Brake pedal feel: How do you like it?

[1 Wild R/T]

Thanks my friend, but I'm now leaning towards saying the Porterfield stuff isn't much better than the old-day
over the counter semi-metallics - which is to say, at this point, I'd rate the factory semi-mets above them
IF you can get ahold of the original asbestos-based ones.

After some time in service, I still don't have that "grab" a good set of shoes gives you - even on the first apply,
so I'm probably going to contact our resident NOS hoarder and fetch the factory stuff from him.

Back in the day we would "Arc" the shoes... Basically mount the shoes on a machine that would sweep the shoe across an abrasive drum that would cut the lining off to match the radius of the drum....

If you take a new shoe and press it against a brake drum whether standard sized or turned you'll find the shoe usually only touches in the center 30% or so... Arcing the shoes increases the contact area... Natural wear will do the same thing but it would take years to get the shoe hitting properly...

found this..

 

[1 Wild R/T]

Following up on the above post, Brake shoe dust is a heath risk... These old grinders were used a lot in the 60's & early 70's... By the late 70's they mostly were shoved into a corner & avoided... But we would break it out for our personal cars....

Later versions of the shoe grinders have vacuum systems..

 

[moparedtn]

Yes, gentlemen - I'm old enough to remember using those as well.
Fact remains, there's nothing I know of that has as effectively taken the place of asbestos in shoes.
I thought maybe I'd found such - but nothing short of the "race only" shoes Porterfield sells might
actually do so (and from what they explain to me, nobody wants to run those on a street car - ever).

 

[khryslerkid]

I did switch to DOT 5 to prevent future paint damage from spills or leaks. THEN I saw "Synthetic" listed on even DOT 3 stuff.
Here is a fair question.....is it the DOT number or the synthetic that prevents paint damage? Of the DOT number is irrelevant, I'll switch back to DOT 3.

DOT 3, 4, 5.1 is glycol based. The glycol is what eats paint and can attract moisture.

There's a difference between synthetic and silicone. The DOT 5 is silicone base which helps prevent water absorption and will withstand higher temperatures.

 

[1STMP]

I did switch to DOT 5 to prevent future paint damage from spills or leaks. THEN I saw "Synthetic" listed on even DOT 3 stuff.
Here is a fair question.....is it the DOT number or the synthetic that prevents paint damage? Of the DOT number is irrelevant, I'll switch back to DOT 3.

It's the synthetic designation that
prevents paint damage. Wether it be
DOT 3, 4, or 5.

 

[Kern Dog]

That would be nice. I could then switch to the more common and less expensive DOT 3.

 

[1STMP]

I'm having some trouble understanding that. I'm not dismissing it, I just have a hard time grasping the concept.
How is it that the brakes work with a disc/drum system with the same hard line diameter front and rear? What difference would a 4 wheel disc system make?
I have the stock sized 3/16" hard line in every old car. 3 of them are manual master cylinder...front disc, rear drum. The red car is the only one with rear discs and a power booster. I've recorded over 1200 psi at the front and the rear.

View attachment 1509166

The pressures recorded on the 4 disc
I have are at around 1800 psi during
a 'panic' stop test. Driver seated
normally, hands off the steering wheel,
hard pressure to the pedal for 3
seconds. (engine running).
Be honest here, It's your baseline.
The smaller diameter in the lines
increases the pressure applied at
the calipers. Another aspect to
consider is the flex that may be
occurring at the caliper. (which can
prevent wheel lock-up). Via
swapping factory components
from drum to disc that are of a
minimal design. Of course tires
and pad materials play a role also.
I know you've been fighting this
for a while now. Hope this helps
some.

 

[moparedtn]

The pressures recorded on the 4 disc
I have are at around 1800 psi during
a 'panic' stop test. Driver seated
normally, hands off the steering wheel,
hard pressure to the pedal for 3
seconds. (engine running).
Be honest here, It's your baseline.
The smaller diameter in the lines
increases the pressure applied at
the calipers. Another aspect to
consider is the flex that may be
occurring at the caliper. (which can
prevent wheel lock-up). Via
swapping factory components
from drum to disc that are of a
minimal design. Of course tires
and pad materials play a role also.
I know you've been fighting this
for a while now. Hope this helps
some.

I've wondered how much the lines actually moving/flexing in the car along their runs also might play a role?

 

[66 Sat]

I have PST (Leed Brakes) discs on front (maybe 10"?, they fit 14" wheels) with factory rear drums (11 x 2.5" I think).
I have probably a half inch of dead travel and then the brakes work progressively, nice feel and get stronger the harder you press. They will lock up too, although I think the rears lock up first.
I adjusted the pushrod in the master cylinder which helped reduce the travel slightly but I've never worked out how to get rid of it altogether.
It's like it has modern car brakes but they work in a different pedal range to a modern car.
I would like to get rid of the dead travel but the brakes are very strong and you soon get used to it. I'll investigate it further sometime.

 

[1STMP]

I've wondered how much the lines actually moving/flexing in the car along their runs also might play a role?

Not so much moving or flexing.
But line pressure. Most of the
flexing occurs at the caliper,
and associated parts/hardware.
The appropriate pressure at the
caliper is key. Utilizing lines
engineered for a 4 drum system
move to much volume of fluid
for a 4 disc system.

 

[moparedtn]

I have PST (Leed Brakes) discs on front (maybe 10"?, they fit 14" wheels) with factory rear drums (11 x 2.5" I think).
I have probably a half inch of dead travel and then the brakes work progressively, nice feel and get stronger the harder you press. They will lock up too, although I think the rears lock up first.
I adjusted the pushrod in the master cylinder which helped reduce the travel slightly but I've never worked out how to get rid of it altogether.
It's like it has modern car brakes but they work in a different pedal range to a modern car.
I would like to get rid of the dead travel but the brakes are very strong and you soon get used to it. I'll investigate it further sometime.

I just wish they weren't so pricy....and that I knew more about that company to begin with.

 

[khryslerkid]

It's the synthetic designation that
prevents paint damage. Wether it be
DOT 3, 4, or 5.

DOT 3, 4, 5.1 are glycol/ester based and whether synthetic or not could still damage paint. The glycol/ester is what eats paint.

DOT 5 is silicone based without any glycol. It cannot be mixed with DOT 3, 4 or 5.1

That would be nice. I could then switch to the more common and less expensive DOT 3.

What I've researched in the past is once you use DOT 5 there is no going back. Apparently the silicone adheres to the rubber in such a way that no amount of flushing will remove it enough to use glycol based fluid. I've been using DOT 5 from the beginning after installing a complete new system. So I guess we're screwed

 

[twecomm]

Recently flushed my MC and brake lines. Drums all around, Dot 3 fluid was last replaced probably 10 years ago when I converted from single pot to dual pot MC and added brake booster and replaced all wheel cylinders, lines and hoses. Fluid was looking funky after all these years, so time to flush and replace with fresh Dot 3.
Have had good luck with Matrix Ceramic brake shoes from from Muscle Car Brakes, but they seem to be out of stock currently..

​

 

[moparedtn]

Recently flushed my MC and brake lines. Drums all around, Dot 3 fluid was last replaced probably 10 years ago when I converted from single pot to dual pot MC and added brake booster and replaced all wheel cylinders, lines and hoses. Fluid was looking funky after all these years, so time to flush and replace with fresh Dot 3.
Have had good luck with Matrix Ceramic brake shoes from from Muscle Car Brakes, but they seem to be out of stock currently..

​

They were going to be my other choice as well - but sadly, they were also out of stock then as well.

 

[EmitRDetsaw]

DOT 3 and 4 are Hygroscopic, DOT 5 is not. DOT 5 fluid, not being hygroscopic, means that any moisture in the system will go to the lowest parts of the braking system, possibly corroding metal parts to the point the braking system will be negatively affected. Which is more detrimental to a braking system? The debate goes on.

 

[1 Wild R/T]

DOT 3 and 4 are Hygroscopic, DOT 5 is not. DOT 5 fluid, not being hygroscopic, means that any moisture in the system will go to the lowest parts of the braking system, possibly corroding metal parts to the point the braking system will be negatively affected. Which is more detrimental to a braking system? The debate goes on.

Exactly what I saw when working on fleet vehicles that the company insisted on using DOT5... Fluid in the M/C looked perfect... pull a W/C or caliper apart & stuff is severely rusted...

DOT3 the fluid gets murky as it absorbs moisture... You see the deteriorating fluid condition & replace it before it causes serious problems...

 

[Cranky]

I've had several manual drum brake cars that were pretty good and the ones that weren't too good were easy to fix. I've also had manual disc/drum systems and those also were good. Now the ones I hated the most were factory power brakes because they were just way too touchy. The worst brake set up I've ever had were Wilwood four-wheel manual discs on a high 9 second car. My 10.60 car had four wheel 11" drum manual setup and those were sweet!

 

[Kern Dog]

Well… how hard is it to purge the DOT 5 stuff and go back to DOT 3?
I only bought the DOT 5 to preserve paint.

 

[Cranky]

Well… how hard is it to purge the DOT 5 stuff and go back to DOT 3?
I only bought the DOT 5 to preserve paint.

Flush it with DOT 3?

 

[Kern Dog]

Well, that sounds easy but I thought that I read that it is hard to get ALL of the DOT 5 stuff out. I'll have to do more research.
I'm not usually a pessimist but many times, what seems easy ends up being far more complicated than I expected.