1964 Dodoge 880-Inadequate Brakes

[Corbin]

Help me out with some pointers....like random modes of failure that come from experience...
1964 Dodge 880. The brakes are inadequate. When the car is off (or brake booster is disconnected) I have a firm pedal. With the car on pedal is soft until last 1/4 or so of travel. Even when depressing the pedal 3/4 or 1/2 the brakes engage and the car will slow. I have to keep my foot down for a seemingly long time to stop the car at speed.

Car has new, dual chamber master (67ish or so Chrysler), new cylinders and shoes on all 4 corners. New soft lines. I've run about a half gallon of brake fluid through the system with a vacuum bleeder at each wheel. In addition to the two person method.

Brakes are adjusted per specs...up until the wheel drags and then off 10 clicks. The fronts are actually of just until the wheel spins. Shoes are on correctly with the smaller, primary shoe on the front.

I should be able to lock the brakes up with ease...I have other drum brake cars that I'm comfortable using in modern traffic...but not this one.

All the parts are Napa (a marginally higher grade of Chineseium)- I had a master fail right out the box from them recently on another car- so that's no guarantee.

I did not have the drums turned (I wouldn't know where to find a shop in this area to do that) and I reused the old hardware. I was hoping to put some miles on the car this summer and this is putting a hamper on it.

I see Scarebird is back in business...I inquired about a kit-but have had no response. I do live in the PNW and no one would argue the benefits of disc brakes in the rain....
I'm running stock 14" wheels and am not changing.

Thoughts?

 

[CBODY67]

Agree on the brake lock-up situation, from my experience on power drum brake cars.

With the correct drum adjustment, the braking should start about 1/4" down from the top, usually. No need to cut the drums if there were no prior pulsations when stopping. We never had to get any cut on our '66 or '67 Newports. Nor get the shoes arc'd either. Just put the new shoes on after the wheel cylinders were kitted and all way well after a day of driving easy to get everything bedded-in.

Can you lengthen the pedal pushrod where it contacts the back of the master cylinder? Some disassembly required. Perhaps match it to the 1967 length, if the same booster is used?

If you get the pedal up to where it should be, to slow the car, and it still stops slowly, you might try a different brand of brake shoes. Years ago, a friend discovered that on a car he has.

When I discovered "Scarebird" about 20 yrs ago, I thought it was a neat concept to use new/reman auto supply parts rather than salvage yard items. Several years later, I looked on the website to see that the recommendations had changed, as the auto supply vendors had deleted some of the parts due to slow/no sales, so substitutions were needed. Which can still be an issue, over time. BTAIM

Please keep us posted on your progress,
CBODY67

 

[Corbin]

That's kinda what it feels like; the brakes just aren't grabbing like they are supposed to. I could not find front shoes any place locally. Fast Undercar sourced them from their supplier in LA. They were not cheap. I bought the last rear set Napa had west of the Mississippi...
I'll try a spacer with the push rod, I can also try putting the old shoes back on the front-see how it performs.

 

[Big_John]

I'll try a spacer with the push rod,

You can't just add a spacer randomly. There is a setting distance. That said, some brake companies are making a gauge to check the depth of hole in the MC piston so you can set the pushrod length to match.

This is from a '65 Plymouth factory service manual. (closest I had)

I see Scarebird is back in business

"Scare" is a good word from what I've seen of their stuff.

 

[CBODY67]

Areed, "no spacer". There is an adjustable, round-end nut on the end of the booster pushrod. THAT is where the adjustment is, if needed.

CBODY67

 

[Dan Scully]

Karp's used to do relines with a material that had a good friction grab. Used it on my wagon and A-100, stops great.
Might contact them, not sure if they still do that.

Home - KARPS POWER BRAKE SERVICE & CYLINDER SLEEVING

 

[Ross Wooldridge]

Whether or not people in the past didn't have to get their new shoes arc'ed to fit their drums, I would STRONGLY recommend that you have that performed.

In my experience, most of the newer stock of shoes are so badly matched to the older drums that the contact area is minimal at best, and would take a LONG time of actual driving to even out.

Not worth it, and dangerous as well.

You may have shoes that are not suitable material for your original drums, and may be simply crappy and not able to do the job, regardless of whether they are "correct fit". @mobileparts (Craig) may be able to help in that regard.

 

[MoPar~Man]

I'm not sure if the OP is more concerned about the brakes not being able to stop the car, vs why there is so much pedal travel when the engine is running (ie when vacuum assist is present) vs seeing no travel and a firm pedal with the engine not running. This phenomena of pedal travel comes up a lot, and not just with old cars, and I'm not sure of the physics behind it.

If you have a firm pedal with no travel with the engine off, then I can't see how adding a rod or lengthening a rod can do anything. There's no slack in the system. On the other hand, your foot force, multiplied by the pedal geometry, pushing directly against the pistons, may not be enough to overcome the brake shoe return springs, so you get the false idea that you're engaging the brakes and they feel hard, and it's only when vacuum assist is present that the addtional force now actually moves the brake shoes and hence you get pedal travel, maybe a lot.

When bleeding the brakes, I think everyone knows that even if a pinch of fluid is released the brake pedal can move a lot. So the shoes have got to be set up pretty close to the drums if you dont want a lot of pedal travel. And yes, probably the arc of the shoes and if they match the drums is important and it might be the reason why the braking force is weak.

Self-adjusting shoes is important here, and I've got this fuzzy idea that the early 60's cars did not have that?

 

[noah300g]

10 clicks sounds excessive. I would back off only until no drag is felt, then maybe tighten by a click or two. Very slight drag is ok, as long as it is even on both sides.
Since you are from the PNW, I'd also suggest contacting AAJ Brakes. They do lots of bolt on disc brake conversions, including cars with 14" wheels (I used them for my 57 Chrysler to get away from the two-wheel-cylinder per wheel on the front and 7/16" manual adjusting cams with good results). They'll even tell you what rotor and caliper to use if you want to buy them separately and just buy the conversion bracket from them and proceed.

 

[CBODY67]

For drum brake shoe adjustment, there is a drum brake shoe caliper adjusting tool. Set the drum side to the current inner diameter of the drum. Then used the brake shoe side to adjust the shoes to match. Much easier, to me, rather than using "the spoon and small screwdriver"/click method of adjustment. That way, each side will be the same in relation to each drum's inner diameter.

CBODY67

 

[Ross Wooldridge]

Also - any chance you installed the shoes backward? Leading shoe and following shoe can be installed backward, and will result in reduced braking capability.

You said in your original post "With the car on pedal is soft until last 1/4 or so of travel. Even when depressing the pedal 3/4 or 1/2 the brakes engage..."
Pedal travel and brake system engagement has to be adjusted, typically by the pushrod coming out of the booster behind the master - the pushrod has a knurled end that is adjustible - when properly adjusted it should "hold" the master away from the booster face 1/16" before the master gets bolted down. This sets the correct preload on the braking system. If you've got a new master, this is a step that always needs to be performed when installing the new master.

So now you've got a couple of things to check.

 

[Gerald Morris]

For drum brake shoe adjustment, there is a drum brake shoe caliper adjusting tool. Set the drum side to the current inner diameter of the drum. Then used the brake shoe side to adjust the shoes to match. Much easier, to me, rather than using "the spoon and small screwdriver"/click method of adjustment. That way, each side will be the same in relation to each drum's inner diameter.

CBODY67

I have one! Good Old Ammco Model 8650 "Safe Set" calipers. This and similar models can be found on the Net. Barring use of this, one can cobble up such a tool out of a pair of wooden rulers, a wing nut, couple washers and suitable machine screw. One can still fine tune the job with a spoon if needs be, though I do well to slip the drum over, and then use my thumb on the adjuster usually to get it right. As soon as the weather cools down about 10 degrees Fahrenheit, I'm going to replace shoes in all 4 wheels..... Got 4 yrs use from these.

 

[Corbin]

Closing this thread: the shoes seemed to be the core problem. The rear shoes were Napa purchased 1st picked up the car. The fronts were Dynamic Friction and purchased recently. Both sets were made in China.

One front wheel would randomly hang up, and once the brake grabbed, it would remain 'stuck'. It was adjusted to the absolute minimum and and it would still hang up. Swapped that side with the good removed shoes (which had almost no wear). Adjusted them to specs and the brakes were better.

Then the rear brakes started to squeal on application. Removed the shoes on the offending side and replaced with the old ones, adjusted again. And we are at 90%.

I'm still keen on swapping to disc, but that can wait until winter when I rebuild the front end. In the meantime I can keep putting miles on it.

 

[USSMOPAR]

No the thread is not closed...the proper adjustment for drum brakes is not 10 clicks back after the shoes drag. The proper adjustment after making sure the wheel bearings are properly set is the shoes are lightly dragging.