Joined: Wed Dec 27 2006, 09:13PM
Location: NJ
Posts: 19
Hi Guys- As the title says, I just swapped my original front drum brakes out for the SSBC disc brake. Unfortunately I’m having some trouble getting the car to stop as it should. It's drivable under maybe 40 mph, but the pedal is hard, no way is the car going to stop in a panic stop.
I have not replaced the booster {rebuilt, been working for years} from the drums. SSBC did not mention that this would be an issue. Can anyone recommend a booster that might help? Part number would be great. Does the new booster fit the dual master that SSBC provided in the kit?
I emailed SSBC about the situation and they sent me a response telling me to test the brake pressure at the caliper. No one I've asked has a caliper pressure gauge, and they cost $200.
Appreciate all help--I'm hoping to get the car back onto the NJ Parkway to the beach!
Hi, I did the same on my '66 New Yorker. My braking was poor until I put in a disc booster. Your choice of booster will be limited if you have Auto-Pilot, but was that even available in '65? Otherwise a disc booster from any disc-braked C-Body up to at least '73 will work.
The SSBC master will work with any Mopar booster, maybe a small adjustment on the pushrod length that's all. (Again, unless you have Auto-Pilot, that changes things!)
Yup... if you have the drum booster, it won't do it.
Gotta change to the disc booster. John and I both have Autopilot in our cars, which is another can of worms, but we have the solution. If you don't have autopilot, as stated above then you can use any disc booster from a c body.
HOWEVER - note the following:
If you have a column shift car, the larger (wider) single diaphragm disc boosters that some later C bodys 1969 through 73 were equipped with will interfere with the column shift linkage on 65-68 cars, and will prevent you from engaging LOW 1 and LOW 2 - you'll still have DRIVE but won't be able to shift farther. Those boosters look like this:
The other "dual diaphragm" boosters are OK, as their bodies are narrower and don't present a problem.
Essentially, the best booster you can get is the one originally designated for your car when disc brake equipped. It looks like this:
Let us know how you make out - we're here to help!!
Joined: Wed Aug 11 2010, 10:15AM
Location: E WA
Posts: 1230
russ wrote ...
Hi Guys- As the title says, I just swapped my original front drum brakes out for the SSBC disc brake. Unfortunately I’m having some trouble getting the car to stop as it should. It's drivable under maybe 40 mph, but the pedal is hard, no way is the car going to stop in a panic stop.
I have not replaced the booster {rebuilt, been working for years} from the drums. SSBC did not mention that this would be an issue. Can anyone recommend a booster that might help? Part number would be great. Does the new booster fit the dual master that SSBC provided in the kit?
I emailed SSBC about the situation and they sent me a response telling me to test the brake pressure at the caliper. No one I've asked has a caliper pressure gauge, and they cost $200.
Appreciate all help--I'm hoping to get the car back onto the NJ Parkway to the beach!
As others have said you probably need a disc brake booster.
However, I installed disc brakes from a 72 Fury into a 66 Newport and the Newport did not have power brakes at all. It certainly took a lot of pedal effort but the brakes worked really well and I had no worries about driving the car on the highway.
Another possible thing to look at is the diameter of the cylinder bore of your master cylinder. A smaller diameter bore should allow more pedal travel for the same amount of fluid displacement and lower pedal pressure.
Mopar C-body disc brake master cylinders had 1 1/8" bore for 1970 and earlier then 1 1/32" bore after that.
Joined: Mon Oct 10 2005, 10:24AM
Location: The Netherlands
Posts: 160
SSBC disc conversion kits usually really seem to be just a bunch of barely matched components when it comes to Mopars. Other conversion kits work fine without the need to change the booster.
Like said earlier, you'll probably be better off with a master cylinder with a smaller diameter so it puts out more pressure on the brake system.
Chrysler used different boosters between Drum systems and Disc systems for a reason. There's no sense in circumventing that engineering to save some dollars...
Your brakes are the MOST IMPORTANT system on the car, therefore, get the right booster. Otherwise, they'll let you down when you need them the most... like when that 5 year old kid just rode out in front of you from between parked cars, or like me yesterday, when the lady in the little Nissan pulled out in front of me. If I'd had a drum brake booster on my system it would have resulted in her death. My disc booster did the job.
Make no mistake, you need a DISC booster, master cylinder bore not withstanding.
Joined: Mon Oct 10 2005, 10:24AM
Location: The Netherlands
Posts: 160
I respectfully disagree there are 'discbrake boosters' for discbrake use. I DO agree there are 'better' booster designs with dual action, which can work better in discbrake setups where the addition of a number of pounds more pedal/linkage force can help slowing a car down easier.
But it's the MC's task to multiply that 'pedal-force' into a 1200+ psi line pressure. This only works with the correct piston diameter.
I've retrofitted '73 Chrysler rotors and calipers on my '62 NY wagon while retaining its stock booster and a 15/16" MC from a late '80s Voyager. This setup, so to speak, could put you through the windshield if desired.
Choosing a correctly sized MC-diameter to go along with your car's calipers & brakepedalratio is way more important than using the 'correct' booster.
SSBC seems negletive in this because they seem to supply the same MC with all their kits, probably thinking, One size fits all Mopars...
