Theralfinator
Member
97 Cat 311B 8GR00134
I finally got a service manual and pressure gauges for my machine to hopefully figure out what's going on with the weak hydraulics.
Cycle times for all implement functions were well within specs.
Relief valves seem to have been turned up previously. Spec is 4350 Psi for all implement line circuits and they were set around 4700 Psi.
The pumps had no problems building and maintaining pressure, but the hydraulics still didn't have as much power as when I first bought the machine last year.
Ambient temps were in the high 50°s F so we could only get the oil up to around 140°F . The lack of power is a lot worse when the oil gets hotter than that, which it does fairly easily on hot days.
We didn't have the right gauges to test fuel pressure or intake manifold pressure. Does anyone know what the manifold pressure is supposed to be? I've read the manual a couple times and haven't found that spec.
Also, I've read that there's a screen in one of the banjo bolts in the fuel system, can someone tell me which one? My manual said there was a filter on the suction line of the lift pump, so I took that hose off but didn't find a screen. I didn't dare take apart any of the banjo bolt connections since I didn't have any new copper washers to replace any worn ones with. The suction line I checked was just a hose clamp over a metal nipple type of fitting.
I'd love any tips or ideas anyone could give me.
I finally got a service manual and pressure gauges for my machine to hopefully figure out what's going on with the weak hydraulics.
Cycle times for all implement functions were well within specs.
Relief valves seem to have been turned up previously. Spec is 4350 Psi for all implement line circuits and they were set around 4700 Psi.
The pumps had no problems building and maintaining pressure, but the hydraulics still didn't have as much power as when I first bought the machine last year.
Ambient temps were in the high 50°s F so we could only get the oil up to around 140°F . The lack of power is a lot worse when the oil gets hotter than that, which it does fairly easily on hot days.
We didn't have the right gauges to test fuel pressure or intake manifold pressure. Does anyone know what the manifold pressure is supposed to be? I've read the manual a couple times and haven't found that spec.
Also, I've read that there's a screen in one of the banjo bolts in the fuel system, can someone tell me which one? My manual said there was a filter on the suction line of the lift pump, so I took that hose off but didn't find a screen. I didn't dare take apart any of the banjo bolt connections since I didn't have any new copper washers to replace any worn ones with. The suction line I checked was just a hose clamp over a metal nipple type of fitting.
I'd love any tips or ideas anyone could give me.
