This is a public service message, hope my experience helps others.
As many of you may know, some SRAM hydraulic brakes levers of recent years (mine are SRAM Guide RSC from 2014) have a tendency to get stiff, not returning after you squeeze them. It's because the pistons inside the levers gradually expand and start to rub or scuff against the inside of the cylinder. This can take months to years before it starts to happen. My levers started doing this after about 4-5 years and a few thousand miles. What causes it? I don't know, but it seems like the plastic-like material from which they construct the pistons gradually expands when in contact with brake fluid??
One solution is to disassemble the levers, remove the pistons, and use fine emery paper to sand them down evenly around their circumferance, reducing the diameter, until they slide freely in the cylinders again. You can find YouTube videos to walk through this. I did this with mine and it fixed the problem for about a year, when it started happening again.
So then I found a final solution: aftermarket metal pistons for these brake levers. They are not expensive and they come with new seals. I replaced the OEM pistons with these about a year ago and they still work like new.
As many of you may know, some SRAM hydraulic brakes levers of recent years (mine are SRAM Guide RSC from 2014) have a tendency to get stiff, not returning after you squeeze them. It's because the pistons inside the levers gradually expand and start to rub or scuff against the inside of the cylinder. This can take months to years before it starts to happen. My levers started doing this after about 4-5 years and a few thousand miles. What causes it? I don't know, but it seems like the plastic-like material from which they construct the pistons gradually expands when in contact with brake fluid??
One solution is to disassemble the levers, remove the pistons, and use fine emery paper to sand them down evenly around their circumferance, reducing the diameter, until they slide freely in the cylinders again. You can find YouTube videos to walk through this. I did this with mine and it fixed the problem for about a year, when it started happening again.
So then I found a final solution: aftermarket metal pistons for these brake levers. They are not expensive and they come with new seals. I replaced the OEM pistons with these about a year ago and they still work like new.
