How to Bleed, Change Oil & Clean a Trolley Jack

You will need to carry our various maintenance tasks on a regular basis if you want to keep a trolley jack in prime condition, thereby ensuring it will operate efficiently and safely.

From time to time it will be necessary to bleed the hydraulic system to remove air, change or top up the oil, clean the device and check all parts are working correctly. You may occasionally need to repair or replace defective or worn parts.

Here's some information and advice about how to carry out the tasks referred to above.

Adding or Replacing Oil: This is a really simple operation and relates to topping up oil in jack that's been working correctly without any oil leaks. If you have noticed any oil leaking form the device you will need to identify the cause of the problem and get it sorted out as matter of importance - a damaged jack which is leaking oil should be repaired as soon as possible and you should not attempt to use it until the problem has been sorted out. A trolley jack operates with a closed system so theoretically, providing there is no leak in the system, the oil level should remain constant. That said, it may be inevitable that a jack that had years of use will lose a small amount of oil and will need topping up.

A jack should be adjusted to its lowest position before refilling completely or topping up the oil. Next you should locate the oil filler screw or plug and remove it. Then you need to open the fluid release valve by with a half turn in an anti clockwise direction. If you plan to drain the old oil out of the jack and refill it with fresh oil you will need to have a suitable plastic or metal container close to hand. 

Next you should rest the jack on its side and allow the old oil to drain away into the container. Then turn the jack upside down to allow any residue oil to train away completely. Now place the jack in an upright position again and close the fluid release valve. Next you should use a funnel to pour fresh oil into the jack. You should add the correct amount which is recommended in your jack's manual or instructions booklet. Also makes use you are using the correct type of oil - this is usually high grade hydraulic jack fluid.

After filling with oil you should wipe away and excess oil that may have spilled with a cloth. Some people also choose to wipe the whole jack unit with an oily rag as this can help keep the device clean and rust free.

Next you should open the release valve with a half turn anti clockwise and pump the jack handle a few times to remove trapped air. Now check the oil level in the device and add more, if necessary. Finally replace the filler plug or screw and your jack should be ready for action again..

Bleeding a Trolley Jack: This process is also referred to as an air purge. It can prove dangerous to have air in a jack's system because the device could be prone to failure, which could have serious consequences, posing a danger to the operator and also the risk of damage to your vehicle. Bleeding a floor jack is a simple operation and can be carried out by most people by following a few basis guidelines.

First you need to extend the jack's piston fully - this is achieved by attaching the handle and pumping the unit a few times. Now, with the ram piston is fully extended, you can release the jack's pressure valve which is located near the base of the device. You will need to insert a screwdriver into the valve's head and turn carefully turn it anti clockwise. This should result in the piston retracting automatically.

Next you need to open up the oil filler plug which is located on the main body of the jack. Be careful not to confuse the filler plug screw with a check valve. If you are unsure, consult the manual that came with your jack. Now removed the filler plug by turning the screen in an anti clockwise direction. At this point you should hear some hissing as trapped air escapes from the system. Then you should reconnect the filler plug to the jack.

You should repeat these simple steps of extending and retracting the piston a few more times until you are confident no more trapped in the jack's system.

General Maintenance: There are a few things you can do keep your jack in excellent condition. It's wise to inspect your jack regularly and every now and then lubricate the hinge points and the front and rear wheel axles with a high grade grease. Check all nuts and bolts to ensure they are tightened securely and examine the handle, lifting and arm and main body of the jack for any signs of wear, cracks, corrosion or damage. If any defects are found you will need to decide whether to repair or replace a jack. When not in use a jack should be stored with its piston in the fully retracted position. You should also try to store it in a dry place to minimise the risk of moisture getting into the device and causing rust to form.

Cleaning a Trolley Jack: A hydraulic floor jack will eventually become gunged up with dirt, oil, dust and grease. The environments these jack are used in, such as auto repair garages and centres, means they are prone to become very dirty. It stands to reason that the longer you leave a jack without cleaning it, the more dirt and grime it will accumulate. Therefore, it makes sense to clean it on a regular basis. You should wipe the surface of the jack with a clean cloth to remove dirt and then rub it over lightly with a lightly oiled rag - this can help to prevent rusting, particularly when a jack is in storage and not being used.

Repair and Replacement Parts: Trolley jacks are very reliable devices and they are not prone to sudden failure - although this can happen occasionally and that's why it's imperative they should only ever be used to raise a vehicle and not to bear a load. Axle stands should always be placed under a raised vehicle after it's been raised with a hydraulic floor jack. If you do have a problem with a damaged or worn part on your jack, you can usually find replacements and spares at online or high street auto stores. The manual which comes with a jack should also provide information on how to buy replacement parts from its manufacturer. If you are reasonably handy at maintenance and DIY, you can consider repairing a jack yourself - however, if your skills are limited it might be best to pass the repair work over to a professional. You may even opt to replace your jack altogether rather than get it repaired - many trolley jacks are relatively inexpensive to buy and it can often work out cheaper to buy a new one, rather than repair an old one. Common spare parts for hydraulic jacks include rubber saddle pads, swivel casters, hydraulic cartridges, seal repair kits, air control valves and handle grips.