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Quest fo a true 7/8" bore master


Mac

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Someone had mentioned to use the Bumper-Bumper master cylinder and make sure it was the 7/8" bore. Just got mine home and no matter what everyone has it listed as, it's only a .750" bore. It looks just like the master that Teddy used. Part number CMA 39896 and identical to the 3/4" bore one I got from RockAuto. Anyone else actually take their 7/8" apart to actually measure? 3/4" bore MC would work best with a 5/8" bore slave.
Dave
 


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Teddyzee

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I didn't measure mine, but it was much larger than my stock one.

 

Mac

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I know there are a lot of 7/8" bore cylinders out there including the F-150 but none mount as needed. What is need is one that has an angled mount as shown.

Dave
 

gsp

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I know there are a lot of 7/8" bore cylinders out there including the F-150 but none mount as needed. What is need is one that has an angled mount as shown.

Dave
Make a mount and push rod.....
 

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I had mentioned the bumper to bumper part. I dont know what it actually measures. I havent bought it yet.my stock master is 3/4 on my 85 ranger. I will say this when i measured my stock m/c it measured 7/8 where the clip holds the rod in place. The inner bore was 3/4. So its pretty safe to say that an actual 7/8 inner bore will measure 1 in or a hair larger where the clip holds the rod in place
 

Fant

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So just take the rubber boot off. If it measure 7/8 across with tape measure then itl be 3/4 or smaller bore. If its 1 in or larger it prolly a 7/8.itl save u time of tearing them apart.anyone that has a true 7/8 bore stock 89-92 ranger master confirm this for me?thats just what im assuming from interior design of the m/c
 

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My question is since its such a popular build why doesnt duff or even this website store offer the part for the swap???
 

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Frm all the things ive read what some ppl have got the 3/4 master to work.from my understanding. U need a mtching slave and line for the master. Im goin to spend the 250 on the master. Slave and line frm bumper to bumper. If it works or not il post to let yal know. Itl be 2 wks before il get it and trans.
 

Mac

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Frm all the things ive read what some ppl have got the 3/4 master to work.from my understanding. U need a mtching slave and line for the master. Im goin to spend the 250 on the master. Slave and line frm bumper to bumper. If it works or not il post to let yal know. Itl be 2 wks before il get it and trans.
You have to remember that a lot using the 3/4" bore MC successfully are using an external slave with smaller bore with a T-5 trans. Internal slave whole different scene. My MC from B-B cost $51.10 and you sure can find them a lot cheaper, almost half that.
Dave
 

Fant

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Im having to buy the whole setup. Master.slave and line. So i was goin to get the whole kit prefilled. My master is 3/4 but my line and slave wnt. The line is 70 or so. Slave is another 70. So i just figured itd be easier buyin whole set
 

Fant

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What other choice do i have?the listing is 7/8 bore m/c.if its 3/4 il start trying to find another 7/8 but i dnt knw what other options i got.any advice?
 

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Has anyone actually fount a place to order the 7/8 master cylinder?and it be a true 7/8 master?ive found a few places when searching for 91 ford ranger with 3.0. But it may be like all the rest. Id like to buy a complete package but theyre high as hell and if the master is wrong id have to send it all back or buy another master. Can yal tell me of what u have successfully got to work?ive got almost 2 grand in this damn transmission and t/c setups now. And i need a master. Line and slave to where it will shift without grinding gears. I have a centric slave due to it being an r2 out of 97 f150.
 

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Cm39896 shows on summit racing .875 bore.anyone confirm this?or is it another 3/4 bore?
 

Mac

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I used RockAuto to buy my Doorman slave, they had it listed as 7/8". Go there now and they have a 3/4" bore for the same application. All applications I have found show 3/4". Using a 7/8" on the same size slave as the 3/4" would sure cause problems. Summit has been proven wrong several times in the past, sure wouldn't believe it to be a 7/8" bore.
Dave
 


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