R6T8net
Member
I’m looking to convert the power drum brakes on my 68 Coronet 440/318 to Dr. Diff’s 10.95 kit. Given my booster, which of the available Dr Diff options would be recommended? 15/16 or 1-1/32? Thanks.
MS Bore Size Recommendation
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gkent
Well-Known Member
Why don't you aski him ?!?!?!
gkent
Well-Known Member
Well you can't order till Monday anyway !! At least you'll get good advice .. asking here will get you so many different "opinions" it'll leave you so baffled you'll be sorry you asked !!
davek
Well-Known Member
Please post what he tells you.
I used my drum power brake booster with a SSBC front disc brake kit 25 years ago and it sucked, took more effort than before and didn't stop very well. I can't remember the master cylinder bore though. If you're keeping the booster, probably best to use a smaller diameter MC. But if I were you, I'd just get a repro dual booster, they're not that expensive, and Mopar used them with disc brakes for a reason.
The Ram Man has videos on Youtube about Mopar brake systems, explains about different master cylinders, etc. Probably best not to order from him though, lots of negative feedback.
The Ram Man Inc.
The Ram Man has videos on Youtube about Mopar brake systems, explains about different master cylinders, etc. Probably best not to order from him though, lots of negative feedback.
The Ram Man Inc.
My best guess would be after your brakes don’t work well you’ll hear”you need a dual- diaphragm booster”, then you’ll hear “ you need a 1.125” master.”
Geoff 2
Well-Known Member
Disc brakes require about 50% more line pressure than drums. So I would use the smaller diam m/c which will produce more line pressure. You will have to check with the manufacturer if the smaller m/c has enough volume to work with the intended calipers.
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Sometimes in instances like this, it pays to at least start with something similar to what these cars had when new.
The drum booster will not be adequate with power disc brakes. It has a single diaphragm, the front disc cars had a dual diaphragm booster as part of the package. Regarding master cylinders, the 3 most common sizes are 15/16", 1" and 1 1/32". It is a matter of preference with this. The smaller the bore, the easier the pedal will move as well as moving further to engage the brakes because of the lesser volume. The large bore gives the firmest pedal feel, moves the least to engage the brakes but also requires the most effort to stop the car.
You don't have to wait until Monday to order, the website works 24 hours a day, 7 days a week. Dr Diff also returns emails often after traditional business hours.
The drum booster will not be adequate with power disc brakes. It has a single diaphragm, the front disc cars had a dual diaphragm booster as part of the package. Regarding master cylinders, the 3 most common sizes are 15/16", 1" and 1 1/32". It is a matter of preference with this. The smaller the bore, the easier the pedal will move as well as moving further to engage the brakes because of the lesser volume. The large bore gives the firmest pedal feel, moves the least to engage the brakes but also requires the most effort to stop the car.
You don't have to wait until Monday to order, the website works 24 hours a day, 7 days a week. Dr Diff also returns emails often after traditional business hours.
You can email Cass and ask for his recommendation, but he will just tell you it is personnel preference. I have been using his 15/16" aluminum masters on all my cars for years now and have been satisfied with them.
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