5:03 pm
May 4, 2004
Offline
Lee,
According to MrBlaine over on JeepsUnlimited, the Dodge Durango master cylinders that bolt up to the TJ brake booster are from 1998 & 1999 4wd models. The '98 has a 1 1/16" bore and the '99 has a 1 1/8" bore, compared to the stock TJ m/c bore of 1".
Which one to use with your Chevy front & Ford rear calipers is kind of unknown. Both will give you more fluid volume to the calipers than the TJ m/c. The '98 m/c will give you higher pressure at the caliper than the '99. The '99 will give you more fluid volume at the caliper than the '98. The '98 should provide a softer, but longer travel peddle than the '99.
If you try one of these, let us know which one and how it works.
5:09 pm
Club Member
July 10, 2003
Offline "FAM" wrote: Dodge Durango master cylinders.
That's what I use 8) Works well with my chevy front and ford rear brakes.
I used to wheel a lot. . .
5:12 pm
May 4, 2004
Offline "JohnDF" wrote: [quote="FAM"]Dodge Durango master cylinders.
That's what I use 8) Works well with my chevy front and ford rear brakes.
Do you know if it's the '98 or '99? When I talked to Lee last night I told him to find out which one you were using.
Since changing over from the Corvette m/c to Chevy C30 m/c on my hydroboost, I've been considering trying the Durango m/c & factory booster too.
5:14 pm
Club Member
July 10, 2003
Offline I believe it's the 98, but I'm not positive. I just asked Foothill what I needed and they told me, sold it to me, and threw it on for free when I bought my axles.
I used to wheel a lot. . .
5:33 pm
July 15, 2005
Offline "JohnDF" wrote: and threw it on for free when I bought my axles.
They were trying to make up for welding your front driver side C on crooked 
__________________
'If we ever forget that we're one nation under God, then we will be a nation gone under."- Ronald Reagan
6:05 pm
Club Member
July 10, 2003
Offline It aint crooked...you are just cross-eyed.
I used to wheel a lot. . .
6:07 pm
Club Member
July 10, 2003
Offline "FAM" wrote: According to MrBlaine.
You loose credibility points when you use his name around here 
I used to wheel a lot. . .
6:20 pm
May 4, 2004
Offline "JohnDF" wrote: [quote="FAM"]According to MrBlaine.
You loose credibility points when you use his name around here
I didn't want to steal the credit (or blame)
6:34 pm
Club Member
July 10, 2003
Offline "FAM" wrote:
I didn't want to steal the credit (or blame)
Just kidding. He knows his stuff (mostly) but can be kind of a jerk getting his point accross.
I used to wheel a lot. . .
7:15 pm
January 12, 2007
Offline Am I missing something? I am using a stock TJ master cylinder with Chevy front and Ford rear brakes. They work great.
7:22 pm
Club Member
July 10, 2003
Offline "Justin" wrote: They work great.
That's highly possible. I only did the upgrade because Foothill told me to. So, I never got to try it with the stock setup. But, I can't believe that a slightly larger MS will make THAT big of a difference.
I used to wheel a lot. . .
7:52 pm
May 4, 2004
Offline When it comes to TJ brakes it seems that what works on one vehicle doesn't necessarily work so well on another.
Lee called last night to ask about brakes. He installed Rob's old D44 on the front of his Jeep and says the brakes aren't good enough now. The peddle is too soft and goes too far to the floor. It sounds like he needs more fluid volume which means he needs either a larger diameter bore master cylinder or more travel in his brake peddle.
I've been working on my brakes ever since Foothill replaced my D35 rear axle with a D44 with disk brakes. I had a combination that worked well, Ford Explorer calipers all around, adjustable proportioning valve, 2 lb residual pressure valves, Vanco hydroboost attached to a Corvette master cylinder. However, I've gone through two Corvette master cylinders in the last couple years. They just don't seem to hold up to the pressure the hydroboost can generate. I've installed the Chevy C30 master cylinder which was OEM equipment with the hydroboost and the brakes work pretty good, but the peddle is harder to press than when I used the Corvette master cylinder. The difference is the Corvette m/c has a smaller bore than the C30. I'm considering trying one of the Durango m/c's using with the factory booster to see if I can get a softer brake peddle with adequate fluid volume and pressure to the calipers.
I've tried several other options with less than satisfactory results, including the Dodge 3500 m/c on the factory booster and Off Again's Navajo booster & m/c combo.
7:58 pm
May 4, 2004
Offline "JohnDF" wrote: But, I can't believe that a slightly larger MS will make THAT big of a difference.
Jumping from a 1" bore m/c to a 1 1/16" bore yields about 11% more volume. A jump to a 1 1/8" bore is about a 21% increase. Although the inch measurements sound small, the difference can be pretty dramatic.
8:33 pm
Club Member
July 10, 2003
Offline I don't think it's the brakes that are the problem...it's that darned automatic transmission 
I used to wheel a lot. . .
8:38 pm
Club President
April 2, 2003
Offline "Justin" wrote: Am I missing something? I am using a stock TJ master cylinder with Chevy front and Ford rear brakes. They work great.
Me 2.
Not sure what's going on?
8:46 pm
January 12, 2007
Offline Another thing to think about is what kind of brake lines you are running. Rubber or cheaper steel braided lines will swell or flex when pressure is applied, while a quality steel braided line will send the pressure to the callipers. When I changed to quality steel braided brake lines on one of my "Vespa's" (109 HP mind you), the first time I hit the brakes I locked up both wheels due to the difference in quality brake lines.
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