Got a leaky hydroboost unit? This complete seal kit from soillar is made to rebuild and reseal your hydro-boost brake booster, matching part number 2771004 (also listed as KIT-501). It's a direct replacement kit that includes all the seals you'll need for a thorough repair — just follow a good tutorial or manual if you're DIY-ing. Comes with a 1-year warranty, which is nice for a repair kit. One heads-up: the star retainer washer included may not fit vehicles newer than 2002, so older models are the sweet spot here. Perfect for restoring brake pedal feel and stopping power on trucks, vans, or older GM vehicles. No extra hardware included, so make sure you have the basic tools handy. A cost-effective way to fix your hydroboost instead of buying a whole new unit!