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3/4 ton brake master and rear disc question.

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Old 02-03-2012, 08:37 AM
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3/4 ton brake master and rear disc question.

I'm about to replace my brake booster and master cylinder and was wondering if anyone knows how interchangable the different types are.My truck origionally had a dually rear end and I'm unable to find any difference in the brake system design between it and the regular setup. I found a 3/4 ton master cyl with a 7/8 in bore and would like to know if this on has any real difference from the LCE one inch bore other than the 1/8 in diameter difference. Also I want to find the best possible booster I can that will mount to an 84 fire wall. I'm considering doing a rear disc conversion later this year, so I'd like to head this off early. Any advice?
Old 02-03-2012, 09:57 AM
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Search the Pirate FAQ. Info is all there.

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Old 02-03-2012, 12:13 PM
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X2 on wabfab. dual diaphram is the way to go with a 1" bore MC, there are tock ones from later years that will fit for cheap. Depending on the year you'll need a residual valve for the rear brake line. and a adj proportionte valve.
Old 02-03-2012, 05:07 PM
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I got a booster off a Taco(dual) and a master(1" bore) from a T100. Bolted right up. Only had to tweak a brake line slightly. Bled the brakes, and my '84 stops much better. Its within a few feet of stopping distance to my wifes '10 FJ.
Old 02-04-2012, 12:44 AM
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There's a couple swap kits that use your trucks front disc and calipers. So upgrade front to LC disc and IFS calipers then move your fronts to the rear. This plus the MC and dual diaphram updrades and you'll have much more braking than stock.

You'll need a parking brake solution though.
Old 02-04-2012, 06:58 AM
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sweet, thanks guys!
Old 02-04-2012, 11:03 PM
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hey rokblok, what year tacoma did you get yours off of?
Old 02-05-2012, 01:19 PM
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I believe it was a 99 Taco 2wd. It seems that all the masters I have seen while searching for my 3RZ, that were on later model(94 and up) were externally the same. Didnt seem to matter if the truck were 2wd or 4wd. The reason for this, I am guessing, is the 2wd trucks have 1 large diameter piston in their calipers(large volume of fluid needed to move the piston same as four smaller diameter pistons).
Old 02-06-2012, 07:25 PM
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The reason I asked was because I did a little looking around and found ones with 2 or 4 hole patterns for mounting to the booster, and one of which was brand new on ebay for a penny and had a four hole pattern.
Old 03-10-2012, 09:58 AM
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I bought my booster and one inch master cylinder, but the master cylinder didn't have any markins displaying which port is for front or rear. Can anyone point me in the right direction?
Old 05-26-2012, 08:41 AM
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I know it has been a while since I posted on this, but I installed the booster and master cylinder. I'm looking at proportioning valves on JEGS.com right now hoping that will sort out the problem of my brakes doing nothing intil I'm nearly on the floor, then suddenly locking up. I was wondering if anyone has any suggestions for which valve to use. I was thinking of a simple knob type adjustable, JEGS brand. Also do I need to remove my Load sensing Proportioning valve when installing the adjustable one?
Old 05-26-2012, 02:34 PM
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Originally Posted by warmonger88
I know it has been a while since I posted on this, but I installed the booster and master cylinder. I'm looking at proportioning valves on JEGS.com right now hoping that will sort out the problem of my brakes doing nothing intil I'm nearly on the floor, then suddenly locking up. I was wondering if anyone has any suggestions for which valve to use. I was thinking of a simple knob type adjustable, JEGS brand. Also do I need to remove my Load sensing Proportioning valve when installing the adjustable one?
It would be better to remove the lspv if you use an adjustable proportioning valve to help simplify the system incase of a failure or problems.

the master was bench bled before install correct? all 4 corners were also bled afterwards? adjusting the back shoes should help also if you're still running drums.

Last edited by 87slosohc; 05-27-2012 at 04:45 AM.
Old 05-26-2012, 06:14 PM
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bench bled and all fours were also. My entire system was dry when I installed also, but I got all of the air out. I checked and bled a second time too.
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