1. Low hydraulic fluid level: check the hydraulic fluid level in the reservoir. If it's low, refill it to the recommended level.
2. Air in hydraulic system: air can enter the hydraulic system if a hose or fitting is loose or damaged. Check for any leaks or loose connections. If you find any, tighten or replace them. You may also need to bleed the hydraulic system to remove the air.
3. Faulty hydraulic pump: the hydraulic pump is responsible for providing hydraulic pressure to the bucket lift cylinder. If the pump is faulty, it may not be able to generate enough pressure to lift the bucket. You may need to replace the hydraulic pump.
4. Faulty bucket lift cylinder: the bucket lift cylinder is responsible for lifting the bucket. If the cylinder is damaged or leaking, it may not be able to hold the bucket up. You may need to replace the bucket lift cylinder.
5. Faulty control valve: the control valve regulates the flow of hydraulic fluid to the bucket lift cylinder. If the control valve is faulty, it may not be able to direct the fluid properly to the cylinder. This can cause the bucket to lift unevenly or not at all. You may need to replace the control valve.
If you can't identify and fix the problem yourself, it's best to take your Bobcat 873 to a qualified technician.
