When you're working long days and need to know your tractor's running at the right RPM, the last thing you want is oil leaking around your tachometer drive. This precision-molded drive seal prevents hydraulic fluid leakage around the rev counter mechanism and maintains proper system pressure for reliable operation while protecting internal components from contamination. Whether you're monitoring engine speed during PTO work or keeping tabs on RPMs during field operations, this seal keeps everything sealed up tight so your gauge gives you accurate readings. What You're Getting Exact 21mm inner diameter and 35mm outer diameter with 6mm width for perfect fit High-quality rubber compound that resists hydraulic fluid degradation and temperature extremes Two seals per package - handy for stocking a spare or doing both sides at once Direct replacement that installs without modifications or special tools Built for Real Farm Work These classic Massey Ferguson tractors like the legendary 135 were some of the most popular tractors ever built, with several hundred thousand produced for diverse farming operations including crop cultivation, hay production, livestock farming, and PTO-powered implement operations. Whether you're running a compact 35 for chores around the farm, a workhorse 135 for hay season, or any of the larger models for serious fieldwork, this seal handles the constant vibration and pressure cycles that come with agricultural use. Made to Last This seal is manufactured from premium rubber compounds specifically formulated for hydraulic applications, maintaining flexibility across wide temperature ranges while resisting swelling and hardening from hydraulic fluid exposure. The materials are built to handle everything from cold morning startups to long hot days in the field, keeping your rev counter drive sealed season after season. Good to Know Installation is straightforward - just remove the old seal and press the new one into place. Clean the housing thoroughly before installation and check that the drive mechanism isn't worn beyond normal limits. A thin coat of hydraulic fluid on the seal lips helps with installation and prevents tearing during assembly. Remember that you'll also need gasket QTP-36862511 if you're doing a complete rebuild of the drive unit.