I think that MAFACs use 42mm brake pads and the modern jagwire X-block pads are 40mm and are available at the LBS for $0.75/ea in a card of 40x pads, so you might want to buy some of those, pry out the pads, and forget about the 4-bump pads and use X-pads instead. If they don't exactly fit you can notch deeper grooves in them with a rasp files, they tend to be wider than vintage pads which means they can be used EVERYWHERE. Whoever designed these pads was a genius.
There are two circumstances I have found where pads will squeal :
1. The rubber is dried out, as in my ALAN 74 with Campy GS brakes.
2. The rubber compound is defective, as in shimano-99 pads, which were so tough they pulled shreds of aluminum out of my mavic CXP 21 rims with my ultegra brakes.
Fresh jagwire X-pads have fixed both problems, with a weinmann X-pad vintage look at a screaming-bargain low price.
- Don Gillies
San Diego, CA, USA