 We have two types of equipment that do essentially the same thing. Apply liquid asphalt. Crack sealers put it down in isolated areas to seal out moisture. And tar pots apply it in larger, wide open areas to prepare a section of highway for resurfacing. Both types of equipment have similar systems. They both have a heating system to heat the asphalt so it stays fluid and ready for use. They both have a circulation system to move the asphalt through the lines. And they both discharge the asphalt right where you need it. Either through an applicator wand or through a spray bar. We've looked at operating both the crack sealer and the tar pot in earlier programs. And we've discussed the preventive maintenance both machines require on a daily basis. In this program, we'll take a look at PMA. The periodic maintenance the operator is responsible for. The procedure is outlined in the preventive maintenance manual under asphalt distributors. The outline covers both the crack sealer and tar pot, as well as the larger types of distributors. That's because each machine has very similar maintenance requirements. The function and operation of the various controls differ, of course. But as I said earlier, each machine does essentially the same thing in the same way. So in this program, we'll concentrate on PMA for the crack sealer. The way to begin every PMA is to complete the inspections called for in the daily checks. That means first just looking over the unit and trying to spot signs of obvious or potential trouble. If you find something wrong, either fix it yourself or let your supervisor know about it. The crack sealer, just like any kind of asphalt distributor, generates a lot of heat and uses flammable material under pressure. It can be a dangerous machine to operate if it's not maintained regularly and carefully. So do your daily checks first, then continue with the PMA. Part of PMA on both the crack sealer and the tar pot is to inspect the packing of the wheel bearings. Just remove the cap and look inside. The bearings should be completely covered with grease. If they're not, repack them with bearing grease. And don't forget to replace the cap so dirt can't get into the bearings. Okay, now on to the engine. You have to change the engine oil and the engine oil filter. So loosen the drain plug at the bottom of the engine and allow the old oil to drain completely from the crankcase. Collect an oil sample to send to the lab for analysis and label it. Include the equipment number and the type of oil in the sample. Now the oil filter. There's a gasket on the outside of the filter that helps keep dirt and air out of the engine. Remove the gasket and inspect it. Keep the gasket clean so it will seal the area around the filter completely. If the gasket is worn, get a new one. It has to be in good shape or the engine could overheat. Loosen and remove the old filter, then throw it away. Coat the gasket of the new filter with grease. That creates a better seal when you tighten down the filter. Plus it makes the filter easier to remove the next time it's changed. And after you install the new filter, remember to put the outer gasket back on. Make sure it fits snugly around the filter to keep dirt and air out of the engine. Now you have to add new oil to the engine. So replace the oil drain plug and tighten it down. Oil through the dipstick tube. Change an oil suitable for the conditions in which you'll be working. SAE 30 or 10W 40 is recommended. Make sure the new oil level reaches the full mark on the dipstick. Okay, now the air filter. Inspect the air filter after every 50 hours of operation. Chances are you'll only have to clean it out by tapping it lightly on your hand to shake out dust. However, if the filter is really dirty, get a new one. The engine needs clean air for it to run efficiently. And before you put the filter back into the chamber, wipe out any dust that is collected in the chamber. Then put in the filter and tighten down the lid. One PMA checkpoint that may easily be overlooked is the throttle linkage. Just a couple of squirts with an all-purpose lubricant should keep it from sticking. Also inspect the linkage for binding or excessive slack and wear. PMA is also the time for cleaning the battery terminals. As you can see, this operator has been taking care not to let corrosion build up on the terminals. So all he has to do is check the water level and make sure the cables are tight. And in good shape. The next checkpoint is found only on crack sealers and not on tarpots. It's the hydraulic oil filter. To change it, first shut off the supply and return valves beneath the hydraulic oil tank. Then loosen and remove the filter. And just as he did when he replaced the engine oil filter, the operator coats the bottom of the new filter with grease before he installs it. Cleaning the hydraulic oil filter isn't something you'll have to do very often. In fact, under normal conditions, changing it once a year is probably enough. Okay, just a few things left. Tighten the pump packing gland. Remember, a little leaking here, several drops per minute, is okay and necessary for lubrication. So don't over-tighten the gland. Lubricate the fittings for the pumps bearings. If you have a grade of bearing grease, you should adjust the auger packing as well. But it's recommended that you do it when the auger is at operating temperature. And wait about 15 minutes between adjustments. Again, a little leaking here is okay, so don't over-tighten the gland. Finally, make sure your fire extinguisher is fully charged, secure, and accessible. And that covers PMA for the crack sealer. As you saw, most of the checks and servicing centered on the unit's engine. That's the case for tar pot PMA as well. Most of the procedure focuses on changing the engine oil and filter and servicing the air cleaner and battery. But the tar pot and crack sealer have one more thing in common besides similar engine requirements. And that's heat. Both types of units use open flames to heat the asphalt to application temperature. And both machines are plastered with warning signs to keep you aware of the potential hazards involved with working with hot asphalt. So pay attention to the warnings and read the operator's manuals and the department's tar pot safety handbook. They'll help you become a better, safer operator. And good, safe operation is the result of thorough daily and periodic preventive maintenance. Done conscientiously and on schedule.