Cat 511–552 harvesters: hydraulics and folded transport

Processing hydraulics and the folded shipping front

Hydraulic preparation matters when a Cat carrier is advertised with a dangle harvesting head. The original publications offer different hydraulic configurations for processing heads and intermittent saw heads. An engine rating does not identify which package was installed.

Trace the head's plumbing and control arrangement against the machine's build information before treating a former felling carrier as a ready-to-work processor.

The smallest carrier has its own pump specification. On the 511, the travel and implement pumps each have 180 cubic centimetres of displacement. A 521, 522 or 532 changes those entries to 200 for travel and 190 for implements, with a separate 55-cubic-centimetre saw pump.

Displacement describes oil volume per revolution; those figures are not gallons per minute. This distinction matters particularly in a parts search, where an incorrectly labelled flow figure could point to an unrelated pump.

The C9's two horsepower lines describe different engine speeds. Cat prints gross output at 1,800 rpm and rated output at 2,100 rpm. The lower number on the latter line must not automatically be described as a net rating: that is not how this brochure labels it.

For the large three-model group, the figures are 305 gross horsepower and 282 rated horsepower. Engine condition and the installed hydraulic package still determine whether an attached processing head can carry out its intended functions.

Shipping length depends on how the boom is stowed. Caterpillar's large-harvester drawing shows a tucked boom for the leveling 552, alongside a substantially longer transport arrangement for the fixed-carbody 541 and 551. The resulting shorter length does not mean the 552 has less operating reach.

Those drawings also assume particular single-grouser shoes, a standard skylight and the factory's wide undercarriage setting. Added guarding or a different head changes the transport problem. Measure the assembled machine.

Oil filling has a specific route on these carriers. An electric fill pump and accessible wand deliver replenishment oil through the filtering system into the reservoir, with a sight gauge showing the level. The reservoir's capacity remains separate from the complete hydraulic circuit's contents.

On a head-equipped machine, substituting the smaller tank figure for the whole circuit would leave the service plan incomplete; the appropriate operation and maintenance manual determines the actual procedure.