Brake advice please.

I have now fitted a new master cylinder on my 89 gti cab. I have bled them through twice now and have a firm pedal. All four brakes are working but I still have very poor stopping power. The car has been sat on driveway for 10months, could it just be rust causing rubbish brake response? Would it be worth investing in new front discs and pads? Any advise please.

When I got my Cabrio the brakes were very poor with very bad fade even after just a few stops. Convinced myself it was a duff M/C. replaced that and bled very old looking black sludge from calipers. Rears had new looking cylinders and shoes. Still less than reassuring.

Replaced front calipers, flexi hoses, discs and pads. Re-bled it all, manually adjusted the rear 'auto' adjusters and its still the worst brakes on any MK1 I've had.

Everything from tip to toe is brand new, now inc the rear flexis swapped for Mr MOT man, and its still not brilliant.

Best brakes were on my old Caddy, GTI are fine, Cabrio brakes are just pants!

How tru you are. This is my second cabrio, the first one I owned I needed to use both feet to stop it. Ive also got 1.8t mk4 and you only have to breathe on the pedal and it stops. I think i will try new discs and pads as vurtually all pipes changed not so long ago, if that dont work it will be an anchor out the window. Thanks for advice again.