From: John [jfowler@bridge.com]
Sent: Thursday, November 02, 2000 8:00 PM
To: 928
Subject: [928] Knocking when brakes are applied - problem solved!

Hi all,
Back on 10/30 I appealed to the list for help in solving the knocking 
problem I encountered after installing new rotors and pads.  I would like 
to thank everyone that replied as it certainly kept me from chasing my tail 
on this one.
The problem turned out to be - and this is why I'm posting this - is that 
if you use metal pads (in my case they were Axxis Metal Masters pads), they 
are very hard to break-in on new rotors.  The surface on new rotors isn't 
abrasive enough to seat the pads quickly. This was explained to me by my 
friend who runs an auto machine shop and incidentally resurfaced and trued 
the rear rotors.  He said you have to either scuff up the new rotors (he 
puts a cross hatch type pattern on the surface similiar to what you would 
see when you hone a cylinder) or give it at least 150 miles or so for them 
to break-in.  He said a lot of brake shops will send him new rotors so 
their customers don't complain when they leave the shop.
It's been about a 100 miles now since the install and the knocking is all 
but gone.
Once again thanks to everyone who replied.
John
rennlist member 990415-1041
PCA member 1998060577
1984 928S 661/blue
1984 911 L90E/black
1986 951 alpine white/burgundy