Motor Parts Direct have the 15Lb Borg and Beck BRC67 in stock at £5 :72. A straightforward cap with nothing fancy on it to fail they have served me well since 1969 ;-)
I fitted one last month to the Plus 8 as the original had got a defective seal caused by the spring getting tired so that is the end of an annoying loss of fluid without obvious explanation..
MPD and in particular the lovely Claire have never let me down with parts for the Plus 8 - the numberplate nonsense doesn't work.
All she needs is the engine type capacity and year and she is away, not restricted to engine, she has the whole drivetrain sorted in her head now, terrific service and loyalty discount.
I shall miss her as in May she is off to the pits to produce a little human for a while..
P.S. It took her 1Hr of trial and error out at the car to sort the fan belt out but spot on she was so I bought two. She has a Cooper S and does her own spannering as far as you can these days.
