I have an old 225 that really has not been moved around much since I bought it 5yrs ago. We use it to pick stuff up where it is, that is about it. However, I need to track it now. I found that one track seems to be binding up pretty bad. It seems to walk around very slow OK, but if I give it full pedal, it will sort of momentarily lock up like something is holding it. I know the track links are not in the best shape but when measured, the links appear to be within the service limit for stretch, the sprocket seems to be worn but still in spec, etc. I have concerns the links are partially frozen but I am having a hard time pinpointing that as an issue. The tracks are so heavy that manually moving them is difficult. I know for sure the brake is leaking and I confirmed by removing the track motor. However, the brake seems to release great and you can feel it release. I suppose it could be the brake but it tracks fine when running very slow. The motor runs perfect and I just drained/refilled the final drive because the seal was missing from the track motor causing water to get in the final. When drained, there were no chunks of anything, only some gray matter I would expect on the magnetic drain plug. I peeked in there with a scope and the gears look pristine. I cannot account for the bearings but the seals do not leak, and having a hard time believing the final is the culprit. I realize maybe popping the track off would prove some of this but hoping we might be able to pinpoint the problem without that hassle? I believe the links are supposed to be sealed. I know they are worn and probably not sealed anymore. It does not have too much tracking to do. I have heard of diesel fuel on the links but not sure how well that would get in the links and if it would really work? Hopefully this vid link works and I apologize for the poor quality. You can hear the popping or binding I describe. Each time you hear that, the links seems to pop deeper into the teeth of the sprocket. I applied grease the the sprocket just to see if it would make much difference and it did not. https://www.youtube.com/watch?v=F8PHHbvu3ng Would I be advised to reduce the track tension further? I set it based off the manual but when picked up, the chain hangs down below the rollers over a foot. That seems like enough to be.
Track looks fine to me, though obviously stretched. When the chains get worn like that the pitch between the links gets longer and they start to slide down the sprocket teeth, makes them jump a bit, but it doesn't look to me like it's actually catching yet. If it was me I would actually tighten them up a bit. Check the idler? Have you tried lifting that track off the ground and letting it run full speed?
Yes, with the track off the ground, it does the same thing and I am worried that the binding will eventually break the track if that is the cause. The video is off the ground. It seems to be a little worse when on the ground as it stalls the track motion, the whole machine wants to turn, etc. It does not come on gradually, it is just going, then complete stall, then release. This happens multiple times per track rev. Though I cannot really pinpoint any exact track locations when it happens. The faster I run the track, it will bind harder and momentarily stall the track in which the engine pulls down so I know it is working for it. It is odd that at slow speed, it seems decent but you quickly identify how fast it can go before this binding occurs. I have looked at the idler to see if there is contact with the frame and it appears that in a previous life it grinding a nice groove there but no contact right now. Probably 1/2" clearance. What do you make of that popping sound? I think I know what you are saying on chain stretch where the pins seem to strike the tip of the sprocket and then have the fight to get in a groove? I know that is not occurring.
Tracks only bind up when pins seize in the bushings and I don't see any sign of that in the video there. Not sure but I think I would lean toward a brake or final drive bearing issue. As I recall it doesn't take much to disassemble those brakes, maybe pull the springs and plates out, make sure the shaft spins free and then try it under power again? Sounds like you need to reseal it anyway.
OK, lets assume the brake is leaking at a rate of probably 1/2gal/min. I realize this is an alarming amount but curious how the brakes might be causing this? Would they not be showing these symptoms continuously, regardless of speed? I will admit that the type of stall I am feeling sure feels like someone just hammers a brake but the clunking I am hearing I am a little worried about. Also, if the final was so bad that it is causing extreme bind of the track, would I not have some carnage showing up in the oil?
Hard to say, but that's a lot of leakage from a brake. Yeah, normally if something's amiss in the final you should see some kind of evidence. I don't know how big a job it is but like I said, probably the easiest thing to check is the brake, yank the guts out of it, make sure there aren't any bearing issues, can't remember if there's input, output, or both bearings in the brake, and try it with no brake plates in there to lock up. I just had a planetary final lock up on a customer because the brake release pressure was low, some of the plates welded themselves together.
If you want to check for brake leakage remove the hydraulic line that releases the brakes and plug it. Hook a Porta-power to the brake port and get the tracks in the air like in your YouTube clip. Pump up the brake pressure slowly until you can move the track in both directions, then stop pumping and see if the pressure holds steady. A slow drop in pressure past the seals would be considered normal. It might also be an idea to try disconnecting the case drain line from each track motor and see how much oil is leaking internally within the motors themselves. I tend to agree with lantraxco that it looks like the track pitch has extended significantly. To measure pitch run both tracks in reverse and stop when the top run is in tension. Measure the distance across 4 link pitches (i.e. pin #1 to pin #5) and post the results here. Repeat the measurements at a number of points, you may find some measurements are bigger than other which will indicate that there are some worn joints in the tracks. If the pitch has extended significantly then the bushes will tend to try to jump out of the sprocket teeth as soon as you put a decent amount of weight on the tracks, hence the bangs you are hearing.
Well, I don't think there is any point to testing the brake. I know it is bleeding bad. I removed the motor before and to determine what was leaking into the final drive. The brake bleeds constantly while the motor runs without a leak. Some prior owner apparently thought having the drive motor tight to the brake was not needed and left it loose. I tightened it up but who knows how long it ran that way and likely got trash in the brake. I am trying to read up on the brake job while still trying to prove it to myself that could be the issue. I know the brake operates on pilot pressure of 335psi and the brake releases at 250psi. The pump will provide upto 18gpm and I know we are not pumping that much out of the brake. the brake has not one bearing in it. It has a common shaft through it that couples the final to the motor like an extension coupler. Now if there is some flow reduction device to the brake, that might start to make sense if the brake is momentarily loosing pressure as it leaks by and not enough flow to keep the pressure up. However, the stoppage seems more mechanical in nature to me. I would be most inclined to point at the track chains but I just cannot see the binding that I am hearing and feeling. I am happy to again test the chain pitch but I have record of what I tested before I believe as being worn but still within service limits. If the chain is the issue, is there a temporary work around such as running the chain loose or tight?
OK, I am pretty sure I am tearing at least one brake off, it not both tomorrow. I am going to need seals and need to know where to find them quickly and economically? I figure CAT will probably have them at some price that I don't wish to pay. I remember rebuilding cylinders and CAT was about double the price. Are the seals so special that I cannot hit my local hydraulic seal supplier for that? I know everything about CAT has to be special. I figure cylinder seals might be easy enough, but brake seals might be either so simple anyone would have them, or so special no one will. Only holding 335psi. can't be that speshal....
I think fixing the both brakes first will be a good idea. At least it removes any doubt regarding their performance. I would personally tear them down first before looking for parts because you never know what else you might find in there that needs replacing at the same time. Regarding "will fit" seals from a local hydraulic shop. Personally I wouldn't when it's something like a brake but that's just MHO. For good parts pricing try Offroad Equipment - www.offroadeq.com/
My 225 has leaking brakes as well. I went through my parts book and got all the seals quoted: http://i.imgur.com/UJyCjWQ.jpg You can ignore the red highlighted parts, those are main pump seals, and some final drive plugs etc. However, I don't have my parts book on me right now, it's possible the brakes use two of the 1U1655 seals, one each. I ran all these parts numbers on eBay and www.napaonline.com , I found a couple at NAPA, but found most of them on eBay for much cheaper than the CAT dealer. EDIT: I tried to remove the attached images, but it's not working... Anyways use the link, it's a much clearer image.
Well my day has been maybe good or bad, depending on...... I pulled both brakes. LH side looks great, frictions are in good cond. Will prob replace all the rubbers, give it a good cleaning, and put it back to bed. RH is another story. Previous *******, I mean neglectful owner left the drive motor loos and knocked of the vent caps on both brakes so they are free to take on some water. Water and rust are evident in the brake. frictions are gone. Metal to metal. I think there again, a good cleaning and reburb and it should work. I can only hope this is where some of the problems were. HOWEVER, as is now the focus of my venture, I found the input shaft bearings to be **** up. Very likely because the drive motor was loose and just hanging on the shaft extension of about 6". The water in the brake got in the final as well as caused the brake to eat itself and all that mess got in the bearing. I think the bearings have been chewing crow for a while. That messed up pinion could certain cause a little binding too I think. I was about to crap, cuss, throw bricks, etc, but I reviewed the books and hoping you bright guys can enlighten but it appears that input pinion stands along and I may be able to just pop him out as an assembly? Then get her on the press for some bearing work? The other side does not have play like this but I noted that some pins are not making contact with the race. A zero-preload condition we call it here. I was going to look into preloading it again but the book indicates possible some axial clearance. They description is confusing to me calling it "end clearance" of .000-.003". They don't say how much force to apply, where, etc I can sure hit 000 when I wrench down on it. Not sure on that yet. Sorry again for the poor vid. https://www.youtube.com/watch?v=xM8nV9c-Z5U
Hey guys. I am wondering if anyone has a parts manual for my 51u23xx machine? Mine covers to later model ones with different final. I need the part number for input shaft on final. Should have a rack that connects to end of it. This is the shaft that runs thru tje center of the input pinion.
try here.... $70 on CD. https://servicemanualpro.com/?page=products&category=9&model=225 EXCAVATOR
Thank you but i really just need the pn for the shaft is all. My other book is accurate on most other systems
Just got onto this thread and noticed no one has asked if the final drive oil levels were checked or if the oil was drained and checked for metal bits. These machines use a linear type final drive and not a planetary. The description of the problem is exactly what I have seen in these types of gear boxes when there are bad bearings or broken gears.
Here: https://drive.google.com/file/d/0B_X5nwOb38dmX2I2Zms4NFhzdFU/view?usp=sharing