Skybrid

A Tost model ?? converted and delivered by Skylaunch in March 2008. Cost of essential maintenance was similar to the cost of conversion: mounted on a twin-axle trailer with large, narrow drums, no paying on gear, new roller boxes and the Skylaunch panel. The winch is powered by an Oldsmobile V8 455 cubic inch (7.5l) capacity engine fuelled with Propane gas. More details about the engine here:Oldsmobile 455 data. The power from the engine is transferred to the drive axle via a GM TH400 automatic transmission unit.

Work Required

• Fit missing rear axle bolts
• Check tyre pressures / determine 'correct' tyre pressures.
• Replace or repair stop lights.
• Line cab with insulation/thin plywood.

NB: re torque half shaft nuts (300 lb/ft) every six months - remember to remove grub screw locking axle nut before torquing.

• re torque exhaust manifold bolts as required (else gaskets blow)

General Maintenance Notes

Winch drum removal procedure

If necessary a drum can be removed without removing the cable, however, note that if this is done the guard rail on the Skybrid drum must be protected.

• Position the winch under the crane with the centreline of the axle under the gantry.
• If air tools are to be used position the gantry crane on level ground within 20 metres of the compressor.
• Loosen the drum retaining bolts, the axle nut and the half shaft end plate retaining nuts.
• Use a suitable rope sling to prepare to lift the drum, take care to avoid damaging guard rails.
• Take the strain and and remove the drum nuts
• Use a pair suitable 10mm bolts to jack off the drum.
• Lift off the drum and tie it to the gantry stanchion. Do not allow full weight of drum to rest on guard rails.
• Remove the half shaft nut
• Removed the half shaft flange retaining nuts.
• Place an oil tray under the flange to catch oil.
• Break the seal between the half shaft flange and the brake drum and slide it outwards.
• Mark the angular position of the flange relative to the half shaft
• Use a sledgehammer and protective aluminium plate to 'break' half shaft taper
• Use a large screwdriver to lift the flange on the bearing retainer, then using a suitable drift unscrew the locking ring
• Remove the bearing retaining ring and keeper plate
• Remove the brake drum
• Note that if the brake back plate is removed that the retaining bolts are drilled straight into an oil reservoir. Be prepared to catch any lost oil.

NB: The oil level in the differential and dog clutch boxes comes half way up the half shaft tube and floods back into the axle bearings. Consequently the only things that prevents the axle oil from leaking out into the brake drums are the brake drum oil seals (type 125 95 13 TC from Simply Bearings). It is recommended these are replaced whenever a drum is removed.

The differential oil must be replenished to the dip stick level with 80W/90 gear oil.

Parts replaced / work done

Jan/Feb 2015

• Following a catastrophic failure of the differential on the Reserve Winch it was found that the Skybrid winch differential had run dry and had sustained serious damage to the pinion teeth as well as damage to the pinion bearing. A rebuilt differential was purchased from Skylaunch and all 'inaccessible' bearings replaced. New half shaft bearings and dog clutch cap screws were also fitted. New hub oil seals were fitted and the differential was refilled with EP80W/90 gear oil.
• NB: On fitting the new differential it was found that the half shaft splines of the damaged axle did not match those in the replacement differential. However, by good fortune the half shafts from the Reserve Winch were found to be the correct type, so these were cannibalised.
• Skylaunch advised that the hub bearings should be lubricated with axle oil at the same level as the differential. However, when new hub seals were fitted it could not be ascertained that they were making a very effective seal. Following a discussion with the Skylaunch engineer who rebuilt the differential it was agreed to set the oil level below the lip of the diff half shaft tunnel and top up the selector boxes to the level of the filler holes. Consequently a lower oil level marker was set on the dip stick.

December 2014

• Replaced worn out right hand brake shoe and adjusted mechanism.

November 2014

• Replaced worn out left hand brake shoe and adjusted mechanism
• Re welded broken cable deflector
• Topped up dog clutch gearboxes and greased u/js

October 2014

• Changed oil and filter
• Changed transmission oil
• Torqued axle nuts
• Fitted new air filter

March 2014

• Flushed engine and changed oil and filter
• Changed auto trans oil and filter
• Torqued axle nuts

• Annual guillotine check found assister springs out of balance and causing blade to bind. Adjusted spring tensions to 'twang' equally. Guillotines stripped, cleaned and lubricated.

• Replaced exhaust blanking stub with fabricated part

• Fitted new floor to winch cab
• Fitted chains to release brake levers

February 2014

• Fixed exhaust leak from LH exhaust manifold. Casting eroded, so new gasket fitted with sealant. Also made temporary repair to leaking exhaust stub. Needs new part.

January 2014

• Fitted aluminium cable deflection plates over damaged cage under drums.
• Moved tow out brake tensioning mounting points, fitted new springs and rope ratchets.

October 2013

• Changed engine oil and filter
• Changed trans oil and filter
• Torqued axle nuts

March 2013

• Fitted cable buffers to protect paying-in gear

• Failed guillotine test

both mechanisms found to be clogged with debris:

Fitted assister springs and re-set guillotine blades on LH mechanism.

POSSIBILITY OF FAILURE DUE TO CONTAMINATION MANDATES FULL STRIP DOWN AT FUTURE ANNUAL GUILLOTINE CHECKS

June 2013

Changed engine oil and filter.

• Tightened exhaust manifolds.
• Changed transmission oil and filter.
• Torqued half shaft nuts.
• Changed air filter.
• Oil leak from base of dip stick tube contaminating starter motor. Resealed with RTV sealant.

September 2012

• Reconditioned starter motor. Contaminated with engine oil. Later found to be due to oil leaking from base of dipstick.

August 2012

• Replaced both exhaust manifold gaskets

June 2012

• Changed engine oil and filter
• Changed auto trans fluid and filter
• Half shaft nuts re torqued

Feb 2012

• Replaced sheared dog clutch cap head bolts (right hand drum)

one bolt missing as could not remove broken screw.

• Replaced right hand exhaust gasket
• Changed engine oil and filter
• Changed auto trans fluid
• Half shaft nuts torqued

Summer 2011

• Changed engine oil and filter
• Changed auto trans fluid
• Half shaft nuts torqued
• Compression checked

Feb/Mar 2011:

• Replaced exhaust manifolds gaskets (ones previously fitted eroded due erosion of manifold face – used cement when fitting)
• Removed broken exhaust manifold stud.
• Winch taken to Lee on Solent for catch rail repair.
• Repaired winch drivers chair.
• Right hand brake tension adjusted to balance pull out tension
• Electrics moved to main control panel and rev counter temporarily secured with cable tie.
• Exhaust manifold bolts re-torqued.
• Failed annual guillotine test. Removed both guillotine assemblies. Cleaned, lubricated and refitted. Both passed annual test.
• Sludge in oil. Checked breather - OK.

Oct/Nov 2010:

• Replacement (second hand) exhaust manifolds fitted.
• Engine oil and filter changed.
• Transmission oil and filter changed.
• Rocker cover gaskets changed.
• Leaking oil pressure switch replaced.
• Transmission cooler fan switch moved away from exhaust manifold.
• Compressions checked.
• Half shaft nuts re torqued.
• Exhaust system braced to prevent silencers swinging on manifolds.