Chinese Tractor Owners Association

Hydraulic cylinder seals cost the manufacturer pennies. They are usually purchased on a low bid basis. But that simple, inexpensive hydraulic seal can cost you thousands in downtime and loss of production if it fails. If you have a problem seal, focus on these four points to help determine the cause of failure.

No. 1 – Improper installation is a major cause of hydraulic seal failure. The important things to watch during seal installation are: (a) cleanliness, (b) protecting the seal from nicks and cuts, and (c) proper lubrication. Other problem areas are over tightening of the seal gland where there is an adjustable gland follower or folding over a seal lip during installation. Installing the seal upside down is a common occurrence, too. The solution to these problems is common sense and taking reasonable care during assembly.

No. 2 – Hydraulic system contamination is a another major factor in hydraulic seal failure. It is usually caused by external elements such as dirt, grit, mud, dust, ice and internal contamination from circulating metal chips, break-down products of fluid, hoses or other degradable system components. As most external contamination enters the system during rod retraction, the proper installation of a rod wiper/scraper is the best solution. Internal contamination can be prevented by proper filtering

No. 3 – Chemical breakdown of the seal material is most often the result of incorrect material selection in the first place, or a change of hydraulic system fluid. Misapplication or use of non-compatible materials can lead to chemical attack by fluid additives, hydrolysis and oxidation reduction of seal elements. Chemical breakdown can result in loss of seal lip interface, softening of seal durometer, excessive swelling or shrinkage. Discoloration of hydraulic seals can also be an indicator of chemical attack.

No. 4 – Heat degradation is to be suspected when the failed seal exhibits a hard, brittle appearance and/or shows a breaking away of parts of the seal lip or body. Heat degradation results in loss of sealing lip effectiveness through excessive compression set and/or loss of seal material. Causes of this condition may be use of incorrect seal material, high dynamic friction, excessive lip loading, no heel clearance and proximity to outside heat source. Correction of heat degradation problems may involve reducing seal lip interference, increasing lubrication or a change of the seal material. In borderline situations consider all upper temperature limits to be increased by 50 degrees F in hydraulic cylinder seals at the seal interface due to running friction caused by the sliding action of the lips.

Here’s a secret – it is not necessary to buy replacement seals from the hydraulic cylinder manufacturer. Many hydraulic seal suppliers have the same exact seals that are used in most hydraulic cylinders and can easily cross reference or match up a replacement. In many cases, if there is a recurring problem with a seal,?a seal specialist (a company that specializes in seals)?can recommend a solution and increase the life of the seal.

This article was written by Jerry Whitlock:

About the author: Jerry Whitlock is known as The Seal Man?. He has over 30 years experience in the seal industry. Jerry owns EPM, Inc. located in Atlanta, GA. His web site www.epm.com is the largest and most visited web site for hydraulic seals on the Internet.

Front-end loaders are valuable, time-saving additions to tractors, especially during the busy haying season. The tractor-loader combination can also be dangerous if not operated properly. Loaders can change the center of gravity of the tractor and therefore affect the stability of a tractor, creating the potential for a rollover. The following guidelines are simple safety tips for tractor operators when using a front-end loader.

• * Only install loaders designed and approved by the tractor manufacturer.
• * Use only manufacturer-approved attachments for handling large hay bales. You will need a grapple fork or spear to secure a large hay bale.
• * Do not carry big hay bales in an open front-end scoop.
• * Use loaders only for the jobs they were designed to perform.
• * Do not use a loader for removing fence posts, towing, or knocking things down.
• * Use a ballast to correctly balance the loader and tractor, front to rear.
• * Move tractor wheels to the widest practical setting for increased stability.
• * Familiarize yourself with the operator?s manual for both the loader and tractor.
• * Use only a tractor that is equipped with a rollover protection structure (ROPS) and always wear a safety belt.
• * Hydraulic leaks can cause severe injury. Check for pressure leaks in hoses and valves with a piece of cardboard, not your hand.
• * Do not exceed suggested load limits and load the bucket evenly to prevent tipovers.
• * Carry loads at a low height and at slow speeds.
• * Do not move or swing a load over people in a work area.
• * Do not walk or work under a raised loader.
• * Do not work from or ride on a loader.
• * Avoid electrical lines, loose gravel and holes when maneuvering a tractor with a front-end loader.
• * When working on inclines, be extra careful. Carry loads forward when going up hill and back down a hill when carrying a load.
• * When loader work is complete, remove the loader before using the tractor for other jobs.
• * Always lower the loader to the ground when the tractor is parked.
• * Park detached loaders on a hard, level surface. Balance and stabilize the loader when it is detached.

When shopping for a used tractor in the market extra care should be taken in checking out the machine. Unlike a new tractor that may have warranty most likely you will be buying the used one As-Is. Follow these tips as a basic guide in your search.

Remember as you are looking at different used compact tractors, some of the things to check out include engine fluids.  Pull the dipstick and check the engine oil and see how it looks.  Does the oil look tan or light brown, or is it black?  Very dark black oil can mean the engine oil has not been changed regularly.  Also, check to see if there are any signs of water in the engine oil.  This might be evident by milky looking deposits on the dipstick which could be a sign of water in the oil.  This could be caused by a coolant leak in the engine such as a cracked head or perhaps a leaky head gasket.  Also remove the radiator cap and check the coolant to see if it has any signs of oil contamination.  Oil should float to the surface and be easy to detect.  If there are any signs of coolant and oil mixing, then definitely move on to something else!  Expensive engine repairs can really negate any savings of a used tractor.  You could easily end up paying more in the long run by buying used tractors with serious problems.  Check the tractors hydraulic fluid by pulling the dipstick on that too and see if it looks clean and normal.  Very dark colors or a “burnt” smell are good indications to look elsewhere!  Also, be sure to inspect the tractor and look for leaks.  Some small hydraulic leaks like light weeping around hydraulic cylinders (like on a front loader) or around hydraulic fittings can be normal on used tractors.  Just make sure that it is not excessively leaking anywhere. 

Naturally, one of the most important things to do while shopping for a tractor is to take it for a test drive!  Listen to the engine.  Make sure there are no unusual sounds.  Keep in mind that most compact tractors are diesel powered, and the engine will have a louder knocking sound than a comparable gasoline engine.  A light “knocking” sound of a typical diesel engine is normal.  If you are not familiar with diesel engines, then try to take someone along who is and can recognize what a normal diesel engine sounds like.  Be sure to shift through the gears on the transmission (or test out the hydro drive if it is equipped with a hydrostatic transmission).  Listen for unusual noises or excessive vibrations while driving.  If any of the used tractors you are looking at comes with implements like a front loader, then be sure to test them out and make sure they operate smoothly.  Also, keep an eye out for the tires and see how much tread is left on them.  Tractor tires can be expensive to replace, so factor that in when figuring price savings of purchasing used versus new.

When you are looking to purchase a tractor from the internet, it is different then going to the local dealer in your area and viewing the tractor.  Here are some simple tips to remember when you are looking to buy a tractor online.

• *Keep copies of advertisements, descriptions, or auction site printouts for any product you purchase.
• *Keep copies of any correspondence you have with a buyer or seller (including e-mail).
• *Do some homework. Check out the seller before you purchase a product:
• *If the seller is a business, check with the Better Business Bureau nearest the seller for any complaints.
• *If the product is being offered by an individual, obtain and verify real world information (such as name, address and telephone number) with the seller’s local telephone company.
• *Establish verbal contact with a seller prior to agreeing to purchase.
• *Ask for and check references
• * Whenever possible, consider paying by credit card, which offers additional protection in case of a dispute.
• *If it seems to good to be true….It probably is!!