Author Topic: Converting to 4 wheel disc..brake pedal pin relocation  (Read 6935 times)

BAN ONE

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Converting to 4 wheel disc..brake pedal pin relocation
« on: November 03, 2009, 03:08:33 PM »
Posted this up years ago before TAC crashed but figure I might as well repost it for those converting their car to 4 wheel disc. The standard rear drum cars use a different brake pedal than the 4 wheel disc. The standard pedal will work but will lack the proper pedal feel if not modified.

Here is a step by step method for modify your existing rear drum brake pedal for proper 4 wheel disc pedal feel.

Comparision
Standard rear drum pedal (top)....4 wheel disc pedal (bottom)


Measurements taken from rear drum brake pedal.


Measurement taken from 4 wheel disc brake pedal.



New hole drilled beside exsiting hole. As you can see, it is very close to the original hole. Final hole size was done with a 27/64 drill bit (if my memory servers me correctly). I would recommend  that you measure your pin to verify it's diameter before drilling any holes. Your center hole measurement should be 2.995+1/2 diameter of pin(radius).  Press fit, your hole should be about .001 smaller than the pin. In this case, the hole was smaller yet but the pin pressed in without any problems.


Methods to press the pin in.

Method one..press


another method...vise (notice tube nut temporarily on other side to allow pin to be installed fully.


Final check on measurement.


Finished product to factory 4wheel disc pedal.


ready to go back in the car.


Hope this helps.
« Last Edit: November 03, 2009, 03:10:25 PM by BAN ONE »
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1977 Y81 Trans Am

Flo

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Re: Converting to 4 wheel disc..brake pedal pin relocation
« Reply #1 on: November 04, 2009, 05:01:50 AM »
short question: Where do I get the new stud to press in? Or did you get the old one out and in without major damage?
Greets
Flo

BAN ONE

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Re: Converting to 4 wheel disc..brake pedal pin relocation
« Reply #2 on: November 04, 2009, 10:04:45 AM »
I found the old one to press out without any problems.
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1977 Y81 Trans Am

radback

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Re: Converting to 4 wheel disc..brake pedal pin relocation
« Reply #3 on: November 09, 2009, 02:27:22 PM »
The standard pedal will work but will lack the proper pedal feel if not modified.

I thought you only had to change pedal if you changed the booster to a dual diaph, otherwise you can keep original pedal.

PS: is the rod is the same from single diaph booster from rear drum cars to dual diaph boster cars?
79 Y84 S.E T-Top 7.2 litre engine
Location: Paris France

BAN ONE

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Re: Converting to 4 wheel disc..brake pedal pin relocation
« Reply #4 on: November 10, 2009, 10:40:19 AM »
All 79-81 4 wheel disc boosters are dual diaphrams. As far as the booster rods, I never checked so I can't say if there is any difference.
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1977 Y81 Trans Am

Re: Converting to 4 wheel disc..brake pedal pin relocation
« Reply #4 on: November 10, 2009, 10:40:19 AM »

h3bubba

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Re: Converting to 4 wheel disc..brake pedal pin relocation
« Reply #5 on: January 21, 2013, 08:19:36 PM »
I just did this in the garage with no press.  I only used a hammer and drill.  It took the better part of an hour.

Thanks for the great info.
1979 Pontiac Trans Am WS4
1975 YT 400,  0.030" over, KRE D-port heads
200-4R, Stage 3
Complete Gen II(PTFB) Front/Rear COMP suspension package
10 bolt w/Moser Street axles, 3.42:1
Bear T4 13" front and SS4 12" rear disk brakes
275/35R18 (18x9) front, 295/35R18(18x10) rear
FITECH Meanstreet EFI

1979 TATA 400/4spd restoration next...

LilSki

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Re: Converting to 4 wheel disc..brake pedal pin relocation
« Reply #6 on: January 22, 2013, 05:33:15 PM »
I really need to do this to my car. I converted to 4 wheel disc but left the pedal alone. It works fine but it definitely makes the brakes a bit over sensitive.
Kevin
79 Trans Am: (77 nose), WS6, M-21, 461, Hotchkis TVS, PTFB Contol arms. 
85 Trans Am: Vortec 350 w/LT1 cam/T56, TPI conversion w/Megasquirt II.

Daleferd

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Re: Converting to 4 wheel disc..brake pedal pin relocation
« Reply #7 on: June 05, 2015, 08:08:30 PM »
My 72 had 4 discs on it when I bought it and the pedal feels soft and I can put it to the floor if I try. It always has the same amount of pressure on it. I was wondering if I did this if it would make my pedal have more pressure?

JC455

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Re: Converting to 4 wheel disc..brake pedal pin relocation
« Reply #8 on: May 21, 2018, 11:13:41 AM »
Back from the dead--
This-->>  NEEDS <<-- to be a Sticky!!!

Been a member since the "original" board started, yet I'm the Newbie!! LMFAO!!

Y84SE

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Re: Converting to 4 wheel disc..brake pedal pin relocation
« Reply #9 on: June 30, 2018, 07:39:10 AM »
Great information, thank you....????????

Re: Converting to 4 wheel disc..brake pedal pin relocation
« Reply #9 on: June 30, 2018, 07:39:10 AM »
You can help support TAC!