1966 Mustang Brake Issues

R

ReturnToHanger

New Member

Feb 13, 2020

8

0

1

Alabama

Mar 25, 2020

#1

• Mar 25, 2020

• #1

I have a 1966 Mustang with a newly installed dual master cylinder with power booster. The car has front disc back drums setup. Also have the proportioning valve with built in residual valve for rear drum brakes.

Everything is plumbed in, but I am suffering from barely any braking power even with the pedal fully depressed. We didn’t have any brakes whatsoever even using the piston adapter, so we tested placing a nut in the cylinder with the piston adapter and got more brakes but still not enough. We have bled all wheels and bench bled the MC.

Please help. Maybe it’s a pedal pushrod adjustment issue?

 

wicked93gs

15 Year Member

Sep 30, 2006

1,198

228

93

Nashville TN

Mar 27, 2020

#2

• Mar 27, 2020

• #2

No one is ever happy with power brake conversions in vintage mustangs, they don't add any stopping power, they just reduce pedal effort. What is the brake line situation? Factory lines? Custom? Any of them running above the level of the master cylinder?(Made that mistake once). When doing anything custom on brake systems, I will always install speed bleeders...they are a big help. What size master cylinder do you have?

 

R

ReturnToHanger

New Member

Feb 13, 2020

8

0

1

Alabama

Mar 27, 2020

#3

• Mar 27, 2020

• #3

This is the kit that I purchased:

FD-251- 1964-66 Ford Mustang Power Brake Booster Conversion Kit Adjustable Block Valve

Shop Pirate Jack for disc brake conversion kits, master cylinders, brake boosters and much more. We carry parts for Fords and GM made vehicles.

piratejack.net

Factory lines from what I can tell. None run above the master cylinder.

 

wicked93gs

15 Year Member

Sep 30, 2006

1,198

228

93

Nashville TN

Mar 27, 2020

#4

• Mar 27, 2020

• #4

How did you bleed the brakes? Did you start at the wheel furthest away and work to the one closest to the MC?

 

R

ReturnToHanger

New Member

Feb 13, 2020

8

0

1

Alabama

Mar 27, 2020

#5

• Mar 27, 2020

• #5

Yes, I purchased an adjustable push rod to hopefully fix it. I’m assuming it’s a push rod length issue.

 

Woody3882

5 Year Member

Jun 19, 2018

84

9

18

Bradenton Fl 34212

Mar 28, 2020

#6

• Mar 28, 2020

• #6

Last year I installed disc brakes on the front of my 65 Mustang. I tried many of the recommended applications along with the regulating valve in the rear drum brake line to balance the stopping. After numerous tries I came to the conclusion that pretty good is the best you are going to get (75%). The stopping power is adequate. Regardless of the position of the regulating valve the brakes still suck, but that is the best they can do without putting discs on the rear. keep your expectations reasonable. Every time I drive the car I flash back to how inadequate the old braking systems really were compared to modern tech.
Best of luck
Woody

 

wicked93gs

15 Year Member

Sep 30, 2006

1,198

228

93

Nashville TN

Mar 29, 2020

#7

• Mar 29, 2020

• #7

If you want an ACTUAL braking upgrade....with numbers to prove it...with rear drums no less

Street/Track Vintage Mustang Brake Upgrade

We install and test before and after effects of Street or Track’s brake upgrade for early Mustangs

www.hotrod.com

 

PaulC69Convt

New Member

Apr 1, 2020

1

0

1

Pisa, Italy

Apr 1, 2020

#8

• Apr 1, 2020

• #8

hi everyone,
with a conversion front disk kit with a power booster and 1"bore dual reservoir mc, shouldn't I be able to lock either the front or rear wheels? I still can't. I bench bled the mc and then the 4 wheels. new rotors & pads. any thoughts?

 

wicked93gs

15 Year Member

Sep 30, 2006

1,198

228

93

Nashville TN

Apr 2, 2020

#9

• Apr 2, 2020

• #9

In all honesty, it sounds like a throw issue(which could well be pushrod). Personally I would use a 1" bore for a manual 4 wheel disc setup...but if I were to install a booster as well, I would be looking for a larger bore MC in order to take advantage of that booster and reduce pedal travel

 

Reactions: msh-r

rbohm

Founding Member

Apr 12, 2002

6,698

550

204

tucson,az

May 4, 2020

#10

• May 4, 2020

• #10

i think the problem is the lack of a proper pedal ratio for the power brake booster. for the 65-66 cars ford used an adapter like this one for installing power brakes;

Power Brake Booster Conversion - #2005-11A - National Parts Depot

Buy part #2005-11A Power Brake Booster Conversion for your classic vehicle from National Parts Depot. Free shipping on orders over $300, fast delivery & everyday low pricing! Order now!

www.npdlink.com

as you can see the pedal ratio is changed to allow for the different pedal throw with the power brake booster. in 67 ford went to a power brake specific pedal with a different pin location as opposed to the manual brake pin location. mustang steve has a number of power brake conversion kits for the early cars, one of which allows you to change the pedal ratio. check out this link;

Power Brake Upgrades

Don't FEAR YOUR MUSTANG. Stop confidently with modern Power Brake Upgrades.

www.mustangsteve.com

more specifically this one is what you would be looking for;

Power Brake Conversion For a 65-66 Mustang - MustangSteve

65-66 Mustang: DO-IT-YOURSELF PARTS KIT (add $159 for Booster) Includes a new redesigned PEDAL PIN and the FIREWALL BRACKET plus the PLANS. This kit also works on 65-66 F-100 Ford Pickup with minor firewall modifications. Uses Fox Mustang 4-cylinder booster or 80 Fairmont booster, or...

www.mustangsteve.com