New brake booster and properly sizing a master cylinder?

Stinkbug

Stinkbug

TJ Enthusiast
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Apr 9, 2016
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Huntington Beach, Ca
I am beginning to investigate sources for brake parts for my 1997 TJ. I will be purchasing a new or rebuilt master cylinder and a new booster. I would prefer a new OEM Mopar part but unfortunately, they no longer seem to be available.

I see master cylinders are available with either a 1” bore or a 1 1/8” bore. Here is my current set up:
  1. My Jeep came with abs but it has been disabled by pulling the fuses
  2. My Dana 35 with drum brakes was replaced with a Dana 44 with discs
  3. I have a 15” Black Magic brake kit up front
Any input on which master would be best with my modified setup would be appreciated.

I am also in the market for a booster. OEM is no longer available. Other than a junkyard replacement, what is considered to be the best solution for a new or rebuilt unit?
 
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I’m running the 16” BBK with rear discs and using the factory master/booster combo. No reason to change it for anything different. Last I looked (it has been a while though) you can still get a Mopar booster. When my master went, I got a replacement from Napa that has been working well.
 
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Mike_H said:
I’m running the 16” BBK with rear discs and using the factory master/booster combo. No reason to change it for anything different. Last I looked (it has been a while though) you can still get a Mopar booster. When my master went, I got a replacement from Napa that has been working well
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I have tried ordering the OEM booster they show available at some dealers but when I order one I receive an order canceled notification within a day or two stating the part has been discontinued. I received the same information from my local dealer.

The reason I asked about the 1 1/8 bore master is that I ran across a website suggesting it for aftermarket axles with rear discs.
 
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Blaine can help you so much. Don’t overlook that resource.
 
Stinkbug said:
I have tried ordering the OEM booster they show available at some dealers but when I order one I receive an order canceled notification within a day or two stating the part has been discontinued. I received the same information from my local dealer.

The reason I asked about the 1 1/8 bore master is that I ran across a website suggesting it for aftermarket axles with rear discs.
Click to expand...

The stock master is a 1" bore and my understanding is that should continue to work for the BBK from Blaine, but he could confirm that. Since I'm on one tons I upgraded to a 1 1/8" bore Wilwood master to match the Wilwood calipers that I have.

I also have a brand new booster that I will no longer need as I am going hydroboost due to the bigger cam in my LS not producing enough vacuum. Let me know if you want it and we can workout a price.
 
Sj's TJ said:
The stock master is a 1" bore and my understanding is that should continue to work for the BBK from Blaine, but he could confirm that. Since I'm on one tons I upgraded to a 1 1/8" bore Wilwood master to match the Wilwood calipers that I have.

I also have a brand new booster that I will no longer need as I am going hydroboost due to the bigger cam in my LS not producing enough vacuum. Let me know if you want it and we can workout a price.
Click to expand...

Thanks for the offer, I will take you up on it. I will send you a PM
 
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Stinkbug said:
I have tried ordering the OEM booster they show available at some dealers but when I order one I receive an order canceled notification within a day or two stating the part has been discontinued. I received the same information from my local dealer.

The reason I asked about the 1 1/8 bore master is that I ran across a website suggesting it for aftermarket axles with rear discs.
Click to expand...
No idea on a booster other than NOS some place. If you find one, buy it, they are very high quality and avoid anything Cardone.

Lots of websites have erroneous information. There is no reason to change the bore size except to fuck up your braking. Stock is a 1" bore, it is designed to work with the booster force into a piston size of 5.22 square inches per side. The dual piston calipers you have each have 5.60 square inches per side.

When Jeep moved to the Rubicon models with rear discs standard in 03 and optional on others, the master cylinder bore size did not change, still a 1" bore.
 
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