My Sears 3 ton high lift floor jack will raise but it won't lift any weight. The jack is only 3-4 years old and it has not had much use. I can't find my owners manual, and I want to know what I can do to bleed any air out to see if I can make this jack work again.

possible blown internal seal

You really need the car on a lift or tall jack stands to do this. You will need a full set of hand tools, a good hydraulic floor jack, a set of Jack stands (AKA Safety Stands) and a 1.5 Ton bottle jack. Raise the front of the car as high as possible and unbolt the old mounts from the engine and engine cradle, then Carefully using the bottle jack (put a piece of wood on the plunger of the jack to avoid damage to the oil pan) raise the engine off the mounts and remove them, and reverse install new mounts, time about 2-3 hours to do the repair.

"A jack lift is a mechanical device used as a lifting device to lift heavy loads or apply great forces. Jacks employ a screw thread or hydraulic cylinder to apply very high linear forces.
A mechanical jack is a device which lifts heavy equipment. The most common form is a car jack, floor jack or garage jack which lifts vehicles so that maintenance can be performed.
More powerful jacks use hydraulic power to provide more lift over greater distances. Mechanical jacks are usually rated for a maximum lifting capacity (for example, 1.5 tons or 3 tons)." (Wikipedia)

A 4310s 3-pt should be able to lift approx. 1-ton at 24inches on the 3-pt lifting arm. I thought there was a hydraulic reservoir and a transmission reservoir and it is not uncommon to put the wrong fluid in one of those You might check that transmission fluid didn't get in the hydraulic tank.

Hi, Gerald -

You either need to top up the oil, or change the oil. Both of these are easy to do.
You'll need some high-grade jack oil, an Allen wrench, a rag or two, and a funnel.

1.) Relieve the pressure and lower the jack arm all the way down.
2.) Remove the tool tray from between the two rear wheels.
3.) Wipe the oil fill plug clean. (You don't want any gunk or debris falling inside.)
4.) Remove the plug with the Allen wrench.

Look inside. If the oil level is at or below the inner cylinder wall, you'll need to add oil. Don't go more than 3/16"-1/4" above the inner cylinder wall.

With the pressure still off, gently raise & lower the arm two or three times. Check and adjust your oil level again. Then screw the plug back in & tighten it with your Allen wrench.

Everything OK? Great. If not, repeat 1 through 4, then lay the jack on its side & drain ALL the oil out (into a container). When it's empty, set it upright & fill it. Again, raise & lower the arm several times.

Replace the plug, tighten it, then test. Raise the jack all the way up, then lower it all the way down, without any load on it. Repeat this two more times. (This helps to dissipate the air bubbles in the oil.) It should now be ready to use.

how do i bleed my floor jack

It sounds like you have MAXED out the absolute HEIGHT that the jack is CAPABLE of extending to.
Try this to test this theory; Remember though before you !!EVER!! attempt to raise a vehicle with a jack, make sure that the vehicle is on FIRM LEVEL ground and that the JACK is likewise. Even if you have to slowely drive your vehicle a short distance in order to attain level ground, DO IT. THIMK! It could mean the difference between whether or not you live to tell about the flat you changed.
Get yourself a piece of 'treated' 2"x10"x 2' lumber which you will put in the trunk of your vehicle with your jack. It is now 'married' to your jack.
Chock the Tires on the opposite side of the vehicle that you will be working on. The weight of your vehicle will be redistributed when you jack up the vehicle. Even though you will have it in 'Park' you do NOT want it to move any at all. The chocks will prevent this.
Place that piece of lumber beneath your vehicle below the 'jack point'.
Place your jack squarely on this piece of lumber and slowly crank the jack up, keeping your eye on the jack point where the jack is in contact, until the tire is off the ground about 1/2 inch, any higher and you are just wasting energy and time. Once the tire leaves the ground it is high enough to remove from the vehicle. You may have to raise the vehicle up a bit more in order to replace the flat with a good tire. Be SAFE, Start low and work your way higher.
The REASON for the piece of lumber under the jack is to distribute the weight that is now bearing on the jack so that it does not depress into the ground. It also provides you with a stable platform to begin with and gives you TWO more inches of height to use with the jack if needed. Use it even if you are on asphalt because depending on the consistency of the asphalt material and how HOT is is from the current weather, the jack could settle a bit into the asphalt and this procedure could prevent this and keep you safe.
If you are using jackstands, use a piece of treated 3/4"x10" square, plywood under it as well to keep it from settling into the ground. Raise the vehicle only high enough to slip the jackstand under the portion of the vehicle where you will be placing it and still allow the tire to be removed.
Be SAFE and live to tell the tale. :)

sounds like either pump piston seals or check valve on pump.

Hi,

I think I have the same jack. Th serial number was on a little sticker that is long gone,but the model number you need might needs is: 875.501390.

Hope this helps.
Gary

I have a Sears 1 1/2 ton floor jack. I was able to buy a repair kit from Astro Pneumatic Tool Company 372 OLD U.S. Hwy 52 South Mount Airy N,C 27030-8093
1-800-221-9705
John