Re: [Chrysler300] Ram K brake pedal

Hi Rich,

Yes pedal assembly, the whole moving thing is different between power and no power ; top of pedal arm is a different configuration related to no booster, on F , but also overall shape and I think length. It might sit a little higher off floor too in normal ‘up” position. Full Out stop is different, you have to fab an outer stop , if leaving pivot support frame bolted in dash. Or else rod can fall right out of master if you lift pedal. (arrgh) You cannot relocate master height with the wrong pedal inside , as then the actuation rod is tilted, a big no no . Reshaping it with an offset does not fix that. Rod has to enter master at an orthogonal condition , hole on pedal arm in line horizontally with master bore…. or else it pushes the master piston to top or bottom of bore..lot of hard knocks behind the above info. If angled on your car, that is wrong. Take away is power setup pedal is useless on manual brakes..1/2 the pressure ; the masters themselves appear to interchange physically despite numbers, as the 4 bolts move with rod hole on the new mount plate . But might have different bores or output valves, or no output valve. If you really get into this, I think you could drill one big hole and two small for Corvette master in line with whichever pedal you choose , height set by pedal hole .Corvette has big bore , maybe 1.125. But same issues about pressure are still there. 67 Dart / Cuda dual master seems to fit too. Some have the shorter covers. Had part numbers but cannot find it. One could think of drilling a power pedal arm to manual location, but easier to just get right arm from a Plymouth or something. And it is a different shape.

So you need all the swinging / moving parts from a non power brake MOPAR and the new manual master location plate . I have seen the pedal arms with two holes vertically but the other one is not for power or not, to my knowledge. It might be for different booster setups ..I do not know about that reasoning behind the two holes at all, but led me in a wrong direction…thought same thing at first, for manual. Did not work. . But stock non power pedal and master location with stock 60 dual leading shoes works well, if this part is done right. It would make sense that the ram /hydrovac on J, K, ram would use a 100% non power (manual brake) setup complete. But I do not know ram J/K , on this aspect specifically. This info from 300F , probably valid through 62 at least ,as I checked out factory manual brake setup on 150 mph red 300H at Pa meet.

I had the ratios too. measured all that ; it is just under 2;1 different , so if you think about that , ---they made the pedal on power, at floor , move ~ half as much, ( hardy touch the pedal!) physically, for same CC of fluid , but takes twice the force which power boost gives you. Try disabling vacuum on PB and then try brakes. It will make your hair stand up! So stopping a 300 with no vacuum is not for faint hearted. So manual pedal moves a lot more at floor , longer lever gives you the psi. hydrovac probably designed for normal non power brake psi on any vehicle or truck, so = a manual ratio? You would never stack a hydrovac on a power brake car?

Interesting stuff, important too. …Discs add another whole page…

From: Rich Barber [mailto:c300@xxxxxxx]
Sent: Thursday, July 13, 2017 1:48 AM
To: 'John Grady'; 'leslie miklas'
Cc: 'chrysler300'
Subject: RE: [Chrysler300] Ram K brake pedal

OK. I blew it by not reading the question correctly. I have my instrument panel out and can see the brake pedal/pushrod assembly. But I can’t see way back within the suspension bracket to see any alternative locations for relocating the pushrod attaching point. We definitely had to change the mounting plate on the firewall side to enable re-mounting a proper non-boosted MC there but made no changes to the pushrod assembly. However, we’re just returning the system to as-was from the factory on this ram car so maybe when the conversion to a standard booster was made the previous owner did not change the pedal. My brakes are a little grabby so I must investigate further.

So, I went to the Parts Catalog and see that the brake pedal for a non-P/B Newport or 300 is the same as for a ram 300K car. The brake pedals for all Newport/300/NY with P/B are the same but different from the non-P/B cars and ram cars. So, yes—the pedals being different indicates the mechanical advantage/leverage may also be different. I did see one picture of a pedal that had two holes in it but nothing more than that.

Rich Barber

Brentwood, CA

From: Chrysler300@xxxxxxxxxxxxxxx [mailto:Chrysler300@xxxxxxxxxxxxxxx] On Behalf Of John Grady jkg@xxxxxxxxxxxxxxxxx [Chrysler300]
Sent: Wednesday, July 12, 2017 4:01 PM
To: leslie miklas <ldmiklas@xxxxxxxxxxx>
Cc: chrysler300 <chrysler300@xxxxxxxxxxxxxxx>
Subject: Re: [Chrysler300] Ram K brake pedal

Hi ,

Do not know about ramK due to complexity of hydroboost behind this question ; probably work either way, but only one is factory right . But on manual brakes without hydroboost the master is higher not lower , as top pivot is fixed.

to get more pressure for a given bore , you raise it . It is almost 2:1 different in 60's F / dodge etc

Sent from my iPhone

On Jul 12, 2017, at 12:46 AM, leslie miklas ldmiklas@xxxxxxxxxxx [Chrysler300] <Chrysler300-noreply@xxxxxxxxxxxxxxx> wrote:

Quick question:

I used to know the answer to this but have forgotten...(Insert old age joke here)

The 64 300s with manual brakes used a different (lower) hole location to attach the master cylinder pushrod to the brake pedal as well as a different firewall support plate than the power brake equipped cars.

My question: Do the Ram Ks use the MANUAL brake pedal pushrod position and related support plate ?

I assume they do !

Thanks !

Jeff Miklas - Ldmiklas@xxxxxxxxxxx

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