MC Bore Size: 1 1/8 vs. 1 1/32
#913750
01/25/11 04:34 PM
01/25/11 04:34 PM
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Posts: 284 Louisiana
kzinge1
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I have the SSBC disc brake conversion on the front of my 69 RR and 10.5" drums in the rear. I am not using the booster that came with the kit. I am running the Strange 1 1/8" bore master cylinder right now and the brake pedal is too hard and the car doesn't stop well enough. Will the Strange 1 1/32" bore master cylinder be right for this combo or do I need to go even smaller than that?
Last edited by kzinge1; 01/25/11 06:25 PM.
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Re: MC Bore Size: 1 1/8 vs. 1 1/32
[Re: Stanton]
#913755
01/25/11 08:56 PM
01/25/11 08:56 PM
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Posts: 284 Louisiana
kzinge1
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Quote:
Keep in mind that less effort means more travel ... you still have to move the same amount of fluid !!! That said, the most common m/c for a brake conversion seems to be the 1-1/32".
A lot depends on caliper piston size as well. The least pedal effort will be achieved with a small m/c bore and a large caliper piston. Determine the size of your pistons versus the mid-70's Mopar calipers. If yours are the same or larger then the 1-1/32" m/c should be fine but if yours are smaller then you'll want to go smaller on the m/c as well.
I believe I have 4 piston calipers, if I remember correct. Should be bigger than factory. Do you know what the bore size was of the mid-70s Mopar MC's?
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Re: MC Bore Size: 1 1/8 vs. 1 1/32
[Re: kzinge1]
#913756
01/25/11 09:00 PM
01/25/11 09:00 PM
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Joined: Jan 2003
Posts: 25,817 Rio Linda, CA
John_Kunkel
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If "the pedal is too hard and the car doesn't stop well enough" I'd say the problem isn't the MC size. With a booster it should stop well if the parts are properly installed.
Have you checked to see that the rear piston in the MC is fully returning?
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Re: MC Bore Size: 1 1/8 vs. 1 1/32
[Re: kzinge1]
#913759
01/25/11 09:40 PM
01/25/11 09:40 PM
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Joined: Feb 2005
Posts: 28,312 Cincinnati, Ohio
Challenger 1
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Quote:
Yep, no booster.
Maybe that's why... I think you would need different petal linkage/ratio and MC bore size with manual verse power brakes.
It's best to call the guys you bought the brake kit from.
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Re: MC Bore Size: 1 1/8 vs. 1 1/32
[Re: kzinge1]
#913760
01/25/11 09:57 PM
01/25/11 09:57 PM
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Joined: Nov 2003
Posts: 36,040 Lincoln Nebraska
RapidRobert
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As said I'd call/email them & see if the pedal ratio and or the bore size is OK w you not using the booster
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Re: MC Bore Size: 1 1/8 vs. 1 1/32
[Re: kzinge1]
#913763
01/25/11 10:39 PM
01/25/11 10:39 PM
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Joined: Jan 2007
Posts: 7,664 IN
ahy
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Quote:
I have the SSBC disc brake conversion on the front of my 69 RR and 10.5" drums in the rear. I am not using the booster that came with the kit. I am running the Strange 1 1/8" bore master cylinder right now and the brake pedal is too hard and the car doesn't stop well enough. Will the Strange 1 1/32" bore master cylinder be right for this combo or do I need to go even smaller than that?
Was your car originally manual or PB? Reason I ask is the PB pedal linkage setup gives less leverage. If you are running the PB pedal linkage without booster that's your first and biggest problem. The MC size would be secondary.
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Re: MC Bore Size: 1 1/8 vs. 1 1/32
[Re: kzinge1]
#913766
01/26/11 12:27 AM
01/26/11 12:27 AM
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Joined: Oct 2005
Posts: 8,873 Ontario, Canada
Stanton
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Quote:
Was your car originally manual or PB? Reason I ask is the PB pedal linkage setup gives less leverage. If you are running the PB pedal linkage without booster that's your first and biggest problem
This is incorrect. The actual pedal and linkage is the same for both power and manual brakes. The leverage change is accomplished with a mechanism that is actually part of the booster assembly (if you notice, the booster rod is actually higher up on the firewall than the manual rod - as a result of this mechanism). If you were to try to use that mechanism with a manual m/c it wouldn't mount properly and I doubt you'd find a pushrod to fit.
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