Gene_Schneider
Ultra Senior Member
Posts: 12260
Loc: Wisconsin..USA
Reg: 09-27-02
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09-13-19 08:44 AM - Post#2775455
My 1957 has factory TreadleVac power brakes. I like the low brake pedal. If I install a conventional master cylinder and a modern replacement power brake booster will I still have the low almost even with the accelerator brake pedal?
ChevGene
1934 Master sedan
1939 Master DeLuxe Town Sedan
1950 Styline DeLuxe Power Glide
1957 Nomad 283 PG
1963 Corvair Convertible |
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Beltfed
Poster
Posts: 43
Reg: 10-04-18
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09-19-19 09:16 AM - Post#2775884
In response to Gene_Schneider
No one has responded to this question so I’ll give it a shot. My first suggestion is to contact companies like “Master Brake” or “Wilwood”. I would think this is a question they could answer.
You need to know the bore diameter of your orginial master cylinder. Also, you need to know your pedal ratio. Pluging these values into several simple formulas will give you your answers. Example: pedal ratio is dividing the length from your pedal pivot point to the center of the foot pad by the distance from the pivot point to c/l of the hole where the master cylinder rod connects. 5:1 to 6:1 is considered ok.
Edited by Beltfed on 09-19-19 09:16 AM. Reason for edit: No reason given.
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sz0k30
"11th Year" Gold Supporting Member
Posts: 444

Loc: Oakland Co., Michigan
Reg: 10-12-08
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09-19-19 12:25 PM - Post#2775896
In response to Beltfed
Pedal ratio is dividing the length from your pedal pivot point to the center of the foot pad by the distance from the pivot point to c/l of the hole where the master cylinder rod connects. 5:1 to 6:1 is considered ok.
Generally speaking the above is true.
Manual brakes usually have a pedal ratio of approx 6:1. To allow for this ratio the pedal is normally higher from the floor and the accelerator.
Power brakes usually have a pedal ratio of approx 4:1. Because of this lower ratio the pedal can be closer to the floor and more in line with the accelerator pedal.
If your m/cyl has a 1" stroke and your pedal ratio is 4:1, the pedal needs to be at least 4" above the floor to give you the required stroke at the pushrod.
On my power brake equipped vehicles the pedal is approx 4" above the floor.
Many times manufacturers had 2 pushrod holes in the pedal arms so they could use the same arm for both manual & power brakes.
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