Stellar Industries 17724 Main Lift Cylinder Seal Kit – 4.00" Bore Description:

If you’re unsure whether this part is compatible with your truck or equipment, please contact us to confirm fitment before purchasing.

The Stellar 17724 Seal Kit is a genuine OEM repair kit for compatible 4-inch-bore main lift cylinders used on Stellar service cranes. It is designed for cylinder numbers D0931 and 9669, restoring the internal seal system without requiring replacement of the complete hydraulic cylinder.

Replacing worn seals helps correct hydraulic fluid leakage, cylinder drift, pressure loss, and weak or irregular main-boom movement.

What This Part Is Used For

The Stellar 17724 Seal Kit contains the sealing components required to rebuild compatible 4-inch main lift cylinders. These seals maintain hydraulic pressure inside the cylinder and prevent fluid from leaking past the rod, piston, and cylinder head.

Common Reasons For Replacement

Hydraulic fluid leaking around the cylinder rod
Main boom drifting under load
Weak or slow lifting performance
Cylinder unable to maintain pressure
Damaged, hardened, or worn seals
Oil bypassing the internal piston seal
Contamination discovered during cylinder service
Scheduled hydraulic-cylinder rebuild

Key Features

OEM Stellar Industries part number 17724
For 4.00-inch-bore hydraulic cylinders
Services cylinder numbers D0931 and 9669
Designed for main lift cylinder repair
Compatible with select Stellar 6620 and 7621 cranes
Helps correct cylinder leaks and drift
Restores internal hydraulic sealing
Cost-effective alternative to complete cylinder replacement