1967 Coupe Brake ?

GotMojo · Dec 15, 2024

I have Kelsey Hayes power disc brakes in the front and stock drums in the rear. When I apply more than light pressure (like for a normal stop), the brakes lock up and I start sliding. There have been times when I had to really hit the brakes—tires screeching—and I still couldn't stop. My classic car enthusiast friends say this is normal for a 58-year-old braking system, but that doesn't seem right to me. This can't be normal, can it?

LILCBRA · Dec 15, 2024

I think the pedal feel could be a case of the person who did the Kelsey Hayes swap didn't install an appropriate master cylinder and/or add a proportioning valve. I'd suggest researching that aspect of everything as I'm not horribly familiar with the swap.

As for screeching tires and not being able to stop - your friend is right about that. This is the reason most, if not all, modern cars have anti lock brakes. A locked up tire acts like a sled on snow, whereas the goal is to get the car to stop. If you've had driver's ed back in the day maybe you'll remember being taught that if you're in a slide to pump the brakes to avoid the sliding situation. As cars have progressed it seems that some of our driving knowledge has regressed since modern cars do it for us.

So, I think the best thing you can do in this situation is to get the braking bias as close as you can. Meaning, if you lock up any brakes you lock them all. So I think, if it were me, I'd be damned sure that the master cylinder was appropriately sized for the system AND I'd add an adjustable proportioning valve. Then, once that's accomplished, I'd take it to a "closed course" and make some test stops to adjust the proportioning valve to equal out the brakes.

GotMojo · Dec 15, 2024

This is what I purchased from Opentracker, it's a complete system that comes with the master cylinder, proportioning valve etc. It was professionally installed.

FORD KELSEY-HAYES TYPE 4 PISTON CALIPER POWER DISC BRAKE KIT V8 – MANUAL OR POWER STEERING WITH AUTO TRANSMISSION (1967 1969)

GotMojo · Dec 15, 2024

GotMojo said:
This is what I purchased from Opentracker, it's a complete system that comes with the master cylinder, proportioning valve etc. It was professionally installed.

FORD KELSEY-HAYES TYPE 4 PISTON CALIPER POWER DISC BRAKE KIT V8 – MANUAL OR POWER STEERING WITH AUTO TRANSMISSION (1967 1969)

LILCBRA · Dec 15, 2024

GotMojo said:
This is what I purchased from Opentracker, it's a complete system that comes with the master cylinder, proportioning valve etc. It was professionally installed.

FORD KELSEY-HAYES TYPE 4 PISTON CALIPER POWER DISC BRAKE KIT V8 – MANUAL OR POWER STEERING WITH AUTO TRANSMISSION (1967 1969)

So it's this system, correct?

Ford Kelsey-Hayes Type 4 Piston Caliper Manual Disc Brake Kit V8 – Manual or Power Steering – Manual or Auto Transmission ( 1967-1969) – Opentracker Racing

opentrackerracing.com

It says it comes with an adjustable proportioning valve, so that's probably all you need to deal with. Like I said earlier, I'd find a "closed course" and do some testing to get the brake bias about as even as I could. A nice, empty parking lot would work where you can gain some speed and have enough room to slam on the brakes, then adjust to your liking.

I'll add that I believe professional installation doesn't necessarily mean they knew what they were doing or they did everything correctly.

GotMojo · Dec 15, 2024

LILCBRA said:
So it's this system, correct?

Ford Kelsey-Hayes Type 4 Piston Caliper Manual Disc Brake Kit V8 – Manual or Power Steering – Manual or Auto Transmission ( 1967-1969) – Opentracker Racing

opentrackerracing.com

It says it comes with an adjustable proportioning valve, so that's probably all you need to deal with. Like I said earlier, I'd find a "closed course" and do some testing to get the brake bias about as even as I could. A nice, empty parking lot would work where you can gain some speed and have enough room to slam on the brakes, then adjust to your liking.

I'll add that I believe professional installation doesn't necessarily mean they knew what they were doing or they did everything correctly.

Thanks for the feedback, and I agree with you regarding the professional installation.

Mcmahst · Dec 15, 2024

Are you saying you get a 4 wheel lockup on typical brake pedal pressure?

LILCBRA · Dec 15, 2024

Good question - I went back and reread.... for some reason, I was understanding it was either the fronts OR rears locking up. If it's all 4 then they most likely did it correctly. The proportioning valve won't help much as far as pedal feel goes.

GotMojo · Dec 15, 2024

LILCBRA said:
Good question - I went back and reread.... for some reason, I was understanding it was either the fronts OR rears locking up. If it's all 4 then they most likely did it correctly. The proportioning valve won't help much as far as pedal feel goes.

I'm not sure if it's just the rears or all 4. Times when I went into a skid there was just 2 marks on the street. The car swerves when it goes into a skid, so I would think if it were all 4, there would be 2 marks on each side as it swerved. I've never adjusted a proportioning valve, I'll have to do some digging on that.

LILCBRA · Dec 16, 2024

I'd venture a guess and say that if it swerved it was likely the fronts that locked up. You definitely don't want that - that's where you lose control. If anything, you'll want the rears to lock up first.

LILCBRA · Dec 16, 2024

Here's the procedure written better than I ever could.

How Does a Proportioning Valve Work? And How Do You Adjust It?

When setting up a street car for performance driving or converting a classic to disc brakes, it is essential to include an adjustable proportioning valve in your brake system. This valve is typically plumbed into the rear brake line or built into the combination valve below the master cylinder...

shop.wilwood.com

GotMojo · Dec 19, 2024

Mcmahst said:
Are you saying you get a 4 wheel lockup on typical brake pedal pressure?

No, only the rear brakes lock up.

Noobz347 · Dec 19, 2024

GotMojo said:
No, only the rear brakes lock up.

If that's the case then you have too much rear brake bias.

This helps to get a good starting point:

View: https://www.youtube.com/watch?v=GVetknwAuzM

limp · Jan 3, 2025

PUll off the rear drums and check to see if your wheel cylinders are leaking... Most the time the cause of the rears locking up.. EX wife had a 73 mustang when I met her and one of the rears would lock up occasionally making the car slide a long ways unable to stop.... A really bad feeling...

1967 Coupe Brake ?

GotMojo

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LILCBRA

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GotMojo

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FORD KELSEY-HAYES TYPE 4 PISTON CALIPER POWER DISC BRAKE KIT V8 – MANUAL OR POWER STEERING WITH AUTO TRANSMISSION (1967 1969)

GotMojo

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FORD KELSEY-HAYES TYPE 4 PISTON CALIPER POWER DISC BRAKE KIT V8 – MANUAL OR POWER STEERING WITH AUTO TRANSMISSION (1967 1969)

LILCBRA

I wish I didn't have all of these balls in the air

FORD KELSEY-HAYES TYPE 4 PISTON CALIPER POWER DISC BRAKE KIT V8 – MANUAL OR POWER STEERING WITH AUTO TRANSMISSION (1967 1969)

Ford Kelsey-Hayes Type 4 Piston Caliper Manual Disc Brake Kit V8 – Manual or Power Steering – Manual or Auto Transmission ( 1967-1969) – Opentracker Racing

GotMojo

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Ford Kelsey-Hayes Type 4 Piston Caliper Manual Disc Brake Kit V8 – Manual or Power Steering – Manual or Auto Transmission ( 1967-1969) – Opentracker Racing

Mcmahst

LILCBRA

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GotMojo

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LILCBRA

I wish I didn't have all of these balls in the air

LILCBRA

I wish I didn't have all of these balls in the air

How Does a Proportioning Valve Work? And How Do You Adjust It?

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limp

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1967 Coupe Brake ?

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FORD KELSEY-HAYES TYPE 4 PISTON CALIPER POWER DISC BRAKE KIT V8 – MANUAL OR POWER STEERING WITH AUTO TRANSMISSION (1967 1969)​

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FORD KELSEY-HAYES TYPE 4 PISTON CALIPER POWER DISC BRAKE KIT V8 – MANUAL OR POWER STEERING WITH AUTO TRANSMISSION (1967 1969)​

I wish I didn't have all of these balls in the air

FORD KELSEY-HAYES TYPE 4 PISTON CALIPER POWER DISC BRAKE KIT V8 – MANUAL OR POWER STEERING WITH AUTO TRANSMISSION (1967 1969)​

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I wish I didn't have all of these balls in the air

New Member

I wish I didn't have all of these balls in the air

I wish I didn't have all of these balls in the air

New Member

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wrap a little cheese around it and its a done

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FORD KELSEY-HAYES TYPE 4 PISTON CALIPER POWER DISC BRAKE KIT V8 – MANUAL OR POWER STEERING WITH AUTO TRANSMISSION (1967 1969)

FORD KELSEY-HAYES TYPE 4 PISTON CALIPER POWER DISC BRAKE KIT V8 – MANUAL OR POWER STEERING WITH AUTO TRANSMISSION (1967 1969)

FORD KELSEY-HAYES TYPE 4 PISTON CALIPER POWER DISC BRAKE KIT V8 – MANUAL OR POWER STEERING WITH AUTO TRANSMISSION (1967 1969)