Brake fluid leak?

[Cummins/94]

I have a leak between my brake master cylinder and my hydro booster on my 2003 ccsb LB7 duramax 126k miles on it trying to figure out what's wrong with it so I can order parts tomorrow if someone could point me in the right direction that would help alot

 

[No Sparkplugs]

It's the hydroboost unit itself. The main seals go bad and leak PS fluid under the hood. You can buy a seal kit and fix it pretty quick, since it's usually just the figure 8-looking body seal, but doing a total rebuild is a PITA. I rebuilt mine at 250k miles and it still works great. This appears to be a known issue, friend had the whole hydroboost replaced on his '04 when it had 800mi on it.

Seal kits: Hydro-Boost Rebuild Kits

Re-seal how-to with pics: How To: Hydroboost Rebuild / Leak Fix - Discussion - Chevy and GMC Duramax Diesel Forum