I bought a front disc brake conversion kit for my 69 Charger with manual brakes from Stainless Steel. I've bled the system and the pedal is firm. The proportioning valve that came with the kit has been adjusted both ways which doesn't seem to help and it's located between the distribution block and rear brakes as per the instructions. I've cleaned the discs with brake cleaner. When I apply the brakes really hard the car just gradually slows down and eventually stops. The pedal only moves about and inch or so and is firm when I do this. At walking speed I stand on them hard and again is just barely works instead of stopping the car. My 10" drums worked way better! Any ideas or has anybody had this problem before?

What master and bore diameter?

John

Those calipers have very small pistons. You need to run a 15/16" bore master cylinder.

I had this same issue with them but i was trying their power brake set up. (which uses corvette master bylinder and booster) No matter how much i tried I could not get them working well. Are you using the ssbc master that comes with it? I ran their 4 wheel disc manual set for a while and their master is a 1 1/32 bore.

They worked well but i had to really really really stand on the brakes to get them to stop. I am currently running that same master with a dual diaphram booster and happy with it, but i am thinking of going to the 15/16 bore like dr diff indicated.

partial blockage somewhere. in my case I had a dented line & I had the exact same symptoms as you.

I have had all kinds of problems with my 4 wheel SSBC brakes over the years and have switched out masters, brake lines, and distribution blocks all with just mild success. They did call for like 500 miles of break in and that did help some. I have pretty much just written them off as an average setup just slightly better than well set up drums. I even have their slotted rotor force 10 aluminum caliper setup that was advertsised as being so great. I do get better repeatablitiy out of them but once again not nearly as good as I thought. Will be going to some type of 13" disk set up like from a Viper before too long. Good luck with yours and hopefully the switch to a 15/16" master will be you answer.
Todd

All the lines are new and no dents there. I am using the master cylinder that came with the kit. Can somebody recommend a master cylinder to use? (i.e. where to get one, what size or for what application car?) Is the 15/16th master cylinder bigger than what I have from the kit and if so, where can I buy one?

This is a common problem. SSBC doesn't even know about the 15/16" master.

Get a NEW 15/16" unit for a '73-'75 A-body POWER disc brake application.

We have the same problem on our 64. The 1-1/32" master cylinder didn't stop the car hardly at all. Put a 1" on it and no difference. Went to a 15/16" and the car stops, but pedal effort is very high. My dad had manual drum cars that stopped better than this setup. Thinking of experimenting with different pads or going to the larger rotor (we have caliper brackets). Is there a larger piston caliper that might work better than the 70's A body?

I have this 7/8" piston master cylinder with 4 piston calipers on the front and single piston calipers on the rear. No booster, manual 4 wheel disc brakes.

Brake pedal feel is firm but not too stiff.

http://store.summitracing.com/partdetail...mp;autoview=sku

They sell rear wheel cylinders for disc brake conversions on e bay. Call them problem solvers, but these are to alleviate air in the line or "spongy pedal" which is caused by moderen master cylinders lacking a residual pressure valve. Do a search on mopar rear wheel cylinders. Mo out

I just had the car out around the block and it's flat out dangerous. I stand on the pedal and it slowly comes to a stop. I don't suspect I'll get much help from the tech line. I'm going to try the 15/16 master cylinder and see what happens. If not, I'm just going to chuck the SSBC kit and put the 10" drums back on so I can drive the dang thing! Why couldn't I have just left it alone?

Yeah, there tech line was awesome when I was first having my problems!!! Guy told me well that car is heavy, if it is stopping from 60mph in anything short of 200' then that should be considered good. My drum brakes were stopping from 60 at around 150'. Boy good thing I spent nearly $2K on their awesome brakes so that my way heavier Explorer and my wife's fat minivan could stop better than my way lighter(3650 lb) roadrunner.
Todd

I think part of the problem is also that most folks go from a "power" drumbrake system to a new "non-power" disc/drum system. I think here's where they (ssbc) don't hold in account that original power-assisted cars have a shorter brakepedal-ratio, causing a firmer pedal and less force to the MC to begin with.

Sure sounds like Pedal ratio. I just went thru this too. Hard pedal & no way I could lock up anything.

Read through this....

http://www.hotrodheaven.com/tech/brakes/brakes6.htm

Mine is a c-body & there's 2 different pedals for the Power & manual setups. Also 2 different hinge points for each Pedal.

Doc diff sent me that link & sure enough my Pedal ratio was 3:1 & I needed 6:1. Modified the pedal & it's much better now. Working on other issues with the Brakes right now.

Butch

yikes

this is not what a guy wants to hear that was considering a manual to power brake upgrade

please keep us posted

My car originally was a manual drum car so I'm guessing the ratio of the pedal is correct for the manual disc brakes.

Simple - you need more line pressure. it is not difficult. Put in a master cylinder with a smaller bore and you will CREATE more line pressure with the same amount of pedal effort. The other post gave you the blueprint, get a 15/16 master cylinder so you can get on with your life. It is indeed unfortunate that an otherwise responsible company would supply the wrong size master cylinder. They probably have a bad assumption going about the pedal ratio.

R.

Ideally you need gauges to test the pressures the system is generating. IE: what pressure is the master actually putting out.
Lot's of variables here but a general rule is 1500 PSI in a panic stop should be a good starting point. The next thing to checkt is what's the caliper seeing???? The same pressure ( it should be. Next is putting a gauge between the pads and mashing the pedal.
Short of having the gauges one can look for deflection of the hoses and cailper brackets as the pressure is applied. If you see no movement then you probably have a master issue.
if you are getting good deflection then you probably have adequate pressure. Next thing to look at is whetehr the pads/rotors are glazed. ANd lastly you might try a set of pads with a more agressive compound. I had a 68 Olds cutlass with SSBS setup on it that did pretty much what your describing. After much hair pulling we installed a set of aftermarket "ROTOR EATERS" and the problem was solved. hope this helps

TIm

Yeah, the bracket under the dash has the 2 pivot points, 1 lower than the other. Basically shortened the Pedal the distance between those 2 pivot points . Cut & re-welded it so that the lower pivot & pushrod lined up, sectioned between the pushrod & the pivot.

The distance between the 2 pivots was about 3.25" & we took that out between the old pivot & pushrod hole. The pedal might just be about an Inch overall shorter than a correct manual pedal (comparing to a friends Manual brake Fury ) but I still got the 6:1 I was looking for.

Yes I had a really good welder do it!

If I can locate a manual pedal later I'll just swap it. harder than hens teeth to find since most of the Barges got power brakes.

Butch

It's a combination of pedal ratio and MC size.

I went through the no-stoppy thing when I dropped a truck MC on the "big" Dippy rotors. Stopping the car required both feet on the pedal and my butt in the air. It was pretty hard on the steering column too. That MC was WAY too big and caused a super-hard pedal.
When I went to the larger calipers, the MC was the perfect size and the pedal effort dropped to normal.

Dropping the bore of the MC will reduce the pedal effort.
Maybe one of the K-car MCs would work?

So the power pedal has the bracket and pivot points and the manual pedal has none, is this correct? I finally called SSBC and the tech said to check if the car came with manual brakes. I checked the pedal and brake rod connects directly to the master cylinder. My 68 Charger has power brakes and there's a bracket assembly with pivot points. Since the pedal connects directly to the master cylinder on my 69 with just the rod and no brackets or pivots, I'm guessing this was originally a manual brake car, right?

A, B and E bodies used the same pedal assembly regardless of brake type. The master cylinder push rod just bolted directly to the pedal if the car was equipped with manual brakes. The pedal ratio is around 6.25:1 stock.

Listen to the Doctor!

R.

Sorry to hear that you have been having so much trouble with your conversion, but as others have already stated, you are not alone.

I used the ECI disc conversion on mine... they work like a champ... Almost to good.

I'll just throw this out there... would a wilwood residual valve(2 lb.?)in the front line from the master make a difference? This would keep some pressure on the pads and not allow them to retract into the calipers. ,D.

At least you've found the issue. Now hopefully somebody with either a 64-65 car to look at or maybe a factory parts book can check it out for ya.

Maybe there's a whole different under dash bracket & Pedal for the Manual cars?

Butch

I installed a 15/16ths master cylinder and the new rear wheel brake cylinders with the residual pressure check valves. There was a "little" improvement but the car still is too dangerous to drive. My 68 Charger with power drums will lock the wheels. Even the manual drums on this car were better. I'm about ready to give up and go back to stock drums. I have a power brake pedal assembly I'm considering installing with a new booster and master cylinder for a disc car. I really need to get this thing to stop. Where can I buy some "rotor eater" disc pads? I'm willing to try anything at this point. I checked the installation sheet and it doesn't list an FMSI# for these pads like it does for most the other kits. I'm hoping these pads aren't specific to SSBC. My kit was the A156 which is calling for an SSBC pad of A1033.

I just bought a new brake pedal. It should be coming today or tomorrow. I posted a question about 62-65 brake pedals and a member measured thiers and it was about 3" shorter, so I found a manual brake car and got that pedal. If we get it on the car this weekend I'll post the results.

If your car had power brakes, measure the brake pedal from the pivot to the bottom of the footrest, and the pivot to the brake pushrod attachment point. Divide that number into the first measurement and that is your pedal ratio. Find someone that has a true manual brake car and ask them to measure their pedal and compare. From the measurements that I got, on the early B-bodies the pedals are different.

The smaller master cylinder will help, but not solve the problem if the pedal ratio is incorrect. Been there, done that.

Ok, been doing some research and it appears the pads I have cross reference to an FMSI Part # of D-11. That's like a 67 Ford Falcon or Fairlane pad. Can anybody recommend an aggressive pad like EBC or something where they've had good success? Thanks

I would think for the high price of their kits SSBC would be helping you more.

What's the piston size/sizes in the SSBC calipers?

They're twin piston 43 mm.

Those are pretty small pistons. If you compare that caliper to the factory A body caliper with a single 2.75 inch piston you'll see that the SSBC caliper has only 75% of the braking force of a stock system.

That means the rest of the system needs to be re-calibrated with smaller components to match. First thing would be to put the smallest rear wheel cylinders that you can find in there and the smallest master cylinder. That might get you back to a properly balanced system.

I picked up a brake pedal for a manual brake car. Noticeably different. The ratio is closer to 6-1 versus 3-1 for the power brake pedal. There are two pivot holes in the hanger for the pedal, but we had to drop the steering column and remove the hanger to get the pedal out. The brake pushrod mounts higher than on the power brake pedal; luckily the firewall had holes and a cutout for a higher mount. But, I had to remake the brake lines to the proportioning valve and line lock. I put the 1-1/32" master cylinder back in and brake effort is noticeably better. Not nearly as good as a power brake car, but much better. I'm sure the 15/16 master cylinder would reduce effort further, but I like the lightweight master cylinder better.

A residual vlave in the front will keep the brakes applied and not release...not a good idea! Have you all checked to make sure the rears are working? increase the rear line pressure it sounds like the fronts are not getting help from the rear...also are the rears adjusted correctly? I know sounds simple but you never know! Ive done a few conversion with no troubles im about to put a set of ford cobra brakes on my early mustang 4 wheel disc 13 in front rotors 11.65 rear fronts dual piston 38 mm 15/16 master is whats recomended...im thinking a hydro boost setup will be the way to go. its basically the same system on late model cobra mustangs and that car stops on a dime and gives u back 8 cents!

If it were me I'd box up that SSBC stuff and send it back, and convert it over to factory Mopar stuff, using either 73 A body disc spindles (or the later F M J spindles) 11 3/4" rotors, calipers and caliper adapters from a Cordoba, a manual disc master from a 73 A body disc brake car and either an adjustable prop valve or a 73 A body disc brake prop valve. That swap has been done hundreds of times by lots of people - the 'hard' part is scrounging up the parts, and they really aren't that hard to find if you look. Only point in buying a kit like SSBC's is the 'convenience' of it being all in one box, but if it works like trash, why bother? My

I have manual discs using spindles and discs from a 73 plymouth and a proportioning valve from a manual disc brake dart sport from the early 70's. manual discs and they work great.

Hey timinator, any updates? Did you get this issue resolved? I just did the same conversion on my 68 Charger and have the exact same problem. Wondering if more aggresive brake pads made a difference.

An old thread but I seem to have a similar problem - did the discotech conversion using

10.87 rotors
72 Ebody calipers
1 1/32 master
all new lines and hoses

No proportioning valve at all....

10*1.75 drums out back of a 69 Plymouth Belvedere.

Not a super firm pedal, car stops but can't lock up anything, felt better with the manual drums!

Where should I start?

Plazomat

15/16" master cylinder. Then you will likely need an adjustable proportioning valve or a factory B body one off a disc brake car.

Kevin

I hope I don't come across wrong but I've read many threads with this complaint. Why do so many people ignore these bad results threads and spring for the aftermarket stuff? There are also many folks that use the factory Mopar parts to adapt their cars and have great results. And a lot of that stuff is available in junkyards and local parts stores. I don't get it.