CORVETTE TIPS AND TECHNIQUES

1953-1962 CORVETTE FRONT WHEEL BEARINGS



PART 2


I mentioned the ball bearings used on the early Corvettes have developed a bad reputation for failing in service. I mentioned it is possible for a front wheel to come off the car if the bearing fails while driving. I even told about an experience I had one day when I saw a car lose a wheel on the freeway. As a matter of fact, we have all seen trailers stranded on the side of the road with a wheel off, the axle sitting at the end of a long groove which was cut into the road as the driver slowed to a stop. I believe the foremost cause of this is improper care and maintenance of the bearings.


The purpose of this article is to discuss normal maintenance and inspection of the bearings and hub so none of us will ever have one of these failures.


None of the bearing races should ever turn on the spindle or in the hub. The movement must take place only in the bearings. This is true of both ball or roller bearings. If the races have been turning on the spindle or in the hub, it will be detectable by inspection. The surface of the spindle will be rough and most likely blue in color if the race has been turning around it. Sometimes, after the races have turned in service, you will not be able to remove the hub at all. I have seen many examples where the hub was stuck on the spindle, and a puller was necessary to get the parts separated. In some rare cases, the pieces have welded themselves together, and the entire spindle, hub and knuckle assembly had to be discarded.


Inside the hub, you will find two outer races. Clean all of the grease out of the hub with paper towels until you can inspect the entire inside of the hub. The races are designed to fit into the hub by means of a press fit. That is, the races are pressed into the hub by a hydraulic press in the factory. This tight fit should keep the races from turning, but if you find they are loose, the hub and races will have to be replaced. If the race is galled, pitted, chipped, cracked, discolored, or in any way different from a new one in appearance, it should be replaced. You can replace it in your garage with the long punch and hammer shown later in this article.


Photo #1 shows a hub with the outboard, outer race in place. The larger inboard race is just opposite this one. You will notice the shoulder the race is resting upon. It is necessary the race rest fully upon that shoulder all the way around. The shoulder has openings in it to allow for the long punch to get access to the back side of the race if it is necessary to remove it from the hub.

















Photo #2 shows some tools used to remove and replace the races. In the top of the photo are two very long punches. Each one measures about fifteen inches long. This enables me to reach down into the hub and through to the other side to push out the race. Below the punches is a ball peen hammer. This one is different as it has shot inside the head. If you shake this hammer, you will hear the shot flop from one side to the other. The reason for this is whenever you strike a blow, the shot lands just a micro second later which keeps the head from bouncing. It is called a dead blow hammer, and it is considerably more effective than a normal hammer. You can change the races with a regular hammer just as well, just be sure to use eye protection whenever you strike a blow with any hammer especially against a steel surface like the head of a punch.


Below the hammer is a special tool I've had for many years. It was made especially for changing wheel-bearing races. It was a premium that was given to a mechanical shop when they bought a large supply of wheel bearings from Delco. You would get a display case, a wall or window sign, and the special tool as an incentive to stock the bearings. Naturally, I bought the program. The tool looked interesting but it doesn't work any better than the long punches.


Photo #3 shows the working tips of the long punches. I have ground the ends for the job. If you will notice, the ends are smooth, flat and ground at right angles to the shank of the tool. The round one is most common. It is primarily used to remove the old race because it fits into the spaces in the shoulder on which the race sits. The oval head punch is used mostly to install new races. It has a wider head so it will distribute the forces more evenly to the race without damage.
















Photo #4 shows a close up of my little dandy Delco M2-223 Front Wheel Bearing Tool. The idea was to grasp the tool over the label and as you gripped the tool the working tips would be placed on the race at opposite sides (e.g. 12 o'clock and 6 o'clock). Because the tool was in contact at two points, it was supposed to drive the race into the hub straight. That is, the race would not get tilted as it was forced into the hub. This was a great idea that really didn't work. All you have to do is watch the race as you drive it into the hub and be sure to tap alternately on one side and then the other and you will be able to put it in just fine with a regular punch and hammer.


I like to leave the hub bolted to the wheel when I change the races because it provides a perfect holding device. You can flip the wheel over to get access to either side. Since the hub is held up off the floor, the race can drop out when it clears the hub. I put a piece of newspaper on the floor under the wheel so the greasy race lands on the paper when it drops. This method works very well when you want to remove the caged ball bearing and seal from the backside of the hub as well. With the wheel on the floor with the front side up, use a wood hammer handle as a tool to reach down through the hub, and, placing the end of the handle against the cage of the bearing, tap on the upper end of the hammer handle with a plastic hammer to drive the caged bearing and seal from the hub. By using a wood hammer handle or other similar device, the cage bearing will not be damaged. The seal, however will be damaged no matter how you remove it, so it will always need replacing.


































Photo #5 shows a wheel/tire with the hub bolted in the center after I have removed the race. In Photo #6 you will see a close up of the outboard race's shoulder, and in Photo #7 you can look through the hub from the back to the front with both races removed. The races are both shown in Photo #8.

















Photo #9 shows the race just placed into position in the hub. From this point, just a slight tapping with the hammer will bring the face down to the top surface of the hub. When removing or replacing a race, you must tap alternately at 6 o'clock and then at 12 o'clock in order to keep the race straight in the hub. If it gets tilted, it will never go into position, and you will certainly damage it if you keep trying. As you drive the race in, the sound the hammer makes against the punch will be uniform. When the race comes in contact with the shoulder, it will make an entirely different sound. This will tell you the race is resting on the shoulder.


Photo #10 will show the reason for the special, oval shaped punch. As you can see, this punch allows the force to be applied to the thin edge of the race with ease.


After the necessary repairs have been made, the wheel bearings must be repacked with wheel bearing grease, the seal installed, and the wheel bearings properly adjusted. Packing the wheel bearings can be done several ways: A mechanical bearing packaging tool can be used. It is designed to force the grease into the cage by hydraulic pressure while the bearing cage is held in the tool. It is just as effective to pack the new grease into the cage by hand. After the bearing is perfectly clean and has been inspected for damage, it can be repacked by placing a golf ball size quantity of wheel bearing grease in the palm of your clean hand, and, using your other hand slide the cage through the grease thereby forcing the clean grease into the cage and around the balls. Packing the bearing simply means forcing the new grease into the cage.


If the wheel bearing grease works like it's supposed to, you should find grease in the bearing after long periods of service. The idea is it is supposed to stay in the bearing and move about to cool and lubricate, but not liquify and move out of he bearing leaving the bearing dry and unprotected. Good quality grease will do that.


We used to repack front wheel bearings every 10,000 miles. That was the recommended interval for most cars. I don't think that is necessary today because of the better quality wheel bearing grease we have. Today, 30,000 miles is more realistic.


Always inspect the dust cap, the little cover that fits over the end of the hub. This is important because it will help keep dirt and water out of the bearing cavity.


Lastly, I want to mention the torque value of the wheel lug nuts. On today's cars it has become necessary to measure the torque on each lug nut as you install it. This is because of the disc brakes used on virtually every new car. If you don't use a torque wrench to tighten the lug nuts in the proper sequence, and to the proper tightness, the disc rotor will warp and soon cause a pulsation in the brake pedal. Once this has happened, it is very difficult to remedy, short of installing a new rotor. Think about it, the uneven force that is concentrated around the bolt circle will cause the cast iron hub and rotor to warp out of round.


On the early Corvette, the same forces are applied. Though we don't seem to have any serious problems with them, I think we should use a torque wrench to be safe. In the past, it was acceptable to use a pneumatic impact wrench to tighten the wheel lug nuts on all cars and trucks. Today, few mechanics will do this.


The proper torque setting is 55 to 65 Lbs/Ft. The lug nuts should be put on the studs and tightened evenly using a star pattern. That is, the nuts should never be tightened in a circle. Instead, they should be tightened across from one another in the pattern of a five-pointed star first to about 35 Lbs/Ft., and then to the final setting of 55 to 65.


I do this by seating all the nuts evenly to center the wheel on the hub, and after lowering the jack to rest the wheel lightly on the ground, tighten the nuts the rest of the way with the torque wrench. Because the wheel is resting on the floor, you will be able to apply the force of the wrench without the wheel turning.



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WheelBearings2.pdf

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