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Manual Front Disc Brakes - Okay?

BPBP440

BPBP440

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I am ready to pull the trigger on a front drum to disc conversion kit with smaller bore master cylinder. Ram Man’s youtube video goes into great detail as to why you have to go power if you want good stopping distances out of disc brakes.

Thoughts?

70 B-body
 
They’re awesome! I hate power brakes and my car came with manual brakes. Due to some power upgrades I decided to bump up the drums to disks. All Mopar parts.
 
BPBP440 said:
I am ready to pull the trigger on a front drum to disc conversion kit with smaller bore master cylinder. Ram Man’s youtube video goes into great detail as to why you have to go power if you want good stopping distances out of disc brakes.

Thoughts?

70 B-body
Click to expand...

Manual disc brakes work as long as you have big enough rotors. The factory 11.75 rotors would be the minimum size for manual disc brakes with a big heavy car like a '70 B body. I have manual disc brakes on my '65 Coronet and it stops really well but I upgraded to 13 inch rotors.

Your car should stop okay if you have 11.75 rotors up front and big drums in the back. If you have the 11 inch drums or can upgrade to them then that will help.
DSC_1148 (Large).JPG
 
The "Ram Man" has some opinions that run contrary to what I have read and experienced elsewhere.
Manual front disc/rear drum systems can be fantastic. I set up a 72 Duster with the 2.75" front caliper, 11" rotors and 10" drums using a 15/16" master cylinder. That is a common setup that I have used in several A-body cars. All of these cars stopped great, as quickly as most new cars that I have driven.
The same principles will apply to B body cars using larger rotors.
 
I'm running discs front/rear and because I had a booster issue I went with manual brakes. After racing with them, I like manual. But for the street... I think power would be better. It's difficult going from three vehicles with power to my Belvedere with manual, but unless I stop racing, I'm staying with manual. I kinda like the feedback from the pedal when I'm racing.
 
I have manual factory front disc & drum rears. They work pretty well. My car is 3700#, stops good, not sure it would be good with repeated stops.
 
I have manual front disc/rear drum on all my cars and really like it. Just a thought, give Cass aka Dr. Diff a call before buying from the Ram Man. Imo a much better place to do business with.
 
My manual disc/drum brakes are just fine at 128 MPH 3700 # + with a fairly long shut down. Never had a concern. A short shut down might a bit more interesting.
 
You can do either like everyone has said already. I would stress the MC sizing is key. 15/16” like @Kern Dog said is the key. Gives you good pedal feel. I will say the last car I did this with I was not happy with the setup on the first drive, but once I got some miles on it and they broke in I was very surprised how well they worked and felt.
 
I'll add on, 4 wheel manual SSBC discs on my 65 going on 15 years now. Works for me.
 
I've manual discs in my '71 Charger and my '55 Plymouth wagon. Great pedal feel and great stopping power. It's my understanding that power brakes don't develop any more line pressure, they just take less pedal effort.
 
I converted the front on the Charger to SSBC discs. The rear are original 10" drums. Manual disc/drum master cylinder. It works pretty well.
 
Sounds like you would be fine with manual front discs with all the response you've gotten. I agree as well! I might add: Another reason to not go power is all the hassle of connecting the power booster, having to make up new lines (with manual, you can literally use your existing lines) and not to mention that big bulky thing hanging out out so far from your firewall, sometimes right over your shock towers. It's not worth it to me.

I ordered a power kit, but then opted for manual when they sent me the wrong booster. I'm actually still using the 1 1/8" bore master cylinder that the kit came with and it's actually not that bad. I will be installing a 15/16" bore MC later like everyone suggests... But even with the 1 1/8" bore (which is for power brakes, it stops pretty good... super hard pedal though).
 
Manual 11.75” disc front and 11” drum rear and 15/16” MC and it stops great. Also need the corresponding disc brake valving for best results.
 
My 76 dart came with manual brakes (front 10.89 disks and rear 10 drums) 1 1/32 MC and had no issues. BUT when I cut down a Cbody 8.75 rear I then had 11" rear drums, still 0 issues. When I replaced the front frame rails and replaced every bushing, I put the 11.75" adapters and disks on the front along with Dr.Difs aluminum master... I opted to stay with the 1 1/32 MC and I am still happier than F$#k with the feel and performance. Yes my experience is with Abody but I cant think of it being much different with a B. My 74 Charger (gone now) had the pin type 10.89 disks with 10" (I think) drums and although that was assisted brakes it stopped great as well.

Edit 1 1/32" not 1 1/8"
 
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