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

You are right Rich,


That stop might be the spring retainer snapping..shoe would go out and grab. the mid year upgrade to 300D. ?No recalls then. Any scratch marks or forming marks on that piece would lead to stress cracking in use and breaking…


Good point about how much the brakes were used at any given race..I always thought a lot, ---The race we had the clip from certainly was,--- but maybe not on a NASCAR big oval.. 




From: Chrysler300@xxxxxxxxxxxxxxx [mailto:Chrysler300@xxxxxxxxxxxxxxx] On Behalf Of 'Rich Barber' c300@xxxxxxx [Chrysler300]
Sent: Monday, February 22, 2016 1:48 PM
To: 'Ron Waters'; Chrysler300@xxxxxxxxxxxxxxx
Subject: RE: [Chrysler300] Magnum Force disc brake conversion


Now this is important.  Brake fade exists on drum and disk brakes and I have always thought it was about the coefficient of friction between lining and drum or disk diminishing at high temperature. 


It is rather amazing that the tremendous kinetic energy of 2 ½ tons of mass at high speed could be so quickly converted to heat at the relatively light drums or disks and wheels and be transferred to the surrounding air.  The hot drums or disks are also transmitting heat by radiation to their surrounding environment.  The big aluminum-finned Buick drums were impressive.


I recall a comment by a Chrysler 300 racer that he only had two stops in the brakes—but only usually needed one—at the end of the race.  I also recall seeing a ’55 or ’56 300 on a track being hit from behind hard by a Ford.  No explanation as to why the Chrysler stopped on the track.  Embarrassing and could lead to whiplash, ruptured gas tank & fire.




From: Chrysler300@xxxxxxxxxxxxxxx [mailto:Chrysler300@xxxxxxxxxxxxxxx] On Behalf Of 'Ron Waters' ronbo97@xxxxxxxxxxx [Chrysler300]
Sent: Monday, February 22, 2016 10:14 AM
To: Chrysler300@xxxxxxxxxxxxxxx
Subject: Re: [Chrysler300] Magnum Force disc brake conversion



Just curious...doesn't brake fading refer to the expansion of the drum due to heat ? So calling linings 'fade resistant' may not be a correct description.


The late Neil Vedder used to talk about a company called Firm-Feel for relining brake shoes. Has anyone had experience with them ?



----- Original Message -----

Sent: Monday, February 22, 2016 12:51 PM

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


Regarding the drum brakes on the early 300's, I had an excellent upgrade through Porterfield in California.  I had the drums ground out just enough to remove any grooves or irregularities, using the local NAPA store.  I measured the exact diameter of each drum with a large digital caliper and shipped out the old brake shoes, taking care to mark each one so they could be dedicated to the correct (resurfaced) drum.  Porterfield installed new linings with a modern metallic/ceramic compound they call R4D, which has not only excellent high-temperature fade resistance, but also very good initial "bite" when cold.  Using my measurements of each drum diameter, they custom-ground (arced) each shoe so they could mate with the dedicated drum.   

Sent from my iPhone

On Feb 18, 2016, at 10:59 PM, 'Rich Barber' c300@xxxxxxx [Chrysler300] <Chrysler300-noreply@xxxxxxxxxxxxxxx> wrote:



Ten years ago I was able to get the new shoes on our ’55 C-300 ground at Clutch and Brake Xchange in Stockton:     Had to, the drums would not go on over the new shoes.  I took the drums to them after a very light cleanup cut on the drums.  Worked very well with occasional adjusting for wear. 

Rich Barber

From: Chrysler300@xxxxxxxxxxxxxxx [mailto:Chrysler300@xxxxxxxxxxxxxxx] On Behalf Of 'Bob Jasinski' rpjasin@xxxxxxxxxxx [Chrysler300]
Sent: Thursday, February 18, 2016 12:02 PM
To: 'Chrysler 300 List' <Chrysler300@xxxxxxxxxxxxxxx>
Subject: RE: [Chrysler300] Magnum Force disc brake conversion


The brakes on my 300G are bone stock and I plan on keeping them that way.  The shoes were replaced back in the '70s when you could still get shoes arced, and the wear on the shoes at this point is maybe 25%.  I do adjust them every couple of years, I don't drive it much, and I purge the brake fluid about every 5-7 years using silicone fluid.  The master and wheel cylinders are all brass sleeved.  The car stops straight, no pulling, and has adequate stopping ability even from freeway speeds at the off ramp.  The only issues I have had are from brake fade, like when driving back from Reno, West bound through the Sierras, they can get a hot and fade.  I suspect this is less of a problem with a G than it would be with an F because the G has 15" wheels and vented wheel covers.

My interest in disc brake conversion kits is not for my own car, but rather those that contact me with questions about converting their 300G or similar car to discs.  They want a modern brake system in a box that shows up at their doorstep and can bolt on, I get that.  Also, many want a dual master for redundancy, and that can be very challenging with a ram manifold.  Another alternative I have heard of is to convert to later Bendix self adjusting, self energizing types like those used on '63 and later.  I've read they work pretty well and are not as drastic a conversion process, but you need to source the parts carefully and probably used.

I guess what I'm saying is that if it ain't broke don't fix it, but if you do fix it, fix it right!

Bob J

From: Chrysler300@xxxxxxxxxxxxxxx [mailto:Chrysler300@xxxxxxxxxxxxxxx] On Behalf Of 'John Grady' jkg@xxxxxxxxxxxxxxxxx [Chrysler300]
Sent: Thursday, February 18, 2016 9:55 AM
To: 'Andy Mikonis'; chrysler300@xxxxxxxxxxxxxxx
Subject: RE: [Chrysler300] Magnum Force disc brake conversion


Right on Andy..this year getting into these pretty good. As much understanding the technology --and the why , as any repair effort. I am so impressed with the 300B winning like that, over and over,  in Nascar on these brakes. Fact. Almost 5000 lbs on NASCAR tracks at 100 mph for hours? Yet “bad brakes”?

We should have asked Vicky about this!!  Maybe we can!

But, like many of us in the past, first thing I did many years ago, was take the brake drums to the local auto machine “to turn them” and then buy “new shoes”. Most of my grief was started right there ; the shoes and drums were different sizes!. That simply will not work with these brakes. Not even close. The carefully and beautifully designed dual self energizing fronts depend on precise diameter fit 360 , for the degree of self energization they exhibit.. It can go either way from weak brakes that barely stop the car to erratic violent grabbing. But not knowing that , at the time, and thinking “they will wear in” led to thousands of miles of grief, hundreds of adjustments etc etc..and occasional lockups,-- so one was soon getting afraid of what the car might do. Who needs this, starts up. Why the 68 discs on the 57 Dodge. ( has a 480” 440)

That grief leads to metallic linings, riveted vs bonded , new drums, all that stuff. Waste of time. Each time you go new on the shoes you reset the “fun party” miles to zero. I am convinced, and it is just my opinion, that turning drums that are round , no matter the grooves etc hurts them a lot in 2016,--- if you have the matching half worn shoes reuse them. . .Mass is gone, by grinding (fade!)  they are more prone to warp (weaker structurally) and they are the wrong size . And many of our drums,  the 12” ones have probably been turned several times trying to fix “bad brakes” .  And that positive experience I had with brakes working fine for 50k  from new in 1960,---and you saying 100k off a set put in correctly on a G just affirms all this. George said the exact same thing..but often not as nicely (smile) . None of his cars had disc brake upgrades, although if he had done so he would not tell you,  and probably paint them with a cover to look like rusty drums. (I miss George..that cam is stock, John---honest).

The new 300G tests in 61 reflect what they do new. When put together right.

Thanks Andy!

From: Chrysler300@xxxxxxxxxxxxxxx [mailto:Chrysler300@xxxxxxxxxxxxxxx] On Behalf Of Andy Mikonis r41hp@xxxxxxxxx [Chrysler300]
Sent: Thursday, February 18, 2016 12:11 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: "John Grady" <jkg@xxxxxxxxxxxxxxxxx>

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