Bobcat 751 is a 38hp skid steer loader powered by a four cylinder oil cooled engine and is supplied by Bobcat. Bobcat 751 loader just like all other tend to experience problems due to their mechanical design and materials properties when exposed to various working conditions. Major reasons for their failure goes to incorrect operating and maintenance procedures, wear and tear and harsh operating environments.
Table of Contents
There are many reasons that cause Bobcat 751 loaders to experience starting problems. The reasons vary from fuel shortages, faulty engine, insufficient oil and blocked filters. Religious inspections of these items as prescribed by supplier helps in reducing or avoiding these problems.
Engines consists of many mechanical components that need proper service to keep them efficient and functional. Bobcat 751 engine has got prescribed oil and fuel that is to be used with it like any other engine and is very sensitive to the type of oil and fuel used. It is recommended to make sure the correct fuel and oil are used for the engine to avoid starting problems.
Common problems associated with use of wrong oil include engine overheating which ultimately results in excessive gaskets and seals damage. Damaged or worn out gaskets cause excessive oil leakages and ultimately engine failure. Operating the engine at high temperatures damages bearings, crankshafts and leads to pistons expansion. Failure of these engine components affect the performance of the engine when starting hence it’s very important and always encouraged to ensure that correct oil and fuel in adequate quantities are always added to Bobcat 751 loader engine to avoid the starting problems.
Spark plugs and ignition coils also present challenges with starting performance of Bobcat 751 loaders. These elements are also prone to wear and tear due to use and therefore their effectiveness in the starting performance of loaders is compromised. All faulty components with signs of being burnt or broken should be repaired where possible or replaced with a functional unit correctly. There should be no signs of damage or broken ignition coil otherwise any broken coil should be replaced with assistance from competent person.
Battery System Failure
The battery system has battery unit powering all loader electrically powered components via electrical cables. The ignition system requires power from the battery to start the engine. Batteries may become defective and fail to supply adequate voltage required for various electrical functions of the loader due to low electrolyte level and defective battery terminals which result in starting problems with Bobcat 751 loaders. For battery to work efficiently, the electrolyte should be available in adequate quantities so that necessary chemical reactions that produces electricity occur. It is therefore recommended to always inspect and top up electrolyte if the level drops. When topping up the electrolyte always be careful not to add contaminated or wrong electrolyte. If the battery still fails to start the engine, replace the battery with a recharged one. When replacing the battery always ensure that connections are done properly. If not sure it is advisable to consult a competent person to assist.
The other check items are the cables. All cables should be inspected and all broken or bare cables properly rejoined and insulated to ensure electrical continuity to avoid starting problems in Bobcat 751 loader.
Electrical continuity allows flow of electric current and once broken due to loose connections, broken or torn cables power will not flow causing the engine not to start. Loose connections should always be checked and tightening done. All wires require proper insulation to avoid shorting the circuits.
Hydraulics system has mainly the pump, hydraulic motors, cylinders and control valves that plays an important role in loader function. Bobcat 751 uses a high flow engine capable of producing high power suitable for its application. Hydraulic system is responsible for all the loading and stock piling abilities of the loader. The pump is the major unit and delivers fluid to all the hydraulic components via hydraulic pipes. Due to high pressure nature of its application, the hydraulic system components particularly pipes are prone to bursts, valves failure due to contamination. Periodic inspections and routine maintenance are critical to keep the system operating efficiently and avoid problems with Bobcat 751 loader.
Loader Failing To Load
The problem is caused by faulty hydraulic pump and excessive loss of hydraulic fluid through leakages. If the pump becomes defective, it fails to supply hydraulic fluid to all hydraulic pipes and there won’t be any pressure to perform loading functions. As a result the cylinders will not lift and loading or stock piling won’t take place. Faulty pumps should be repaired by a competent person and properly fitted onto the machine system. Pay attention not to wrongly connect fluid pipes. The pump can also be replaced with a working pump to solve the problem. Secondly, to solve the problem always check the hydraulic fluid pipes for any loose connections and tighten if any. Pipes should also be inspected for leakages through burst sections which should be replaced.
This problem with Bobcat 751 loader is very common. In some cases the bucket ram cylinders will extend and fail to retract thus fails to achieve lifting and lowering of the bucket. This problem results from malfunctioning hydraulic system. The hydraulic fluid valves are the main cause of this problem in Bobcat 751 loaders. Contamination of valves usually results in misbehaving hence valves should always be checked and cleaned where necessary. Depending on the conditions or working environment, the cleaning or servicing frequency differs hence it is recommended to follow supplier manual. Valves also fail due to wear during use and hence they should be replaced when no longer working. The problem again can also be caused by deformations along the cylinder piston length. These deformations causes in and out movement of the cylinders hard and hence piston should also be checked for deformations. Leakages also cause cylinders to get stuck, if leakages are on the return pipes the cylinder will not retract. Leakages can be visually identified and replacements done to solve this problem.
Piston Moving Slow
The piston movement is determined by the performance of the pump and absence of any leakages within the hydraulic system. The piston is designed to move in and out at a defined speed. Bobcat 751 loader experiences problem with slow piston movement as a result of either pump failure supplying hydraulic fluid at a very slow rate and resultantly the cylinder movement becomes slow or fluid leakages. All malfunctioning pump components should be replaced by a competent person to improve pump performance. Hydraulic fluid leakages also contribute to slow piston movement and hence should be avoided.
This is a useful troubleshooting guideline but however it does not replace the owner’s manual.