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2006 CAT 242B Pilot Valve Leak Repair

Discussion in 'Skid Steers' started by ThreeCW, Jan 6, 2020.

  1. ThreeCW

    ThreeCW Well-Known Member

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    We recently bought a 2006 CAT 242B skid steer (SN - BXM03117) with 1800 hrs. Although low in hours, there was some catch up maintenance and repairs required.

    I am currently in the process of repairing a minor (but messy) hydraulic oil leak in the Left Pilot Valve that controls direction and speed. I understand from a previous HEF thread (https://www.heavyequipmentforums.co...-246b-cat-any-advice.13186/page-2#post-168031) that CAT had issued a Product Support Program for a similar leak but that program expired on Dec. 31, 2008.

    I removed the pilot control from the skid steer and noted the leak occurring between the lower body (shuttle valve – Part Ref. 9 on diagram) and the main body of the pilot control. Upon disassembly, I noted that the 6 “O” rings (shown in Part Ref. 8) had hardened slightly, but no cracking was evident. I decided against fully disassembling the pilot valve after viewing an excellent HEF thread on the subject: https://www.heavyequipmentforums.com/threads/repairing-a-leaking-joystick-control-valve.21529/, as I “believed that the leak was likely as a result of the hardened “O” rings.

    With Cat Seal Kit 151-4965 (C$95 / US$73), I replaced the “O” rings and also replaced the 6 “O” rings on the hydraulic connectors (straight adapters) on the base of the pilot valve. I torqued the shuttle valve retaining screw to 13 ft-lbs as per HEF thread: https://www.heavyequipmentforums.com/threads/cat-delayed-steering-response.21590/#post-272356

    I looked at the skid steer this morning and noted that over night, some hydraulic oil had leaked again from the same place between the lower and main body of the pilot control. It appears that the 6 “O” rings were not the problem. Note that this leak is occurring with no pressure on the system … only the hydro-static pressure from the hydraulic oil tank return line is acting on the pilot valve at this time (the skid steer was not started after the repair).

    The only other place that I can determine where it “may” be leaking from is the assembly bolt (with “O” ring) that is shown in Part Ref. 7 on the diagram. If I can, I would like to only replace the small “O” ring on this assembly bolt … but may have to purchase Seal Kit 289-9560 (C$275 / US$212) ... again Part Ref. 7 on the diagram.

    Does anyone have any experience with this repair or ideas on other possible leak paths?

    Can anyone suggest another source of compatible “O” rings other than buying the seal kit from CAT? I like the idea of a $2 “O” ring rather than a $212 seal kit.

    Regards, 3CW

    Left Pilot Valve Breakdown 218-6119.JPG Left Pilot Valve Breakdown 218-6119.JPG

    Left Pilot Control Breakdown Parts 218-6119.JPG
     
  2. ThreeCW

    ThreeCW Well-Known Member

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    A few photos from my disassembly and attempted repair:

    IMG_1353 - B.jpg IMG_1376 - B.jpg IMG_1506 - B.jpg IMG_1522 - B.jpg
     
  3. ThreeCW

    ThreeCW Well-Known Member

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    The weather is turning cold this week, so I drove the 242B up to the house and into the heated garage in case I have to work on the skid steer later this week.
    After warming it up, I put all the hydraulics through their paces on both pilot controls and then parked it in the heated garage. There was no noticeable leak in the repaired pilot valve after running it for 10 minutes. I have a drip tray under it and will see how much (if any) drips out overnight.
    At a minimum, there is no apparent increase in the leak after the hydraulic system was pressurized. Hopefully this is a good sign or can at least aid in the troubleshooting.
     
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  4. ThreeCW

    ThreeCW Well-Known Member

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    Just an update for anyone who is repairing a similar pilot valve leak. Since bringing our skid steer up to the heated garage some 10 days ago, I have not had any more leaking from the pilot valve assembly … perhaps it was not actually a leak … it may have been hydraulic oil accumulated from when I was assembling the hydraulic lines (some were spilling oil during assembly). We have had a week of cold weather … down to -34 C (-29 F) but it is supposed to warm up tomorrow to about 0 C (32 F) … looking forward to the heat wave.

    We don’t usually get much, if any, snow when it gets that cold, so I did not have to do any plowing since I did the “O” Ring replacement on the pilot valve. I hope to do some plowing in the pasture tomorrow to clean up some feeding lanes for the horses … so will check again if there is any leakage on the repaired pilot valve after putting a few hours on the skid steer.

    I was thinking that CAT may have updated the original “O” Rings for this pilot valve (218-6119-02) given the Product Support Program that expired at the end of 2008, but the repair kit “O” Rings appear to be pretty much the same as what I pulled out. There were no visible cracks in the “O” Rings that I replaced … perhaps a bit of hardening, but that is not surprising after 14 years (assuming they were original equipment).

    For reference, the measurements on the “O” Rings were as follows:
    Original “O” Rings = 0.800” OD x 0.055” CS (cross section)
    “O” Ring recess in lower part of shuttle = 0.800” ID
    New “O” Rings = 0.800” OD x 0.057” CS
    The larger cross section of the new “O” Rings (+0.002”) may be due to flattening of the original rings.

    If I had to do it again, I would see if I could locate some quality “O” Rings in the above size rather than spending C$95 / US$73 for 6 “O” Rings, a retaining screw and a spacer pin.

    P.S. - I was kind of surprised that the original Pilot Valve (from 2006) and the new "O" Ring kit were both manufactured in France. I would have thought those would have been made in the USA.

    IMG_1502.JPG
     
    Last edited: Jan 19, 2020
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  5. 92U 3406

    92U 3406 Senior Member

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    Spend enough time looking at Cat parts you'll see they're made everywhere around the globe.
     
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  6. Nige

    Nige Senior Member

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    To echo the comments above. Cat are a global company. They manufacture everywhere.

    The Seal Kit only came into use when the SSL Pilot Valves were updated to the 343-xxxx numbers in 2009.
    For the former Pilot Valve Part Numbers 299-9xxx the Seal Kit was not listed as a serviceable part.
    The below from a May 2009 Service Magazine.
    The 151-4965 Seal Kit existed long before 2009 though. It was used as a seal kit for pilot control valves on track-type tractors and track-type loaders before it started to be used on SSL machines when the Pilot Valves were updated.
    upload_2020-1-19_6-48-21.png
     
  7. Nige

    Nige Senior Member

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    A couple of other random thoughts.
    1. Agree that the difference in thickness between old and new parts is probably due to age and the effects of temperature.
    2. They are most likely to be metric sizes.
    3. if you do investigate other sources of supply be aware that the usual way of specifying the diameter of an O-Ring is the I/D as opposed to the O/D that you measured.
     
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  8. ThreeCW

    ThreeCW Well-Known Member

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    Thanks for your comments on the parts supply … little did I know that CAT’s were assembled with parts from around the world.

    Nige – thanks too for your tips on the “O” Rings … I will keep that in mind if I decide to look at alternate parts sources.

    I spend some time today with a scraper and screwdriver cleaning out oil saturated dirt after removing the belly pan access plate. I think that I mentioned previously that this new to me 2006 242B needed some catch-up maintenance … and I was catching up today. I pulled about 5 gallons of oil saturated dirt from the belly pan and will have to get the rest that I can’t reach in the spring with a hose or perhaps idling a pressure washer.

    When I changed oil on the drive chain cases a few weeks ago, I noticed that left chain case had a reduced oil level while the right chain case was full to the filler plug … I believe that today I found where this oil was leaking to. When poking around to remove 1 to 2 inches of oil saturated dirt from the belly, I poked at the lower bolts securing the drive motors (PN 220-8152) and found that all 5 of the lower bolts on the left side drive motor were loose and 1 of 5 lower bolts on the right side drive motor was loose.

    I originally thought that the oil saturated dirt in the belly pan was only from the leaking left pilot control valve but it now appears that it was likely a combination of oil from the left pilot valve and the left chain case via a drive motor mounting leak.

    The bolts securing the drive motors are M12 x 1.75 according to my parts CD with a grade stamp of 10 on the nuts (10.9 MPa). I did not have the CAT torque specs available, so looked up generic torques online and torqued up all the lower nuts in stages to 90 ft-lbs. Each loose nut took from ½ to a full turn to tighten / torque up.

    My concern now is if the existing black silicone gasket maker material remaining on the drive motor and body will make an effective seal. The oil level in the chain cases is at about 2” above the base of the chain case (i.e. filler plug elevation) and the drive motor bolt holes are about 3” above the base of the chain case. Under normal operation, the drive motor bolt holes would not be submerged in oil … only subject to oil splashing … or so it seems to me.

    Tomorrow, I need to move the skid steer to my shop (which is unheated ... but it is supposed to be above freezing tomorrow) where I can tip the cab to access and torque up (if required) the 5 upper nuts of each drive motor.

    I am not sure how significant a loose drive motor is in the scheme of things, but I hope my repair plan make sense.

    I also had to make some repairs to the removable belly pan. Before and after photos are attached. This should go a long way to prevent dirt from getting in!

    IMG_1610.JPG IMG_1619.JPG IMG_1623.JPG IMG_1625.JPG
     
  9. Nige

    Nige Senior Member

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    It certainly looks like it would benefit from a good dose of the pressure washer in there. Just be careful not to spray it directly on any electrical/electronic parts.

    Keeping dirt out of the belly pan will be a never-ending battle, despite you straightening the access panel. If you find a reliable way to do it I suggest that you patent it PDQ.... You'll probably never have to work a day in your life ever again and instead be able to live on the income from the patent rights.
     
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  10. Nige

    Nige Senior Member

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  11. ThreeCW

    ThreeCW Well-Known Member

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    I used to pull the belly pan on every oil change on our New Holland LS160 and clean it out. It made accessing the oil pan easier than just removing the cover plate. Even in that small machine, the plate was pretty heavy.

    I look forward to flushing out our CAT 242B in the spring. I have pulled out / shop vacuumed out about 15 gallons of dirt and crud so far ... another 5 gallons to go and she should be clean. It is a "she" isn't it?

    I lifted the cab and torqued up the top nuts securing the drive motors. On the right side, the nuts were pretty tight but still snugged up a bit when torquing to 90 ft-lbs. On the left drive motor, all top nuts were also loose ... which was not a surprise give that all bottom nuts were also loose on that motor. I torqued them up (about a full turn per nut) and then plowed snow for about an hour. I will monitor for oil leakage from the left chain case ... hopefully torquing the nuts on the left motor sealed up the leak from the chain case o_O

    So far there is no further leakage from the pilot control, so it looks like the "O" Ring replacement fixed the pilot valve leak. :)
     
  12. ThreeCW

    ThreeCW Well-Known Member

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    An update on my previous "attempted" repair of my drive side (left) pilot valve on my 2006 Cat B242B ... after replacing the six O-rings with seal kit #151-4965, the leak came back from between the lower body and middle body of the pilot control. It is more of a nuisance leak that did not get worse under pressure. Even when the skid steer is parked, there is a slight leak that drips into a catch pan I placed under the pilot control ... perhaps only 50 ml/month (2 oz per month) ... but enough to make a mess over time.

    As I stated in my first post of this thread, I understood from a previous HEF thread (https://www.heavyequipmentforums.co...-246b-cat-any-advice.13186/page-2#post-168031) that CAT had issued a Service Letter (Product Support Program) for a similar leak but that program expired on Dec. 31, 2008. I discussed this today with a CAT Parts Person who was kind enough to send me a copy of the expired Service Letter # REBE1552-01. In it, the problem is defined as follows: Some drive side pilot valves were assembled with the incorrect O-ring on the valve stem bolt. The O-ring is undersize and cause leakage on certain valves.

    Eureka! This explains why my previous repair did not succeed. I ordered two O-rings (8T-0117) from CAT at $2 each (1 is a spare), a jug of CAT Hydro Advanced 10 and a Face Seal O-Ring plug (PN 6V-9509) for the 13/16" x 16 TPI female connection on the one live hydraulic line that leaked oil during my last repair (which I previously plugged with a wooden golf tee and some electrical tape ... which was a messy process). I believe that this line gravity feeds from the hydraulic oil reservoir.

    Find attached a copy of the Service Letter for this problem which I hope is helpful to others who may be experiencing this problem. The $2 CAT O-ring will take the place of a $284 (CAN$) seal kit that I would have had to buy to address this problem. There were no O-rings in Canada, so I will hopefully get them next week with parts shipped from the US. I will update this thread again once I have hopefully resolved this problem.
     

    Attached Files:

    Last edited: Dec 17, 2020
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  13. ThreeCW

    ThreeCW Well-Known Member

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    Updated Post:

    I replaced the O-ring on the valve stem bolt of the drive side (left) pilot valve on my 2006 Cat 242B by loosely following the procedure outlined in Service Letter # REBE1552-01 (attached to my previous post). I have used the skid steer for plowing snow for about 10 hrs over 3 days since the repair and am very happy to report that I have NOT had any hydraulic oil leaking from the pilot valve … this repair has been successful!

    That is the Reader’s Digest version. In case you are experiencing a similar problem, I will also detail my repair with some recommendations as follows:

    I said that I “loosely” followed the procedure in the Service Letter. There were some steps that I added and others that I neglected to follow. I will attach a copy of my modifications to the Service Letter procedure.

    Worth noting again prior to removing the hydraulic lines from the left pilot valve, (1 larger hydraulic line with an 11/16” fitting and 5 smaller hydraulic lines with 9/16” fittings) the first thing that you want to do is to mark the lines. In my previous attempted repair, I had marked the lines with dots using paint stick markers. Before disassembling this time, I also marked them with color coded zip ties as suggest by another HEF member in another thread. It is important to make sure that the lines do not get mixed up and they are reinstalled correctly to ensure your pilot valve functions properly. Another tip is to keep track of the order that you removed each line … as there is limited wrenching room available, it is important to reinstall the lines in the reverse order of removal. In my first attempted repair, I did not keep track of the removal order and had to take some lines off again to be able to tighten some of the inner lines.

    The Service Letter recommends in Step 3 to “Pull a vacuum on the hydraulic tank to minimize loss of oil”. I did not do this in my first attempted repair as I did not have a copy of the Service Letter at that time and it resulted in a considerable mess with leaked hydraulic fluid … as you know, a little oil spill goes a long way. During the current repair, I used my shop vacuum with a pointed hose nozzle inserted into the hydraulic tank opening to pull a vacuum on the hydraulic oil tank. From my previous experience, I knew that only the larger 11/16” fitting hydraulic hose would gravity feed hydraulic oil from the tank. With the vacuum on and the 11/16” hose removed; I did not lose a drop of hydraulic oil. During my first attempted repair, I plugged this line with a golf tee and electrical tape … which was a messy process with the line leaking oil. I was more prepared on the second repair attempt as I had bought an 11/16” Face Seal O-Ring (FSOR) plug from CAT (CDN$15). The FSOR plug was well worth the investment as I was able to plug the line and so I could shut off the vacuum. Note that the plug did NOT come with an O-ring but I anticipated that and had also purchased the O-ring for it. I removed the other 5 hydraulic lines that I believe are 9/16” fittings with no vacuum on the tank … keep in mind you can only keep your shop vacuum sucking a vacuum on the hydraulic tank for so long before burning out the motor as there is no air going through it. I did not want to buy another 5 pieces of 9/16” FSOR plugs at CAT prices … but I did orders some from a local hydraulic hose supplier for about $1 each … but did not have them in time for this repair. I attach a photo of the 11/16” FSOR Plug for your reference (in my next post) … this is highly recommended. And if I had to do it again, 5 pieces of the 9/16” FSOR plugs are also recommended to keep everything clean.

    More in next post

    IMG_3838.JPG IMG_3840.JPG IMG_3841.JPG
     

    Attached Files:

    Last edited: Dec 27, 2020
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  14. ThreeCW

    ThreeCW Well-Known Member

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    I followed the clamping procedure in the Service Letter to remove the Valve Stem Bolt … I am glad that I had the Service Letter as I would not have thought about using a clamp. A photo of this is attached.

    The O-ring on the Valve Stem Bolt was a little damaged which explains why I had the hydraulic oil leak. Since this O-ring was supposedly undersized, I also measure it compared to the replacement O-ring as follows:
    Old O-ring = 0.750” OD x 0.094” thick
    New O-ring = 0.745” OD x 0.100” thick
    Not much of a difference … but enough to keep the oil from leaking.

    I also attach a photo of the Valve Stem Bolt and O-ring for your reference. Note that the O-ring on my Valve Stem Bolt was seated in the O-ring groove of the bolt … and this is how I reinstalled it with the new O-ring. The Service Letter photo of the Valve Stem Bolt shows the O-ring above the O-ring groove … which can be a little deceiving … what they are actually showing is the O-ring being installed and is NOT the final correct O-ring position.

    I reassembled the pilot valve using the torque values identified in the Service Letter, reinstalled the 6 hydraulic lines in the reverse order they were disassembled … using my shop vacuum again to pull a vacuum on the hydraulic oil tank for the 11/16” line which gravity feeds from the tank … again with no oil lost.

    The repair was successful … like I said earlier in this thread, this was catch up maintenance (and repairs) for a “new” to me Cat 242B … not too sure how long this had been leaking but I suspect a long time. As it turns out, with the right information and tools, this is a fairly easy repair.

    IMG_3877.JPG IMG_3855.JPG IMG_3862.JPG IMG_3866.JPG
     
    Last edited: Dec 27, 2020
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  15. ThreeCW

    ThreeCW Well-Known Member

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    And one last photo of the installed pilot valve with no leaks after 10 operating hours.

    IMG_3879.JPG
     
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  16. FlatTire

    FlatTire Member

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    I just did a control valve seal job on my Bobcat, and cleaning the belly out was half the battle. Tried bending metal into different shapes to scrape all the various nooks and crannies, and eventually realized that a pressure washer was the only practical way to get it done. Was careful with electronics, and it took an eternity to break apart the concrete like dirt chunks. Hope your project worked out! Anyone that reads this, just break out the pressure washer for previously neglected belly pans.....
     
  17. ThreeCW

    ThreeCW Well-Known Member

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    A correction to my earlier posts ... the O-Ring Face Seal (ORFS) plug that I used for the one larger hydraulic line was a 13/16" x 16 threads per inch (TPI) ... CAT part number 6V-9509 and NOT the 11/16" size that I reported earlier.

    According to the CAT parts person I spoke to, the other 5 smaller hydraulic lines are 9/16" ORFS x 18 TPI - CAT part number 6V-9507. I did not use plugs on those 5 smaller lines (they did not gravity feed from the hydraulic tank but still seeped a bit) ... and I completed my repair before my aftermarket ORFS plugs arrived.
     

    Attached Files:

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  18. Nige

    Nige Senior Member

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    Nothing like using the correct plugs/caps to seal off lines when doing hydraulic repairs. Kudos.
     
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  19. ThreeCW

    ThreeCW Well-Known Member

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    I picked up the aftermarket plugs I ordered from a local hose and fitting supplier. They were very economical ... I purchased an assortment of ORFS plugs and plastic caps that will come in handy for future repairs.

    The cost of all the plugs and caps in the photos (CAN$17) was about the same price one CAT plug and O ring.

    IMG_4012.JPG IMG_4013.JPG
     
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