Re: [Chrysler300] 300C Front Brakes (take 2)

["Warren R Anderson" <wranderson@xxxx>]

the inside of the right front drum was not smooth. It was a bit wavy (at a
microscopic level)

Probably tool chatter from a bad setup on the part of the lathe operator or
something like a dull bit. Hard spots in a drum show up as islands in the
braking surface and does not sound like you have this condition. Drums with
hard spots must be ground to restore the braking surfaces. Finding someone
to grind drums may well be as hard as finding a brake lining arcing machine
(which BTW have big vacuum cleaners attached to catch the dust; oh, yeah).
Hard spots are noise makers.

I do not have the drum IDs. Hopefully they are both the same.

I definately like the diameters to be equal (replace drums in pairs) but
have seen .030 difference side to side and no problem.

There is clearance at both ends when centered in the drum. I'll have to live
with that and "break the shoes in".

There should be, must be clearance at the ends with the shoe centered on the
drum braking surface. This relationship is what the cam grinder does (when
the shoes are relined). The lining should actually rock but slightly.
Clearance should be something and up to .020" and do not try to make it less
as brake lining will seat in just fine and very quickly.

I noticed that the right front brake shoe contacts the drum at the top end
of the shoe (rather than the middle) when installed. It can be seen by rub
marks when adjusting the brake.

This is exactly what will cause uneven braking, grabbing etc. This is why
brake lining must be ground with clearance. If your shoes fit the drum
properly off the car and are hitting on one end or the other when installed,
there is a problem with the installation of the shoes (etc) on the car.

The front shoe won't center itself either like the right rear shoe does.
Also, the front shoe doesn't adjust correctly. The adjusting cam needs to be
backed off way to much for the shoe to come off the drum. That's why I think
the brake shoe return spring is weak because the shoe is hanging up and not
returning. The brake support plate is also suspect because the shoes could
be hanging there when returning.

There is a good product to use where the shoe rests on the anchor and where
the shoes rest on the backing plate. It is made by CRC; Sta-Lube Brake
Caliper Synthetic Lube. A little bit will work wonders at letting shoes
return properly providing that backing plate surfaces are super smooth, flat
and clean. Needs to be used on anchor also and too much will screw up brake
linings.

There are some truck brake configurations that benefit from using the brake
pedal to center the linings in the drum during adjustment.

Wayne Graefen suggested replacing the front hoses. I will. It seems the
inside of a hose can break down and prevent fluid from returning to the
master cylinder. I heard that from others too.
Joe McCormick gave me a lead on return springs from Northwestern Auto Supply
in Grand Rapids, MI. I'll call them first thing in the morning.

New brake hardware is cheap and with a big positive payoff. New hoses; the
same. ALL the hoses BTW.

There seems to be a list of problems with the front brakes on this car but
the rear brakes can cause pulling also.

Warren Anderson
Sedona,AZ