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When rebuilding an engine, the clearance between the main bearings and the crankshafts main bearing journals are critical. Too much clearance results in engine knocks, while not enough clearance results in burned bearings because they cannot get proper lubrication. These clearances are especially important to measure and adjust after machining the crankshaft to remove imperfections. Although it sounds complicated, measuring the clearances and adjusting them to specifications is really quite simple.

Instructions

1

Dip a set of standard size main bearings in engine oil and slip them into the block and main bearing caps.

2

Set the crankshaft in the block, ensuring that the main bearing journals of the crankshaft sit on the main bearings in the block.

3

Smear a light coating of grease across the center of the bearing journals on the crankshaft. Put a string of Plastigauge in the grease on each main bearing journal. The grease will keep the Plastigauge in place.

4

Install each bearing cap in its original position, thread the bearing cap bolts into the block through the bearing caps. Tighten the bearing caps with any tools necessary from a toolkit. Torque the main bearing cap bolts with a torque wrench.

5

Remove the main bearing caps, one bearing cap at a time. Measure the Plastigauge with the built in scale on the Plastigauge packaging. Subtract the recommended factory main bearing clearance from the Plastigauge reading. The result will be the size of the oversize bearing needed for that particular main bearing journal. Repeat for all main bearing caps.

6

Remove the crankshaft. Slip the appropriate over-sized bearing in the block required for each crankshaft journal, depending on their individual Plastigauge readings, after dipping them in motor oil. Slide the other half of the bearing into the main bearing cap after dipping it in motor oil. Plastigauge each bearing again to ensure all bearing clearances are correct before proceeding any further. Adjust the bearing sizes as needed.

The bearing assemblies on vehicles allow the wheel to rotate, as well as keeping the wheels adhered to the vehicles body. Bearing types vary, but all perform the same function.

Types

There are two types of bearings: hub and wheel. Both employ the same physical characteristics of a bearing in that they house bearing spheres that are lubricated for spinning to allow the wheel to rotate.

Identification

A major difference between the two is how they are assembled. Wheel bearings can be taken apart, lubricated and reassembled to be used again. Hub bearings are prepacked at the manufacturers factory and are sold and installed as a complete unit. These cannot be taken apart for re-lubrication, but must be replaced.

Warning

Proper care and observation are necessities in keeping bearings lubricated and safe for use. If grinding noises are ignored or regular maintenance of the bearings is put off, lubrication can breakdown and allow the bearings to overheat or break.

The alternator in a vehicle takes gas and converts it into power that the vehicle can use. According to Mister Fix It, the alternator is vital to keeping a vehicles electrical system running at optimal performance. When the alternator bearings on a vehicle are not working properly, the alternator does not turn properly and thus the alternator does not work.The alternator bearings turn the alternator so it can convert power from gas to electricity for systems like the air conditioner, radio and headlights. The symptoms will show different problems with the alternator bearings and other issues in the vehicle. Once the symptoms are identified and the problem is known as an alternator problem, fixing it is possible.

Progressive Squealing Sound

A progressive squealing sound, or a sound that gets louder and makes a squealing noise, is a sign of alternator bearing problems. Usually, the bearing is loose when this occurs. The mechanic should rule out other potential problems that come with similar symptoms, such as timing belt problems. Once it is determined that the alternator bearing is loose, replace it because a loose bearing gets damaged.

Dim Lights

Alternator problems cause dim lights. If the alternator bearings are not properly turning the alternator, the lights will not work properly because they are only getting power from the battery and not from the gas. Dim lights alone, without other symptoms, are usually caused by dirt or old bulbs, but if other explanations are eliminated, the alternator is a potential cause.

Car Lights Come On

Alternator problems or issues with the alternator bearing cause the warning lights to turn on. The "Batt" or "Gen" lights are the most common lights that come on when there is a problem with the alternator. These do not always come on, especially if the battery has plenty of charge, but when these lights come on there is a good chance the alternator or alternator bearing is the problem.

Replacing the wheel bearings in your 1989 Chevy S10 Blazer involves replacement of the entire hub assembly, as it is a complete assembly and not separately serviceable. A replacement hub assembly and bearing is available from most auto parts stores, or may even be available from select Chevy dealers. Removal of the hub assembly may take several hours, but you can do the job at home with basic hand tools and avoid a large repair bill for the work.

Instructions

1

Loosen the lug nuts on the wheel where the bearing is defective, using a lug wrench or socket and breaker bar. Raise the front of the truck with a jack and position a set of jack stands under the frame to support the truck.

2

Remove the lug nuts and pull the tire and wheel off the vehicle; set it aside for now. Locate the two retaining bolts at the top of the brake caliper and loosen the bolts with a socket and ratchet.

3

Remove the brake caliper bolts then lift the caliper off the brake rotor and support it with a piece of wire or twine. Do not allow the caliper to hang on the brake hose, as the weight of the caliper will damage the hose.

4

Slide the brake rotor off the hub assembly and set it aside. Locate the castle nut in the center of the hub and remove the cotter pin that retains the nut using a set of needle nose pliers. Discard the cotter pin, as a new one will be used during reassembly.

5

Place a hub nut socket on the nut, and using a breaker bar, rotate the nut counterclockwise. Remove the nut from the shaft. Move to the rear of the steering knuckle and locate the three hub retaining bolts that thread into the back of the knuckle and hub.

6

Remove the three hub retaining bolts with a socket and ratchet. Set the bolts aside and move back to the front of the knuckle.

7

Separate the hub from the knuckle using a cold chisel and hammer, driving the chisel into the seam between the two pieces. Pull the hub out of the knuckle and off the axle shaft. Discard the old hub if the bearing is defective.

Replacing the hub assembly on the front of your Jeep Cherokee is the only way to service the front wheel bearings. Because the hub assembly is a sealed unit, you cannot repair it without special tools. Replacement units for the Jeep front axles are readily available through most auto parts stores and of course the Jeep dealer network, however. The job can become time consuming, but in the end doing the work yourself can save you a substantial amount of money.

Instructions

1

Locate the hub nut and cotter pin in the center of the front wheel on the side on which you will be working. Remove the cotter pin from the shaft with a pair of needle-nose pliers, then discard it. Place a large socket (generally 36 to 45 mm) on the axle nut, and use a breaker bar to rotate the nut counterclockwise until it loosens.

2

Loosen the lug nuts with a lug wrench, then place a jack under the front of the Jeep. Raise it off the ground, and place a set of jack stands under the front axle to support the Jeep. Remove the wheels, and set them aside for now.

3

Locate the two brake caliper retaining bolts on the top of the brake caliper. Remove the two retaining pins with a socket, then ratchet the lift the caliper off the brake rotor. Support the caliper from the top of the suspension with twine to keep it from hanging on the brake hose.

4

Slide the brake rotor off the hub, and set it aside. Locate the three 12-point bolts on the backside of the steering knuckle that retain the hub to the steering knuckle. Remove all three bolts with a 12-point socket and a ratchet. Set the bolts aside.

5

Remove the axle nut from the axle shaft, and pull the hub out of the steering knuckle and off the axle. If it has rusted to the steering knuckle, use a cold chisel and hammer to work around the edge of the hub, separating it a little at a time. It will come out with enough persistence.

6

Clean the interior surface of the steering knuckle with some break clearer and a clean rag then coat it with some anti seize compound. Slide a new hub over the axle shaft and into the steering knuckle. Install the three 12-point retaining bolts from the back of the knuckle and into the hub. Tighten the bolts, drawing the hub completely into the knuckle.

7

Slide the rotor onto the new hub and wheel studs, then position the brake caliper on the rotor. Install the retaining pins into the caliper, and tighten them with a socket and ratchet.

8

Install the axle unit onto the axle shaft, and tighten it until snug. Torque the three 12-point bolts to 75 foot-lbs. with a torque wrench. Install the tire on the hub, and tighten the lug nuts until snug.

9

Raise the front of the Jeep off the jack stands, then remove the stands from under the axle. Lower the jack, setting the Jeep on the ground, and tighten the lug nuts the rest of the way with a lug wrench.

10

Tighten the axle nut to 175 foot-lbs. with a torque wrench, and install a new cotter pin in the end of the axle shaft, bending the legs over with a pair of pliers to hold it in place.