Are 940 40mm piston cailper the same fitment as 38mm
 

I have 940 40mm piston cailper on my 92 940 i b
Can't get the new but can get 38mm ones are they the same fitment

Yes, as are the 36mm ones

If you're changing the caliper size, please change the axle pair as the difference in bore will mean different piston displacement so they'll be unbalanced otherwise ;)

Thanks for the helpn