Common sense should be the guide when addressing chipper maintenance. A tune-up time is crucial in order for chippers to have optimum performance during the chipping season.

The primary resource to aid you in this scheduled maintenance is the manufacturer's and engine supplier's operator's or maintenance manuals. Always follow the appropriate shutdown instructions in those manuals prior to performing any maintenance activities. Some of the maintenance items covered in those manuals will undoubtedly include:

Start with the engine battery. If you have been running continually, this may not be an issue. But if the machine has been idle for 60 to 90 days, check the battery. Recharge it if necessary so it has a full charge.

Washing chippers may seem unnecessary, but it will help you identify engine oil leaks and hydraulic oil leaks during annual maintenance. Keeping the brush chipper washed during the year serves the same purpose.

Change the engine oil and the oil filter. Also, check the hydraulic oil filter and the fuel filter, and replace them if necessary. If the unit is a gasoline model and has sat idle for a month or two, varnish may have started to form. If so, the gasoline may need to be drained. This is not a concern with diesel units.

Check the hydraulic oil carefully for moisture content. If the unit has sat idle for any length of time, condensation may have formed and settled in the oil itself. This will significantly reduce the hydraulic oil's efficiency during operation. If the unit has been operated, condensation in the lines will have burned off. Excess moisture will show up in the hydraulic oil as a milky consistency. Drain the hydraulic oil and replace it with proper hydraulic oil as recommended by your brush chipper's manufacturer.

If you have regularly checked and maintained your chipper's air filter, replacing it at the annual maintenance may be unnecessary. However, if you have not maintained it, checking it now is crucial. Debris entering the engine can significantly reduce engine life.

Always follow the engine supplier's recommended procedure for air cleaner removal inspection and replacement. Remove the air cleaner, and using compressed air or water, clean the paper elements. Do not tap the cleaner elements against the side of the brush chipper thinking that you can knock out debris particles. If you jar the paper elements and they rip along a seam, you've opened a hole for the debris particles to enter the engine.

Check the brush chipper's wheel bearings. Since you have the unit in the shop, remove the wheels and check the grease packings. Repack them with fresh grease. Also, check the brakes and their adjustment. Make sure they work properly along with the unit's tail and brake lights. Check the undercarriage for worn wiring. You may have towed the unit into a brush-filled lot and disturbed wiring harnesses.

With the engine compartment cleaned, you can do some serious checking for current or potential hydraulic oil leaks. Since you will be checking the system under pressure, be sure to wear appropriate personal safety equipment, including safety goggles. With the engine running, look for hydraulic oil drippings on the shop floor. These are the kind of oil drippings that you could have missed out in the field if the chipper was parked over grass or field dirt.

Stop the engine and see if there are any drippings inside or outside the unit. Check the connections of the fittings, and tighten as necessary. If the fittings are tight, turn the engine back on and hold a light piece of cardboard under the hoses to see if any hydraulic oil is sprayed onto the cardboard. Any fluid under pressure can penetrate the skin and cause personal injury, blindness or death. Always heed the manufacturer's instructions and warnings when undertaking all maintenance procedures.

Now, recycle all the hydraulic systems. Operate the feed rollers with the engine running, and visually check for leaks. On some larger units, you may need to operate and check other hydraulic functions such as grapples or winches.

If you do discover hydraulic hose leaks, before you replace the hose, check and see if the leak was due to the hose rubbing against something. Reroute the hose if necessary. Don't replace the hose only to experience the same problem.

It should go without saying that you should start your production year with sharp chipper knives. The most important maintenance task that a tree service firm can perform to lower equipment costs and get the most useful life possible out of a chipper is to keep chipper knives sharp. There is nothing that will slow down a trimming operation faster and create more engine problems than dull knives. They are the number-one cause of reduced lifetime for brush chippers.

Always follow proper shutdown procedures before attempting any maintenance of the chipper knife area. Chipper knife inspection should be done not only for the knives that are bolted to the disc or drum of your chipper but also to the shear bar or bed knife. The distance between the chipper knife and the shear bar is crucial to proper chipping. Adjust this gap to the proper distance as recommended by your brush chipper's manufacturer.

While you are working in this area of the chipper, check the disc or drum for any material failure or cracks. Foreign metal objects may have been fed into the chipper, and they may have damaged the disc or drum.

Check the drive belt; the alternator belt and any belt that may run from the engine to a pump for wear and cracks.

If the unit is water-cooled, check the radiator. Debris buildup in radiator fins can severely hamper engine performance. Many chippers have blower fans that blow debris away from the engine. Using compressed air, blow the debris back toward the engine. If you use high-pressure water, you will get the chips and stuck debris wet, making them harder to remove. Make sure you clean all the way to the edges of the radiator.

If you have an older brush chipper, one with 2,000 hours on it or more, you may have experienced in feed slippage of logs caused by roller wear. The steel ribs or edges welded onto the roller blades may wear to the point that they do not efficiently grab and hold logs.

To give these rollers more useful life, with the engine turned off and the key in your pocket, take a small grinder and sharpen the in feed roller edges so they grip better.

Routine maintenance is the key to keeping most every mechanical machine working properly. The right adjustments at the right time, following suggested manufacturer maintenance schedules and procedures, and reviewing the owner's manual are all key to ensuring your brush chipper has the ability to work reliably for you.

NOTE: The items listed in this article are only a partial list of items generally applicable to all brush chippers. Further, for complete maintenance of your brush chipper, it is essential that you follow all maintenance procedures and instructions as provided in your brush chipper's operator's/maintenance manuals.