450C - power beyond port question

[Donnie_Ray]

I have been working on attaching a backhoe(9300 model) to my 1975 450C crawler loader. From a number of helpful tips on this forum plus the manual I have been able to plumb the backhoe, however I seem to be overlooking something or I have a faulty power beyond valve because there is very little oil flowing through the power beyond valve. Does the power beyond valve need to be opened from some hidden lever or switch?
I'm very confused because the power beyond port had a threaded plug in it and I simply removed it and attached my power line to it. Question...if oil is suppose to automatically flow under pressure when I attach a hose to the power beyond port then why wouldn't pressure build up in the power beyond block with the plug in the port? Please excuse my terminology, all of this is brand new to me. So basically I would like to know what could be the problem with the oil flow? Any help would be greatly appreciated!!

Thanks,

Don

[JWB Contracting]

These is suppose to be oil flowing out of the power beyond directly to the backhoe attachement, thru the value and then return it to the tank.

You may not have plumbed it in corectly - the machine will not run if there is an interuption in flow from the power beyond, such as the installation of a plug.

I am not an expert on this, but we have 2 350C with hoes that we have had for 30 years and in removing and mounting a hoe a few times i know that oil needs to have an unrestricted flow to the valve and return to the tank.

[Donnie_Ray]

Thanks for responding Jason. My problem isn't that I have a restricted flow problem beyond the power beyond. The problem is that there is no oil flowing out of the power beyond port. I'm not sure if the power beyond has ever been used on my crawler. Do you know if there is something that has to be done to the power beyond to "activate" it so to speak? Is there something in the power beyond valve that could be broken that is causing the blockage?

[MattE]

Genericly speaking when power beyond is not used there is a plug that is removed from the journal of the valve body to allow fluid to flow across the valve body. When you wish to use the power beyond capability this cross port needs plugged. So yes, there is something you need to do to "activate" this. I need to look at the valve breakdown to determine exactly what it is. If your crawler never had any rear mounted equipment then the valve is not configured for it as it sits (more than likely). I will look at the valve breakdown tonight and let you know I don't have a manual in front of me

[Tiny Crawler]

the cap you removed and added a hose to, look inside the port, you should see another plug, remove that plug, when installed, the plug prevents neutral oil from returning to the reservoir. then reinstall the hose to the outside port that was capped, then it should work.

tiny.

[MattE]

Tiny's all over it... One thing more to note. When that plug is removed you will have to keep the hydraulic lines connected when not using your backhoe to allow fluid return to the tank. That should go without saying, just thought I'd throw it out there.

Good luck.

MAtt

[Donnie_Ray]

Thanks Matt and Tiny for your replies. I'm going to check to see if that plug is in the port. I'm assuming (hoping) it is. I did know that the lines had to be connected when not connected to the backhoe. Hopefully I can finally get to using my machine this weekend!
Thanks again for your assistance.

Don

[MattE]

If it is removed there is one other possibility. If the spool on the aux valve is not returned that too would bypass fluid, but you should be able to hear that in the pump and your other hydraulics would have not function correctly

[Donnie_Ray]

Okay, I checked for a plug in the power beyond port and unfortunately there is no plug and no place for a plug to be. It's just a smooth curved opening inside the valve. Also, the hydraulics on the loader work fine so I don't think the spool on the auxiliary valve is out of place.

[MattE]

The plug would be between the two valve journals. I will look at the one in the shop tonight and try to determine where it is at without tearing the valve apart. If you have a schematic of the valve I can tell you where it is at. I didn't get a chance to check my books yet. I will let you know tomorrow

[MattE]

I checked all the literature I have on 350 and 350 b and I don't have any breakdown of the aux valve. I looked at one on a crawler last night and I don't see anything. Unfortunately with out a schematic I can't tell you much more. Hopefully someone here has a schematic of the aux valve they could up load. Sorry I couldn't be more help. I would hope it is not between the valve stacks, but no way for me to know without tearing a valve out of a crawler, which I don't have the time to do right now.

Good luck

[Donnie_Ray]

Thanks Matt for looking into this for me. Yes, hopefully someone here has some more information on the auxiliary valve because I'm not sure where to go from here.

[KenP]

deleted

[Tiny Crawler]

Ken is right, the sleeve is screwed into that port and it closes off the neutral circuit to the valve return port.

I have this in a PDF document for the bulldozer hydraulics, if you PM me your email I will send it to you.. if you want it as well

tiny.

[Donnie_Ray]

Thanks Ken and Tiny, the power beyond sleeve was indeed what I was missing. I wasn't able to purchase a sleeve so I took my power beyond valve into a hydraulics shop and they made it for me without too much trouble. I have now finally got my tractor and backhoe transported to my woodlot and it is working quite well.
Here are a few pics.

Thanks again,

Don

http://i845.photobucket.com/albums/ab18 ... ackhoe.jpg

http://i845.photobucket.com/albums/ab18 ... uzzled.jpg