Repair 7

Axle shafts are used on most non-commercial vehicles to allow the drive wheels of your vehicle to move in a circular manner. The shafts are located in your tires wheel well, near the differentials. They stretch across the bottom of the car, connecting two wheels together. Obtaining a measurement for an axle shaft is necessary when the axle shafts need to be replaced.

Instructions

1

Locate the axle shaft in your tire well. The axle shaft will have a large, grooved bearing near the center of your tire.

2

Place one end of the measuring tape at the edge of the grooved bearing of the axle shaft. Have someone hold the tape measure in place.

3

Extend the tape measure across the axle bearing until you reach the connected tire. Measure the length based on the distance from one tires grooved bearing to the other tires grooved bearing.

Welding hard steel, such as 4140 steel, is a complicated process that involves heating levels that are unusual to achieve in a home workshop. However, in the right shop, it is possible. You will need a good oven and good welding skills to accomplish this task, but as long as you have the right facilities, it will not be a complicated procedure. AISI ers to the American Iron and Steel Institute and its industry-accepted steel standards; AISI 4140 is a versatile alloy steel used in many industrial applications, including plating and shafts, and is easily weldable with traditional methods.

Instructions

1

Heat the damaged steel to about 1,250 degrees Fahrenheit.

2

Match weld material to 4140 metal, including a minimum of 1.25 percent manganese, 1.75 percent nickel, 0.3 percent chromium and 0.25 percent molybdemum. If repairing a crack, this filler metal should be lower in carbon than AISI 4140, which has up to 40 percent carbon content, to prevent development of a brittle layer called martensite and possible future cracks.

3

Use softer filler metal in building up a shaft for re-machining, followed by a harder layer. This buffer layer should be very low in carbon content to prevent carbon from leaching into the hard-facing layer, one of several specialized alloys, causing it to crack quickly. The hard-facing layer should be thin, as thicker layers will, counterintuitively, fail faster than thinner layers. Preheating, as mentioned above, is vital to prevent distortion and failure of the hard facing, which will lead to rapid erosion of the buffer layer.

4

Cool the steel very gradually by placing an insulated welding blanket over the bar or by burying it in sand. Rapid cooling will cause the layers to distort and spoil the job. The piece should not cool more than 150 degrees Fahrenheit per hour; for large parts, this may require a temperature-controlled furnace to cool the part precisely.

A camshaft controls the timing of valves on an automobile engine. Lobes on a camshaft, called cams, push on the valves to open the valves. Springs on the valves close the valves. Camshafts ride on thin films of oil on camshaft bearings. A camshaft bearing goes bad, or is "wiped," when oil fails to get to the camshaft bearing. Your vehicle engine will not operate if a camshaft bearing gets wiped. The engine would seize and shut down. Regular maintenance on your vehicle, such as regularly checking the oil, prevents a camshaft from failing.

Popping Noises

A popping noise develops in the engine as a camshaft begins to fail. As the camshaft begins to fail, the timing starts to go bad, which causes the engine to develop a popping noise. This popping or backfire could indicate bad valves or valve springs, or it could be that the camshaft is failing. Mechanic John Hix says that with any engine he can hear whether the engine is not running right. The timing will lead to louder popping noises as the camshaft gets worse.

Poor Gas Mileage

Poor gas mileage will manifest itself as your car loses power and burns more gas. You will find the car burning more gas to get from point A to point B as the camshaft goes bad.

Loss of Performance

The loss of engine performance emerges as the timing deteriorates. The engine power will go way down and your engine timing will be way off. When climbing hills or trying to pass, you will notice the car will have no accelerating power. As soon as this sign manifests itself, you should have the vehicle checked by a mechanic.

Metal in the Oil

A check of the engine oil might reveal flakes. Prior to the shaft wiping, metal parts will come off the lobes of the camshaft. These naturally wear from use. Excessive wear means they need replacement. Metal flakes indicate that metal in the camshaft has contacted the metal of the bearing. The bearing metal is made from a softer metal, hence the term "wiped bearing." The metal from the shaft literally wipes the softer metal from the bearing. These metal fragments will then end up in the lube oil system; when you drain the oil you will notice metal flakes floating in the oil.