Sumitomo caliper rebuild - rt132 corona

[theremm]

Hi all,

Just picked up some front sumitomo calipers out of an 1981 rt132 corona, intending to use these in my xt130. Seals and pistons look as though they could use replacement..wondering if anyone has done a rebuild on any sumitomo calipers before? Tips and info appreciated. Cheers

[AJPS]

javal will be here soon

[Lexsmaz]

I don't know what they look like as in do they have opposing pistons or just one single, if they have opposing cylinders i don't recommend splitting the housings as getting the seal between the calliper halves could be tricky & also there is the torque of the bolts which you would be hard pressed to get hold of, I just put a block of wood between the pistons or the piston & the side allowing say 5 - 10 mm of clearance & lightly apply air pressure through the brake line which will force out the piston to the wooden block, then remove the air supply & fit a thinner block of wood & repeat the process until the piston pops out, then clean inside the housing using Metho & tooth brush & then some 800 or so wet & dry, clean inside the back of the piston seal in the housing too & then dry & wipe out & then clean again with the metho. ( I don't recommend using anything stronger than Metho as it could linger after you have assembled it back together rotting / perishing the new seals ) .. Give the pistons a good clean on the outside using some 1000 or so wet & dry even a wire brush on a grinder can work just don't press to hard & keep an eye on things too & dry & inspect the Pistons for any pitting etc .. Fit the New piston seals in the housings Dry & install the piston dust seals dry too & then but a thin coat of rubber grease or brake fluid on the piston & then work it into the dust seal & make sure its dead square & slowly gently press it back into the housing, it should go back in without to much effort / force ..

[theremm]

Thanks for your help, have been looking into this a little as of late. By the sounds of things perhaps something best left to the pro's.. going to look into getting a rebuild done by a brake shop or alternatively find something of same/similar in good cond.