Re: [Chrysler300] Magnum Force disc brake conversion
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Re: [Chrysler300] Magnum Force disc brake conversion

Yes, 12" brakes were optional on Plymouth and Dodge. They came standard on late 50s Ply and Dodge police cars.
----- Original Message -----
Sent: Thursday, February 18, 2016 7:37 PM
Subject: Re: [Chrysler300] Magnum Force disc brake conversion

I think the 12 inch brakes were a heavy duty option on the Dodge and Plymouth.
I have never had issues with the original drum brakes that I haven’t been able to fix. Linings separating from the shoes, and stretched springs come to mind. I always do new master and wheel cylinders, and don’t turn the drums unless they need it. If there are hard spots on the drums, you can’t remove them with a regular brake lathe. An old time shop that used to be in this area had a grinder attachment that could be used on their lathe to take care of hard spots. They also arc grinded shoes for many of my cars. I have my own arc grinding machine now thanks to the late great John H.
I have had issues with disc brake conversions, and dual masters though. The pedal ends up being way to low for comfort, and the stopping power is not that much better. The plumbing is a pain too. Chrysler designed them well in the first place.
Sent: Thursday, February 18, 2016 6:36 PM
Subject: Re: [Chrysler300] Magnum Force disc brake conversion

Very interesting info Andy, thank you for sharing.

Surprising that a 2100 pound Daimler with disc brakes took 33 feet more to stop!! Chrysler brakes were not that bad!! Dart a few hundred pounds less than the G, explains the 125 feet for the Dart, which probably was equipped with 11 inch brakes ...vs 12 inch for G.



From: Chrysler300@xxxxxxxxxxxxxxx <Chrysler300@xxxxxxxxxxxxxxx> on behalf of Andy Mikonis r41hp@xxxxxxxxx [Chrysler300] <Chrysler300-noreply@xxxxxxxxxxxxxxx>
Sent: February 18, 2016 5:11 PM
To: chrysler300@xxxxxxxxxxxxxxx
Subject: Re: [Chrysler300] Magnum Force disc brake conversion
Yes, John, I agree. One of my mechanic mentors who opened a service station in 1957 always told me the problem with these brakes was with the mechanics and not the engineers.
He always arc ground. (In fact, I have his arc grinder now.) The linings he ground for me in 1990 are still on my G after 100K+ miles.
Other things I have published in the club newsletter the newbies wouldn't have seen:
Paul Mallwitz, a Chrysler engineer who spoke at a club meet in 1982 was asked: "How did you get the brakes to work on these cars?"
Reply: "With great difficulty. Those Center Plane brakes had to be put together like a watch in order to make them work properly."

Next, in the April 1961 issue Motor Life magazine tested a 300-G and recorded a 60 to 0 of 131 feet. That's average for today's cars. Mistake? Don't think so. Dart D-500 in the same issue: 125 feet!
Other cars in the same issue:
Olds Super 88: 159 ft.
Olds F-85: 171 ft.
Daimler SP-250: 194 ft. (2090 lbs. with disc brakes)
300 editor
In a swiftly warming Chicago

On Feb 17, 2016, at 1:18 PM, 'John Grady' jkg@xxxxxxxxxxxxxxxxx [Chrysler300] <Chrysler300-noreply@xxxxxxxxxxxxxxx> wrote:


Just a FYI<


A lot of the fitment differences for a total upgrade are because they changed at various times the lower (at least) ball joint OD , how it fits, (press or screw in to lower arm) and the size of that ball joint taper that goes into the steering knuckle. I know it was long ago, details not 100% clear tonight , , but I put 67-68 Dodge police car package steering knuckles, discs  and ball joints into 57 Dodge control arm by reinforcing the end of lower control arm with added ring of 1/4” steel and then boring that out for what I think was the larger (than 57) 67-68 lower ball joint. I think top 57 one fit the knuckle or spindle ok, or found one that fit. . That let us put on stock 67 or 68 police car disc brakes, the “big discs”-- hot set up long ago --before disc kits--- on 57 Mopar.


Now they have kits that fit the old knuckle…and leave the small ball joints. Two kinds of kits?? ..special adapter  knuckle-- or not . By way of awareness, not comparing. But insight into why some years and not others.


This change to discs on my 57 was made , really, because I had frankly screwed up more than one total contact brake setup,  through not knowing what I was doing, after buying all new parts, ,  and was fed up with “all the problems”. They are real problems.   But is it the brakes?


I had a brand new 60 dodge , in 60, manual brakes , bought then because I liked  two leading shoes on the manual, had heard and seen many horror stories about power brakes in general 55-60, --60 Dart was a great set up! I beat it unmercifully. It was perfect in every way , brake wise; used to laugh at best friend’s GM 57 Pontiac power brakes with on-off feel. Beating unmercifully,  was street drag racing several nights a week to 100 mph + ,=  going was the problem,  not stopping. No pulling no grabbing..


The basic torsion bar suspension design  is about the same across these years ; all this by way of info, not advocating doing it, but good to think or know about. .


Do you need discs??   Sort of falls out of it? Idiot proof as far as assembling the pads….


I am in the middle of doing some discs, but still ambivalent. Not if drums are working right,  is one answer. They worked right at the beginning.


Also looking back, many of the problems with total contact , or other Chrysler brakes are errors caused by experts (who are not) in putting them together right, especially arcing the new shoes to a turned drum. If you do not, with all new parts, the brakes do not work. Discs get into front/rear balance, another possible can of worms, despite that  balance “valve” . They have inherently different actions..


They won all those NASCAR races with them, stories about “fade” on the street leave me cold. Worse than fade--- -------if the shoes are not touching the drum , most of the way around!


Sure ,  not as good as modern discs, but awfully good brakes.


Did you know GM put MOPAR total contact brakes on the racing Corvettes with Buick drums about 1960??  they watched the 300B race,  brakes and all, and win . . So would I. On a light corvette? Bulletproof . And the “fading after 3 panic stops from 120+ mph”  in contemporary 300 tests  is not exactly how we use our cars today. What reminded me of all that , was seeing that 300B race clip a few weeks back , on this site . No disc conversions , yet racing competitively for real, in 2015? Braking hard on corners over and over….. (he did have Buick drums too..which have aluminum fins on them.  60 to maybe 62. That forces a wheel change too ). Before discs, that was the hot setup. Rods, Bonneville etc . The brakes we take off.


My problems with these brakes on 300F over the years was not fade..they were pulling, grabbing, low pedal , poor stopping rate, squealing  etc etc . 300 B or 60 Dart was not like that ….  Why?


Just sayin….there is a disconnect here somewhere. Others see it?




From: Chrysler300@xxxxxxxxxxxxxxx [mailto:Chrysler300@xxxxxxxxxxxxxxx] On Behalf Of 'Bob Jasinski' rpjasin@xxxxxxxxxxx [Chrysler300]
Sent: Wednesday, February 17, 2016 4:46 PM
To: 'John Nowosacki'
Cc: 'Chrysler 300 List'
Subject: RE: [Chrysler300] Magnum Force disc brake conversion


I sent them an email.  I'll report back with what they send me.



Bob J


From: John Nowosacki [mailto:jsnowosacki@xxxxxxxxx]
Sent: Wednesday, February 17, 2016 1:22 PM
To: Bob Jasinski
Cc: Chrysler 300 List
Subject: Re: [Chrysler300] Magnum Force disc brake conversion


pictures say 57 to 61, but when I click on the link for picture or part number, it says 65 to 72?


On Wed, Feb 17, 2016 at 3:42 PM, 'Bob Jasinski' rpjasin@xxxxxxxxxxx [Chrysler300] <Chrysler300-noreply@xxxxxxxxxxxxxxx> wrote:

Has anyone  looked into or installed the disc brake conversion kit offered by Magnum Force?


They offer several kits and appear to be fairly new offerings. 


Bob J





Posted by: "Ron Waters" <ronbo97@xxxxxxxxxxx>

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