty sure that sealant was used on this 242B.

I have reviewed the repair procedure for a 2008 Cat 236B2 where the recommended sealant is Loctite 5127 Flange Sealant, a Anaerobic Methacrylate Ester. I understand that Permatex also makes a similar anaerobic flange sealant.

Can anyone with access to SIS provide me with the Drive Motor removal and installation procedure for my 2006 CAT 242B skid steer (SN - BXM03117)? Thank you.

Here you go. Based on past experience I'm sure that you will post back with loads of photos for future reference.

Thank you kindly for the procedure Nige. I will certainly do my regular photo write up when I perform this repair. I'm thinking that is will be into the new year before I can begin this project but I am starting to gather parts and pieces for it. I'm thinking that I will want to pick a warm day for this project.

Interesting enough, the CAT removal procedure says to "remove the gear pump". I can only assume this "extra step?" might be required to make some additional room for getting the drive motor out. I won't know until I tip the cab and get a better look, but I'm think that the gear pump removal might become an "optional" step.

I'm wondering if an engine hoist / motor lift / floor crane might be a good tool to have around for this job? That motor weighs about 104 lbs and I am not as strong or nimble as I used to be.

Only issue I see would maybe be getting enough height since the rigid boom can only get so close to the motor. It's an issue I've had in the past. Still might give you enough to muscle it around easier.

ThreeCW said:

Interesting enough, the CAT removal procedure says to "remove the gear pump". I can only assume this "extra step?" might be required to make some additional room for getting the drive motor out. I won't know until I tip the cab and get a better look, but I'm think that the gear pump removal might become an "optional" step.

Click to expand...

I don't think the drive motors will go far enough inwards to clear the chaincase so you can lift them out without removing a pump or three. YMMV.

Those older units are a bit tighter in there than the C and D series.

Since you're just re-sealing it you might be able to get away with not actually having to remove the motor as long as you've got room to prep the surfaces and get new sealant on the flange.

As the Brits say, I will have to "suck it and see".

Just to clarify (and so I don't get censored here), it means "to try something to find out if it will be successful" ... at least according to the Cambridge Dictionary.
https://dictionary.cambridge.org/dictionary/english/suck-it-and-see

ThreeCW said:

As the Brits say, I will have to "suck it and see".

Click to expand...

I prefer "Let's sit down and see how we stand" myself......

My Brit lingo goes back about 20 years ... it was perhaps more politically correct then ... than now

92U 3406 said:

Those older units are a bit tighter in there than the C and D series.

Since you're just re-sealing it you might be able to get away with not actually having to remove the motor as long as you've got room to prep the surfaces and get new sealant on the flange.

Click to expand...

I will have to tip the cab to see how much working room there is, so I can plan on what replacement parts I might need if I have to remove the gear pump.

After looking at my parts diagrams, I'm thinking that the removal of the gear pump could be a bunch of work. The parts diagrams are not really clear on the hydraulic connections, so when I tip the cab I will have a better idea.

Yes ... hopefully I can clean up the drive motor in place and reseal it without pulling the drive motor all the way out. That would be a bonus if the stars align.

Nige - Is there a specific procedure for the Gear Pump removal and re-install? My gear pump is part number 236-5106. If I remove the Gear Pump, I'm thinking that I should also replace the large "O" Ring (3.987" ID x 0.103" x-section dia. - Ref. 4 in the diagram below) between the Piston Pump and the Gear Pump.

Here's the R&I. From a quick look there doesn't appear to be much to it other than the usual.

Thank you Nige for providing this R&I procedure.

Is this the kind of detail that I would get if I purchased the Service Manual for my 2006 242B (RENR4890)? Or does SIS provide a higher level of detail?

The Service Manual will have exactly the same level of detail as SIS. The only difference would be that if you buy a used paper version it will be "frozen in time" at the date it was originally printed and will not contain any updated information (that would automatically be uploaded to SIS) that may have come along since then.

https://www.ebay.com/itm/304352940855

Thanks Nige ... that explanation make sense.

We were able to get some warm weather in January (sunny and above freezing anyway) and I was able to get after fixing my “Chain Case Leak Around Drive Motor” … but it turns out that it was not that leaking at all.

I started out by checking my chain case oil levels and did not see any noticeable drop in the oil levels from when I changed the chain case oil 3 years / 150 hours ago. When I tipped the cab, I noticed there was a very small amount of oil leakage (seepage?) from the chain case around the bottom of the motor … but not enough to be leaving the oil spots that I was seeing recently.

I noted that the hydraulic oil level had dropped in the sight glass … yes, the sight glass that is hidden behind the loader arm and is not the slighted bit convenient to check without using your cell phone to take a picture of the level. Anyway, my level was down about an inch or so in the gauge.

I noticed some oil accumulation in the back half of the belly pan area where there was still lots of debris that I had not clean up from the original owner … I am going to have to quit blaming the darn original owner as I have owned this now for just over 3 years.

I spent the better part of a day cleaning up oil saturated dirt, grass and sticks from the belly pan … used a couple rolls of paper towels, dug up and sopped up about 5 gallons of crud before determining that the Hydraulic Oil Leak was coming from the area of the Hydraulic Return Manifold. Reaching back as far as I could, I cleaned the area of the hydraulic manifold and determined the leak was coming from a 2-inch (or so) clamped hose on the return manifold.

I was able to get a ratchet on the offending hose clamp and tightened it up and also snugged up a second hose clamped line. There certainly is not much room for working in this area and I am glad it was only a hose clamp to tighten and not one of the other hydraulic lines.

Lesson Learned: If you have an oil leak and you are not absolutely certain where it is coming from, clean up the entire work area (belly pan in my case) to identify where the leak is originating from.

Thank you to the HEF members who provided me support on troubleshooting this problem.