Disk Brake Conversion

MustangMando

Member

Jul 16, 2011

107

0

17

Dec 29, 2014

#1

• Dec 29, 2014

• #1

Hi guys,
I did a disk brake conversion on my 68 mustang, and added a booster. I bought the whole set up from a reputable dealer. Ive been having issues, as the brake pedal feels weird. It kind of feels firm then goes down fast. My question is, i didnt change the proportioning block. It is drum/drum, does this matter?

 

N

n8rfastback

Member

May 28, 2014

135

7

18

Dec 31, 2014

#2

• Dec 31, 2014

• #2

That should not matter, is it leaking fluid anywhere? What kind of shape are your drums and shoes in? I would make sure its bled correctly and there is no issues with your vacuum supply. What motor, how much vacuum at idle?

 

65ShelbyClone

Founding Member

Sep 9, 2000

4,675

38

119

Antelope Valley, SoCal

Dec 31, 2014

#3

• Dec 31, 2014

• #3

MustangMando said:

My question is, i didnt change the proportioning block. It is drum/drum, does this matter?

Click to expand...

n8rfastback said:

That should not matter,

Click to expand...

Yes, it DOES matter. Disc brakes take more line pressure to deliver the same braking power and a drum-drum prop valve won't do that correctly.

In addition, Mustangs with power brakes used a different brake pedal that changes the pedal force and travel substantially.
http://www.mustangsteve.com/fyi_brakepedals/msFAQbrakepedals.html

 

horse sence

15 Year Member

Nov 29, 1999

12,169

7,981

233

Wile Coyote's stunt double

Dec 31, 2014

#4

• Dec 31, 2014

• #4

A lot of these brake boosters in the kits are junk .A friend put two different boosters from the same company on his 66 with the same results you have .He finally went with a guy in orange Calif. that is doing a different type kit .Fixed it completely .His pedal was going to the floor and it was all he could to stop the car with the old boosters .

 

N

n8rfastback

Member

May 28, 2014

135

7

18

Dec 31, 2014

#5

• Dec 31, 2014

• #5

A leak down in pressure shouldnt be caused by the proportioning block, even if its not the perfect one for his setup. I would also suspect the rubber seals in the new master cylinder are bad.

 

jbojo

Member

Dec 30, 2014

15

3

13

WA.

Jan 1, 2015

#6

• Jan 1, 2015

• #6

Using the correct proportioning blocks does matter as was mentioned earlier. I went with 4 wheel disk setup and had to use a Disk / Disk proportioning block for it to work correctly.