Thinking of Going BACK to Front Drums

[Gerald Morris]

I would ditch the works, get an OEM Bendix/Bendix clone master cylinder, a manual brake pedal and mounting bracket, a nice set of drums, shoes, an OEM "control valve" if that isn't present up front, and put it all back as Ma Par rolled it off the line. I admit that since getting our '83 D150 with manual disk brakes up front, that maybe one CAN attain a stable, safe manual disk brake system, despite what the brake shop "experts*" oink about "throw." If I were to put disk brakes on a mid 60s C body, I would study how this truck is constructed and use that for my model . Be that as it may, I like the original all drum setup with good quality components best. Manual brakes require naught but some muscle to drive them, working just as well with the motor off as on.

 

[TAD STIELSTRA]

I read the thread about Tux’s problem and it sure sounds like a booster problem, as does this ‘69 Fury. I’d try another booster (I know that sounds easier than it is) Also, are you sure that the primary and secondary shoes aren’t swapped, in the rear? I love the color combo on Tux! One last solution would be to just sell me Tux…

Have a 70 in the back yard with power drums if you haven't found some sw michigan

 

[1966newport]

only that can cause this issue is bad master cylinder. bad booster wont cause this

 

[NitrousTuner1]

Definitely have a pressure issue...
And being a avid drag racer that sees alot of fast street driving as well...
THERE IS NOTHING WRONG WITH 4-WHEEL DRUM BRAKES!!
As long as YOU have the Properly made brake shoes & have them adjusted properly. They were designed & made to use asbestos material. NOT semi-mettalic like what your now buying & using.
We have multiple sources where we still get NOS brake shoes & parts.
Here's a pic of the 11×3 1974 NOS set I Just installed...

 

[Gerald Morris]

Definitely have a pressure issue...
And being a avid drag racer that sees alot of fast street driving as well...
THERE IS NOTHING WRONG WITH 4-WHEEL DRUM BRAKES!!
As long as YOU have the Properly made brake shoes & have them adjusted properly. They were designed & made to use asbestos material. NOT semi-mettalic like what your now buying & using.
We have multiple sources where we still get NOS brake shoes & parts.
Here's a pic of the 11×3 1974 NOS set I Just installed...

View attachment 587015

I've horded up a good stash of front shoes, but for the rear I have to choose between old re-line shoes or graphite-metal. Running old relines just now, but will switch to some of the better graphite shoes later this spring, when I do some other rear end stuff. I refuse to pay $125+ for asbestos for the rear. NO! I've tuned my brakes to stop very nicely w all drums, and really prefer them

Rejoice that the EV enthusiasm has resurrected drum brake development.

 

[Blusmbl]

While I agree drums are ok in some applications, there is no way I'd remove a set of disc brakes to put drums back on. The OP's problem isn't the discs, there is something else wrong in the setup.

 

[70bigblockdodge]

If you want drive the car, I would ditch the booster all together. Some people want to ride in their cars, so figure out why your booster does not work, and keep it.
The rears locking first is dangerous. Adjustable proportioning valve should be all the way out then if locking rears start turning it in to reduce pressure to rear.
Rock hard pedal is booster or master cylinder.

 

[Gerald Morris]

If you want drive the car, I would ditch the booster all together. Some people want to ride in their cars, so figure out why your booster does not work, and keep it.
The rears locking first is dangerous. Adjustable proportioning valve should be all the way out then if locking rears start turning it in to reduce pressure to rear.
Rock hard pedal is booster or master cylinder.

Boosters are OK for those who lack the muscle to stomp their brake pedal hard when needed, but those of us blessed with the strength to do so get better braking with our native strength in part because we can feel how hard we're pressing the brakes and how they're responding! The booster gets in the way of this sort of fine tuning. If I were pulling a heavy load, I admit I would want a booster to help me, if it had no brakes on it.

 

[Nadir Point]

While I agree drums are ok in some applications, there is no way I'd remove a set of disc brakes to put drums back on. The OP's problem isn't the discs, there is something else wrong in the setup.

This. The one and only time those things almost got me killed was coming down out of the mountains on I-70 after a ski trip one day back in 1984. I scrapped that car and bought one with discs on it, just to be safe.

 

[fury fan]

1) The master cylinder and power brake booster are from Leed Brakes (an aftermarket disc brake conversion company that sources from others to make kits).
2) The discs and calipers are from a company called SSBC (another aftermarket disc brake conversion company that sources from others to make kits).
3) Brake booster vacuum is fine.
4) I have had to add an auxiliary pull-up spring to bring the brake pedal back to the fully retracted position.

Leeds and some of the other companies are selling this booster, reportedly the booster comes from China and has a high failure rate. (read that on FCBO recently)
Looks like there is a 7" and 9", so maybe you have the smaller booster, or a bad booster?
Your rock-hard brake pedal suggests a bad booster.

The need for a spring on teh pedal also suggests the master cylinder pushrod might not be adjusted properly?
Or at least some other problem in that area.

The SSBC brakes are ~11" rotors, so are B-body sized, and you are losing some braking torque due to being about 3/4" less dia than a factory C-body disc brake.
I've heard some guy liked the SSBC brakes on their cars as the braking was better and they could keep 14" wheels/tires/hubcaps.
But IIRC those were all Slab owners, and a Fusey will be heavier - another obstacle for a brake system that needs some attention.



As for the disagreement for which wheels should lock first - either set locking is bad, and requires you to reduce braking pressure, which is another bad thing.
Ideally, no wheels will lock and with enough braking power for a quick controlled stop.
Modern 'tire thought' is that in wintertime the best tires go on the rear, to keep it from sliding into a fishtail.
Personally, I would rather have a front wheel lock - I would rather ease up on braking and get my steering control back, rather than trying to correct a rear end coming around.
But ultimately, it all depends on the driving scenario which would be better.

 

[Gerald Morris]

Leeds and some of the other companies are selling this booster, reportedly the booster comes from China and has a high failure rate. (read that on FCBO recently)
Looks like there is a 7" and 9", so maybe you have the smaller booster, or a bad booster?
Your rock-hard brake pedal suggests a bad booster.

Sure does! IFF I HAD to use a booster, say, for towing in hilly country, I'd get an old OEM booster rebuilt by a reputable shop rather than trust COTS* stuff made now.

The need for a spring on teh pedal also suggests the master cylinder pushrod might not be adjusted properly?

It suggests something SEVERELY WRONG, to be sure. Tear this potential wreck apart NOW, and FIX IT! I would check that master closely, and probably replace IT if it required much diddling, A brake pedal that won't return to its proper rest position likely is not releasing somewhere else. I've seen reference to valves in the rear wheel cylinders failing, thus retaining fluid and their brake pressure. Check also the SPRINGS in THOSE. Hmm, yes, the rear wheel cylinders may well warrant major attention. Pop another set on, and see if this problem persists.

I hate expensive, modular "fixes" but Time is Money, and one often can save time this way, IFF the modular replacements are GOOD. I've found for much anything consisting of more than 1 moving part being made on the Asiatic landmass, south of ~42 degrees latitude, Kwollitee gets dropped into the pit under the outhouse.

*Consumer Off The Shelf

 

[Knebel]

How much vacuum does your engine make? I'm thinking you need a electric pump...

 

[Gerald Morris]

An electric vac pump and a vac reserve canister both help vacuum intensive applications such as brake boosters, but I say such is just more baroque design applied to a marginally good idea. Still, IFF one is determined to use a brake booster, both of these additions would help, sho' 'nuff, provided everything ELSE WORKS PROPERLY.

 

[fury fan]

Agreed. No need to start throwing crutches at it until more diagnosis is done.

 

[fury fan]

only that can cause this issue is bad master cylinder. bad booster wont cause this

Problem was reported as this:
This thing doesn't stop for sh_t! The pedal is rock hard.

Rock-hard pedal and no stopping power could have several potential causes, and a bad booster is one of them.

 

[Gerald Morris]

Problem was reported as this:
This thing doesn't stop for sh_t! The pedal is rock hard.

Rock-hard pedal and no stopping power could have several potential causes, and a bad booster is one of them.

Yowza yowza! Before I'd spend a cent on anything to do w a booster, I'd make at least 110% sure of every other component. I was never so happy as when I totally removed the dead leaky booster from this '68 ragtop, got the manual pedal and bracket on with the Bendix master, and could safely stop with ease.

 

[NitrousTuner1]

I've seen multiple car's where bad replacement was done & they use the wrong hole on the brake pedal...
There's 1 for power brakes & 1 for manual on alot of car's

 

[Gerald Morris]

I've seen multiple car's where bad replacement was done & they use the wrong hole on the brake pedal...
There's 1 for power brakes & 1 for manual on alot of car's

IDK about later model C body Mopars, but for the slab sides, they used two distinct pedal and bracket setups, which bolt through the firewall to the master. They don't mix. Despite the shorter length of the manual pedal arm, it pivots on the master piston rod at a lower point on the pedal, giving the driver a greater moment length, thus leverage, to drive the piston all the way in the master cylinder. If one attempts to use a booster pedal and bracket manually, one will find that it feels exactly like it has a DEAD BOOSTER, and is difficult to push home. NOT a desirable state with braking.

I suppose one COULD cut down the booster pedal arm, drill it, and improvise something approximating Mopar's manual brake setup, but I wouldn't recommend it. It would likely be better to get an after market manual brake setup if so determined. I'd go scour junkyards and the Net for a manual brake system meant for Mopar C bodies.

 

[Another Generation]

I'm probably chiming it too late on this, but.....

I have a 66 fury that the previous owner converted to power disc brakes. It has 4 piston fixed calipers on all 4 corners. Similar problem.... brake pedal goes about 2/3 of the way and is rock hard. I measured my brake pedal ratio and found that I have a 2.6 to 1 ratio. This means I would have to exert better than 300 pounds on the pedal to get enough pressure to fully engage the pads!! I am in the process of fabricating a new brake pedal assembly that will render the necessary ratio of 4 or 5 to 1 to get the proper pressure. I'll let you know how it goes!!

 

[Gerald Morris]

I'm probably chiming it too late on this, but.....

I have a 66 fury that the previous owner converted to power disc brakes. It has 4 piston fixed calipers on all 4 corners. Similar problem.... brake pedal goes about 2/3 of the way and is rock hard. I measured my brake pedal ratio and found that I have a 2.6 to 1 ratio. This means I would have to exert better than 300 pounds on the pedal to get enough pressure to fully engage the pads!! I am in the process of fabricating a new brake pedal assembly that will render the necessary ratio of 4 or 5 to 1 to get the proper pressure. I'll let you know how it goes!!

Wrong Approach! You will do far batter for the effort to either restore the Budd disc brake system if this isn't one, or replace this with something more efficient. Even if you devise a pedal and bracket which pushes harder on this malfunctioning master cylinder and system, you've simply re-invented something like the MANUAL brake pedal setup, which has far better leverage than the power brake pedal and bracket does.

Since purchasing the 1983 Dodge D150 Miser pickup, I now KNOW BEYOND ALL DOUBT THAT A VIABLE MANUAL DISC BRAKE SYSTEM CAN BE BUILT FOR 2 TON VEHICLES! If I really want front disc brakes for any C body I'll drive, I plan to base it on the design and specs used for that pickup truck.

Have you gone beyond drawing board stage with your idea? If not, look at these early 80s Dodge trucks for possible hints.

Best of luck and blessings on your project.