bob

Hi Guys,

Long-long-long shot here but chasing some info on the early pre-92 twin-pot calipers with the 41mm pistons, - found in Galant, E38a, vr4 89-92
not the 43mm pistons used by every other twin pot system RVR through to EVOX.

the early caliper is MB699450, runs pistons MB618229 which are 41mm - found in Galant, E38a, vr4 89-92
the rvr/evo 1-3 is MB950176, runs pistons MB857837 which are 43mm
both use the same frame bracket.

every caliper onwards runs the same piston (43mm) right through to the evoX

Has anyone ever noticed this variance - seen impacts of swapping to later model calipers?
Does anyone have an old pair of early 41mm bore calipers lying around?

back story:
I have a pajero io (small 4g94 powered hairdressers 4x4), brakes have always been Meh, I've gone and upgraded the fronts to twin pot calipers from an RVR, this is a very common mod for all single-pot front mitsi's like fto etc all before i knew about the piston size difference on the io. it should be a straight swap no master cylinder changes needed (like every other mitsi)

pajero io front piston is 57mm, unlike every other single pot front (lancer, fto, outlander single pot, airtrek) that have a piston of 60mm, 
pajero io rear disks which have a piston of 35mm, unlike every other rear disk end that has a 38mm piston.
The smaller pistons in the io have much to do with it's ultra-short master cylinder (strut tower in the road) i.e. less stroke on master cylinder needs smaller volume pistons etc etc. no other mitsi has a stupid short master cylinder and there is 3/4" between end of master cylinder and the front coil spring so no joy there.

symptoms are softer pedal and more travel required to get brakes clamping hard, and the rears come on early. i.e. front calipers need too much fluid to actuate aka bores too big.

When you ratio the standard single-to-twin caliper piston sizes of evo's / rvr's, fto's etc back against the io i really need a twin pot with 40.8mm bores, the early 41mm caliper is the closest i will get.

Help!