EXCAVATOR PROBLEMS

Best learn your machine as call out fees range up to $500 in NZ. NOT CHEAP.

If you have excavator problems send to us and we will post for you. If not right then lets put it right. You help us and then we help others.

24 VOLT BATTERIES:
Use 2 12 volt as its 24volt system. Hook up – to – Battery. Then other battery + to + terminal. The other 2 terminal – to + .

BUYING AN EXCAVATOR:

Check list: Tracks, track links, sprocket wear, turntable movement very important; hours, hydraulics and leaks,

TURNTABLE NOT GOOD:
Operate drop the boom or dipper to the ground then watch as it pressures down to the ground to lift the body (house) off the H-frame (track frame). If the tracks lift instantly off the ground then the bearing is probably good for up and down play. If there is any movement of the house,(upper body) before the tracks move up then you have to bend down and watch the turntable bearing to see if that is where a gap opens up between the top and bottom of the bearing. Better to check it with another person watching the bearing while you operate the boom. Any vertical play is bad, if it is 1/16" I would note it but not condem the bearing. However the hardened surfaces of the bearing could be gone and it could start to get worse quickly. This is only for vertical wear. Look for grease for leaks out of the bearing (bad seal). also on larger excavators. Oil pours out of the swing bearing because the swing motor seal blew out. The side to side play in the gear teeth could be excessive, if it has a lot of side to side play it will make the excavator harder to zero in on the bucket target as it rocks to a stop.

Check the swing brake at this time. When I operate the swing, it should smoothly and quietly come to a stop when you center the swing control. Any noises or chattering or no stopping are usually expensive swing brake or hydraulic motor repairs. Look under the center of the machine for leaks from the swing motor seal or as mentioned before oil leaking from the turning table bearing could be from a bad swing motor seal. . Anything over 0.070 up and down is worn out. Swing brakes do not stop the house from turning. They only hold the house in place after the controls are all released for about 7 seconds or so. Swing motor pinion leaks show up on the swing bearing.

SLEW RING GEAR LEAK:
Hydraulic oil leak appearing from around the ring gear (where cab swivels on the tracks). Pump controlling the tracks overhauled hasn't cured the problem. Dipstick on the pump beside this one  (for the ringgear??) which is not showing any oil despite the level indicator on the hydraulic oil reservoir varying between min and max depending on the position of the boom. Where the leak is coming from & is it the ringgear pump.

Ans: is it a thick oil, like a 80/90 weight? or lighter viscosity like hydraulic oil? If the swing gear gearcase is empty, the bottom seal is gone from where the pinion goes thru the bottom to drive the slewing ring. Then you must remove hyd. swing motor, do this without removing any hydraulic lines, just swing it off to the side, and then remove the gearcase, replace seal & check other parts. Can do without removing upper structure from undercarriage. The pump comes out from behind the boom. Couple hours, check your planetary gears and hoses for wear and tear. Oh don't forget to bleed the pressure off the hydro tank.

SLEW RING GEAR KEEPS TURNING:
The swing system is equipped with a double counterbalance valve which provides dynamic braking as you stop swinging. When the house comes to a complete stop, a static failsafe brake is spring applied. The failsafe brake is spring applied & hydraulically released. In most counterbalance valve bodies there is a shuttle valve which moves over and applies hydraulic pressure to the brake to release it in when the operator starts to turn the housing. Check the shuttle valve. The spring that holds the shuttle ball in place in the one direction may be broken and jammed or a piece of dirt may be preventing the shuttle ball from moving. If not this then no stopping could be expensive swing brake or hydraulic motor repairs.

Check your slew and main relief pressure? Get some specs to compare with too but anyone can help here send to us. Check the relief pressures of other functions too and tune up as required. Swing pressure is never higher than main relief pressure in any excavator. It is generally at least 500 PSI less than main pressure.

SWING ROTATION:
Excavators are generally made to start swinging a loaded bucket from dead stop to full rotation speed in an engineer determined amount of time. Swing power is generally determined by the reduction in the swing gear box and the sizes of the swing pinion and ring gear. Make the swing too powerful and the speed is reduced loosing production. Make the swing too fast and you loose start up power and use more fuel because of the increased load on the engine. The upper range of excavators use two sets of swing machinery to get the house turning. In either case the swing torque is limited to reduce the amount of side loading on the house and car body

GREASE NOT LOADING UP WHEN CHANGING TRACKS:
Grease fitting should be clean. Track adjuster grease nipple should be loosened before track replaced.  Push idler back using a post from your bucket to the track front to get idler to go back and allow easy track off. Grease should spurt out now. After the track was back on to adjust track sometimes it won’t take grease. This is caused by idler arm jammed so just jack it up a little to free it or use a porta power or even tap it. A bit like a jack that’s back in its housing sometimes needs a kick. If your track loosens up you definitely have a grease leak. It may not show up at the fitting. Cgeck leaking out of the seal at the end of the adjuster ram.

DRIVE MOTOR
A drive motor is a gear box that doesn't change gears. 250hrs of working a simple rule of changing the oil is open oil plug check colour of oil if dirty then change & if it still looks like new oil leave it. It's cheaper to change oil than to rebuild final drives & use 80/90gear oil. Planetary gears give you a stronger gear set up in a smaller package with the old bull gears they were huge heavy and you had 1 tooth at a time making contact. With a planetary you have 3 or 4 teeth making full contact in a smaller package. Also try locking the outer hub you create a reverse force. The motor engages a spline and then turns the planetary set up, it allows for greater torque, and better efficiency. Oil sampling can give you an idea of decreased oil change intervals depending on your working condition (lots of travel VS lots of digging with minimal travel) the environment would have more of an effect on the undercarriage wear items, if the torque hubs and motor are sealed correctly then nothing is getting in the casing and therefore won't matter in regards to fluid change intervals.

MOVING ON UNEVEN GROUND
Try not to run with the idlers behind you, when on rocky or uneven terrain. Also keep the tracks adjusted. keep the sprockets on the low side. If you are walking up a hill the sprockets should be behind you. If you are walking down a hill the sprockets should be in front of you.

KEEP YOUR EXCAVATOR LUBRICATED:

One of our mates worked many years for roading contractors & gave this hint. Neville is 73 now & still work on machines in Levin. Excavators are one man machines just like a chainsaw. You lend it--the borrower will never do what you would do as not his machine? you lose if anything happens to the machine? Lubricating and greasing after each job is a must & even daily. Pay attention to your bucket pins and all the other nipples. Check water, oil and even fuel tops ups and make sure your tracks are in good shape as not sense is crying when youre out in the sticks by yourself with a track off. Good maintenance and care ensures a good machine will work and last.

CHANGING TRACKS:
It’s a good time to check your rollers for wear. Like everyone has mentioned before, relieve the pressure [ grease nipple or grease track tensioner  ] and push the idler back in. Lift up the side with your bucket and rest. Replacing a track start with the sprocket end first. Once on the sprocket, put a chain on the outside of the track with a hook eg snig chain; behind the idler and chain to your bucket or another anchor point. On our old 9 tonner we used another excavator to hold as we turned the track. Track forward slowly and pull forward and in (crowd out and swing in) with your bucket as you track slowly forward. Having two guys with digging bars to pry it over the idler helps a lot so keep bars handy. We have used them many times.

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