Brake experiment

[rkrochen]

My 66 Sport Fury is equipped with 4 wheel power drum brakes and has the dreaded touchy pedal. I have no intentions of changing to disc brakes due to the fact that I don’t drive the car in traffic and I live in a rural community that is located in extremely flat land. The car is properly set up and will lock all 4 wheels up with ease so I am happy with their performance. For me it is no problem driving the car but my wife won’t touch it. Due to this I was trying to think of ways to reduce the touchiness of the brakes and am thinking about trying something.
The design of the drum brake incorporates two shoes of different length and friction material. The shoe with the short friction material is the leading shoe and goes to the front. The shoe utilizes friction material that will engage with the drum and rotate towards the rear shoe forcing the rear shoe into the drum. The rear shoe uses material that will provide the majority of the braking power.
My thought is to switch the shoes thinking that if the longer shoe is on the front it won’t apply the rear shoe as efficiently therefore taking more effort to apply.
I was wondering if anyone has tried this or heard of this before.
Also any concerns regarding this please let me know. Lastly do I do the fronts or backs or all four. Presently thinking about doing either the front or back first and then possibly all four if I have favourable results.
I need to do a master cylinder upgrade and a bearing repack this spring so I can do it all at the same time.

 

[mrfury68]

Do not do this! Your car will not stop well going forward but better in reverse. The shoe with the smaller area of lining material ALWAYS goes to the front. That is the way the systems were designed. These cars of ours are 4500 lb rolling slabs of USA made steel, you do not want to experiment with swapping brake shoe location. The problem is not the position your brake shoes are in. Are the shoes adjusted correctly? Instead, research why your pedal is so touchy. Correct booster? Pedal rod length correct? Too much vacuum? Get a factory service manual (FSM) if you don't have one. I'm sure others here will respond with some valuable info. Good luck and keep us posted.

 

[57fury440]

Do what mrfury68 has said. Don't fool around with your brakes. Maybe your shoes are bad. I've seen some that were contaminated and were sticking. Are they new?

 

[CBODY67]

Your car is basically operating as designed. Almost all power brake cars from that era were that way. I have a '70 Skylark with power drum brakes on it. Every time I would move it in the driveway, I would almost be "eating steering wheel" at that first brake application. But with a more careful second and later application, no issue because I was getting used to it again. Driving it all of the time, I got reacquainted with the power drum brakes and there were NO further issues, just had to get used to the equipment again.

ALL vehicles are NOT the same, especially when you put 1960-1970s era vehicles in the mix. Have to learn the equipment for best results, whether it is brakes, steering, or even operating the transmission controls (i.e., Chrysler pushbuttons).

Before we got the '66 Newport (at 7100 miles and one year old), which was the first car we had with power brakes, we KNEW the brakes would act differently (use your toe rather than your foot), so WE had to learn these things too. But as the mark of a luxury car (or luxury car option) was "very little or decreased operating effort", we learned to enjoy those things. Not to forget the power steering of that era, too!!!

The other thing is to drive the car. Generate brake dust in the drums, THAT will dull the braking response a bit, from our experiences.

Just some thoughts,
CBODY67

 

[FURYGT]

I found that replacing the brake booster resulted in a less touchy pedal. If your wife will drive the car, you may want to think about an upgrade to disc brakes.

 

[rkrochen]

Do not do this! Your car will not stop well going forward but better in reverse. The shoe with the smaller area of lining material ALWAYS goes to the front. That is the way the systems were designed. These cars of ours are 4500 lb rolling slabs of USA made steel, you do not want to experiment with swapping brake shoe location. The problem is not the position your brake shoes are in. Are the shoes adjusted correctly? Instead, research why your pedal is so touchy. Correct booster? Pedal rod length correct? Too much vacuum? Get a factory service manual (FSM) if you don't have one. I'm sure others here will respond with some valuable info. Good luck and keep us posted.

I hadn’t thought about reverse and is exactly why I am posting this. It is some that I need to seriously consider.
As for the adjustment and everything else it is set up perfectly. I personally don’t have an issue driving it.

 

[Big_John]

My 66 Sport Fury is equipped with 4 wheel power drum brakes and has the dreaded touchy pedal. I have no intentions of changing to disc brakes due to the fact that I don’t drive the car in traffic and I live in a rural community that is located in extremely flat land. The car is properly set up and will lock all 4 wheels up with ease so I am happy with their performance. For me it is no problem driving the car but my wife won’t touch it. Due to this I was trying to think of ways to reduce the touchiness of the brakes and am thinking about trying something.
The design of the drum brake incorporates two shoes of different length and friction material. The shoe with the short friction material is the leading shoe and goes to the front. The shoe utilizes friction material that will engage with the drum and rotate towards the rear shoe forcing the rear shoe into the drum. The rear shoe uses material that will provide the majority of the braking power.
My thought is to switch the shoes thinking that if the longer shoe is on the front it won’t apply the rear shoe as efficiently therefore taking more effort to apply.
I was wondering if anyone has tried this or heard of this before.
Also any concerns regarding this please let me know. Lastly do I do the fronts or backs or all four. Presently thinking about doing either the front or back first and then possibly all four if I have favourable results.
I need to do a master cylinder upgrade and a bearing repack this spring so I can do it all at the same time.

I don't think this is a good idea and quite frankly, isn't going to help your problem. The power brakes in cars of the 60's is more sensitive by their nature.

If your brakes are "touchy", what exactly do you mean?

 

[rkrochen]

I found that replacing the brake booster resulted in a less touchy pedal. If your wife will drive the car, you may want to think about an upgrade to disc brakes

 

[rkrochen]

It’s worth considering although I feel it’s about the same touchiness as other cars of this era.

 

[rkrochen]

I agree

I don't think this is a good idea and quite frankly, isn't going to help your problem. The power brakes in cars of the 60's is more sensitive by their nature.

If your brakes are "touchy", what exactly do

I agree on the sensitivity but unless you are from a generation that grew up driving these cars you won’t understand this.
They take light application to apply. If you try and drive it like newer cars or no booster style you will be eating the steering wheel. As I mentioned I drive it just fine it’s just my wife has issues with it.

 

[bronze turbine]

One thing I don't understand, I have driven 3 different 1968 Chryslers. 2 of them have the usual touchy brakes. The third one the brakes work more like a modern car--not touchy, but still stop the car well. I haven't been able to figure out what the difference is.

 

[Triple Pickle]

I would see what bore the master cylinder is. A 1/16” can make a big difference on travel and effort of the pedal. You probably have a 1” bore. Going down or up a 1/16” will change how touchy they are. I’m not sure which way to try but I’m thinking smaller?

 

[Big_John]

I would see what bore the master cylinder is. A 1/16” can make a big difference on travel and effort of the pedal. You probably have a 1” bore. Going down or up a 1/16” will change how touchy they are. I’m not sure which way to try but I’m thinking smaller?

Larger. That will increase the effort to push the pedal, but will decrease amount of distance.

 

[Ross Wooldridge]

John just beat me to it. Smaller will make for greater leverage, and increase the grab-factor. Go BIGGER 1/16th.

Too bad your wife won't drive it... or is it??

Some of us may remember or have seen the ad campaigns about power brakes from the 60s - an egg under your foot and you could still stop the car without breaking the egg.

I agree - you may have shoes that are contaminated, or are not the best choice for the car.

If you do consider going up a size in the master cylinder bore, now is a great time to change out to a dual circuit master cylinder. While not doing the full safety upgrade to discs as you noted above (and for reasonable, well concerned decisions as you said above), changing to a dual circuit master will really up the game to a way more safer system, regardless of the type of brakes used. With a single circuit, if you lose a brake line/fitting/flex hose/wheel cylinder, you lose ALL brakes. And typically, you don't have time to figure out another way to stop. With dual circuit, you still have 1/2 your brakes, and that can save a life.

 

[Triple Pickle]

Larger. That will increase the effort to push the pedal, but will decrease amount of distance.

But smaller would give more travel and control, right? Although it would be even easier to push.

 

[Ross Wooldridge]

Yes - that's the trade off.

What we're suggesting here is essentially splitting hairs, or comparing apples to oranges. If the system is safe and properly adjusted, as the OP is saying, then it really boils down to personal preference. He's trying to get the car into a setup that allows his wife to enjoy driving it in the same way he does - and the inference is that he is potentially more adaptable to the change in braking pedal action, which will allow the car to be set up for his wife.

This is of course, something that he may consider AFTER checking for contaminated shoes, or poor linings... and that may be moot already if he's done that.

I get the idea that the OP is someone who goes to the proper lengths to research and learn, and his questions and answers to our advice gives me confidence that he'll make well informed and intelligent decisions, unlike some of the other posts we've been involved in (eh @Big_John? lol...).

 

[Triple Pickle]

A friend of mine had a ‘67 Catalina when we were teenagers. I was used to the manual brakes of my ‘68 Barracuda. The first time I drove his car and hit the brakes I ate that “energy absorbing” steering wheel!
We called cars like that “touch me not” brakes!

 

[rkrochen]

But smaller would give more travel and control, right? Although it would be even easier to push.

Well this is giving me some good ideas. I like the option of changing bore size especially now that I will be doing a dual cylinder install. Just trying to think about bore size and it might be smaller is the trick. My thoughts are that the same force is applied to the piston regardless of size therefore if you have a larger piston it creates more psi and a smaller piston should be less. Need to think about this to make sure. Anyways I will try this option and see what happens.

 

[Ross Wooldridge]

Respectfully, I think you've got the leverage/hydraulics backwards. Unless I have it backwards... If you want to reduce the touchieness, go LARGER bore.

 

[rkrochen]

John just beat me to it. Smaller will make for greater leverage, and increase the grab-factor. Go BIGGER 1/16th.

Too bad your wife won't drive it... or is it??

Some of us may remember or have seen the ad campaigns about power brakes from the 60s - an egg under your foot and you could still stop the car without breaking the egg.

I agree - you may have shoes that are contaminated, or are not the best choice for the car.

If you do consider going up a size in the master cylinder bore, now is a great time to change out to a dual circuit master cylinder. While not doing the full safety upgrade to discs as you noted above (and for reasonable, well concerned decisions as you said above), changing to a dual circuit master will really up the game to a way more safer system, regardless of the type of brakes used. With a single circuit, if you lose a brake line/fitting/flex hose/wheel cylinder, you lose ALL brakes. And typically, you don't have time to figure out another way to stop. With dual circuit, you still have 1/2 your brakes, and that can save a life.

Not that anxious for the wife to drive it but sometimes when you are at a friends pLace you may tend to overindulge. Pretty handy for her to feel comfortable driving the.