It's always interesting to read messages from guys just running into the
challenges of '55 MoPar brakes. The special tool referred to is the no
longer available and very rare MT-19-L and its use is shown on pages 61-64
in the '55 Chrysler Service Manual (See John Holst's most excellent website
for all sorts of parts and service manuals:
http://www.jholst.net/55-service-manual/brakes.pdf ) It is a tool that
will fit on front and rear drums and front and rear spindles/axle ends. It
is used to measure the inside radius of each brake drum and then provide a
reference dimension for setting the OD of the shoes on that corner of the
car to the drum radius less 0.006" for clearance. A clever mechanic could
probably rig a similar tool and I've thought it might be neat to reproduce
the tool. IF the new shoes are already arc ground to match each individual
drum or IF you get lucky and the new shoes are the approximate correct OD,
it would assure the drum would fit over the shoes and the shoes would be
reasonably close as installed and the pedal would be hard at least half-way
down.
But, then it would still be prudent to spin each wheel and use the
adjustment to get even closer. You can hear the drums start to engage the
drums as you wrench on the adjusters and a little more will slow the
spinning wheel. This is somewhat of an art, but one this fumble-thumb
teen-age grease monkey learned while servicing these cars in the '50's.
Once I learned which-a-way to crank the adjusters, I could do a great job
of getting a high, hard pedal in about half the time spent on a car with
star adjusters. We'd send the cars out with just a touch of shoe drag,
knowing that the high spots would soon wear down and create that desired
0.006" clearance. I doubt if any of the professional mechanics in the shops
ever used the tool much as more time would be spent in set up than would be
saved by having the shoes set close on first try. Setting the shoes out and
bringing them in just enough to let the drum slide on would produce similar
results. If the shoes are not arc ground and will not let the drum slide on
in the fully retracted position, it will be necessary to arc grind them.
Chrysler spec's call for 0.200" thick linings.
Good luck in developing and preserving the art. You will only read about
mechanic art here and in similar venues. Manufacturer's manuals must have
everything set up with detailed measurements as company policy, I guess.
Rich Barber
Brentwood, CA
e-mail: c300@xxxxxxx
'55, '64 & '86 Chryslers; '93 & '99 Jeeps; '05 Durango; '95 Tioga RV; 2.5
car garage
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