Touched on this before a bit but still not sure where i stand.
The brakes on the P38 have always felt poor. But its a big heavy car thats fairly old, and comparing it with modern cars is quite difficult, modern stuff always feels a LOT more powerful due to much greater power assistance (some might suggest too much). Its the heaviest car i own, and also has the smallest brakes of any car i own or have owned for a number of years. So i'm unsure if its right, or it has an issue.
When i bought it the accumulator was burst, so it got a new accumulator and a full system bleed following the instructions in rave. It all worked well enough, but the pedal always felt a bit "wooden", There wasnt a lot of bite to the brakes, and you needed quite a lot of pedal effort to stop quickly. If you heaved on it, it did stop, as we discovered when my mate was driving and didnt notice a motorcyclist, and full emergency stop spec braking had it stood on its nose.
Last year, one the the rear calipers had siezed. Upon inspection the opposite side had been replaced recently (it was shiney silver vs the siezed one which was very rusty) so i replaced the siezed side and bled the new rear caliper only, using the hydraulic pump (ignition on, open nipple, press pedal, wait till nice clear stream of fluid, close nipple, release pedal)
After that the brakes felt noticably better with a more positive pedal feel, which puzzled me at the time, given i'd only replaced one caliper.
When i did the front suspension a few months ago, i noticed the front caliper dust boots were all torn, and shortly after the drivers front started sticking, and also developed a horrible "warped brakes" vibration. I decided to fix it all properly, so ordered a pair of new calipers, and nice new brembo disks and pads (not fancy drilled or owt, just decent quality standard parts). I guess, after things improving so much when i replaced the rear caliper i expected big things...
Today i managed to get them fitted, and bled the system following the rave instructions, except i didnt touch the rear booster or rear caliper bleeders as i figured those hadnt been disturbed.
Took it for a drive and i'm still not convinced its right. Maybe the new parts just need some time to bed in, but the pedal feels (i think) softer than it did before, and not really any more effective. I had expected it would have improved a decent amount once i replaced the siezed calipers, instead its left me feeling a bit "meh". I did 20miles, mostly motorway so not a great deal of braking, and it did seem to be improving towards the end of the trip, so potentially it does just need bedding in.
I'll put some miles on it and see, maybe i should redo the whole bleeding procedure including the rears... what would be really handy would be having a go of a good working P38 to see how it compares. Unfortunately i'm not sure anyone on the forum is particularly local to Fife/Lothians area.