Re: [Chrysler300] C300 brake upgrade
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Re: [Chrysler300] C300 brake upgrade

I did do a swap on a 55 to 56 booster years ago, and remember that some firewall cutting was involved. Not much room to work there either.
Sent: Wednesday, November 30, 2016 5:42 PM
Subject: RE: [Chrysler300] C300 brake upgrade

Hi Jack..did you happen to see that U tube clip maybe 4-6 mo back about the 56 300B running competitively in modern vintage races?? ..he had Buick finned aluminum drums ( circa early 60’s) on total contact 300 backing plates. Probably ‘Chrysler 2.5 “ wide shoes , although Buicks had 3” (!!) ,and the drums can do that. (or either apparently) It  appeared easy to do, as he did it , some hub machining . Impressed me, sharp thinking there. .

But I did not notice what he did to drive the brakes ; 55 and 56 seem to have about same firewall, might be a path for you already proven by a guy who actively races his B; I hesitate to experiment on brakes, and learn by pain, if someone else already did that part. I do know those Buick drums were the hot set up too on Bonneville high speed racers, preferred by many , for years over discs. And they often used the dual leading shoes big car 12” Mopar setup inside them to gain self activation on both front leading shoes without a booster (in light cars, and poor vacuum in race engine , or a blown up engine at 200 mph) I have a 60 Electra 225 with them stock, they are better than most discs stock.  That said modern discs like Wilwood are terrific if the master drives them right without a lot of dead pedal space. ( due to filling up the big Disc caliper pistons) Your booster is probably OK if rebuilt by a pro (?) and a dual master ought to fit to it , I have used the dual from Dart and police Dodge in 67-70 time frame , but not on your car type . ; drums , or drum/disc might not be unreasonable is all I am saying, the master came that way stock on those police disc/drum dodges. . Wilwood might even make something for your car in front . Forwarned..lots of pistons = lots of dead space fluid. One drawback that might matter a lot, is new wheels to the Buick bolt pattern. I think Kiekhoffer (sp?) used Imperial wheels with a larger bolt pattern, he did not like the 4.5. (apparently,  neither did Buick!)

I also note the hot rodders use S-10 chevy GM boosters and MC due to small size , small OAL.  I think AAJ uses GM calipers too…so that should work. As should dart or dodge on your own booster

I would check out that guy racing the B. I bet he has a lot of info. Has to work well for him to race with it. Especially what he has on firewall.

Others with more direct early 300 experience will no doubt help you too, as well as all of Tony’s work on his F brake setup. . The 300 brakes have problems, due to duffers getting at them , mostly,  but when new were pretty good. The only real problem is lack of heat storage, so they fade with 2-3 70 to zero panic stops in a row , (magazine tests!) or mountain downgrades (use transmission) . But for a first hard stop in traffic ought to be ok with drums working right….? I had a brand new 60 Dodge in 1960, you could easily lock the wheels all stock, no power brakes . I liked it BETTER than the on-off feel of power brakes, back then. Maybe by 60 the leading shoe setups  were better shaken out….

From: Chrysler300@xxxxxxxxxxxxxxx [mailto:Chrysler300@xxxxxxxxxxxxxxx] On Behalf Of 'Jack Boyle' jackcboyle@xxxxxxxxx [Chrysler300]
Sent: Wednesday, November 30, 2016 10:58 AM
To: 'Chrysler 300 List'
Subject: [Chrysler300] C300 brake upgrade

Good Morning all.

We have been driving our C300 more and more since my retirement and as always we are enjoying it a great deal. I have put over 100,000 miles in this car since 1967.

A concern that I have had for years is the one year only power brakes on my ’55. Their performance is adequate at best and panic stops are just that – panic. We are planning many more road trips including the freeways of Texas, California and the east coast. We want to balance the enjoyment of classic motoring with safety. To accomplish this we are planning on upgrading the brakes to discs and most importantly a dual master cylinder.

I have been reviewing AAJ and ECI products and have a few questions:

1.     Does anyone have experience mounting a modern dual master cylinder on the front of the 1955 boost unit?

2.     Has anybody found a modern booster and dual master cylinder combination that is easily adaptable to the 55-56 firewall and pedal set up? (appearing as something that looks factory and not too out of place is important to me)

I am looking forward to this upgrade as much as the switch to radial tires 10+ years ago.

Thanks in advance for any guidance or tips.


Jack C. Boyle

(913) 544-4650

Shawnee, Kansas


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