Hello. SN# RLL06130. Hydraulic fluid puking out Starter as well as inspection hole in flywheel housing. The leak drained the entire hydraulic tank....what a mess. Im assuming its the seal in the hydrostatic drive pump? Any other ideas of what it could be. I just pushed it into my shop and Im preparing to dive into this. Just thought I'd post to see if someone could start steering me in the right direction of what this could be?? Thanks!
If it has actually failed the shaft seal on the pump the $64k question is why.? Usually a seal failure is indicative of bigger problems somewhere else that resulted in the seal failing. How about the bearing #24 right next to the seal.?
Thanks for the diagram. If its not the shaft seal I'm not sure what else it could be? It seems the easiest way to get at this is from the back by removing the engine. Im certainly interested/hoping for any tips from the group on the best way to approach this??
Just as a follow up the machine has less then 450 hours on it of light use.
I kinda figure "complete hydraulic failure" being brass plugged filters, not a leak, albeit a sizeable one. And, seal leak on a 16.5 year old machine.
I took it to mean that the hydraulic system failed to work because all the oil ran out of the tank through the leaking pump shaft seal. It is quite likely to be the shaft seal leaking but the question is did something else cause the seal to leak, especially a massive leak like the one that you are describing.? Usually there is something else involved but only disassembly will reveal the cause. I would agree. Engine & pump out together, split the pump off the engine then disassemble it. If you have never been into anything like that pump before you really need hands-on help from someone who has in my opinion. That’s something like a $10k pump you’re looking at there.
Thanks Nige. Yes I have never been into anything like the pump before and Im certainly a little leary about digging into it. Would it be possible to replace the pump seal if I just left the pump in the machine and just pulled the motor?
If you are going to inspect the pump when you do this I would suggest just lifting the cab, drain and removed hyd tank , remove lines and pump mounting flange bolts and remove just the pump. Leave the engine in. Prepare to replace the nylon coupling also. If it blew the shaft seal out there is a good chance the pump has high case drain pressure. Remove the hydraulic filter and inspect it first.
Don't know TBH. Never done one. As I have said above the root cause of the problem may NOT be the seal. It may only be a symptom of a much more expensive problem elsewhere in the pump. Before you go anywhere, as a minimum have you removed the hydraulic oil filter, cut it open and inspected for the presence of "sparklies".? See this VIDEO , I know it's an engine oil filter but you'll get the idea. Post photos of what you find.
Ok thanks for the video. I have not inspected the hydraulic filter yet. I will get at that tonight and see what I find. Mobiltech, sorry for my lack of knowledge but could you or someone else summarize what high case drain pressure is? I really appreciate all your help!
"Case drain" Hydrostatic pumps and motors bypass a small amount of oil from the pressurized components to flood bearings and such in fresh oil. These flooded areas, the "case", need lubrication and, as such, need to "drain" the flooded oil, without restriction, back to the hydraulic tank. A "drain" restriction will pressurize components not designed for pressure, such as shaft seals.
The volume of case drain will also indicate if the pump is failing. Case drain should be a trickle of oil . If the oil is gushing from the case drain line you likely have a port plate or piston slipper problem. In your case you can’t really test it if it’s puking oil out the front seal so looking at the filter will be your best bet.
Is your engine and maybe pumps sitting on dirt rather than the mounts?
I inspected the hydraulic filter. There are some small silver specks stuck in the paper filter but nothing that looks like it would be a problem. I assume there would be some small specks from normal wear? There was no real indicators within the filter that pointed to any concerns, it looked clean. I took Mobiltech's advise and pulled out the hydraulic tank and I'm preparing to remove lines and pump mounting flange bolts and just remove the pump. My kid has a hockey tournament this weekend so I will have to put this hold for a couple days.
How about posting some photos of the filter media.? Don't try to remove the particles from the paper, just post them "as-is".
OK, I will try to upload some pics tonight.
Here are some pics of the filter.
If that's all there is I wouldn't get too bent out of shape over it.
Yeah it seemed quite clean, so that's a good thing. I'm really hoping its just the shaft seal that has failed. Once I get some time to pull the pump out Im hoping it will be obvious, fingers crossed...and I'm hoping I can replace the seal without getting too involved into that pump.
Here's the complete parts listing. Unfortunately there is no disassembly & assembly procedure that I can see, a sure sign that the factory don't want "the wrong people" going too deep inside the pump. The upside is that what you have is an "improved" Part Number of pump that was fitted as standard to machines of S/N RLL04482-Up, which includes yours.
Allegedly this is NOT for your specific pump, but at least it will give you an idea.
Thanks Nige. I really appreciate your help and diagrams. Unfortunately it doesn't look like its an "easy" shaft seal replacement. It's starting to like this is a bit over my skill level. I'm kind of leaning more towards just remove the pump and take it in to CAT for servicing, if they will even do that for me?
Take some Vaseline with you........ Remember their labour will be north of $150/hr and unless you agree to let them install the "repaired" pump then there would very probably be no warranty on the repair IMO. They might try to talk you into purchasing a Remanufactured (Reman) pump assembly. FYI the 289-6340 Pump Gp is now updated (through a couple of iterations) to 398-7470. The Reman for that P/N is 20R-7877 but I don't know whether or not any Part Number earlier than that would be an acceptable Core Return for a Reman pump. If it is not then you end up buying a new pump - $$$$$$$$. Aftermarket pumps seem to be available. Reman 20R7877 around $4000, new 289-6340 about $4500.
Good grief... Well, I guess I will take that pump out and see what I can figure out. Once I have it out and on the bench I may be able to convince a roaming HD mechanic to assess the situation and see if I can pay him to dig into.
You think that's expensive. Drive motors for the newer tracked machines are today getting up in price somewhere close to $10k a pop.......!!
Hello. I'm back and have pulled the pump out of the skidsteer and its now sitting on my bench. I have included a few pictures to help describe the situation. It appears that the shaft seal has failed, as there is a noticeable gap, more so on one side then the other, but nonetheless it doesn't look like its a "good seal". The bell housing is full of hydraulic fluid but the nylon ring looks to be in good shape. My question is where do I go from here? Im really hopefull if I just replace the seal all will be good. But if I have a situation of "high case drain pressure" as was suggested, how does one diagnose that without putting everything back together and starting it up to see if it blows the seal again? As always, any help would br greatly appreciated!
How did it get rusty like that.? Chain case full of water.?
Not sure, good question. I assumed that rust was normal?
Each chain case supposedly has around 1.6 gallons of oil in it. Did you drain about that much from it before you removed the drive motor.? Have you inspected the condition of the chaincase breathers.?
Nige, you're in the right church, wrong pew. That housing and input shaft are the engine bellhousing and pump input shaft.
Ah yes, I was confused on what you were saying Nige. The pics feature the engine bellhousing and pump input shaft.
How many hours on this contraption? Was the hydraulic filter changed at normal intervals? Restricted filter can cause that. What grade hydraulic oil is in there? Too heavy grade of oil can cause that in colder weather? Could the drain hose be compromised (crushed)?
Good point. I had the drive motor in my mind somehow.
Although its a 2006 skidsteer it only has 439hrs on it of light use around the acreage. I inspected the filter and it didn't seem bad. Hydraulic oil was typical SAE10W hydraulic oil. I never examined the drain hose thoroughly. I will certainly give that a look.
That seal has definitely seen high back pressure to roll it out like that. I would check the case drain line for obstructions and if that all looks good I would certainly inspect the inside of the pump. Maybe try to find a hydraulic shop that specializes in pump repair because the chances of them knowing what they are doing is better than some random cat dealer mechanic. That is if the dealer doesn’t have a hydraulic rebuild specialist.
I would also take the mounting flange off the flywheel housing to let the oil out.
Where is the metal gear that slides on the pump shaft? Is it laying in The bottom of the flywheel housing?
No, I took that off to get a good picture of the seal for you guys. I did ensure to measure and record the distance form the toothed hub to the pump cover before removing it.
As I don't know where the "case drain line" is on this machine, I was hoping you guys could point me in the right direction to purchase a shop manual for my unit. I can find several places selling them on-line but I want to be sure Im getting one that's worth its salt.
The port in the first picture is where the case drain hose connects to the pumps.. Unfortunately, the ports in the second image can only be tested while operating. 2nd pic
Thanks for the diagrams Heymccall. That at least gives me something to check and a good source of information. You wouldn't happen to have a disassembly & assembly procedure for that specific pump would you?
That was covered earlier. There isn't a D&A procedure relating to your specific pump Part Number as far as I can see. The one I posted on Page 1 was of a very similar pump.
I appreciate that Nige and thank you for the procedure you sent, I was just double checking to see if Heymccall may happen to have access to something different.
Gotcha. All i can tell you is that there is nothing in the Cat system relating to the D&A of that pump.
Here’s what I found on disassembly instructions for your hystat pump, @Nige correct me if I’m wrong here.
Awesome. Thanks a lot ahart! That certainly looks like the correct pump.
That's it..! I'm baffled as to why I couldn't find it before because the same document popped up on the system for me just now using the OP's Serial Number.
That’s SIS for you. Temperamental
Looks like high pressure in the case drain system. Restriction maybe, or the high loop is leaking more than the case drain can handle. Did it operate good until the leak?
Fixed that for you........ The new system is a lot more temperamental than the former version.
Off topic but I like SIS2.0 way better than the old version. Probably a generational thing.
FWIW now that I've got used to it I like it better than the older version as well. There are still a few gripes for me though. For example: - 1. It doesn't accept Boolean search terms (e.g. "speed sensor") and find all the instances of where those two exact words pop up in that order. 2. If you search for a word such as "neutralizer" it will also throw up anywhere that "neutral" or "neutralize" show up. Why..? 3. I'd still like to be able search as it was on legacy SIS where you could specify a group of machines first - narrowing down the field if you will. That's still not possible on SIS2.0. Rant over.........
Yes some search features could be improved, though legacy sis you could literally search for something and yield 0 results but find the exact phrase you searched for by combing through. SIS has always been about knowing the phrasing and back alleys in order to navigate quickly. It helps to have a working knowledge of the machine you’re looking parts up for as well. I don’t know how some of the young parts counter guys ever catch on to it.
yes the skidsteer worked great until the leak. I was just warming up the unit (maybe 10 minutes) and then noticed the hydraulic fluid gushing out it.
I will take the older version of sis any day. I have tried 2.0 but it just feels foreign. It definitely helps to know the cat terminology. Like pump group fuel injection meaning unit injector.
Hello. Its been a while but i finally have the pump back in my skidsteer and ready for start up. I talked with a CAT service tech and he stated it was likely just the seal that failed based on the hours on the unit and the findings from the filter exam. He basically said try that and see what happens...As such, I replaced the seal and fingers crossed that will be the ticket... Couple questions for you before I test it out. 1. I have a good source of Rotella T6 Synthetic 5W40 Diesel Oil. It seems to meet all the specs in the manual for the Hydraulic Fluid requirements. Would it be Ok to refill and use this oil for my Hydraulics? 2. Since I had the pump out and all hydraulic lines off, is there any issue with air locks or methods for purging the lines I need to be aware of? As always, any help is appreciated. Thanks!
Hi MiJo. I "assume" that your location of FSJ means Fort Saint John, BC ... which means cold winter weather. If I am "assuming" correctly, you will want to match your hydraulic fluid selection with your ambient operating temperature, which for FSJ can be -40 C (-40 F) or colder. But I will back up a bit first and tell you about when I made a hydraulic repair to my 2006 242B and had to replace about 25 litres of hydraulic fluid. My Operation and Maintenance Manual states that the Hydraulic Tank Refill Capacity for the 216B and 242B is 35 L / 9.3 USG. I was not able to find any specification for the Total Hydraulic System in my manual but did stumble across the Hydraulic System Capacity of 55 L in a CAT 232B 242B brochure from 2004. The brochure also confirmed the Hydraulic Tank capacity of 35 L. My concern was that if I replaced 25 L of fluid in my Hydraulic Tank, there would still be 30 L of original fluid left in the system. I did investigate a total system flush option which was not easy or efficient to perform from my research here on HEF. Long story short, I also considered using Rotella T6 0W-40 or 5W-40 as a DEO (Diesel Engine Oil) option that was shown in the hydraulic system lubrication options of my manual, but I was concerned on fluid incompatibilities between the existing hydraulic fluid and diesel engine oil. I decided use CAT Hydro Advanced 10 instead which would be compatible with the original fill of CAT Hydro fluid. CAT Hydro Advanced 10 costs about C$8.40 per L compared to Rotella T6 Synthetic at C$7.50 to C$8 per L, so much the same cost wise without the concern on fluid incompatibility. Back to cold weather options, CAT Hydro Advanced is recommended down to -20 C (-4 F) and has a pour point of -39 C (-38 F) which I found was acceptable for our climate near Calgary. We rarely dip down to -40 C (-40 F), but I typically don’t use my 242B in those temperatures and will have it in a heated garage if low temperatures are expected. Other cold weather options that come to mind include: CAT Bio Hydro Advanced – rated to -30 C (-22 F) at C$23 per L CAT TDTO Cold Weather SAE 0W20 – rated to -40 C (-40F) at C$11.20 per L Find attached some CAT Technical Fluids information for your review. P.S. - Could your pump seal failure be associated with cold temperature operations with a hydraulic fluid not rated for cold temperatures? i.e. Too thick to pump during a cold start and a seal blows? Have a look at page 29 of the attached SEBU6250 for hydraulic fluid temperature ratings.
A couple of things you omitted in your assumptions is whether or not the machine is stored inside out of the weather, and whether or not the OP plans on operating it in ambient temperatures as low as you mention. The fluid viscosities mentioned in the manual are only really applicable to “cold-soaked” starting down to the ambient temperature mentioned.
Thanls fro the info ThreeCW. Yes, Im in Fort St John and as you stated it does get bitterly cold. I try not to operate my equioment if its below -25C but sometimes its a must. My skidsteer lives outside and has the block heater plugged in so it certainly does get cold soaked. I never thought about the cross contamination of the residual hydro fluid in the machine. I guess I will just play it safe and stick with the Cat Hydo 10. Just curious if anyone has tips on start up/purging the hydraulic lines or if this is necessary? I never split the pump apart so there is still likely some residual fluid in there for the initial start up to buffer metal on metal contact.
The hydraulic tank oil level/outlet is above the level of the pump inlet, correct.? If so then oil should gravity-feed into the pump when you fill the tank. Regarding the outlet I would suggest that you initially crank the engine over for a couple of seconds at a time for a few cycles without allowing it to start. Loosen a couple of outlet lines and wait to see oil at that location, then tighten the connections and go on to start the engine. Are you working on the machine inside or outside.? The engine won't be cold-soaked if you keep the machine outside and use a block heater but the hydraulic system certainly will. So long as what you add is basically compatible with the HYDO 10 you have in there right now there will be no issue. Either TDTO-TMS or TDTO Cold Weather are 100% compatible with HYDO 10, they simply contain more additives for transmission service.
Excellent Nige. I certainly appreciate all your help through this ordeal! My skidsteer is in currently in my shop, I pushed it in with my mini-excavator when the seal failed, luckily the seal failed when it was parked right in front of my shop door.
Starting it in shop conditions will be nowhere near as difficult as starting it outside. TBH if you had said it was outside I would have suggested you waited for warmer weather before attempting to crank it for the first time.
I would imagine you have a Petro-Canada distributor close by.? What about thier Produro XL Low Temp.? That would work and is also compatible with HYDO 10. Petro-Canada PRODURO™ TO-4+ XL Synthetic Blend Lo-Temp | PRODURO | Petro-Canada Lubricants PRODURO TO-4+ XL Synthetic Blend Lo-Temp provides reliable performance for off-road fleets.Read more. petrocanadalubricants.com