Re: {Chrysler 300} Re: Front disc brakes 1963
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Re: {Chrysler 300} Re: Front disc brakes 1963



Hi, the rears are not total contact design, as you know so only one shoe does most of the work, like Bendix, so they are pretty trouble free. And rear discs can be a hassle with a lot of F to B balancing issues. Solvable, yes. But non progressive feel is kind of uncomfortable (to  me).   Gotta really press.   Inherently, they (rears) will only do , by design, maybe 30% of the work. So don't really need discs in back and the front ones in kilts are really too small for these cars ..no whoa . Dodge dart size. I Did do that, several times. . Now I get stock working right , (rare) or go larger wheels/ front larger discs. 

I have found an easy way for the back , E body rear drops in , cheap $ and gets you a solution to E brake hassles if going say 727,  or 518. Not advocating trans swap just info, it comes up. E axle can be disc or drum, I chose drum. Available new aftermarket too . I did do one rear swap Dana 60 made for a race E body, into F , with Cadillac brakes, Cad has a caliper e brake.

However a great reason to get into this is ,IMHO, is it is practically impossible today to mount new 12" drums on the tapered  hubs and have it come out right . Nothing to do with discs, that is a separate decision, ----Oddly, guys sell 12 " drums (kantor for one) for 57-62 , 11' for dodge too, same deal. but there are no index pilots on the hub . I think Chrysler  machined the hubs and drums as a unit when these were made. Or some wild tooling. Including machining inner brake shoe  diameter on the taper centerline , --so that part is  perfect --and I think originally  intended to be serviced as a unit. I notice some pretty beefy balance weights on some of them stock, as that factory approach might end up out of balance if drum casting metal  happens to be  eccentric to machined centerline. This is 1930 stuff. 

 I inquired,  after really a LOT of pain while working with a great machinist (how do you mount the hub parts in a normal lath? Cutter is  on wrong side, have to deal with centering taper(?) you have to make tapered pilot/ use live center , and any taper machining you do has to be perfect, as you have tapered air in the middle. . Quite a dance. We bought an  old AAMCO (sp?) brake lathe taper set, but they do not fit small end, so we bought VW tapers , they do, but the two arbors are different OD  sizes,  and all this is $ and lots of frustration. And the end product still has slight runout. Even spent $ to have lathe checked , it was fine .Then 3 jaw vs 4 jaw.... Time is also money. 

 I discussed all this with  older ex Brake Shop guy ---after literally 30 hours at trying to do it (drum  can also "wobble " in that 90 degree to axle  plane, a new hassle )------He told me there was a complicated process, to change drums on hubs, way back, special tooling for AAMCO brake lathe  involving a "deep hole saw" looking cutter to cut 5 X around the  studs where "swelled up ' or factory swaged to hold drum on hub  (if you animal press it out , you destroy precision alignment /stud hole size as forcing the  swage through  rips it up ----been there,=  hub is instant scrap metal) then they had special oversize wheel studs , that press through both stock old  hub and replacement drum with holes smooth and  sized for this --- and they were made to be swaged again from wheel side to hold drum. Another tool in a press.  .So studs locate drum , only studs . and if not all clean , orthogonal and flat  you get drum wobble. Turning after assembly did not fix it as the slightest wobble ruins that. 

Now, later drums (or rotors) have a center pilot circle just slide drum/rotor off studs , drum is clamped but not centered by studs (dodge 11" taper hubs are now even rarer than 12,  ,everyone has grabbed good 11" assy's  from junkyards, since 60's) . Rotors can run out radially does not matter much, wear track lands where it lands. 
So in retrospect, pedal still vibrates a bit on the car with all this, drum replacement on tapered hubs, gave up on fronts,(same issues as rear on this vintage)  Not going here again. 

--and as noted,  runout in this radial direction with a rotor does not matter, if anyone ever did that w taper hubs . Forget it .

So what might be good is to work with like Moser or Strange to make flanged axles that fit the tapered wheel bearing set up (that is a great setup) but have 5 studs? Then put rotor or drum on (put pilot for drum/rotor  on face ) like later cars. I have worked with them  on other things,---- 5" bolt pattern and brakes  in a mopar 9.25 axle truck to get GM 5" warn hubs on Dodge 4 wd. Custom axles, not too bad $. 

Little different take on some very good reasons to solve all this. Call it encouragement. If your 300 brake drums hit the ID limit you will be a busy man as it stands now.(the cause of doing all this, mine had been turned by a moron in a "pro brake shop" beyond the max oversize. 

Don't turn them is my advice . Ever , --- -scratches do not matter, your new shiny ones, post turning are scratched in 1000 miles, and are one step closer to scrap. . All info from school of hard knocks. Keep used shoes and matched drums on car, leave it alone if 50% left. 
And discs do eliminate 'turning new shoes problem" in a  total contact setup, if you do not,  it grabs and pulls. Cannot find that "turn brake shoe to match drum" guy. . Large Discs on front and 17 " wheels, now you are talking, ----but not stock look . YMMV
J

On Thu, Jul 31, 2025 at 2:53 PM Paul <amidcenturymopar@xxxxxxxxx> wrote:
I have a 300F that I purchased in February.  The previous owner had installed a front disc brake conversion kit that was built by Engineered Components Inc.  The system works well, and the discs and calipers clear the stock 14" wheels that came on my 300F.  The conversion kit is sold by Andy Bernbaum, but it is advertised as fitting 1957 - 1961 Chryslers.  The maker (ECI) has many kits available and trades under the name of Hot Rod Brakes.  The website is https://ecihotrodbrakes.com .  

Mark Reid is the owner, and I am presently collaborating with him to develop a rear Disc Conversion Kit for the early Chrysler 8-3/4" rear ends that use the tapered roller bearings and cannot use the "Green Bearing" conversion that the rear disc conversion kits for later versions of the axles require.  The "Total Contact" service brake system was used with the early version axle, and when Chrysler redesigned these brakes for the 1965 model year, they went to the later axle which is the more common version of the 8-3/4" rear.  This is the axle that was used throughout the muscle car era on B, C and E bodies.  The early axle used tapered axle shaft ends, which had wheel hubs that were also tapered and press fit on to the axle ends, using a 5/16" square keyway and a castellated nut to hold the hub on.  The later version of the axle had the wheel hub permanently attached to the axle shaft.  The axle shafts are two different diameters, which is why you can't execute a "Green Bearing" conversion on the earlier axles.

Hope this is helpful.  If anyone out there is interested in the rear disc conversion, I'll keep you posted.
On Thursday, July 31, 2025 at 1:25:41 PM UTC-4 firemc1958 wrote:
Forgot,I already have changed to 15” wheels.
Sent from my iPad

> On Jul 31, 2025, at 12:24 PM, Richard McFarland <firem...@xxxxxxxxx> wrote:
>
> I have a 63 300,383 auto. Does anyone know if a kit exists for installing font disc brakes? Booster,proportioner the whole bit? I see kits for different mopars of that era everywhere but not sure what will work. Not looking for original just want what will work. I drive the car a lot on trips,highways everywhere. Planning on doing Route 66 and just want it safe.
> Thanks to all
> Sent from my iPad

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