Bobcat CT122 Hydro Problems

   / Bobcat CT122 Hydro Problems #1  

njsnowremoval

New member
Joined
Jun 25, 2014
Messages
2
Location
clifton, NJ
Tractor
Bobcat CT122, Gravely 812 & 818T
Hello Tractor Gods.

My name is Dave, I am the technical director at a YMCA ( I fix anything others can't lol)
We have a Bobcat CT122 Tractor with a loader on the front and plow on the back. It was purchased new and had only 30 hours on it and then sat for the last 5 years or so with no use because the old maintenance guy had a nice A300 skid-steer that he used for everything including snow removal on the property. Well he quit and of course they want to use the little ct122 for everything. I replaced the battery and checked all the fluids and it started pretty much right up. Hydros were strong ( could lift the tractor up at low RPM).

I advised the other people operating it not to exceed around 6-800 pounds with the plow as ballast but they tried moving a stack of huge tables and since then we seem to have steadily lost power on the hydros. The bucket takes forever to go up and the 3-pt wont go up all the way with the plow on, it will with it off.

I had read in a few forums that if the hoses on the suction lines are bad then that could indicate a bad hose. I replaced all 3 on the line because they had some minor dry rot. I wasn't able to replace them with OEM hoses but I got some good ones at a local hydro shop. The guy there thought it was crazy that the thing can be at 2300 lb pressure with regular clamps even after i told him that its the original design : P

Anyway, I tested the pump per specification in the service manual and found that the pump at full RPM is only pumping out 1200 maybe 1500 psi and it should be at 2250 according to the manual. I tried adjusting per manual directions, the main relief valve on the flow control valve assembly and that didnt do anything. There is no relief valve on the right joystick valve assembly ( although it indicates there is one on the valve...weird)

I also have heard a dirty modulation valve or relief valve can be the problem. Im pretty sure at this point since the rear 3-pt and bucket hydros have the same crappy performance then it must be the pump? I'd hate to take the pump off and have it rebuilt if thats not the problem especially since the loader brackets have to come off, i know its only 8 bolts but it just doesnt sound fun. Anyway, any advice is greatly appreciated. Thank you!

-Dave
 
   / Bobcat CT122 Hydro Problems #2  
Dave I don't have the answer, maybe a question. Why did you caution the employees not to lift heavy loads with the tractor? There is no problems with attempting to lift something too heavy that would cause the relief valve to open. That is all that should happen. I have opened the relief valve thousands of times by attempting to lift something that caused the pressure to rise above the relief valve pressure.

You could still have an issue with a partially stuck relief valve in my opinion. Attempting to lift a heavy load should in no way damage your pump. You mention replacing suction lines. Suction lines don't have any high pressure on them. You mention 3 lines. That does not sound like anything I have ever seen on a tractor. Going to your loader valve you would have the line coming from the pump, the line going back to the tank and the power beyond line going back to either the first selective control valve for the first remote or to the 3point if you have no remotes. No suction lines here.

The suction line runs from the "tank" to the inlet of the pump. If a hole develops in a suction line air can ingress and prevent the pump from working properly and getting the amount of fluid it needs from the tank.

So again I don't have the solution, but I don't understand what you replaced and I don't think you have explored the relief valve possibility. I would not be too hasty to have the pump rebuilt just yet. I don't have the workshop manual on that machine nor any experience with it, but perhaps if we can keep this thread going for a bit, someone who has will offer some more advice.
 
   / Bobcat CT122 Hydro Problems #3  
One other question, did you try replacing the Hydraulic filter? If the filter is stopped up, this would prevent the proper amount of fluid from entering the inlet of the pump.
 
   / Bobcat CT122 Hydro Problems
  • Thread Starter
#4  
Thanks for the reply James, I only cautioned them based on reading in other threads about trying to lift too much without the proper ballast. I understand though what you are saying about the relief valve. I never have really done much work with or on a tractor this large. I own a small gravely 818T so loaders are new to me. I have a hydro filter which I was going to replace next but it the machine only has 50 hours on it so i figured it was a waste of oil and a filter to change it so early. Then again it will be a waste of time rebuilding the pump so a simple filter replacement would be a nice solution. I suppose I'll try that out next. As for the suction lines, I only replaced the rubber hoses that are along the line. They seemed a bit rotted so i figured i'd go for that first but like you said there isn't high pressure on the suction lines. I'll try the filter out and let you knoew what happens. I'll throw up a few pics to, the things a little beast when it works.

PS: if i get it working again id really like to put a fork attachment on but without bolting them on to the bucket. Any idea if they make aftermarket forks that can replace the bucket? Thanks!
 
   / Bobcat CT122 Hydro Problems #5  
Thanks for the reply James, I only cautioned them based on reading in other threads about trying to lift too much without the proper ballast. I understand though what you are saying about the relief valve. I never have really done much work with or on a tractor this large. I own a small gravely 818T so loaders are new to me. I have a hydro filter which I was going to replace next but it the machine only has 50 hours on it so i figured it was a waste of oil and a filter to change it so early. Then again it will be a waste of time rebuilding the pump so a simple filter replacement would be a nice solution. I suppose I'll try that out next. As for the suction lines, I only replaced the rubber hoses that are along the line. They seemed a bit rotted so i figured i'd go for that first but like you said there isn't high pressure on the suction lines. I'll try the filter out and let you knoew what happens. I'll throw up a few pics to, the things a little beast when it works.

PS: if i get it working again id really like to put a fork attachment on but without bolting them on to the bucket. Any idea if they make aftermarket forks that can replace the bucket? Thanks!

Ok on the ballast.. yes that is necessary for safe lifting. I am assuming you checked the fluid level in the transmission/tank. The Hydraulic and Hydrostatic filters are both supposed to be changed out at 50 hours. Many guys do not change out the fluid until 400 hours, although I changed mine at 50 on my DK35se. I was thinking the Kioti/Daedong equivilant tractor the CK20s does not have SSQA (Skid Steer Quick Attach) on the loader bucket, but I am not sure about the Bobcat version your CT122. Does it have SSQA? if so then here is what I would buy.

Everything Attachments Compact Pallet Forks with 42" Tines

If you bucket is pin on, you can get an SSQA adaptor to pin on and it will accept SSQA buckets and forks or grapples. You would need to modify your bucket to SSQA. If you want a good laugh you can follow my project in doing this.

http://www.tractorbynet.com/forums/....html?highlight=so+you+think+converting+a+pin
 

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