JD350 Loader Boom not working - Hydraulic Pump Disconnect??

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bobdoss
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JD350 Loader Boom not working - Hydraulic Pump Disconnect??

Post by bobdoss » Fri May 27, 2016 8:04 pm

I just bought a JD350 (straight) loader. Engine and undercarriage look good, but I have not been able to move it because the boom won't raise off the ground when I move the control lever.

I suspect the hydraulic pump is not pumping, but I'm not sure how/why. With the disconnect lever horizontal, the fork connected to the the lever is all the way back on the coupling (against the rear flange of the rotating coupling). When I raise the disconnect lever to about 45 degrees, the fork moves to the front flange of the coupling, but it stops moving and doesn't move the coupling when I pull the disconnect lever the rest of the way to a vertical position.

It seems to me that the fork should move the coupling forward when the disconnect lever is vertical. Am I right? If so, why isn't the fork moving the coupling forward and engaging the pump?

If I'm wrong about this, how else can I troubleshoot the fact that the boom will not raise?

Thanks in advance for any advice - I need to get this thing working so I can load it and bring it home.

PS: Should I be moving the disconnect lever with the engine running or stopped?

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Re: JD350 Loader Boom not working - Hydraulic Pump Disconnect??

Post by bdbundy35 » Thu Mar 14, 2019 11:11 am

I’m having a similar problem with a 350B dozer I recently bought. I’m curious if you found a solution? And any additional info on the hydraulic pump disconnect would be helpful. Thanks

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Re: JD350 Loader Boom not working - Hydraulic Pump Disconnect??

Post by Jim B » Thu Mar 14, 2019 1:04 pm

Does your machine have a pump disconnect? According to the 350B parts catalog; serial number 191897 and before had a disconnect with lever. 191898 and after used a splined drive shaft, not the lever disconnect set up. Either way you need to get eyes/hands on the actual pump shaft to see if it is turning when the engine is running or to try turning the pump shaft by hand when stopped. That will be easier on your dozer than his loader, either thru the right side or the grill.

Go to https://jdparts.deere.com/servlet/com.d ... anguage=19 . Put 350B in the model search box and it will give you a drop down to pick from. The 350B crawler tractor is PC1169. You can see diagrams of both types of pump drives in the section containing Hydraulics.

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Re: JD350 Loader Boom not working - Hydraulic Pump Disconnect??

Post by NWJD fan » Thu Mar 14, 2019 3:14 pm

The drive hub which bolts on to the fan belt pulley on the engine seems to be a relatively common failure point. Just changed one on my 450C and the same part number crosses over to 350's as well. If you have the splined hub just check that the pump driveshaft is rotating at high speed when the engine is running. Mine was still turning but only about 10 rpm when the engine was spinning 1200 rpm

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Re: JD350 Loader Boom not working - Hydraulic Pump Disconnect??

Post by bdbundy35 » Sat Mar 16, 2019 6:09 pm

Yes my dozer has the pump disconnect. It looks to me to be disengaged. The disconnect doesn’t look to be whole either the splined coupling has come off and I’m missing and the lever hopefully not much more then that. I’m pretty new to these machines so I don’t have any experience using the hydraulic pump disconnect or seeing it in use. I have the owners manual but don’t see much info on how it works. If you guys have some experience with it i would appreciate any additional info. Thanks!

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Re: JD350 Loader Boom not working - Hydraulic Pump Disconnect??

Post by Jim B » Sun Mar 17, 2019 6:32 am

Just asking some questions to get all the info clear, since we can't see what you are looking at. What is your serial number? Was it working when you got the dozer and quit after working a while? I only ask as you saying it is missing the splined coupling and lever. I take that to mean the sliding coupling that engages with the adapter fitting on the crank pulley. Is the fork that moves it still there? The splined coupling, moved by fork which is controlled by the lever, should have been a captive piece. I believe the shaft would have to have been removed to get it off. Or are you missing the second splined coupling located at the hydraulic pump shaft? Did you look at the two different styles of pump drives in the parts manual? The newer one only has a coupling at the pump shaft, no lever and sliding disconnect.

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Re: JD350 Loader Boom not working - Hydraulic Pump Disconnect??

Post by bdbundy35 » Sun Mar 17, 2019 10:46 pm

My serial number is 117554. It is the older style pump. The fork is there. I bought it with the hydraulics not working.

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Re: JD350 Loader Boom not working - Hydraulic Pump Disconnect??

Post by Jim B » Mon Mar 18, 2019 5:21 am

You still haven't said you have checked to see if the hydraulic pump shaft is turning, either with the engine running as NWJD fan suggested or by trying to turn the actual hydraulic pump shaft by hand (pliers, etc.) with it stopped. It might be something else, but you need to know the pump is turning at engine speed first. You said you have the "owner's" manual; is that the Operator's manual JD # OM T46859 or the Technical manual JD # TM 1032? Lavoy can help you with manuals if you need to get any. You have the link to the JD parts catalogs in an earlier post I made.

A previous owner may have done something to bypass the disconnect, since you say the sliding coupling and lever are missing, but the fork is there. It doesn't seem those parts would just fall out. May be they welded some parts together and now a spline is worn out. Are you sure they haven't updated it with the newer drive, having no disconnect? The disconnect image below is from a 450B Technical manual but your machine should have the same parts so the info should apply. Does your shaft and other parts look exactly like the ones in the image, minus the sliding coupling and lever? I can't see it so I need to ask. It would seem you are close to the point of getting in there with wrenches, taking it apart, see what you have, then find parts and repair it.

What is your general location? You might add it to your profile. It may help to know if you end up looking for parts, people might have a better idea of likely options in your area for you to check.

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Re: JD350 Loader Boom not working - Hydraulic Pump Disconnect??

Post by dtoots1 » Mon Mar 18, 2019 8:15 am

Howdy JimB,

bobdoss...says that he does have the lever on the disconnect...it does move the coupling...just won't move it to engage all the way...would appear something broke or possibly in misalignment? splines or shaft bent or dropped down? maybe loose?

am sure it is in hard to see location...i don't have that equipment on jd440

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Re: JD350 Loader Boom not working - Hydraulic Pump Disconnect??

Post by Jim B » Mon Mar 18, 2019 9:15 am

Hi dtoots1,

Hope all is well with you, and your 440IC.

This is a "trick" one, two different posters. bobdoss made his one post about his loader in May of 2016 (no follow up on it) and hasn't posted since August of 2016. bdbundy35 tagged on to it last Thursday about the disconnect on his dozer, everything since his post is replying to him. bdbundy35 said he is missing the lever and coupling. I am thinking it may have been modified in some manner, or he should be missing more parts. I don't think the sliding coupling can get off the shaft unless physically removed by someone; or leaving a path of destruction if it removed itself while the engine was running. Hopefully we can get it figured out.

Jim

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Re: JD350 Loader Boom not working - Hydraulic Pump Disconnect??

Post by Lavoy » Mon Mar 18, 2019 9:44 am

My suggestion would be to start a new post to end the confusion.
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Re: JD350 Loader Boom not working - Hydraulic Pump Disconnect??

Post by dtoots1 » Mon Mar 18, 2019 2:02 pm

oops ...missed that!

and my jd440ic is running great! just needed that condenser....getting her full of mud this past week and more rain coming the next 2days..so she gets back in her little dry cubby tonite!!

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Re: JD350 Loader Boom not working - Hydraulic Pump Disconnect??

Post by bdbundy35 » Fri Apr 12, 2019 7:19 pm

Sorry for the confusion. It’s been a while since I’ve been able to reply I’ve been swamped with work. I was look at the pump further and I believe the previous owners put a newer pump on it and just left the disconnect there. Thanks for everybody’s help I appreciate it.

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