Bobcat T870 is a four cylinder, liquid cooled diesel powered compact track loader. It is powered by infinitely variable hydraulic piston pumps that powers hydraulic motors. Like any other loader, Bobcat T870 is susceptible to various problems and failure modes as discussed in this article. Loader care and servicing is critical to ensure optimum equipment performance and increased life span. It is recommended to follow supplier manual for all the servicing and problem troubleshooting of the Bobcat T870.
Table of Contents
Bobcat T870 compact track loader is powered by hydrostatic transmission. The system has hydraulic pump, fluid lines and hydraulic motors. Failure of these component unit causes transmission problems with Bobcat T870 transmission.
Incorrect Transmission Fluid
This is one of the most overlooked cause of transmission problems in Bobcat T870 compact track loaders. It is recommended practice to always stick to supplier prescribed transmission fluid to avoid clogging of transmission elements due to use of substitute fluids. This is due to different properties possessed by different fluids. When refilling the transmission fluid always make sure to use the correct fluid.
Use of Dirt Transmission Fluid
This also presents problems with Bobcat T870 compact track loaders. Contamination of fluid may come from storage containers, dirt pipes exposed to various contaminants. It is advisable to always make sure storage containers for the transmission fluid are always clean and shielded from external environments. Contaminants in transmission fluid causes clogging of pipes and filters resulting in malfunctioning transmission system.
Transmission Fluid Shortages
One of the major causes of transmission system failure is shortage of transmission fluid. The purpose of the fluid is to transfer power from engine, provide lubrication for transmission parts. If the fluid level drops significantly the transmission fails. Therefore, it is important to always check and make sure the transmission fluid level is OK otherwise refill using correct fluid. Fluid shortages are also caused by leakages on the tank or fluid lines. It is therefore important to always inspect frequently the tank, transmission fluid lines and all connection for leakages. Loose connections and pipe fittings should be tightened and all broken and leaking points sealed or totally replaced.
Hydraulic Pump Failure
The hydraulic pump is the most important part of the transmission system. If the pump fails all the hydraulics of the loader fails. To check pump functionality, remove the pump outlet pipe and switch on the engine, transmission oil should be ejected from the pipe outlet otherwise the pump is not working. Great care to be observed when conducting the test above to avoid skin irritations and burns from high temperature fluid. It is recommended to consult competent person in troubleshooting these problems.Faulty pumps should be repaired where possible otherwise replacement is the only solution.
Blocked Transmission Oil Filter and Pipes
The purpose of the transmission oil filter is to clean the hydraulic fluid of all debris so that clean fluid enters the pump. Dirt or debris accumulation causes filter clogging and transmission oil flow becomes restricted. The transmission is affected as there is not enough medium to work on energy transmission. Filters therefore require periodic inspection and cleaning. Faulty transmission oil filters require replacement. Blocked or kinked transmission fluid pipes also cause transmission problems in Bobcat T870 compact track loaders.Pipes should be periodically inspected for blockages and kinks. Pipe cleaning to remove blockages can be done using pressurized air until blockages are removed.
Faulty Drive Motors
Bobcat T870 compact track loaders have powerful hydraulic motors that drives the wheels in both forward and reverse direction. When these motors fail the whole transmission system stops functioning and hence they should always be properly maintained to keep them functional. Checklists provided by supplier are of great importance in care and servicing of these motors. Damaged motors require repairs or replacement as per recommendation from technically competent persons.
The boom is also another part that is susceptible toproblems or failure on Bobcat T870 compact track loader. This is due to the intense movement of the boom links during loader operation. The boom has a hinge secured using high strength pins which require periodic lubrication to minimize friction and excessive wear. When these joints lack lubrication, they wear and result in pins failure. The boom will not be able to properly hold the bucket in place due to misalignment. Boom failure can also be caused by faulty cylinders and valves. The good sign of lubrication shortage is sound from the hinges. All bearings also require lubrication to minimize seizure.
The Bobcat T870 compact track loader engine problems arise from many factors including mechanical component failures, poor or compromised fuel system and malfunctioning ignition system.
To start Bobcat T870 loader without any problem, battery power is required in adequate voltages. If the battery voltage is low, the loader will not start.This starting problem with Bobcat 870 loader is caused by low voltage due to either broken battery terminals or cells. Low voltage is also caused by excessive battery discharge. To test battery functionality, using voltmeters measure voltage across the battery terminals. If voltage is low recharge the battery to required voltage. If the battery does not accept charge probably the cells are damaged or electrolyte is low. Check and top up electrolyte when volume is low. Defective batteries need to be replaced.
Open & Short Circuits
Open and short circuits are some of causes of engine starting failure. Open circuits are cause by broken cables and connections while short circuits are caused by contact of bare cable with other conducting path. To address these problems, inspect all cables and connections for broken points and bare wires. Broken or excessively damaged wires need to be replaced and properly insulated from other metal parts. Loose connections also need to be tightened. These are the basic troubleshooting guide to resolve Bobcat T870 compact loader start up problem.
Defective Spark Plugs & Ignition Coil
Spark plugs and ignition coils form an important part of the loader ignition system. If these two elements fail, the loader will not be able to start. It is therefore recommended to always check the spark plugs and ignition coil for damages or contamination. Damaged coils and spark plugs need replacement. Incorrect gaping should be corrected to supplier recommendation.
Maintenance is key to proper asset management, it is a small price to pay compared to the inefficiencies caused by lack of it.