Broke the Curl of my loader

[firefighter ontheside]

Ok tractor folks, oak was too big for my loader to lift so I was pushing it with the forks.  When I curled the forks up to make the log roll there was a bang and now the forks will not curl up.  I'm assuming I screwed up the hydraulic ram.  There is no visible damage, no leak.  The hydraulics in general are fine.  Loader will go up and down.  3 point works fine.  Can the ram be rebuilt or would it need to be replaced?  It has always dropped down over a short time.  Maybe the leaky seal gave out completely.

[armechanic]

Lots of questions,  Do the forks fall as you raise the loader ?  One cylinder or two ?  When you said it made a noise made me think broke rod or piston came off the rod inside the cyl.

[Oliver05262]

What do you have for a tractor? What is the model number of the loader?
You won't know until you take the cylinder apart. Does it try to curl back on either side? 50/50 shot if you don't see any difference. Possibly the piston came off the rod, and you can restore the threads and replace the nut. In any case, you'll want a seal kit.

[firefighter ontheside]

This is a Kubota L4200 with LA680 loader.  Yes, when I lift the loader the fork curl down on their own, but it will curl down if i tell it to.  It will not curl up.  With the forks hanging down, I can manually lift them up.
It does have 2 cylinders for lift and for curl.  If I had to guess, Id say its the right side thats broken.  Seems like the left side tries to do something.  It will move just a smidge when i try to curl it back up.

[Oliver05262]

Kubota parts page shows two different cylinders; possibly a number stamped on the barrel somewhere. Both have the piston held on the rod by a nut. One is called out as 5/8" the other has no description.
Kubota Parts | Buy Online & Save

[mike_belben]

Did the forks pivot over center?  I had that happen with the stump grapple.  Will they lay flat on the ground when you put the loader down or are they bound in the fully curled down position?


No fluid coming out and nothing visibly broken is a peculiar situation for loud bangs.   

[mike_belben]

If you ripped the piston retainer nut off the rod then i suppose all fluid would pass through that side back to tank and it would sit still.  


You could test this by pullingg and plugging the hoses for that ram and trying it solely on the other. 

[firefighter ontheside]

Thanks, my plan was to call Messicks in the morning tomorrow.

I don't think so Mike.  The first thing I looked for was the rod to be bent, but its not.  They will lie flat on the ground.  Just now to put the tractor away I lowered the loader to the ground with the points of the forks on the ground and put the loader in float and backed up until the forks were flat on the ground.  Thats gotta be whats happening otherwise I would not be able to move the forks without fluid spilling somewhere.

[firefighter ontheside]

I had that thought too.  Plug the ends and then see if the other cylinder will work.  Have to find some kind of plug.  I came in here to read responses before I go and remove the hoses and then the cylinder.

[mike_belben]

Well, if you just unplug the hose on the blind end of either and get constant flow out of it without the forks curling that proves its bypassing.  Youll be able to feel and with a stethoscope or screwdriver to the ear, hear which one its flowing thru. 

Tapingg a 2 liter or gallon jug to the hose works good to keep the mess down if you havent got a helper.

Maybe someone resealed that rod and forgot to torque the piston nut? Ripped off tbe last few threads perhaps.. ?

Let us know

[Ljohnsaw]

Maybe someone resealed that rod and forgot to torque the piston nut? Ripped off the last few threads perhaps.. ?

:P
That sounds the most reasonable.  Breaking a rod would be pretty tough to do but snapping a thread or two...that would be something I'd do :-\

[firefighter ontheside]

I took the cylinder off and got a face full of hydraulic fluid while doing it.  Certainly doesnt seem broken, but I didn't take it apart.  It slides in and out pretty easily, hence the face full of fluid.

Is there any chance something failed inside the control valve?

[Autocar]

I would say you pulled the nut off the end of the ram. Because it is pretty tuff to pull and push the rod back and forth  with the seals 

[kiko]

I agree with Mike and AC. I would venture one of rods has broken right in front of the piston.  Often when this happens you can pull the cylinder to its full extension and the rod will pull right out of the can. Gotta check the other one too .That is what the pop was. It needs to addressed immediately before the tractor is even started again. Simply engaging the tilt cylinders while trying to diagnose the issue still creates a flow and can distribute metal contaminates to other parts of the hydraulic system. If this a hydrostatic drive , cleaning the hydraulic system can not be short cut.  When you find the damage in the cylinder attempting to find all the prices can give you a clue about the level of contaminates.

[firefighter ontheside]

Thanks for the info guys.  I took one ram off today.  I will pull the other off tomorrow.  The one I took off extends but does not pull all the way out of the case.  It could be that it is the other one that is broken.  It just seemed to be the right side.  After watching a video about how to rebuild them, I think I will just take them to the dealer or hydraulic shop.  I will call the local kubota dealer and also Messicks.  I really need to  get this fixed ASAP.  I got the big log on the mill manually like I used to do with my smaller tractor, but I'm going to quarter saw the thing and I need to use the forks to take cants off.

[mike_belben]

I understand the calamity but its very easy to order parts that arent broken on a hunch.  Kiko does make a good point on spreading contaminants.  Next thing you know relief valves in the trans and control valves are jammed with chips.



On the cylinders youve removed, very carefully [ppe] use a rubber tip blow gun to shoot air into the ports and see if the rod moves or if you can restrain the rod yet move stuff inside.  Or get air to blow in one port out the other.

[BargeMonkey]

Wish I had taken a picture, putting a load of logs on a couple weeks ago, landowner is using his 763 Bobcat with a brush grapple, had it out all the way and hooked a stump, YANKED the end off the cylinder about 50ft from the roaring brush pile 😆 700 bucks and he was going again. You've broken the nut off, I went thru this with a tilt cylinder yrs ago on a machine. What these guys said about contamination☝️☝️☝️ could haunt you for yrs and be alot more expensive than a cylinder. 

[nativewolf]

FYI I've found it much less expensive to take our cylinder work to an expert shop an hour or so away.  They built a cylinder for a grapple on one of our loggers JD skidders.  Decent sized cylinder, cost to make the bore and rod and seal kits was a few hundred less than JD cylinder.  They'd done innumerable jobs over the last few years for ourselves and friends and I don't even bother calling OEM anymore, the kicker on the grapple cylinder was that it took them 3 days to do it and that was faster than waiting on JD shipping.  So I'd ask around and see if you have a really good cylinder shop within an hours drive because it probably won't be the last one.  

The shop I go to will literally build a full large cylinder, for example the forwarder main lift cylinder, in the same day if you pay a rush fee.  

[mike_belben]

This spring i ordered seals for my forklift tilt cylinders, by machine serial number, direct from nasco who made the whole truck.  It was $75 each plus shipping and they were wrong. Hard to get them on the phone, machine apart for a week,  out of pocket shipping, a dozen calls to get a refund.  

Local cylinder manufacturer 30 mins away had them on the shelf for $55 out the door just by handing them the seal puck and gland endcap.   Thats my first stop from here out.  No more crawling in the mud wirebrushing for hidden serial numbers.  

[Don P]

I ordered the seal kit for one of the tilt cylinders on the skidsteer. Waited too long and finally called, it had gotten lost somewhere, they direct shipped in a few days, then a month or so later shipped again, then a month or so later shipped again. I'm hoping they just start working their way around the machine :D. If its just seals I'll fix it but if somethings busted, which this sounds like, it's shop time. On the Lull there is a decontamination section in the manual, you might want to check.

[firefighter ontheside]

I'm not afraid of doing things myself in general, but i have limited experience with hydraulics.  I took the second ram off this morning and took both to the local hydraulics shop.  I think one is broken inside and the other is not.  I'm hoping the repair is half or less of purchasing 2 new rams.  New for both would be about 1300.  Unfortunately someone brought in 4 rams ahead of me for repair, so mine have to wait in line behind them.  Until then, my tractor will sit.  I will look into the contamination issue.  I bought a new filter a while back but didn't put it on yet.  Seems like a good time to buy some fluid and do the change, after rams are back on.

[mike_belben]

Price them on surplus center.  Probably 250 each or less. 

[firefighter ontheside]

Thanks.  They will call with an estimate before they do any work and then I'll decide if I need to replace them.  Im actually looking forward to the curl not sagging when its all done.  

[kiko]

I always try to find cause of failure. With the forks tilted down even slightly with the load on the end of a lever and the possibility of the tractor pushing at the same time creates a pressure spike between the cylinder piston and  relief valve . The relief valve cannot dump fast enough to keep the pressure  below the engineered capacity of the cylinder.  This same dynamic can damage the relief valve just the same. 

[firefighter ontheside]

@kiko yes, there is the possibility that the cylinders are not the problem.  IF they call me and say they are not damaged, then I will know something else is wrong.  I did wonder if something could have failed in the control valve.

[mike_belben]

If you follow your curl hoses back to the valve, theres probably a plug or cap between the hoses.  Look under there. Dont lose the pieces or forget the order.  Talking and showing the details into your video camera as you remove them always works.

[nativewolf]

If you follow your curl hoses back to the valve, theres probably a plug or cap between the hoses.  Look under there. Dont lose the pieces or forget the order.  Talking and showing the details into your video camera as you remove them always works.

+1

[firefighter ontheside]

I talked to the guy at the shop.  He said one rod is definitely broken and the other one is slightly bent.  I hope that means that nothing else is messed up.  He hasn't given me an estimate.

[firefighter ontheside]

I just approved the shop to repair my cylinders.  He is replacing both rods and seals.  Total for both will be $650.  That's exactly half of the cost to buy new ones, so I'm happy with that.  Not as happy as if I hadn't broken them, but I'll settle.  It's gonna be a week before I get them back.

[Hilltop366]

If a person was in need perhaps they could disconnect the bucket hoses from the quick connect and put a couple pieces of chain or steel where the cylinders go to hold the forks level to get by in the meantime, and/or even better rear forks for the heavy ones and save the loader, front end and rims from early failure.

[47sawdust]

I believe that loader has a lifting capacity of about 1300#.
Hilltops suggesting of using 3pt. hitch forks is a good one. Not only greater lifting capacity but the tires and front hubs take a beating under load. A hyd. top link is a real plus.

[caveman]

A boom for the 3 pt and a set of log tongs may not be bad for lifting/loading the bigger ones. I would have a few different attachment points on the boom. Rear forks and a hydraulic top link would also prove very useful, as previously stated (not to beat a deaf horse, but  There's more than one way to skin a calf).

[firefighter ontheside]

The lift capacity is listed right at about 1500 lbs for the loader.  It is more than adequate for most logs I deal with.  I will just have to be more careful when pushing around logs that are too big for the lift.  I should probably put the bucket back on for those.  It works better for pushing logs around. I have thought about getting some forks for the rear too.  The added benefit being that I can keep a log on there for ballast.  

[mike_belben]

When youre really maxing out the loader, take off the forks and the bucket, and use a pair of chains. 

[firefighter ontheside]

Well, I finally got my cylinders back from repair and reinstalled on the loader.  All is well.  There was a moment of panic when nothing moved for a while and I thought it wasn't working.  Clearly that was just air working out of the system, because after holding the handle for about 30 seconds it starting lifting the forks.

[Jim_Rogers]

Well, I finally got my cylinders back from repair and reinstalled on the loader.  All is well.  There was a moment of panic when nothing moved for a while and I thought it wasn't working.  Clearly that was just air working out of the system, because after holding the handle for about 30 seconds it starting lifting the forks.

Many system do self bleed out the air. But afterwards you should check your fluid levels again. With the air out the level maybe low.
Jim Rogers

[firefighter ontheside]

I added almost a gallon of fluid.

[Ed_K]

 That's not bad. Last time I had a cylinder rod bend due to broken pin I lost over 5 gals >:( :(.