Master Cylinder Differences?

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nqkjw

nqkjw

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This is on my challenger but the same MC as on my 72 dart and 69 cuda.
Below is a pic which explains it all.
My car was originally a 1970 318 non boosted disc front drum rear.
It's now a 440 non boosted disc front drum rear.
The master installed is the one that came on the car when I got it.
The master on the left is a new one that I have.
A bit of research tells me I need a 1 1/8" bore MC which seems pretty std across disc models except hemi cars.
Can someone tell me what's with the mirror reversed reservoir shapes?
Is it just different manufacturers?
Could be an aftermarket thing?
Something to do with patent designs maybe?
Anyone else ever come across this?

1zoupf9.jpg
 
that 1 1/8" piston master will require a lot of leg.
..you might like a 1" bore master better?
 
Ran into this last year for 75 Duster. I tried Advance and Pep Boys - both looked like what you found. I got this one at Autozone for under $20. It is the 15/16 bore (P# 1571 I think), which (contrary to the what the auto store specs show ) is original to the car from what I can tell. It has disk front and 10" drum rear, slant 6. You said 1-1/8, I did not see that size - everything I looked at was either 15/16 or 1-1/32. The other place I saw the round front style was if you can find an NOS Wagner - there were a couple on ebay when I was looking, but a bit more expensive and I did not want to wait for shipping.
Just an FYI on finish -so you don't make the same mistake I did. I thought these had a coating on from manf. Mine was covered with rust in a couple months. If I had known that I would have cleaned it and clear coated before installing. So ended up painting it black....
 

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ir3333 said:
that 1 1/8" piston master will require a lot of leg.
..you might like a 1" bore master better?
Click to expand...



Just pulled the MC out of my challenger and it's actually 1 1/16" bore.
The new one I have is 1 1/8" bore.
You mentioned with non boosted brakes I should be using 1" bore.

Can someone tell me what I SHOULD have in there?
I'm happy to purchase the correct part so it's not about trying to save a dollar.
The sort of info I need just isn't available in Australia,that's why I ask you good people and those on C-C.com.
 
nqkjw said:
Just pulled the MC out of my challenger and it's actually 1 1/16" bore.
The new one I have is 1 1/8" bore.
You mentioned with non boosted brakes I should be using 1" bore.
Click to expand...

From the research I did for the NON boosted brakes the smaller the bore the better/easier the peddle effort.
I recently did a disk conversion and used a 15/16" bore per what I had read.
The peddle effort does not seem excessive and I was very happy with that choice.
 
Thanks for the reply.
No one seems to have a definitive answer and trying to check what was original seems to come up with several different answers.
I seem to have found they came in bores of 1 1/8",1 1/32",1" and 15/16".
Can't find any reference to 1 1/16" which is what was in there.Measured it again and it's definitely 1 1/16" so maybe it's been sleeved or something?
Anyway,the brakes seemed OK but firm with the 1 1/16" so I'm thinking if I try a 1 1/32" it will require a little less leg effort.
If I'm not happy with the result it's no big deal to try a smaller bore later.
 
If you could find a 7/8", ..... sweet. I know it seems backwards, but smaller bore=less leg.
 
Apparently smaller bore = more pedal travel = pedal closer to the floor on hard application.
Seems it's a bit of a balancing act with several influences and repercussions.
I'll just start trying and as I said,try a different bore if I'm not happy.
 
The 15/16th bore will give you better pedal control and feel. It gives you extra "leverage" over the wheel cyls..
Without the booster, you'll need/appreciate the extra advantage..

The extra travel you mention would be less than 1/4 inch with properly adjusted brakes.. getting no-where near the floor..

Try the 15/16, you'll love it,, so will your leg..

If you do a search, you'll find numerous threads discussing this.. cheers
 
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