Cat 312C 2003 2 way hydraulics

[Jamesbarle]

Good morning,

I have been really really struggling to get help in converting my Cat 312C's auxiliary hydraulics from 1 way to 2 way.

I have read plenty on the forums that say the manifold is simply blanked off for the 2 way circuit and all you need to do is run some pilot lines and feed the return pipe back into the manifold rather than dumping the fluid straight to the tank.

I didn't feel confident to do myself so rang a couple of local hydraulics firms to come out and rig it up. Both lots came out looked blankly and said they couldn't do it and they would just fit a diverter valve to the shroud ram and use the flow from that. I dont want to do that! Both charged me a fortune for a site visit and neither offered a sensible solution! I have rung a certain auxiliary hydraulics specialist in the UK over 8 times over 3 months with absolutely no luck. They just keep saying one of their engineers is looking at it. i am at the point of part exchanging the machine in against one with 2 way and talking the loss.

If I press my foot pedal forward it activated the hydraulics. If i press it the other way nothing happens. I have switched the pilot line to the other blanked off port on the valve for the foot pedal and it works in reverse. So my foot pedal is 2 way.

Could anybody possibly give me a shopping list and very basic diagram how to hook it up? I have the Cat schematics for the hydraulic system but i just find it too confusing.

Thanks in advance for any help

Pictures below

https://imgur.com/a/emH86oj

 

[jonno634]

This was posted here before... seems like what you are looking for.

https://www.heavyequipmentforums.co...ay-hydraulic-conversion-qs.14593/#post-185217

 

[heymccall]

In the Caterpillar world, I cannot search for your answer without an exact serial number to pull build configuration, and to ensure correct images.
Or at least the prefix to get in the neighborhood.
After all, there are only 8 s/n prefix options for a 312c

 

[Nige]

In the Caterpillar world, I cannot search for your answer without an exact serial number to pull build configuration, and to ensure correct images.
Or at least the prefix to get in the neighborhood.
After all, there are only 8 s/n prefix options for a 312c

Stock response from my learned friend above - If you want accurate information regarding a Cat machine - post a Serial Number. Anything else is just guesswork.

 

[Jamesbarle]

CAT312CLBNN00502

 

[heymccall]

As built...1 way, 1 pump auxiliaries. Circled is one way pressure out.
Under X is return oil.

Gonna dig some more to find conversion info.

 

[heymccall]

Build arrangement

 

[Jamesbarle]

Thanks Heymccall that first diagram is spot on to what i have got. Hopefully there is a way and appreciate your help greatly!
I dont know if you saw my pictures i uploaded but my auxiliary lines go into 2 large blocks before returning to the tank and the manifold. Do you know what these do?

 

[Nige]

Here's the photo so we can all see it. I assume you're referring to the blocks in the red circles.?

 

[Jamesbarle]

yep they are the ones. The red appears to be the high pressure line from the manifold but not sure what the crossover black pipe does from the high pressure side back to the other block?

 

[Jamesbarle]

So it doesn't look like it is possible to rig up 2 way hydraulics to the existing system for this machine.

I have fitted a 6 way diverter valve and had one question.

The 6 way diverter has a 1/4 BSP dump port that needs to return to the hydraulic tank. If i fit a 3/4 BSP T with 1/4 BSP reducer can it be tapped into the 3/4 hydraulic line circled in red? Will this circuit allow the fluid to be dumped back into the tank or is it only open when you press the hammer circuit button?