Cat 308E2 Cr blade not holding pressure

[TSalmon]

Hello…I was wondering if anyone could share a schematic for the relief valves on a 2014 cat 308e2 cr…fjx00370…just purchased and blade does not have enough blade pressure to lift the machine…will stop once it hits ground resistance…not making any noise and no visible leaks..used the bucket to lift the machine up and bottomed out the blade…when I lowered the machine down it immediately raised the blade to ground height…no noises and no visible leaks..thinking air bound or bad blade relief valve…could there be any other areas to check? Thanks for any help. Todd

 

[Nige]

could there be any other areas to check?

Leaking between the blade circuit and the travel circuit in the centre swivel.?

Attached the parts breakdown of the blade pilot valve but nothing I can see to show how it operates.

 

[Nige]

Here's a thought. Is the pilot valve somehow returning to thre FLOAT position.?

 

[TSalmon]

thank you Nige…I have noticed that when I lower the blade lever that it seems to lock in the float position…we do not have float on one of our smaller machines with a blad…2016 Bobcat E42…and I have never had an excavator with a float option…so I did not know if that was what it what supposed to do..I would have assumed it was a quick lock when pressed forward but I am pressing the lever forward and when it meets the ground resistance it seems to lock in…thanks again for your help

 

[Nige]

The blade control on your 308E should have 4 positions.

Starting with it pulled right back (RAISE) if you let go of the lever it should return automatically to the HOLD position. If the blade is up it should stay up.

Move the control forward slightly (again it should return back to HOLD if you let it go). This is the LOWER position where the blade will "power down" and should be able to lift the front of the machine off the ground.

Push it all the way forward past the LOWER position; you should feel a detent. Then you have the FLOAT position where the blade will simply follow the contours of the ground as you move the machine.

 

[hyde155bhp]

My blade has lift but if you raise it, it will start lowering back to ground. It won’t stay in raised position. No visual leaks anywhere

 

[Acecadet]

Probably should have started a new thread for your problem. However since I’m here, how about raising the blade, block it up and then remove the hose on the base end of the cylinder and try raising it again. If oil keeps flowing out of the cylinder your piston seals are blown out.

 

[hyde155bhp]

Probably should have started a new thread for your problem. However since I’m here, how about raising the blade, block it up and then remove the hose on the base end of the cylinder and try raising it again. If oil keeps flowing out of the cylinder your piston seals are blown out.

I did it here and started a new thread. But that’s a good idea. I didn’t know if this was a normal occurrence with these machines

 

[Hwg]

My blade has lift but if you raise it, it will start lowering back to ground. It won’t stay in raised position. No visual leaks anywhere

I have a similar issue with the same machine. Did you ever find the problem?