Ask Dr. Dirt: Hydraulic Clutch Leak

Dirt Rider’s Chief Physician AKA Dr. Dirt is Scot Gustafson. If you have a question about bike maintenance, set-up, tuning, or if you need help diagnosing a problem or just want to know how something works, send your question, along with your first and last name and your city and state, to We may edit your letter and might also use it in Dirt Rider Magazine’s letters section.

Dr. Dirt,

I have a 2012 Husaberg TE300 and my clutch bleeds off. It doesn’t look like it is leaking anywhere, but I will be riding and once the clutch gets hot it has nothing there. If I pump it a few times it will build up pressure then slowly bleed off. I've tried getting air out and it’s fine until the bike warms up. On the trail I have removed the top of the clutch reservoir and wiggled the clutch and a few little bubbles came out and it seemed better. Do you think the plunger in the reservoir could be leaking back? Or is there still air in the line? The clutch works good when it does engage.

R. Church

Your hydraulic clutch is fading because there is a leak in the system and it is no longer sealing properly. This often occurs over time or from a crash to your clutch lever. Replace the piston in your clutch master cylinder and the o-ring on the piston in your slave cylinder. I would invest in the OEM clutch bleeding kit (p/n 50329050000) or similar kit if you don't already have one so you can properly reverse bleed your system.