EXNAVI Brake Lever Internals Rebuild Part Piston Assembly kit for Sram Guide RSC Ultimate

Replacing to my old swollen piston on my ultimate guide and fits good and slicky

I used these to rebuild my SRAM Guide RSC brake levers. Perfect fit, better than OEM quality, and they come with new seals. Perfect function too, back to snappy quick lever action.A year ago, I had already rebuilt the levers and emery papered the pistons to slightly smaller diameter to fix the stuck lever problem. But over the past year the seals (not the pistons) gradually swelled making the levers slow again, so I needed new seals. But I couldn't find new seals alone, only full lever rebuild kits (shame on SRAM for not providing a simple seal replacement kit). These pistons were the solution to this problem.

Finally discovered this faulty oem part that was causing sticky brakes in warm temperatures. Definitely use the official sram tech youtube video for instruction. You will also need the red sram brake tool. You will NOT need c clip pliers. As others said its better than new now, super snappy lever action couldn't be happier. btw, putting a ziploc bag of ice on the lever will temporarily loosen the piston up for removal, just point away because it can shoot out like a cork.

I had the sticky lever syndrome (levers would not return if over about 15 degrees c temperature) and these cured it. You need good light, a clean work area, and reasonable mechanical aptitude to complete this switch, be warned! Watch a couple of youtube videos before you start. Full bleed required afterwards, i had to do this twice to firm up the lever feel.

It technically seals nicely, but the distal o-ring is slightly too large (too wide) and plugs the port into the reservoir so you are unable to bleed or have fluid exchange with the reservoir when the contact point adjuster is all the way in. The work around would be to turn the adjuster to the + side a bit, but for brakes it's better to just get the 100% working solution.