Hi all,
This is slightly off-topic, but I need to fix the power steering on an
old JCB backhoe loader, and I thought there might be an expert here who
could offer some suggestions. I think the design of this power steering
system dates back a long way. The machine has a regular tractor steering
box, but in between the steering link and the crank which turns the
wheels is a hydraulic ram. One end of the ram is attached to the
chassis, the other end to the steering crank (i.e., the crank at the top
of the king pin) and the link from the steering box attaches to a large
pin on the side of the ram. It appears that when a force is applied to
this pin, it operates a pair of spool valves inside the body of the ram.
A separate pump operates the steering from the pump which drives the
backhoe and loader. I think - but I'm not sure - that the steering pump
continuously forces oil through a small orifice and the spool valves
simply divert a bit of oil into the ram when the steering wheel is
turned. This avoids needing a pressure relief valve I guess. The
steering ram/valve unit is marked "Hydrosteer 33/64. Patents Pending. VC
140017." The steering doesn't work, but the ram isn't leaking or
damaged, and the spool valves seem to move freely enough. I wonder if it
is some kind of adjustment problem. I know the chances are slim, but is
anyone here familiar with this kind of hydraulic steering and what the
common problems are?
Best wishes,
Chris
- posted
16 years ago