How to Repair the Drum and Motor
The drum of the dryer is usually turned by a motor-and-belt assembly. There are two very clear signs that the belt is malfunctioning: You can easily spin the drum by hand when the dryer is off, or you hear a heavy thumping sound coming from the drum when the dryer is running. Here's how to test and replace the drum belt:Step 1: Locate the belt by removing the back or front service panel. Depending on the type of dryer you own, you may have to prop up the drum to keep it from sagging. Don't let the drum hang; the bolts that hold it in the cabinet could be damaged. Don't remove any more parts than necessary.
Step 2: Identify the belt. The old belt may be threaded around the idler pulley and motor drive shaft. Draw a diagram showing how the pulley is installed so you'll be able to replace it properly. If the old belt is worn or frayed, but not broken, leave it around the drum as a pattern for positioning the new belt; cut the old belt and remove it when the new belt is in position.
Step 3: Remove the old belt from the pulleys and stretch the replacement belt into place. The new belt must extend around the dryer drum and the pulleys. The trick is to align the belt on the drum with the pulleys -- the ribs on the new belt go against the drum.
Step 4: Once the belt is aligned, turn the drum by hand, if possible, to make sure the belt is tracking. You may have to reassemble part of the cabinet to do this.
Some older dryers have a V-belt pulley drum drive. With this system, two or three pulleys of different sizes set the speed of the drum. To change this type of belt, decrease the tension on the idler pulley and install the new belt in the V-grooves of all pulleys. Then place the idler pulley back into position.
With any dryer, make absolutely sure that you replace the old belt with a new one made especially for the dryer. Any difference in belts can change the speed of the drum and cause problems with other dryer components.
 ©2006 Publications International, Ltd. When replacing a drum belt, you may have to prop up the drum to keep it from sagging. Don't let the drum hang; the bolts that hold it could be ruined. |
With the back service panel off, check the drum bearing around the dryer drum shaft. You may have to remove the dryer belt to reach it. If the bearing looks worn and dirty, or if it's loose, it should be replaced with a new bearing made for the dryer.
A screw in the center of the drum connects the shaft to the drum. Remove this assembly and then lift off the drum pulley. Support the drum to prevent it from sagging. The bearing fits around the drum shaft and is slip-fit. Pull off the old bearing and install the new one, securing it the same way the old one was held.
On some dryers, the bearing and shaft are held by a U-bolt, and there are two tapered blocks supporting the bearing and shaft. Remove the bearing by first removing the U-bolt and blocks.
When reassembling the bearing unit, make sure the parts go back together the way they came apart. If the part is assembled with shims, the shims should be placed between the bearing and the support channels. Do not overtighten the screws holding the parts; overtightening could cause damage to the bearing. If the bearing has a lubrication wick, saturate it with auto transmission oil.
Servicing the Drum Rollers
The front of the dryer's drum is usually supported by two rollers. These wheels are either metal with a rubber rim or pressed nylon. If the rollers squeak but appear to be in good condition, apply a few drops of 20-weight nondetergent motor oil (not all-purpose oil) to them. If the rollers are worn, you can replace them if the roller assembly is not riveted. To replace drum rollers:
Step 1: Remove the front of the cabinet. Rollers are usually held on a metal shaft by a spring clip.
Step 2: Remove the rollers by prying the spring clip off with a screwdriver. Under the clip are a washer, the rollers, and another washer. You might have to remove a small nut at the back of the shaft and remove the shaft itself to reach the rollers. Remove the rollers from the shaft and clean away built-up lint and dirt before installing the new roller. This dirt and lint buildup could cause the drum to turn slowly, which prevents proper drying and strains other dryer components.
Step 3: Install the new rollers on the shaft with the washers in the same position.
Servicing the Motor
Motor malfunctions usually call for service by a professional. There are three main causes of motor failure: lack of lubrication, a defective motor switch, or worn or frozen bearings. A humming sound can be related to a burned-out motor or a defective switch. Check these trouble spots before you call a professional service person or take the motor to a repair shop. Here's how to check a dryer motor:
Step 1: Remove the back access panel. Then reach behind the drum, motor pulley, and idler arm pulley. If these areas are clogged with dirt and lint, undue strain on the motor may be causing the humming noise. Worn or broken belts can also cause a humming noise. Check the belts for wear and damage. If the belts look all right, you may be able to stop the noise by spraying them with fan belt dressing, available at automotive and hardware stores and home centers.
Step 2: Turn the dryer on. The noise you hear may be the whirl of the spinning drum, not the motor. Some noise is normal.
Step 3: Force a little 20-weight nondetergent motor oil (not all-purpose oil) around the ends of the motor shaft. This lubrication may stop the humming noise. If this doesn't solve the problem, remove the motor and take it to a professional service person.
The centrifugal switch on the dryer motor may be located on top of the motor. Humming, no motor power, and no heat can be caused by a faulty centrifugal switch. If the switch is externally mounted, check the terminals of the switch to make sure they are tight and not burned. If you spot trouble, remove the switch and take it to a professional service person for testing. A faulty switch will probably have to be replaced. Some centrifugal switches are located inside the motor housing; you won't be able to remove the switch in this case. Remove the entire motor and take it to a professional for repairs.
If the motor hums, but won't run the pulley on the end of the motor shaft, try turning the pulley by hand. Caution: Before turning the pulley, make sure the power to the dryer is turned off.
If you can't turn the pulley, or if the pulley is very hard to turn, the bearings in the motor may be worn. Remove the motor and take it to a professional service person for repairs, or replace the motor. Replacement may be cheaper than repair.
Some motors have overload protectors that turn off the motor when excess strain is put on it. Often, dryers are equipped with a reset button on the control panel. If the motor won't run, let the dryer cool for about ten minutes. Then press this reset button. If the dryer still doesn't operate, check for an overload protector on the motor.
Test the overload protector with a volt-ohm-milliammeter (VOM) set to the RX1 scale. Disconnect one lead wire to the protector and clip one probe of the VOM to each protector terminal. If the meter reads zero, the protector is working. If the needle jumps to a high reading, the overload protector is faulty and should be replaced. Remove the protector by prying it off or unscrewing it from the motor housing. Replace it with a new one of the same size and type, connecting the new protector the same way the old one was connected.
Routine maintenance will keep your dryer working properly, especially when you need it most. You can handle most maintenance and minor repairs yourself by following the guidelines in this article.
©Publications International, Ltd.
