MC bore

TW71 · Post by **TW71** » Wed Jul 12, 17 11:11 am

Can anyone tell me what they would recommend for the maximum master cylinder bore size for manual braked discs (4 piston calipers, drums on the rear)

I was thinking of going no larger than 1'' bore?

The one I am looking at is 1.032''

Thanks

Blue · Post by **Blue** » Wed Jul 12, 17 11:37 am

I have a Strange MC in that size on the Valiant, I have another to fit to the Barracuda. That's what Strange recommend for a disc/ drum combo and I'm happy with the way it works.

MrNorm · Post by **MrNorm** » Wed Jul 12, 17 12:06 pm

I think you are right in the ballpark. I generally hear the 15/16 bore recommended, which you can still get if you have the right pt# eg http://www.rockauto.com/en/parts/raybes ... inder,1836 for my Challenger, assume likely the same part for your 71?? That is for the standard single pot calipers and it obviously is affected by your 4 pot piston surface area etc, you'd have to do the maths but around an inch is about right I believe.

Mick70RR · Post by **Mick70RR** » Wed Jul 12, 17 1:41 pm

I fitted an SSBC disk brake kit that came with a 1 1/8" bore master cylinder. Brakes were crap so fitted a 15/16" bore master cylinder and there was some improvement but more pedal travel. Brakes were still poor, I don't think you can get enough pressure on the pedal with your leg. So I fitted a servo and it transformed the brakes, now they are pretty good and up to the job.

TW71 · Post by **TW71** » Wed Jul 12, 17 5:45 pm

Thank you gentleman for your quick response!

That's the make Blue I am looking at. The smaller bore seem to be the cast iron OEM style which I would use no problem, the car being around 3800 lbs with driver I reckon I may need to?

I think it may be too hard a pressure required other wise

I was hoping not to have to fit a servo due to other constraints, maybe a case of suck it and see first?