This machine had dug up peat all of its working life and was in a fair condition and complete with all of its covers. It was a late production model with the later 580C Modifications. Sevreral of the bolts around the slew ring had sheared off in the bedplate so there was no choice but to seperate the platform from the undercarriage. The boom and dipper arm were first removed and then the remaining bolts from the slew ring. A 30 ton Daewoo took very little effort to lift the 580C platform from the undercarriage. Undercarriage The tracks were then split. They are the 30 ins grouser pads which are 6 inswider than the standard pads and offer less ground working pressure from working on peat moors (some Hymacs were specially equipped with 48 ins wide pads for this type of work). There was very little wear on the track pins and the bushes so they were re-fitted. The undercarriage was completely stripped of all of its component parts including the bottom rollers. Undercarriage welding (later production machines) had the thicker wall cross tubes and the tub so there was no need for any welding. The undercarriage was shot blasted and painted. The idler wheel bearings had not collapsed but were dry of any lubricant and could not be knocked out, so the assemblies were taken to Finning (CAT) to be pressed out. The idlers were then rebuilt using new bushes and new face to face seals. The shafts cleaned up fine. The track adjusters had both new seals and chrome bars fitted. The bottom rollers were shot blasted and painted. The top rollers had flats worn onto them and were replaced. The track drive gearbox components were all cleaned and checked and the brake fastener pinions replaced, along with bearigs and seals and gaskets. The brake shoes were relined and the brake cylinders resealed. The final drive assemblies, which are piece part built into the frame on the Hymac 580C, were all checked for wear. It was the heavy duty final drive with a thicker drive shaft (later production). The drive sockets were blasted and painted. The shafts and bearings were cleaned along with the retianers and spacers. The face seals were renewed. Transfer of movement from the gearbox to the final drive sprocket is via a heavy duty roller chain. They had stretched and were replaced. The track drive gear drive motors were were stripped. The motors were reconditioned and then run on a test rig to confirm both pressure and delivery. The platform had the same treatment of blasting and painting, all the tanks being cleaned both before and after then sealed. Hydraulics Elm327 software. The hydraulic pumps on the Hymac 580C are gear type hamworthy 2100 series triple in line design directly driven from the engine flywheel through a flexible coupling. There were fitted to the test rig before being stripped to check the flow rates as the machine was very slow especially on tracking. The reading weren't too bad when tested from cold however the oil soon became hot, which is a good marker for worn pump components, and the test rig readings soon fell away drastically, especially on the two front pump sections. A new pump would give a 10% fall off in flow at 2,000psi. The readings demonstrated that this was where the sluggish tracking was coming from. When i stripped down the pump and saw the model plate and serial number, this was the original pump some 30 years old, turning at 2,000rpm. The pump was recoinditioned using all off the shelf parts. The reassembled pump was put back on test and under load the flow figures showed that the pump was now operating like new. The valve blocks (Dowty Husco Type) were stripped and all pressure set while hot on the test rig. Slewing Motor It was a Staffa radial piston type slew motor and had very good inner components, slippers, pistons and crank lobe etc. However, the crankshaft itself had a crack that ran from the bottom of the pinion keyway which had been due to the pinion working loose. A new crank was ordered and the motor was rebuilt using new bearings and seals. Slew Rig The slew rig was the Raballo type and some of these rigs have a double row of steel ball bearings but this was the taper roller type where each roller is fitted through a plugged hole in the bearing wall. This is a pre loaded bearing making the last rollers very difficult to get in to the track. The slew ring is fitted to a seperate bedplate with the motor and pinion bolted in, the bedplate can then be adjusted to give the correct backlash in the teeth. The slewrig assembly was then fitted back on to the undercarriage and the platform dropped back on and bolted down. At this stage all of the platform components were refitted including all of the control linkages which had been overhauled. Engine The Perkins 6,354 engine that was in the machine was a good runner with plenty of power but had an annoying knock (suspected little end bearing). I did have a Ford 2703E engine from a Hymac drilling rig and it was decided to fit this motor along with the Hymac / Ford skid frame. Hymac used both makes of engine in the production. Tje buld up engine powerpack and repaired canopy were refitted and all fuel pipes re-connected. All of the hydraulic lines were re-connected, making sure that the lines to the front end were sealed off as it had not yet been refitted. The hydraulic tanks were filled with 90 gallons of fresh oil and the system bled of air. At this point there were no electrics back on the machine apart from the reconditioned started motor and alternator so a jump battery was fitted. With full throttle and the excess fuel button engaged the engine burst in to life after a couple of turns. With the hydraulic gear pump circuits the full flow of the 3 pumps is immediately picked up and dispensed around the pipework, so with over 70 gallons per minute of fresh oil thrashing about its a frantic run round to check for any leaks in the system. With the machine now having hydraulics to the final drive, the tracks were able to be pulled on and adjusted to the correct tension. Front End Equipment All of the hydraulic cylinders had their seals replaced and the rod eye was replaced on the dipper ram. The welded bosses in the dipper arm were all worn and it was sent out to Strutt engineering which manufactured and welded new bosses in to place ensuring they were correctly aligned. The front end equipment was then re-fitted with new pins and bushes and the pipework connected. The machine had already been painted the front end equipment had been painted off the Hymac. The rotted cab base was plated, shot blasted and painted and the glazing rubber replaced. A new wiring harness and dash panel were made up by Howard Webster, a former Hymac electrician. | 
