Hi I have a nice old 262b - bucket would bleed down real slow. This stayed the same for a year. I replaced cylinders in the boom. Still had issues. Then yesterday it got a lot worse. It will just curl down as if I have the lever making it. it has to be 1) valve body 2) pilot control 3) bucket level solenoid thing. Can anyone point me in the direction of diagnosing this so im not winging parts at it ? Thanks
Woiuld be a good idea to post your serial number. Will probably need to do some pressure testing, and by-pass testing. Were the cylinders you changed out both OEM or repaired by someone else. Do you have O-Ring face T-Taps for testing. After a few tests, you may have a better chance at diagnosing properly first time. Simon C
PDT00748 Is the serial number. I was told by my dealers tech support that it's common for the main hydraulic valve going bad on these. The quoted me 2300 to rebuild it and 3600 for new...... The valve under the joystick is dry and seems to function properly...... so Thoughts on the rebuild? or go new. it's a 2004 machine. The curl cylinders are new cat parts not rebuilt
UPDATE : 2500 BUCKS LATER .....UGH I have CAT rebuild the main control valve ... did not fix it. Im left with the joystick and possible failure in the pilot valve. The cat tech line said usually they leak externally when they go bad.... mine is not........ bucket still floats down pretty fast the I let go of the stick. Im wondering if I have a bad seal / spring / etc in the pilot valve thoughts ????
Going back to your original post. You said you replaced the cylinders and still had issues, but did the problem get better even though the cylinders didn’t totally fix it.? Where did the replacement cylinders come from and how much do you trust them never having seen inside.? I assume that you have done a test by capping the tilt function hydraulic lines right at the cylinders fittings and observing the results.?
cylinders are new Cat parts from dealer..... its almost like I got dirt or something in the pilot valve causing it not to seal.
Thank you for the reply, but it didn't answer the question "You said you replaced the cylinders and still had issues, but did the problem get better even though the [replacement] cylinders didn’t totally fix it.?" The answer to that question is somewhat important. IMHO your problem needs a systematic diagnosis instead of firing the Parts Cannon. Regarding the bucket tilt function I'm going to use the terms which are more familiar to me. Dump is when the bucket is rolled forward, rackback is when the bucket is rolled backwards. From the title of the thread "curl leaking down fast" am I correct in assuming that it doesn't matter where the bucket is positioned in the range of tilt movement, it moves towards the dump position with no operator input when the engine is running.? Does it move all the way until the tilt cylinders reach the end of their travel.? If the above is whatt's happening and if you set the bucket flat on the ground does it it still try to dump, thus jacking the machine up somewhat, or does it just sit there flat on the ground.? Is there any detectable change in RPM when this happens.?
I wil use dump and curl - makes better sense..... I think I have figured it out - one of the cylinders is brand new from cat - the other one was rebuilt but the piston is scored bad ( didn't have money for 2 new cylinders from cat at the time..... I think the one that was rebuilt has failed causing it to bleed off the new cylinder and causing the bucket to dump ( machine on or off). Cat has "yellow mark) which is new old stock for these old machines and I can get a new cylinder for under 1K. The machine does seem to operate (in general) better with the new control valve tho.... I will probably keep this machine till it dies because it's handy to have around the farm....... just wish I would have tested the cylinders first....... live and learn
You could confirm that quite easily by plugging the ports on the repaired cylinder right at the cylinder itself. If the bucket does not move, or moves very little, then apparently you have found your problem. I need to correct you there. Yellowmark is not "new old stock". It's just a cheaper version of new parts manufactured to less exacting tolerances using lower quality materials. I don't know what others think but personally I wouldn't entertain using a Yellowmark hydraulic cylinder on anything. I would suggest that an aftermarket cylinder is preferable to a Yellowmark. The Part Numbers to search for are 230-3687 if you want a LH cylinder and 230-3697 if you want a RH one.
Well the part the gave me came it a cat box with part number on it.. I can not find these cylinders anywhere after market. I can get a used one but not doing that
any chance you would have the plug size ? I dont think my hardware store would have them but worth a try
I think the one they gave me was oe cat because it had the part number you gave me- they have updated numbers on the new cylinders. New number 631-6300
Yellowmark are still Cat parts with Cat decals on the box. They just aren't very good in my experience. Interesting that the parts system reference for that number states - "stocks of part to be exhausted". So either Cat been experiencing problems with it or it has been decided the part does not give any value. There are updated Part Numbers that are NOT Yellowmark for both tilt cylinders. the updated numbers appear in a lot of aftermarket suppliers including AVSpare.com 230-3687 -> 295-6954 230-3697 -> 295-6953 ORFS Dash 8.
looking at some of theses and specs. the stroke is different ... im going to play it safe and get the matching one from cat if they have it. Just so both are the same. The part number you gave seems to fit other machines...... cat doesn't make it easy thats for sure
Just remember that even at the level of Part Number there are different numbers for LH & RH cylinders, just like the earlier part numbers.
Thank you for your help.
You're welcome. That's strange. I just double-checked all 6 part numbers and the data is below. I don't see any difference. 230-3687/3697 - 70 mm bore x 354mm stroke 295-6953/6954 - 70 mm bore x 354mm stroke 631-6300/6307 - 70 mm bore x 354mm stroke
ahh ok - I was going off an listing on eBay for one of the updated numbers - thanks !
Not exactly guaranteed to be the most reliable of resoucres at the best of times, IMHO.
From my own experiences I would never buy Yellowmark parts for anything internal to an engine, transmission, final drive etc. Bought a spacer plate for a 3406 once and it didn't even measure within the spec range straight out of the box. A coworker once had to get a Yellowmark part for an old dozer final drive turned down several thou to get it into spec as well. Bearing surface on the shaft was too large to fit the bearing. YMMV.
Yellowmark & Cat Classic......................which is the best of 2 evils
The correct reply to that question is - "None of the above. They're both *****"
I was told YM was just what the Classic was rebranded to?
I refer my learned colleague to my reply in Post #22..........
I would agree if I was getting a part that was manufactured under yellow mark. These cylinders are new old stock that they are depleting.....So they are the ones that came on machine originally and about the same price as after market and I can have them next day...... There is an updated cylinder at almost 800 more. This is a 20 year old machine used around a farm and small side husltle jobs. If I have another 5-6 years out of them im ok with that....... Should be back up and running tomorrow
If it's new old stock wat Part Number are they selling to you.?
Everyone is always looking for that deal. Sometimes it pays off, sometimes it gets you laid off. I am all for looking for that deal myself but sometimes I just do bad decisions. Good luck, sincerely.
Ok update and still issues.... I have 2 brand new cylinders ( original cat number not the updated part number) I have a rebuilt ( at cat ) main hydraulic block....... skid ran amazing it would curl and hold what ever I asked it to for about 2 weeks...... then it started to bleed down again. Not as bad as before but it will bleed down while running with anything attached to it - even pallet forks. I bought some plugs and isolated each cylinder one at a time. Both bled down...... No leaking joystick valves etc.....no leaks anywhere. What are the chances of the relief valve in the rebuilt block going bad so soon..... it's not making sense to me logically...... Thoughts ????
OK, so one cylinder at a time isolated it bleeds down. What happens if you isolate BOTH cylinders at the same time.? Another thought. Disconnect and plug the tilt pilot lines into the main control valve. What happens then.?
I will need to go get 2 more plugs and 2 more caps to isolate bother cylinders..... Wouldn't this be a redundant test ? Last time when isolated the bad one it was really obvious. I will trace the lines tomorrow and see if I can disconnect them and plug them... hoping the plugs are the same..... local hydro shop is very proud of these plugs and caps........
If you plug/cap both cylinders simultaneously and the tilt function does not move you have conclusively proved that the cylinders are not the problem. Try doing it with some weight on the front end such as a loaded pallet on the forks. Having confirmed (fingers crossed) that the cylinders are not the problem from the previous step then if you cap/plug both tilt pilot lines and the tilt function starts to drift the problem MUST be in the control valve.
Maybe jumping thr gun a bit but this information might be useful to you. Understanding how the control valve works may be key to troubleshooting it. Also it gives probably the clearest illustrations regarding how the valve is SUPPOSED to be assembled, so that you can check it is actually assembled that way. It wouldn't be the first valve of this type I have seen that was assembled incorrectly.
I went and got some more plugs and caps from local hydro shop. Was chatting with the guy for a bit going over everything....... his money is on junk in the system has the relief valve not closing all the way....... kinda makes sense - I did flush out tank best I could and have replaced the in tank filter. I also have put a total of 4 new spin on filters on it after first repair..... one a day for 4 days straight just. to be extra sure I got any junk out.... it operated perfect for a few weeks... so im sure things where assembled right from cat.... but I will 2x check and report back
Or something is preventing the tilt spool moving freely back to the neutral position when the pilot signal is taken away. Surely if anything was affecting the relief valve it would affect both the lift and the tilt circuits. Maybe wortwhile to pull the spool out for a look.?
for sure ..... Im going to cap off both cylinders and lines to just make sure it's not a cylinder. .... then im pulling control valve back out and taking back to Cat. Its under warranty for 1 year
I would advise caution. I know you have a 12-month warranty on the valve repair but if the dealer were to find external contamination in the control valve is the cause of the issue then he would be quite within his rights to deny warranty because the symptoms you have were caused by a problem over which he had no control. At that point you get invoiced a second time. It would be different if the dealer had the complete machine to do the control valve at the previous repair, then he would be responsible for the entire system, not just the valve.
They will tell you and they are probably right, that you have trash in your system. I recently replaced a drive motor in a skid steer and flushed as many lines as I could and drained hydraulic tank and used 2 cans of Brake Kleen to get all the gold out. After I flushed it with gas and blowed air through it, till it was completely clean. Now I’m saving up for the drive on the second side as I expect it to crap out soon. Hopefully, I won’t be doing the pumps. Also borrowed a filter cart and ran the oil through that a few times while exercising all the hydraulics.
So you said earlier it bleeds down when capping one cylinder at a time. That would indicate that both cylinders are leaking. How are you capping these cylinders? To do a proper test you would only cap one port at a time in this case where tilt down is the rod end you would cap the rod line on the cylinder while the forks are resting on the ground. Once capped lift the loader arms a bit so the weight is on the forks. If it continues to drift with one cylinder capped then the capped cylinder is bypassing.
So more testing - and results. I capped both cylinders and plugged lines going to cylinders. started machine and picked up boom with heavy grapple attached. Tilt cylinders held solid.... Then I removed caps from left cylinder and repeated - tilt held. Re installed caps on left cylinder and removed ones on right and repeated test. Tilt held. So I can say that the tilt cylinders are good. So now Im on to the main valve ( newly rebuilt) or the auto level valve.
can I pull the valve apart in the machine to see if it has debris in it ? Would it be the relief valve or spool in the schematic that I need to check ?
On my 287b if I turn on the self leveling tilt I get tilt cylinder drift. As soon as I turn that off it holds a load with very little drift. Have you tried switching off self level.
yes I have turned it on and off - does not make a difference. I never really use that feature in my day to day use on this machine. I guess my next move is to pull the main valve back out and take it back to CAT. the guys there are really cool and willing to help..... even if I have to pay them to redo the tilt part of the valve it will be worth it to have machine running again...... its a pain to run it like it is
I understand your thinking but if the rest of the implement hydraulic & drive system has not been thoroughly cleaned of contamination at the same time as you have the control valve removed what is there to prevent the exact same thing happening again.?
The guys at the cat hydraulic shop said bring it in and they will pull it apart and see.... I plan to clean the system out the best I can. Pull the tank out and flush it real goo and blow the lines out...... I do not plan on putting it together with out an honest try to clean the system out. I did put a new in tank suction filter ( about the size of a rock screener ha ha ). I also put a new spin on filter every day for 4 days straight after last go around..... when I pulled filters off and dumped them and cut open I did not see any noticeable junk (for what its worth)
If you changed the filter every day for 4 days there should of been absolutely nothing in it by the 3rd or 4th filter. I hope that is what you are saying or you have something grenading elsewhere. If you can take the valve out without getting dirt in the lines, I am sure you could clean up the valve. Simon C
I am confused about the fittings on top of that pump, that and the tape and caps. Nothing on that valve block looks correct.
yeah that pic was taken when I was putting it back together after it was rebuilt. I connected one line at a time and kept tape and caps on till I hooked up a line to each port. I did not want to risk getting dirt etc into valve when putting lines on. I cleaned he machine the best I could but its a skid steer and still has dirt etc around.... just being cautious