Main hydraulic pump has broken bolts on pump and crank shaft end four times. Any advice on what to check?
There were two different types of shaft for that tractor. One was mostly a solid shaft, everything was rigid. The other type has a flexible disc at each end that gave some flexibility. Why do I mention this? The former shaft (rigid) is HIGHLY dependent on alignment, in other words, basically if the pump moves in relation to the crankshaft, something will break. Sometimes it's the bolts other times it's the pump bushings and/or input spline. The semi-rigid (aka flexible) shaft was developed for later L48's for this very reason; as well as it will compensate for any frame flex.
That's one thing to consider.
The other is load. If they keep breaking, I'd suggest looking at the pump's loading. It could be as simple as a quick-coupler stopping flow, causing excessive loading on the pump, which loads the shaft & attaching hardware. Or it could be something else causing excessive loading.
Another possibility is the bolts themselves. Is it possible that the bolts are too long, bottoming out? It is possible that they're coming loose at some point? Are they the correct bolts? I think they want flange bolts in them, with thread locker-but I may be wrong (check the WSM).
