Repair And Fix it

A bumper jack raises a vehicle in either the front or rear to gain access to the parts underneath for repairs. An air bumper jack is a bottle design that uses air pressure to raise and lower the jack. In the manual mode, you pump the handle up and down to add air pressure inside the jack and extend the saddle upwards to raise it. An air compressor connects to the bottle jack to use for raising the jack automatically instead of pumping the handle up and down.

Instructions

1

Park the vehicle on a flat surface and engage the emergency brake. Place a wheel chock or brick in front of each front wheel if you are jacking the back up. Place a wheel chock or brick behind each rear wheel if you are jacking up the front of a vehicle.

2

Insert one of the two handle pieces that are smooth on both ends into the other. Press the spring pin in one, insert the other and align the pin with the hole in the second piece. The pin will pop out and hold it in position in the hole in the handle. Attach the third handle piece to the bottom of the first two pieces in the same manner. The bottom handle piece has a U-shaped fitting on the bottom end.

3

Insert the bottom of the handle into the release valve on the bottom of the air bottle jack. Turn the handle clockwise as far as it will turn to close the release valve.

4

Turn on an air compressor and let it power up until it cycles off. Attach the air compressor hose to the air compressor by pulling the quick connector ring back, inserting it onto the fitting and releasing the quick connector. Attach the other end of the air compressor hose on the air control valve on the front side of the bottle jack in the same manner.

5

Push the bottle jack with the handle to position it under the vehicle bumper where it attached to the frame while allowing access to the air control valve. The air control valve is above the air compressor hose fitting on the jack. Place a piece of wood or two-by-four board on the round saddle of the bottle jack top.

6

Grasp and squeeze the air control valve to add air to the jack and raise the saddle under the vehicle. Release the air control valve when the vehicle is high enough off the ground.

7

Place a jack stand under the vehicle to support it. Turn the jack handle counterclockwise in the release valve slowly to lower the jack. Pull the jack out from under the vehicle.

When your hydraulic jack stops working then its likely a seal has failed. This causes hydraulic fluid to leak out, the pressure to drop, and the jack to stop lifting. Replacing a seal can be a tall order and sometimes the replacement parts can cost more than a new jack. However, if you can isolate the leak to one seal in particular then you should be able to replace that seal for relatively little money.

Instructions

Find the Source of the Leak

1

Open the cap for the oil reservoir. With the bottle on its side, fill the jack until it is about 1/4-inch below the level of the hole. Replace the cap and wipe the outside clean with the cloth.

2

Place the jack under a vehicle and pump it up until there is weight on it. Continue to pump and watch the jack to find out where the fluid is coming from. It is likely to be coming either from around the piston at the top of the jack, around one of the screws in the bottom of the jack or around the piston under the handle.

3

Lower the jack, wipe it down and place it on a bench for further work.

Leakage from the Top

4

Drain the oil from the jack by opening the oil reservoir and letting it into a tray. Stand the jack so the piston extends vertically and youll find it looks like a bottle. At the top of this bottle there is a nut called the tank nut, through which the piston extends. Undo the tank nut using a pipe wrench. You may have to use a clamp or vice to hold the jack in place.

5

Remove the piston from the jack. Once the tank nut is undone the piston will slide out. There are several pieces to the piston, record their positions as you remove them so you can put them back the same way. The positions and order will depend on the jack you are repairing. Examine the seals around these pieces to see whether they are pinched, cracked or broken. Replace any that look worn.

6

Replace the pieces of the piston inside the jack and tighten the tank bolt.

Leakage from the Bottom

7

Drain the oil from the jack by opening the oil reservoir and tipping the oil out.

8

Remove the screw that shows the leak and look carefully into the hole. There will be a ball or a pin if it is the release valve, or two balls and two springs if it is the overload valve. Carefully remove each of these pieces and make a note of the order in which you removed them.

9

Verify all the balls and springs are present and then examine the inside of the hole for the O-rings and washers creating the seal. Examine these for cracks, breaks or pinches. Replace anything in bad shape.

10

Put the balls and springs back in the hole in the order you removed them. Usually it goes small ball then small spring, then large ball and large spring. Depending on the jack, you may also have plates and guides to keep the balls and springs in place.

11

Once the balls and springs are back inside, replace the screw.

Leakage from the Handle

12

Drain the oil from the jack by removing the reservoir plug and letting the oil into a tray.

13

Remove the bolts securing the handle to the piston and to its pivot. There are usually three or four bolts. The number depends on the manufacturer.

14

Place the jack in a vice and pull out the pump piston, which is attached to the handle. It is not bolted in place but it may require a lot of force to remove. Put aside the piston and examine the O-rings and washers for any sign of pinching, cracking or breaking. All the seals are on the inside of the hole, in the body of the jack. Very few jacks have seals on the handle itself. Replace any worn seals.

15

Push the piston back down into the hole and replace the handle assembly, securing it with the same bolts you removed.

Finishing

16

Replace the oil in the reservoir. Open the reservoir cap and fill it with hydraulic oil until it is about 1/4-inch below the level of the hole when the jack is on its side.

17

Remove any excess air from the jack by opening the release valve and vigorously pumping the handle. Close the release valve, then raise and lower the jack as you normally would. If there is still air in the system, the jack will not reach its full range of travel, so repeat the process until you get the full range of travel.

18

Wipe the jack with the cloth to clean the outside and lift the vehicle again. Determine whether there are any other leaks by examining the outside of the jack.

Hydraulic jacks are relatively simple machines. If you have one in your workshop that no longer lifts, then you should consider trying to rebuild it. Many jacks are designed to be disposable and thrown out as soon as they break, but high quality hydraulic jacks can be rebuild instead of being replaced and some manufacturers offer rebuild kits. The procedure is the same whether you have a bottle jack or a floor jack. A floor jack has a bottle jack inside, so remove the bottle before starting the procedure. This procedure should not be part of your routine maintenance routine but it may help if the jack is not working correctly.

Instructions

1

Drain the oil from the jack by removing the drain plug. This is usually the uppermost plug if the bottle were standing on its base. Once the oil is drained, clean and replace the drain plug.

2

Remove the handle assembly. This is usually held in place by a few bolts. Once you have it off, pull the pump piston out from underneath the handle. This can be done by hand, though you may want to secure the jack with a vise.

3

Remove the release valve by unscrewing it. There is usually a ball or pin to regulate flow under the cap. Remove this by using the pencil magnet and keep the ball and cap together.

4

Remove the overload valve. This valve is often under a screw and close to the release valve. Remove the screw or bolt holding it in place and then use the pencil magnet to remove the two balls and springs underneath. There may also be some dividers, plates and guides underneath it. As you remove these, make a note of the order they were removed. This will help you when it comes to replacing them.

5

Use the pipe wrench to remove the tank nut from the top of the bottle. Once this is off, the piston will slide out and you will be able to slide all the pieces apart. Make another note of which piece was inside which, so you can put them back together afterward.

6

Examine all the o-rings and seals for pinches, cracks or breaks while everything is apart. Replace the o-rings and washers with new ones. When removing the o-rings do not use the side that creates the seal as leverage as this may damage the surface and prevent the new ring from sealing correctly. You can also soak the new soft o-rings and washers in hydraulic oil to improve their initial seal.

7

Reassemble the piston by referring to the directions you drew up when you removed it. Slide the piston back inside the bottle and tighten the tank nut.

8

Replace the balls and springs in the overload valve. Usually the smallest ball goes first, followed by the smaller spring and then the large ball and large spring. Refer to the directions you wrote when removing them if you have additional parts. Replace the cap on the top of the hole.

9

Replace the ball or pin inside the release valve by dropping it in to place and then replace the release valve screw or bolt.

10

Push the pump piston back into place under the handle and replace the handle assembly using the bolts you removed earlier to secure it in place.

11

Open the oil reservoir cap, refill the jack with oil and bleed any excess air from the system. To bleed the air, open the release valve and pump the handle vigorously several times. Then close the vale, pump the jack to its full height, open the release valve and let it down. Repeat this process until the jack reaches its full height.

12

Wipe the jack all over with the cloth and test it by lifting a vehicle. Carefully examine it following the test for any evidence of leaks.