Welcome to Netrider ... Connecting Riders!

Interested in talking motorbikes with a terrific community of riders?
Signup (it's quick and free) to join the discussions and access the full suite of tools and information that Netrider has to offer.

Brake caliper piston questions

Discussion in 'Bling and Appearance' started by D4SPADA, Jun 6, 2008.

  1. Hey hey,

    I'm posting this because i just realised my front brakes aren't working quite as well as they should. AKA i tale ended a retard cager who pulled in front of me and then decided to slam the brakes on :evil: . Only damage was a broken clutch lever and tenderness from smacking the tank rather hard :( guys you feel my pain.

    Question time. When i removed my brake caliper from the disc and squeeze the brakes to see if the pistons were working only one piston closed, the other didn't move at all. Both pistons should force the discs closed yes? or is that just a stupid thing for me to assume.

    Seeing as it's only a 2 piston caliper i would really hope both are working
    Btw its a Honda Spada if you didn't gather from my name
  2. 1 piston may be a bit free'er than the other.

    Did you try putting a block behind the free'er piston and then applying pressure to see if the 2nd piston moves ok ?

    BTW. be very careful not to overdo it as the piston can come out of the caliper if you allow it to travel too far.

    CRC make a product called "Brakekleen" which is useful in these circumstances. We use it to keep brake parts clean on race bikes, as we are always looking for absolute minimum rolling resistance in the 125's

    If you suspect the brake performance is not all it could be, you need to look at the following as well

    * how scored and grooved is/are the disc/s ?
    * are the rivets in good condition and the disc float as it should ( floating disc only )
    * does the caliper slide freely on the pins as it should ( floating caliper only )
    * what condition are the pads in ?
    * are they good quality pads or just the cheapest you could find ?
    * what condition are the brake lines in ? old rubber ones usually= soft = spongy.
    * does the mastercylinder operate properly.. leaks..pumps up ok then goes spongy after a while ??
    * does the system need to have the brake fluid replaced and bled properly

    If you are not sure about your mechanical skills .........brakes are somewhat important to your staying alive....... so get a trusted professional to check them for you.
  3. I am pretty sure the Spada uses sliding pin calipers. If that is the case, there is only one piston side and it pushes against the pad and disc, pulling the other pad against the disk, resulting in you stopping. Or not.
  4. My last bike was a Spada and I did some work on the front brake caliper. They are a sliding pin design with dual pistons on one side. When I was checking mine out I also found that when I squeezed the brake lever, one piston would move and the other didn't. It just because one is slightly freer than the other. As previously suggested you can put a block in there and check it out. As the moving piston closes up the gap and hits the block the other piston should start moving. This doesn't matter when the brake is assembles as the clearance is so small, both pistons work when you brake.

    Why do you think your brakes aren't up to par? Mine were dodgy because of air in the lines. No amount of bleeding could get rid of it. After a bit of researching I found some tips on how to remove trapped air and it worked a treat. Took some time though.
  5. thanks guys,

    i'll try the block on the main free'er piston and let you know how it goes. Might give them a good clean to (thanks mike, awesome reply). I will bleed the brakes to and see if that helps.

    You've at least cleared up my question a bit. It doesn't automatically mean faulty brakes which is good :)

    keep you posted