1969 Fairlane brake upgrade

[69Cobra428]

Looking to improve the brakes on my 1969 Fairlane. While they work, they aren’t as crisp as I would like. Especially not that my kids want to drive my car

[gregaba]

If you have power steering I change all of mine to Hydra Boost systems. Best power brake up grade I have ever done.
If you don't have power then a Wilwood or other disc upgrade kit works great.
Try not to order the cheap Chinese parts.
Greg

[69Cobra428]

Not sure why the rest of my post didn’t show.

The car does have power steering.

It has a power steering booster with original front disc setup and a rear disc replacement setup. It does work but it’s not as crisp and solid as I would like.

[GerryP]

Elaborate on that "...not as crisp and solid as I would like." statement.  What exactly is it not doing?  Don't use vague terms like "crisp" since that means different things to different people.  Describe how the brakes and the car behave at different application pressures and speeds.  It's possible for crappy brakes to be a problem with the tires, or the suspension.

[69Cobra428]

The brake pedal is somewhat soft. It helps if I pump the pedal but it still takes firm pressure. The brakes were bled by a reputable shop after I installed the rear discs a year ago and there are no leaks.

Tires are brand new and all brake pads, rotors, etc have less than 1,000 miles on them.

When I say crisp, I just want a firm pedal and confidence that my kids can drive the car safely. I don’t want or expect them to have to pump the brakes or risk rear ending someone.

[fastf67]

I'm interested in hearing the brake pad material. Not trying to run ceramics are you, there great for less heat in the pad and keeping wheels clean but do not offer the most friction or stopping power.https://www.autoanything.com/resources/what-are-the-best-brake-pads-ceramic-or-semi-metallic/

[GerryP]

If you have to pump the brakes to get a firm pedal, you might want to recalibrate what a "reputable" shop is.   They might be honorable and pretty swell folk, but not have the right technical skills for thorough brake work.

Is this a problem where the pedal goes too far to the floor but is firm when you meet resistance, or is it that the pedal is soft as you meet resistance?

If, after a brake bleed, is the pedal firm and are the brakes functioning properly?  If so, then how long driving does it take for the pedal to go soft again and brake performance to decline?  If they start firm and gradually get mushy, then the problem is most likely in the rotors pulsing the caliper pistons and inducing air.  It could also be that you don't have the residual pressure valves to keep a tiny pressure on the pistons to keep them from retracting too far into the caliper.

If the pedal just never gets firm in the bleeding process, then you should probably do a bench bleed on the master cylinder.  Getting a good bleed on the master can sometimes be difficult, so you have to take nothing for granted.  Get a small bleeding kit for the master.  You can do either a flush bleed or a block bleed.  You might have to tilt the master around to dislodge trapped air. If that doesn't firm up the pedal, I would also recommend a brake pressure gauge.  There are a variety of them out there, but I believe Speedway has them for around $40.

[69Cobra428]

I'm interested in hearing the brake pad material. Not trying to run ceramics are you, there great for less heat in the pad and keeping wheels clean but do not offer the most friction or stopping power.https://www.autoanything.com/resources/what-are-the-best-brake-pads-ceramic-or-semi-metallic/

Should be semi metallic on both front and rear.

[69Cobra428]

If you have to pump the brakes to get a firm pedal, you might want to recalibrate what a "reputable" shop is.   They might be honorable and pretty swell folk, but not have the right technical skills for thorough brake work.

Is this a problem where the pedal goes too far to the floor but is firm when you meet resistance, or is it that the pedal is soft as you meet resistance?

If, after a brake bleed, is the pedal firm and are the brakes functioning properly?  If so, then how long driving does it take for the pedal to go soft again and brake performance to decline?  If they start firm and gradually get mushy, then the problem is most likely in the rotors pulsing the caliper pistons and inducing air.  It could also be that you don't have the residual pressure valves to keep a tiny pressure on the pistons to keep them from retracting too far into the caliper.

If the pedal just never gets firm in the bleeding process, then you should probably do a bench bleed on the master cylinder.  Getting a good bleed on the master can sometimes be difficult, so you have to take nothing for granted.  Get a small bleeding kit for the master.  You can do either a flush bleed or a block bleed.  You might have to tilt the master around to dislodge trapped air. If that doesn't firm up the pedal, I would also recommend a brake pressure gauge.  There are a variety of them out there, but I believe Speedway has them for around $40.

It’s soft until it hits resistance and then is firm. It does help to pump it a little.

[69Cobra428]

If, after a brake bleed, is the pedal firm and are the brakes functioning properly?  If so, then how long driving does it take for the pedal to go soft again and brake performance to decline?  If they start firm and gradually get mushy, then the problem is most likely in the rotors pulsing the caliper pistons and inducing air.  It could also be that you don't have the residual pressure valves to keep a tiny pressure on the pistons to keep them from retracting too far into the caliper.

If the pedal just never gets firm in the bleeding process, then you should probably do a bench bleed on the master cylinder.  Getting a good bleed on the master can sometimes be difficult, so you have to take nothing for granted.  Get a small bleeding kit for the master.  You can do either a flush bleed or a block bleed.  You might have to tilt the master around to dislodge trapped air. If that doesn't firm up the pedal, I would also recommend a brake pressure gauge.  There are a variety of them out there, but I believe Speedway has them for around $40.

I know the car does not have any residual valves on it.

I will look into bleeding the master again. I also have a mechanic friend I can have look at bleeding it for me.

[GerryP]

If there is air in the brake system, the pedal will be spongy (soft) as soon as it hits resistance.  This is the air in the system being compressed.  You don't seem to have air in the system since you say the pedal is "soft" until it meets resistance and once it does the pedal is firm. 

I don't know what it is you're describing.  Is your problem the pedal travels too far before you get brake action and that pumping it once or twice raises the height of where the brake action occurs?

If it's doing that, you don't have enough fluid capacity for your brake system.  This means you need a larger diameter master cylinder or a lower brake pedal ratio.

If it's something else, you're going to have to go all out and elaborate on all the details of the issue.

[69Cobra428]

Most of my original post didn’t show up for some reason.

When applying the brakes, the pedal goes almost to the floor before it gets firm. Pumping it helps move that position up a little but it still takes effort for the car to stop.

Someone on another forum mentioned I need a disc/disc master cylinder to help with the issue. Does that seem reasonable along with a larger diameter master?

[GerryP]

If you're using a drum (or a disc/drum) master cylinder on a disc/disc system you don't enough fluid volume.  Drum brake wheel cylinders take a tiny amount of fluid compared to a disc caliper.  Use a disc/disc master and see if that fixes your issue.  If it doesn't then you need a larger diameter master.  It really depends upon what calipers you are using and what the piston area is to know precisely how much fluid volume you need for a functioning system.

[69Cobra428]

I have original disc brakes on the front and swapped the rear drum to disc brakes.

Do you know a good option for a disc/disc master swap? Is there an OE style that will fit? Or should I look into aftermarket like Wilwood?

[Falcon67]

As I kinda indicated on FB, swapping in rear disk was kind of a waste of $, but they are there so there.  Pumping the pedal says air, brakes bled or not.  Also, beware the high firm pedal - that could signal too large a bore master cylinder and low line pressure.  If the swapped rears are multi-piston calipers, you might get away with a stock disk/drum because the volume to operate something like a 4 piston caliper is lower than the older big single piston units.  If you change masters, for a manual system you will need to keep the bore under 1".  The pedal travel will be more with a smaller bore master, but the line pressure will be higher.  My dragster for example uses 4 piston calipers on the rear with a single 7/8 bore master.  A good bit of pedal travel but stops well from 125+ MPH. 

Pads - on the street/strip cars I use organic pads on the fronts (single piston calipers), not semi-metallic.  They bite better and don't glaze the rotor when stopping repeatedly from big MPH.  Rears are 10x2" drum.  I never saw a need to put disks on the back.