I have a D-6c serial#10k10536 about a 1976 year dozer that has an oil leak coming from the control rod coming out of the hydraulic tank. Resealed the rod thinking that would solve the problem, reinstalled the tank, not an easy job, still is leaking, very frustrating!Anyone else ever experience this problem? Any suggestions would be greatly appreciated!
OMG! Steve!!!!!…….I’m soooooo happy you have another problem!
The shafts wear and get grooved where the seal lip sits, did you check the shafts carefully for this kind of wear? Did you use the genuine Cat double-lip seal, or just a "will-fit" bearing house seal?
I did a visual and hand rub check , no groove on leaking shaft. Did not use cat seal , maybe that is where I made a big mistake. The seal was national seal so I just ordered the seal from Napa.thanks for the reply!
Yeah, you have to keep in mind that Cat do not necessarily follow SAE standards, nor do aftermarket manufacturers necessarily produce items to Cat specifications. Cat will change specified measurements and materials to suit their own ideas, often to improve durability. I've had Cat bearings that were standard dimensions for outer and inner measurements - but they had .002" additional operating clearance between rollers and races, which made them a "proprietary bearing", and bearing houses were unable to supply the precise bearing. I could buy a standard bearing and risk a shorter lifespan or pay extra for the Cat bearing and get the designed lifespan. The same goes for seals, Cat will produce seals made with more heat-resistant seal material, whereas aftermarket seals will use a generic seal material. Cat also tend to use double lip seals a lot, and an aftermarket supplier will often provide a single-lip seal as a "will-fit" offering.
That makes perfect sense, just wish I would’ve checked that out. I’m going to take it back out and replace the seals with cat seals. Should the shafts and inner bearings be replaced if there’s no visible wear on the surface of the shaft?
If there's no visible wear on the shaft, there should be no problems. Feel for shaft sideways movement, there should be very little, a few thou at most.
Thanks ozDozer for your input, you are very helpful.
Inquiring minds want to know how your dozer has been running since you finally got it back fixed properly? As far as the seal could the leak be from somewhere else? Even though Cat may use a double lip seal it seems if a single lip f its tightly it should still seal although won't last as long or seal quite as good. Double check there's no groove forming on the shaft. If there's even slight wear a speedi-sleave might be a good option. Put a couple drops of oil on the seal when you install it on the shaft.
Dozer has been running great. No problems except minor issues, track tensioners needing new seals, bolts broke for alligator connection link, had to replace,I’ve put about four hundred hours on the machine, nothing to complain about, great running tractor.
Welder Dave, oil is dripping from the shaft where it connects to the length adjustment rod for the blade tilt. No visible groove on the shaft, real smooth surface. I was thinking that maybe I should have filled the tank halfway with water and checked it before putting it back together, maybe the leak would have shown.
Glad that it has been running great! I wouldn't put water in the tank. That's just asking for problems. I wasn't sure where this shaft came out of the tank so having the proper Cat seal may be all that's required. Make sure it's installed the right way.
Never put water in any hydraulic system, if you want to test for leaks, use diesel. The D6C is one of Cats finest machines ever built, Cat built their reputation on these tractors. As a full-time contractor, I part-owned 2 of them with the brother, bought both new, did D7-type work with them, wore them out as far as I was concerned, traded them with over 13,000 hrs on the clock, after 6-7 years of hard work - and would you believe it, the brother just recently found the first D6C we bought, it's 57 years old, and still working!! It's probably done over 50,000 hrs by now! However, it's largely out to pasture, an old prospector owns it, and only uses it part-time.
Thanks ozDozer for the tip about using diesel fuel to check for leaks. This D-6c is a great,Very! reliably machine! That’s alot of hours for a machine that old of a machine!
There should be disclaimer to the statement, This D6C is a great, very! reliable machine! This D6C was the subject of the most epic thread in the history of this forum and likely any forum for that matter. It is great that it got sorted out and is working good. Using water to test for leaks in the hyd. tank I'm sure would have delighted Vetech63 and shares in popcorn would have gone up substantially.
Is there not an o-ring that seals the bearing assy to the side of the tank, and if so, did you change it too?
No o-ring that I could see, just a seal on the rod end in the tank with the rod coming through the tank, then the bearing on back end of valve block. I’m thinking maybe the bearing had some play in it causing the rod to move enough to not seal well.
That truly Amazing, Makes me wonder if in today's throw away world the machines of today will be around 57 years from now and still operable. If so, I wonder what condition the plastic parts will be in?
Here’s a parts diagram that I got online.
What’s the Hydraulic Control Serial Number.? It will be on a plate on the side of the tank, probably a 163-something. I can try to find a parts listing relevant to that particular S/N. It may be different to the diagram you have.
Nige, here’s a picture of the plate .looks like 39g14787.
Here's the Tank & Valve Gp corresponding to 163 Hydraulic controls with Serial Numbers from 39G12797 to 16642. I didn't look at it to see how it compares to the illustration you have.
Thank's Nige, that’s a big help
#16 is a gasket between the bearing assy and the tank. Maybe its seeping?
I see that. Don’t think the gasket is the problem but I will replace it. I ran yesterday for about 3hours, lost 5 gallons of hydraulic oil. Dripping bad after oil warms up, not noticeable at startup. Thanks for the help 56wrench!
No problem. Its a miserable enough job that i would change the gasket while you’re in there just to eliminate it. They don’t usually leak but on an old machine, you never know
Does anyone have a sure fire way of checking for leaks after installing the new seal, gaskets and bearing assembly before putting two halves together? The problem happens when oil is under pressure and hot.
5 gallons of oil in just three hours? That is one hell of a leak! Is anything gaining oil? Been way too long since I worked on a D-6 but is the a breather or some kind of pressure relief for the tank? Seems like I recall most Cat loaders had some type of Sintered Bronze Breather with a pressure relief to keep a little pressure in the tank, just enough to keep pump from cavitating.
It is a bad leak.dripping very steadily after warms up! Don’t know if there’s a leak underneath above the belly pan . Don’t want to take that off unless I have to. I’ve got to fix tank first.
I've never done it but you could always make an adapter to plug the filler with an opportunity to pressurize the tank with air and then use the soapy water method to see if you could identify any leaks.
Are you sure that all of the gallons of oil you are losing are from the tank.? Are you even sure that it's the tank that is actually leaking.? Could you possibly have more than one leak.? If so dropping the belly pan might just reveal the source of another leak if there happen to be multiple ones.
I’ve thought about another leak maybe down below. I’m quite sure it’s leaking from the control rod for blade tilt, visably dripping fast after running for awhile.Another leak is possible though Nige.
I guess that’s possible but looking for a simpler solution. Thanks for the advice though
In the pic. of the inside of the tank with the rag stuffed in an opening, there looks to be crack of some sort above the rag. May not be a concern though. If the tank is in half, can you place it flat and plug the openings? If so you could warn up some oil and pour it over where the shaft is leaking. It wouldn't be under pressure but assuming the tank is venting properly could still indicate if there's a leak. Let it sit for a while.
No visable cracks in tank but will definitely check that when I take it off this week.diesel fuel was suggested, it would be thinner than oil , would be more prone to leaks. Wierd thing about it is that the other control rod had a groove worn on shaft but wasn’t leaking!
Just for fun you could take a one gallon paint can poke a 1/4 inch hole in the bottom and fill it with warm oil and see how long it takes to empty. Then multiply that time by 5 and see how it compares to your leak. Five gallons of oil is a lot and should be leaving puddles all over the place every time you stop. Someone should call the EPA!
May not be just a seal problem, there are two sleeve bearings in there that may be worn beyond the range of the seal working.
I’m not saying that you are wrong, there very well could be a hose connection or some other problem on under side of the dozer. I’m going to fix the known problem leak first which is bad after oil gets hot and is in a pressurized tank.
With that big of a leak you're lucky you didn't take out a pump or other hyd. component. Definitely investigate further. I think it would make more sense for a blown hose to leak that amount of oil but see Old Magnet's post above.
I'd be looking carefully for corrosion pinholes or cracked welds. Welds on pipe flanges commonly crack with vibration.
I think that I am going to just take the tank off, take up to Ziegler caterpillar, let them go through it,hopefully they can get it fixed correctly and then warranty it. Thank you OM for your help.
Well how about putting a catch can of some kind under the "known leak" and see how much it is actually leaking? I agree with Old Magnet about the bearings that shaft runs in, should only have slight side to side or up and down movement. I'm still having a hard time wrapping my head around a 5 gallon in 3 hours leak that does not jump out on you. Like I said before been long time since I worked on or around a D6C but wonder again if this "leak" is an internal leak and not external leak? I know the hydraulic pump is mounted on the flywheel housing but don't recall if it leaked if the oil would be going into the motor oil or into the converter/transmission oil. I might be able to see a leak into the transmission not showing up right off. Took some looking but looks like the transmission oil capacity is around 25 gallons so if estimate of 5 gallons was off or transmission was low to begin with one might not notice right off the added oil.
That will be the next step after tank is fixed.No visable leaking on any hoses or cracked welds that I can see. Oil is dripping out very quickly after warming up! Pretty sure that’s where I’m losing it, not 100%sure though!
Well good luck! But still have to wonder why you don't want to drop belly pans and remove some floor boards to check for other leaks. Even if none are found I would be surprised if there isn't a problem hiding in there that will cause a future problem from rust. Seldom dropped a belly pan that did not have lines or other parts buried in wet dirt rusting out!
The thing that I didn’t consider after taking the shaft out, checking for grooves, checking seal and finding seal worn out,was play in the bearings, my mistake! Shaft didn’t look worn or grooves in it so I just put in new seals, my mistake!
Not saying that I’m not going to do that but first things first. Dropping the belly pan is not fun!
Actually, compared to some jobs, its not that bad
3 pages. Steve, you have given me renewed hope my friend.
There's a few posts on ways to safely remove belly pans. How is your relationship with Ziegler Cat after they tried to screw you over? Do as much investigated on your own as you can. If you're absolutely positive the leak is coming from the shaft you already repaired then it would be a good idea to have the dealer look at it.
Maybe not, but more fun than writing the check to Ziegler and then find out the problem is either the bearings on that shaft or something down in the belly pan!
You have a great memory! Thought you would have forgotten about that incident. Get along great with the cat dealership, great people if you pay your bills!
Nobody will ever forget that "incident"! That's the same dealer that tried to make you pay them a big chunk of money and they kept the machine.
Welder Dave, It all ended well! They did a fantastic job of putting the machine back together again! I couldn’t be happier about the job they did for me. They went above what I was expecting from them!alls well that ends well.
What??? As I recall vividly it took getting Cat corperate involved to get the dealer to repair it properly since it was their screw up initially. Without Cat's intervention and advice from this forum you were close to letting them keep your dozer and having to pay a large repair bill to boot. Nobody can forget that.
You are correct Dave . All I’m saying is that in the end, everything worked out perfectly! I got a great running machine but it wouldn’t have been possible without the support and help from HEF
I just ordered my popcorn.
Update on my hydraulic tank leak. I ended up taking tank out and putting new shaf,seal,new gaskets on the blade tilt control rod and valve body, put back together and installed then other shaft was leaking bad.pulled it off again and replaced the shaft, gaskets and the seal for the blade raise control.No leaking now! I did have to take belly pans off because there was a leak on the underside hose so you guys were right about checking on hose leaking down there,long story short, its fixed and I am going again with this beautiful old gal! I love this lady! I am posting some pictures of the seals and the machine. There’s a difference in caterpillar seals and national seals,the double lipped seal is the caterpillar seal, much better seal, in my opinion. Thanks for all your help with this issue.Merry Christmas to you all!
That a good looking “old girl” Nice job on repairs!
Couple more of the shafts I replaced couple more pictures of the shafts that I replaced.about $360 for the shafts,bearings,gaskets,time drilling out the old shafts and plug welding new shafts in and labor but it was worth the cost and time.
Well done! It's good to do repairs properly, even though it's a few hours and a few hundred dollars invested, repairs done properly repay you in spades, with good trouble-free performance for a long time to come.
You’ve got a leaking bolt on the tank flange?