I'm just getting to know this EX270LC. Overall it seems in good condition, but it does have a gear oil leak from the pump transmission. It only leaks when the machine is at operating temperature and the oil is warm. Just to clarify what is leaking, the pump transmission is the part that the hydraulic pumps (two large pumps and one small pump in between) bolt on to. It holds about 1.3 quarts or litres of gear oil. It presently has 80-90 semi-synthetic gear oil in it. The service and parts book show a seal on the input shaft from the engine to the transmission. Most likely, that seal is leaking as the gear oil drips down from between the engine and the pump transmission. (This definitely is gear oil and not an engine oil leak. I collected a bit to make sure.) First question: Can anyone tell me if there is an easy way to change this seal, or is it necessary to remove the entire assembly including all three hydraulic pumps and the pump transmission? Based on looking at the manuals, I'm afraid that this is the case. If so, how big a job is this? How many hours should it take? Second question: Has anyone had luck with any gear oil additives (Lucas Heavy Duty Oil Stabilizer or some other product) for slowing down or stopping this kind of leak?
actually not a too bad to get done. I have done more pumps and pump gear boxes than I would like to admit. We had some issues with Zaxis 800 and 800C pump gear boxes and in the end I began running the Lucas gear additive. Helped a lot with noise and thats about it. You are going to need to drain the hydraulic tank, preferably transfer into a 55 gal drum. Remove pumps with gear box attached using a small crane, presto. Seal p/n 4310055 Pay very close attention to the engine coupler p/n 4314298. This item is a weak link so like I said take a very close look. Remove it and you can gain access to your seal. You will need to remove the pumps from the housing if you want to rebuild the gear box, which isn't a bad idea. Only a few bearings and the gears are usually good.
Is the breather clear as the heat can pressurise the housing ?
I am not sure what you are asking.
The filler plug has a small hole in it; I think that small hole serves as the breather. It's clear. ncbschzzt, thanks for the advice. How long do you estimate that the entire job should take? And would you try the Lucas Heavy Duty Oil Stabilizer before pulling things apart?
no stabilizer will fix your problem, you are going to have to pull it apart. The Lucas oil will just keep it from getting noisy and make it last longer. Pulling the pumps should only take about 2 hours after draining the tank. Then another hour to replace the seal and then give your self a few hours to inspect and reinstall. So it pretty much a all day job, but take your time and look at everything you can to make sure there is no damage. You don't want to have to do it again so pay close attention to details. The gearbox is extreme simple in design so you should catch something wrong pretty quickly. The coupler you might want to think about replacing even if it doesn't look bad. Like I said it is the weak link. Also make sure your hydraulic oil is clean and replace the tank filter while you are there. I would also pull your suction screen at the bottom of the tank and look for metal. It is always good practice to do this while the tank is empty.
After procrastinating for a long time, I finally got around to pulling the pumps and pump transmission. Maybe someone can give me some advice before I put it back together. As expected, the seal on the pump transmission shaft is shot. It was extremely dry and brittle and the center section (the part with the little spring embedded in the rubber) had separated from the main body of the seal. I know that this might be the time to poke and prod further into the transmission, but I'm tempted to just replace the seal. On draining the gear oil from the pump transmission, no metal filings or other strange things came out. I also put an extension magnet in the drain hole and it picked up nothing. The outer bearing, the one that one can see after pulling the seal, looks good. The only thing that I see that concerns me a little is that the shaft has a quite pronounced groove at the point where the seal rode. But to change that shaft means taking the transmission apart. And I suppose one then should replace gears, bearings, etc. So, what do you think? Would you tear this apart further? Is a groove on the shaft likely to cause the new seal to leak or fail prematurely? Or is it possible to buy a seal that will ride at a different point on the shaft? Any comments are appreciated.
Have you ever used a "Speedy Sleeve" to repair a shaft that has a seal groove?
Atco, good idea! I forgot about those. Now that you mention it, I remember using a speedy sleeve (or the same thing by a different name) on a driveshaft yoke on a Chevelle a few years ago.
Well, there you go. All you needed was someone to kick your brain and get your butt working! You might have to machine a tube to press it on with as I'd say you'll have to go on a shaft that's several inches long. And apply some Loctite 620 retaining compound to the shaft/sleeve where it fits over the grooves in the shaft. It will fill the void where the grooves are and help make a leakproof seal for the sleeve.
Hi there Atcoequip, Was wondering about the speedy sleeve you were talking about? What is it, how does it work, are they good? Never heard of them over here!
speedy sleeve here you go cps , i did look into getting some for my ccu , but found another ccu for spares http://www.eriks.co.uk/Rotary-Seals/eriks.asp?title=Speedi-Sleeve&pageid=946 cheers graham
You got it Graham. I've used repair sleeves a number of times, have even taken apart components that have a sleeve on the shaft from a previous repair and the sleeve is still in good shape. It's a perfect solution to repair shafts that have a seal groove worn in them. You place the flanged end of the sleeve on the shaft and send it down the shaft with the installation cup provided. On applications like a wheel spindle shaft that has some length to it, the installation cup won't work because the spindle shaft is in the way. That's when you have to make an installation tool, like a pipe, that properly fits the sleeve and presses on the sleeve flange. You have to have a tool that presses the sleeve around the full circumference of the flange. Once you have the sleeve in place, some applications allow you to leave the flange in place. On applications that the flange would not be desireable, you simply nip the flange with a pair of angle cutter pliers down to the score that's on the sleeve, then take a pair of pliers and peel the flange away.
Don't know if you guys have ever heard about KRYTOX But it's the stuff for high stress items Gear boxes, spines, drive shafts ect. We use krytox on the Top Fuel and Indy cars that I make parts for and what it has done to life span and wear reduction is amazing. On the rear ends of fuel cars 10 passes was the normal life span before KRYTOX but after, a 1/2 season. Krytox comes in oils greases and fluids. I have had great results with this this stuff.
A few more questions for you guys who have experience with these hydraulic pumps and transmissions. First, as mentioned above, I have not pulled the transmission completely apart and do not plan to do so unless something appears amiss. The main shaft running through the transmission has about 1/8 inch movement front to back. In other words, one can push and pull the shaft about 1/8 inch, into and out of the transmission case. The parts diagram does not show any shims in there or any adjustment. So, can anyone confirm that the movement is normal? If not, what would cause it? Second, can someone provide a detailed procedure for refilling the hydraulic system and getting the air out of the system before startup? I completely drained and cleaned out the hydraulic tank and pulled both filters in the tank. Thanks for your help!
Anyone? Since posting the previous post, I took the dial gauge and checked the end play on the transmission shaft. It's not as much as I thought. It measures at .070", which is just a little more than 1/16 of an inch.
Shaft movement is normal at your spec, once everything is back together you will need to remove both pressure test port plugs to bleed the hydraulic pumps. The plugs are on opposite sides of the pumps towards the front of the pumps and I think the heads are 19mm. Just add your oil and then remove both fittings and wait till you get oil out of the them. reinstall plugs and crank engine, but do not start. Do this about five times, this will help get some oil flow going at very low rpms, less chance of damaging pumps. Then start and leave at idle for a minute, no functions activated. Shut off and check oil level, restart and activate boom up slowly. Remember all this time you are going to be listening for any abnormal noise and looking for any leaks, if you here any grinding noise you need to stop immediately. After you have done all this heat to spec and check for leaks and you should be good to go. Don't forget to keep an close eye on your gear box as well for any leaks etc....
ncbschzzt, thanks for the help. Each of the two main pumps also have a big plug right on top (maybe 39mm?) that one fastens lifting hooks to. They come out easily. Would it do to pull those plugs or is there an advantage to pulling the smaller plugs that you mention? Is it also necessary to bleed the pilot pump, or does it take care of itself? I guess that stories about damage to pumps may have made me overcautious . . .
The plugs are on top of the regulators and you are right I double checked the size is up in the 30mm range maybe 36mm. That's more common of these machines. No need to bleed pilot pump. Just make sure when you do the pumps that oil starts to come out those bleed ports and then cap them up. Like I said if you here noise shut it down quickly and re-bleed the system.
The level in the tank has to be high enough to bleed through as well-those plugs are pretty high.
Bleeding the hydraulic system went well. I just loosened the two plugs and waited until oil began to flow out of the plug holes. After running the machine a minute or so, I shut if off and bled it again. I also had to loosen the hydraulic tank cap at that time to remove the suction and let the oil level rise in the pumps again. After that, I bled it a few more times but little air came out. While I had it apart, I changed the two hydraulic hoses from the bottom of the gear pump to the big right pump. They had abraded by rubbing on each other. SInce I did not know the pressures involved, I put on four wire hoses instead of the cheaper two wire. I lost some oil doing the work but reused most of the hydraulic oil, which I had drained into a barrel. The bottom of the tank and the two filters were clear of any metal. The biggest thing I found in there was a small O ring, about 1/2 inch in diameter, cut in half. I showed it to the service advisor at the dealer in Saskatoon and asked if he had any idea where the O ring came from in the system. He just laughed. To filter the hydraulic oil as I refilled the system, I pumped it through a new fuel filter (Goldenrod type) with an electric fuel pump. Then I topped it up with about two pails of new oil. The pumps are quiet and the transmission leak appears to be fixed. So far so good, although it has only run about half an hour so far. :thumbsup Since this was the first time I did this job, it probably took twenty hours or so. Quite a bit of that was spent on cleaning the tank and other parts. It would go faster if I needed to do it again.
That maze of hoses and the size of the parts intimidated me. But it wasn't really worse than pulling an engine from a car. A couple of pics: before pulling the pumps and transmission, after shields removed, and unit hanging from the fork on the tractor bucket. Because of the height and reach required, a rolling shop crane/engine puller would not work. A log fork bolted to the tractor bucket did the job perfectly. The engine leveler also helped. I suppose that most people that do this job in the field have a swing out arm/hoist on the service truck.