Could someone confirm if the rear brake piston of a 95 VR4 be the same size as the smaller piston in the front? I’m thinking just getting the front kit and using the parts for the smaller piston out of it.
I’ve redone my front calipers last year and parts I purchased fit properly. I’m now redoing my rear ones and ordered a repair kit from Rockauto, didn’t know the rears were single cylinder so I got the two sizes I thought it would be. Turns out neither fits well, mainly due to the rubber cover design. I got the Dorman D351212, 1.375 in dia. and Dorman D352116, 1.50 in dia. ones. the small o’rings that came with the D351212 don’t fit in the space between the two pieces of the caliper and the other one doesn’t even have o’rings. Figured it’s not that expensive I’d get the fronts, but then of those aren’t good it’s just more waste.
Anyone had similar experience and where were you able to find the right ones for the rear?
If you only have single piston calipers on the rear then someone changed them. 94+ VR4’s got dual piston calipers (one on either side) I’ve got a set right here and the pistons measure approximately 1.3125 OD based on a rough measurement with a tape measurement, but there may be more under the seal.
Looking at whats available its likely the 1.375" kit, but don’t hold me to that. If you truely have the single piston it could be the 1.5" piston, but again don’t hold me to it, I’d have to go through my receipts when I rebuilt my rears on the my NA.
Here are some of the pictures I took while trying to put the rubber covers on them.
Piston measures 36 mm in diameter if I remember correctly which was around 1.41 inches i think. I don’t have measurements of the front Pistons from when I redid them but somewhere I read they’re around 42.6 mm and 40 or something like that, seemed a bit bigger difference when I did them then 2 mm but maybe I remember wrong . And I also saw in the same place rears being 36 like what I have. Interesting this is not the first time I’m finding out discrepancies, when I rreplaced my front exhaust I was told I should have had an oxygen sensor where’s the two pipes come together from the header, but I only have them at the precats. This looks to be a fed spec car so may explain the O2s I had this car since 99 purchased with 40,000 miles on it, not sure if anybody would have made these kind of changes in the previous four years.
On my set of calipers which are JDM the rears are nominal 38mm diameter pistons and the fronts are nominal 40mm & 43mm, obviously the actual sizes vary by a small amount but I have not had as much as your 42.6mm differential on a 43mm Piston.
The problem I came up against was that the dust covers that I was able to obtain were slightly to large on the return that should fit into the recess at the top of the piston when using OE Pistons, and I was told by the manufacturer of the dust covers that they could not make a precise copy of the Mitsubishi part due to patents but who knows how true that is.
The non OE replacement pistons have a larger slot at the top to accept the slightly larger return on the aftermarket dustcovers, the Rubber sealing washers that sit in the Caliper seem to have a greater tolerance as even the OE ones are not a incredibly tight fit
I appreciate that this information may be of absolutely no use to you if the USDM units are actually different
40 & 43 seem more likely as for a difference between the two that i remember for the fronts.
I remembered wrong and just confirmed my rears are 38 mm dia so same as yours, I incorrectly stated 36 before. These ones I got the piston opening is actually smaller than it should be as I had to stretch them quite a bit. But the main concern on these is the way the covers are made, the ring clip does not hold them to the caliper and they pop up. The shoulder on the caliper doesn’t have any grooves it’s just straight and the rubber has a lip which doesn’t let me put the clip on the outside and putting it on the inside does not help as it raises the clip by the thickness of the material. Maybe I’ll try cutting that lip off and seeing if that helps. I also ordered another front set maybe the 40mm would be ok to use, will see. Thanks.