450C weak hydraulics.

[deepsouthoutdoorsman]

I have a new to me 450C loader. I bought it knowing the hydraulics are weak. Boom wont even lift unless at high rpms. So I purchased a pump for it thinking it was the pump. Same thing. No hydraulic pressure. Every control is the same way. So I drained the tank. New return filter. Cleaned the suction screen. Refilled to half way is sight glass. Still same thing. Weak pressure. I removed the pump again and checked the coupler splines and they are good. Is there a Main releif valve on the system they may be stuck open not allowing any pressure to build? If so where or which valve body would it be in?

[Jim B]

If you just have a loader I expect you have only one hydraulic valve body. Yes there is a relief valve in the loader valve body. They can fail (broken or weak spring, something stuck in it holding it open, etc.). Is the boom lift the only problem or is the bucket roll back weak as well. If it is just the boom circuit it could be a cylinder packing issue. If you don't have them, you should get the manuals for your machine as the technical manual will the diagnostics section and adjustments for the same. I believe the Operator's manual is OMT62743, the Technical(service) manuals is TM1102, and the parts catalog is PC1443. The parts catalogs are available to use for free at https://jdparts.deere.com/servlet/com.d ... andingPage. For the other manuals send Lavoy an email (postmaster@jdcrawlers.com) and I expect he can help you get the right ones. His store provides this site for us to use so it is right to support him when we can.

Because of wrong decals being installed on machines and past misidentification caused by confusion with letters tied to the model number, are you sure you have a "C" model. If you are not sure, please post your machine serial number and someone will break it down to confirm what you have.