Why won't the blade on a Cat 308E2 CR hold pressure or lift the machine properly?

[Lily Anderson]

I'm trying to track down an issue with the blade hydraulics. The blade will go down, but it doesn't seem to have enough pressure to actually lift the machine once it hits ground resistance. There's no strange noise, no visible leaks, and the hydraulics seem smooth otherwise. Has anybody run into weak blade pressure like this before on these machines? Trying to figure out where to check next before I start replacing parts

 

[James R.]

If the blade moves smoothly but won't lift the machine under load, the most common causes are a relief valve opening too early, internal cylinder seal bypass, or low system pressure from the pump.