Front caliper piston problem.

[Halfa1200]

Just replaced the front pads on my 2013 F700GS and noticed that when you apply the brakes the top piston moves out before the bottom piston follows more slowly. I replaced the seals on the bottom piston as the top piston easily moves in and out. Resembled the caliper, put in new fluid and bled the caliper. Still the same result when the brakes are applied.
You can push the top piston back in with your fingers but the bottom one has a lot more resistance.

1. Should I have replaced the seals on both pistons together?.
2. Are the brakes designed to work like this?.

Had the bike since new and done 34k in all weathers.


Any advice appreciated.

Halfa 1200

 

[PankGS]

What happens is you get corrosion behind the seal, remove and clean with wire wool wash with brake fluid. Hope this is helpful .

 

[Halfa1200]

Have replaced both sets of seals. There was some slight buildup of corrosion behind them. Washed with brake fluid and Muck Off brake cleaner. The larger piston still comes out quicker. I have been told that the larger piston will come out quicker due to fluid dynamics and to prevent brake squeal ?. Anyway brakes work fine.

Anyone seen the Cyclops LED light conversion kit on the Sport Touring Website. Just ordered a kit. Will update when fitted.

Halfa 1200