Exchange top arms with new oilite bearings fitted and reamed. 
The arms are blast cleaned and then the old bearings removed the arms are then checked for damage and dimension.
The arms are zinc plated for corrosion protection and then new oilite self lubricating  bearings fitted and then reamed to final fit. In most cases because the bearings have more surface contact with the pivot pin this will eliminate the need to replace the pivot.
The arm bearings require an occasional drop of oil through the oil hole. 
The knocking and poor steering response are eliminated.
The exchange price is £130 plus vat per pair.
NB:  A surcharge of £30 is payable/arm if arms are damaged or unserviceable.
Rear arms also available for £160 plus vat/pair.
Exclusive service from Mike Satur.