Hi All, I have the skid steer running, and have rebuilt the lift arm cylinder that blew out. Now I have another issue , when I raise the lift arms and release the peddle the bucket drops about 6 to 10 inches before it will hold. Also if I have the bucket lowered all the way down and tilt the bucket down to use it like a blade to smooth the work area it mostly just pushes the arms up instead of tilting the whole machine. Could you guys help me with what to look for to correct this? Thanks, B-Crazy
i'd be looking at your lift cylinder... was it doing this before you rebuilt the cylinder?
I don't recall it doing the 6 inch drop thing although I only ran it for about 30 minutes before it blew out the cylinder. But I do recall that it had like a slow steady lowering on its own. Does that give you any clues to what it might be, or does it still sound like it could be the cylinder which I rebuilt. I have rebuilt several cylinders in the past and have never had an issue with them. However I am not saying that I am the number one most experienced cylinder rebuilder either.
My guess is you don't have the piston nut tight enough on the cylinder, they really need to be tight. When I did my tilt cylinders it was torqued to 100 ft lbs, then make a mark and turn the nut 2 1/2 flats past it to get the what the manual wanted (if I remember correct). I don't know if yours will require quite that much torque on the nut however mine is a S300. Also you could have air trapped in the cylinder yet which would give you spongy hydraulics as well.
Hey guys thanks for that info. I am pretty sure that the nut is tight enough as I usually make sure that it is torqued out. I am also pretty sure that I rebuilt the cylinder correctly as it is not my first. I could easily have air trapped in it as I didn't bleed it in any way. So I will try to check that first before moving onto harder fixes. Thanks B-Crazy
it could be air trapped, but usually after a few full cycles of the cylinders it works its way out. might be worth checking the other lift cylinder just for ***** and giggles. does it drift all the time? engine off, as well as running? engine running PTO NOT activated, or activated?
Yes the best that I can tell it drifts all of the time. I will have the chance to work on it again tomorrow afternoon so maybe with you guys help I can get it working right. Thanks Guys
OK, I had time to work with it a couple of hours this afternoon. I found that when I release the left peddle it still has the 6 inch drop. And if I put just a little bit of pressure on the heel of the left peddle it will continually drift. I have just rebuilt the control valve just before the cylinder blew. Could the control valve be out of adjustment some how? Thanks
Possible it's not centering
since you had the valve apart, check the lift detent assembly.
Lift detent assembly? Would that be the same as the Lift arm release valve? That valve does have a small leak. If it is old enough to be leaking out side could it be leaking or allowing bypass inside?
the emergency boom down valve could be a problem if it's leaking...
A little more update. I had some time yesterday to work on the Bobcat. Symptoms are still the same, When lifting, the arms seem to work good (but may be just slower than normal), when I release the peddle the arms drop approx. 6 inches. If letting arms down they stop in place correctly when I release peddle. With arms all the way down, when I tilt bucket down to raise front of b-cat arms do not stay in the down position and will not hold the extra weight/pressure. They do hold some of the pressure but still it quickly equalizes. If the arms are lifted and I put a small amount of pressure on the heel of the left peddle the arms will start coming down at a slow pace (not fast as in powering down, slow like a pressure bypass). But when I press the heel of the peddle on down they start up. I have temp bypassed the emergency boom down valve, (not the problem). Dissembled the lift arm cylinder which I rebuilt, thinking that I may have damaged a seal (all was good). At this point I am thinking that it has to be something that I did wrong when I rebuilt the control/spooling valve. (I assume both of those terms are use for the same valve?) I guess that my next venture will be to disassemble that to see if I damaged a seal, installed a seal backwards, etc. I do not see that there is an adjustment to this valve, am I missing the adjustment? Any ideas would be much appreciated. Thanks All, B-Crazy P.S. Yes I am almost crazy for sure and not just Bobcat Crazy because of this Bobcat
an assbackwards seal wont cause the problem, seals will fit either direction, but if it's backwards they usually wont seal for very long before they start leaking. ive reread your postings several times, my conclusion is either.. A) the detent assembly on the back of the lift spool isnt assembled correctly, or the detent assembly is loose on the spool, and is letting the spool "drift" in he bore B) you have the lift load check poppet not seating properly. (this accounts for the " trying to lift slightly and the boom drops" or you may have an internally damaged/cracked control valve
Crew Chief it seems you have all of the answers. I now remember that when I disassembled the detent valve that the little spring and little balls jumped out. I reassembled them in what I thought was the correct way. With the info that you have just provided, I'm thinking that I either lost a tiny part to that or did not assemble correctly.
i think willeB 's thread on "bobcat loader control valve seal replacement" might help in the reassembly of the detent. inside the aluminum bonnet are 2 springs and 4 balls. might help if you go to bobcat.com, online parts catalog and take a look at a parts breakdown.
I keep getting ''no results found" when searching for the post/thread by willieB (obviously I don't know how to search the forum correctly). I have looked at the diagram on bobcat.com and I did assemble the detent valve correctly. I don't think that I left it loose but I will check to confirm that. So now I am thinking that it could be lift load poppet check not seated correctly. Is that something that I could have gotten out of adjustment when rebuilding the control/spool valve? I tried to search the poppet on the bobcat.com site, but I got a half million hits on that site (yes I may be stretching that a little ). Is the poppet a part of the control valve? Thanks Again for all of your time and help with all of my questions!
Here is the link to willies control valve rebuild thread . Good luck HeavyEquipmentForums
typically what happens is a small piece of debris get stuck under the load check poppet, and holds it open. load checks are typically on the face of the valve where all the fittings screw in.
Hi All, I am back again with the same problem. I did find a piece of debris in one of the valves (see pic) which I thought sure was causing the issue. But when I tried it again after checking all 5 of the valves like this in the control valve it still has the 6'' drop when releasing the left peddle. I am not sure where to look next????
You pulled the check valves as well? (metal tapered plunger, a spring, and an o ring should be all thats in that port, if I remember correctly)
That looks like a chunk of cylinder Putin seal
Yes I removed all 5 of the valves that screw into the control valve. All were clean except for the one pictured.
Okay, I have already rebuilt one of the lift cylinders because it started leaking only about 30 minutes after I got it going for the first time. If the inner seal in the other cylinder is going bad could it cause the problem that I'm having?
Well Crew Chief is right again! After CC said that the piece of debris looked like a chunk of the cylinder seal, I decided to pull the other lift cylinder apart (I knew it would need rebuilding soon anyway if I ever get this thing working right) and guess what. Well the pics below speak for themselves. Not only does that cylinder need a seal kit it needs a piston also. I am not sure what happened to this piston but whatever it was it was a bad result. Does anyone know a good supplier for new cylinder pistons other than Bcat?
Let me try loading the pics again. Check them out
The piston itself may be fine once you get that destroyed piston seal material off, but that chrome rod looks terrible, but hard to judge anything by looking at a pic
Sorry willie59 I guess the close up pic is a little misleading, what you are seeing that looks like the rod in the pic is actually the spacer that is used in these cylinders. The blue/green looking coating the part that keeps the piston centered and protects the cylinder bore. I don't think that it can be replaced. On the good pistons in the other cylinders this coating looks to be make on the piston and only the tan/orange??? seal is replaceable. Does that sound correct? Thanks for your help. B-Crazy
I don't know your machine S/N, but after viewing parts pages for various S185's I believe you're correct, the green part looks to be a bearing material that's bonded to the piston, only the tan/orange seal is a replaceable part, looks like you're going to need a new piston after all. As for aftermarket, I don't know of a source myself, you'll most likely have to get a piston from Bobcat, but I can't say for sure.
For parts I just used AGA parts for my engine rebuild. They are a little slow on shipping but their prices were way cheaper then my local bobcat dealer and they are still original bobcat parts. Worth a look, I just look up the part numbers I need and send a request for a price. On oversized pistons and rings my local guys quoted me 1400, for the same parts plus a head gasket, a switch, radiator screen cover, and an o ring, with shipping I was at 1300. But it did take a month to get those parts they were all bobcat orignal parts in bobcat packaging, I was a little skeptical at first but they seem to be on the up and up.
Thanks for the info I will certainly try them on the next one. I called the local Bcat place this morning and much to my surprise they had it in stock so I went ahead knowing that if this fixed I could use it this weekend.
All, I have good news! After replacing the piston and seals in the damaged cylinder, I think the Bcat is ready to work! ALL HAPPY FACES TODAY!!!!! This has been a long haul and I would like to say THANKS to everyone who has taken time to offer advise, suggestions, or have just put up with all of my questions. Fixing the stuck engine was not much of a problem, I am used to working on engines. But as you can tell from all of my questions, pics, and maybe a little whining the hydraulics have given me a lot of challenges. And honestly have worn my back side out. I am soooo happy to have finally reached this point!! THANKS ALL!!! B-Crazy
Its nice to definitely get it back up and running. Hopefully you will get to put it to use for a while before it needs any more attention.