CASE 450 HYDRAULIC PUMP PRESS. ADJUSTMENT

Phil H

Member
Has anyone out there ever adjusted the hydraulic pump pressure? I may need to increase the hydraulic pump pressure on my case 450 loader. I have a brand new pump and I put a 4 in 1 bucket from a case 455 on it. The original bucket was an 8/10 yrd. bucket and the 4in1 is 1.25 yrd. It is a LOT heavier than the original. I would rather increase the pump pressure just a little,(not a lot) rather than increase the lift cylinder size. Or I could just load the bucket lighter, which I would probably do if things don't work out. Just was kicking the idea around if it isn't a big deal to increase the pressure a little bit. This is my real work horse and is the go do machine when I need to get things done. thanks Phil
 
you can not do anything to the pump to increase pressure but you can do it at the bypass valve at the control
 
As per marloweg's post you can adjust the pressure relief valve. That regulates the pressure the pump develops. If it has not checked and adjusted recently it may be below spec. I don't know what the specified pressure is supposed to be for your machine. Your service manual should cover checking and adjusting the pressure. A few things to consider. If your pump is worn it may not be able to develop the specified pressure, much less develop more pressure. The system was designed for a specific operating pressure and running the pressure above that can shorten the life of components like the pump, hoses and packings/seals in cylinders. Pump cases have been split by over pressurizing. The flow (= cycle speed) may be reduced as the pressure is increased if the pump is worn. If the pump can't meet specs you will need a rebuild or replacement, no adjustments for the pump.

That bucket may have been an option for the machine when it was new, some research should tell you that. If it was an option, I would expect the specified pressure would be all it needs.
 
According to the parts list it's the same pump and cylinders on both machines,the main regulator valve is at the corner of the control valve chest,the adjustment is under the acorn nut, that valve is set at 2000 psi plus or minus 50,there are a few different makes of valve,according to the manual the port valves are set on the bench with a hand pump,the main pressure can be checked and adjusted by attaching a 0 - 3000 psi gauge to a bucket crowd line with a tee on the crowd cylinder,the machine should have been able to manage the 4 in 1 as its no different than lifting any extra weight say a heavy material like sand or gravel,the o'rings on the main valve body often go hard and let the pressure escape,if your dealer was near I would replace them,if you are going to chance turning up the pressure without a gauge do it half a turn at a time,does this machine have a backhoe.
AJ
 
Thanks AJ the pump is brand new, and the bucket control valve to open the jaw is new, and not the one from Case. This valve is a self return to center when the jaw is opened or closed. I haven't tried to load any gravel or any thing yet, so it just may be no problem. The machine has a hoe on it as well and everything works great. The hoe could use some new bushings but works good for me. I had to have one of the loaded pins where the 4 in 1 bucket attaches to the big lifting arms moved (in) 1/2" because it was just a little wider than the attaching pins on the original bucket. This 4 in 1 is like NEW BUT IT IS A LOT HEAVIER than the original. Just a lot stronger and beefier, I use this new bucket to pull trees, and clean up the pasture. Haven't used it to load any dirt yet. I am glad to know the hydraulic systems on the 450 are the same as the 455, so like you say everything should be just fine. thanks, Phil
 
Thanks for the reply. Like I told AJ the pump is NEW, and there are no leaks and all the hoses are the same size as the original from CASE. I haven't had a chance to load dirt or dig around with it. It will lift good sized OAK TREES, with no problem but some times they are a little to much for it. Don't know what the OAKS weigh, so loading the bucket with dirt will be the best way to check it out. thanks for the comments, Phil
 
I will have to look at the valves to see where the bypass is, that is something I didn't know, which is REALLY good to know. I will look at my book and see if it shows me where it is. Seems like I did read where they showed how to check the hydraulic pressure, so I will check this out. Thanks for the comments. Phil
 
This is a picture of the online parts drawing if it will help,you remove the acorn nut (dome nut),then slacken the jam nut and you move the screw in to increase and out to decrease.
AJ
mvphoto26796.png
 
Thanks AJ
I printed the picture. Where is this online parts? I will try to GOOGLE it in the meantime. Phil
 
Go to the link below,it will take you to the Case online parts site where parts for any Case machine can be looked up,go to the link,first page opens,on the top menu bar click on Find Parts By Model,page changes,type in the search box the model of the machine only (ie 450 and click on search,a new page appears listing all the models with 450 in the number pick the one with 450 crawler tractor,the page changes,on the left is a list of the sub sections,click on hydraulics,the hydraulic system parts are listed for both the dozer and loader,there are three pages,at the bottom click on the arrow head to go to the next page.
Good luck
AJ
Case Parts Site
 
Thanks AJ
I looked up the parts from this web site and printed out the picture of the valve.....Phil
 

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