Cat 287 low charge pressure

[77v46a]

New to this site looking for any info or advice on our cat 287 serial number cny.
It seems that the right track brake is dragging and sometimes will stop machine all together. We have performed basic hydraulic test everything is in spec except the charge pressure at low idle. Charge is good at high idle. We changed charge and implement pump and still have same symptoms. The implement side of the double gear pump must have been worn because bucket response and strength is much better. I think we have a internal leak hydrostatic pump or drive motor? Any advice? We did test the brake silionode, works but only have the low pressure about 200 to 240, spec is 465 psi. Is charge pressure what releases the brakes? Thanks

 

[Olly.guyding]

Was anything ever found with this, hydrostatic pump internal leakage? Currently having same issue. Have eliminated out motors as blocked them off right at hystat pump, have low charge pressure but will build 400 psi high idle.

 

[TVA]

Don’t know your particular machine.
But at low idle leaking high speed and brake solenoids might affect the charge.
Leaking brake piston ( should show up as external leak or overfill in planetary side of final drive). See what else you have in the charge circuit, like fan or pilot controls.
And of course you always start with the filter.

The only 287 I worked on was D3 - chasing damned famous leaks out of loose swivel ORB fittings, moving hoses to eliminate rub outs, and cussing all the way!!! Whoever assembled those machines needs to get their arse kicked until begging for forgiveness!