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Anyone Know master cylinder bore size?

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Shealey

Shealey

Jedi Trainee
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I think I found a great deal on a duel master cylinder. I need to know the bore sizes for the bugeye and also later sprite bore sizes. I have some other parts on order now. If I can get a quick answer I may be able to add this to my order today.


TIA
 
i believe (don't quote me), that the bore size is 7/8". someone should be along any time now to either refute or back that up!
 
7/8" for drum brake setups (Bugeye, early Sprite Mk2 and Midget Mk1). Later disc setups were 3/4".
 
Thanks, That's what I was looking for. I have a Bug with disc brake conversion.

BTW: I'm purchasing a new duel master cylinder very simaler in appearance to the stock unit.
 
Ben is right, most folks when they do the conversion just try and make it work with the larger bore. It's been recommended to try and switch to a 3/4" bore if you can find one, or have your master re-sleeved to the smaller size. There is a guy who is trying to have 3/4 pistons manufactured right now, as they're not really available anymore.
 
Ben,

I found a source for a "stock style" duel master cylinder. I can get it with
bore stroke
5/8"-5/8" 1.5"
3/4"-3/4" 1.4"
3/4"-7/8" 1.6"
7/8"-7/8" 1.7"

The fit is a little tight in the stock pedel box. But the price is around $ 200. vs the Moss price at $ 400.00

If you need to have OEM look this is not for you. But if you are looking for a master cylinder with modern parts this may work well. I'll give you a report when I have it and try it out.

BTW: If I would have checked the Moss online catolog first I would have had the info as they list the two sizes there.

Duh
 
Hey I'm interested in this source. Anymore details?
 
If it fits in the original pedal box...I'm in too!!
 
Allow me to make a suggestion on the pedal boxes. I had had mine off once and sandblasted and painted with rustoleum and went back to using it for almost a year.The spills of brake and clutch fluid and scratches,etc. had it rusty and looking rough again in no time. This time I cleaned it down with a wire wheel and used laquer thinner and cleaned it and put a couple coats of black por-15 on it. That stuff dries shiney and (even though I got a couple runs) looks good and is hard to scratch and brake fluid seems to have no effect on it at all. I would not pull a pedal box off to do it, but if I had it off, I would definitely do it. You can get a pint for $20 or so and a quart for $35 and it goes a long way. Its much thinner than rustoleum but adheres well to anything(even fingers). I bought a quart and it was enough to do my trunk and floorpans and engine bay area and part of the underneath.
 
Next time around I powder coat mine.
 
LOL, lets see some pics of this work.
 
Gerard <pixelsmith@gerardsgarage.com>
Is having the 3/4 bore parts made.
Disc brake cars all used a 3/4 bore master
Drum brake cars used a 7/8
 
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