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Brake fade, potential problems

  • Thread starter Thread starter monk302
  • Start date Start date May 22, 2004

monk302

Founding Member
Apr 18, 2001
742
2
16
New Jersey
May 22, 2004
#1
  • May 22, 2004
  • #1
Just put in the Granada swap with 74 Maverick MC non power or booster. Here is my question. My brakes are very spongy. In order to get some pressure you have to pump the brake pedal several times. At that point the pedal will become a bit more stiff. However, if I don't pump the brakes for a minute, that pressure that just built up will fade and the pedal will hit the floor. Also, now when I bleed the brakes there is no air in the tubing coming from the speed bleeder. I used a suction unit to the bleeder and was pulling the fluid out with the pump from the driver front wheel and when it comes out under pressure somewhere bubbles are getting into the line. I am thinking there is a small leak but I can't figure it out. What do you guys think?
 

monk302

Founding Member
Apr 18, 2001
742
2
16
New Jersey
May 22, 2004
#2
  • May 22, 2004
  • #2
Setup consists of the following:

74 Maverick MC non power/booster
Wilwood Proportioning valve
new line to the rear
New line to front driver
Slotted Granada discs
 

mustang70

Founding Member
Nov 15, 2001
2,445
2
48
San Diego
May 22, 2004
#3
  • May 22, 2004
  • #3
You might want to check around the MC and the firewall to see if there's any leakage. Also, I might be reading this wrong, but you did bleed all four wheels right?
 

68keyblr

20+ Year Stangneter
Mar 17, 2003
946
20
49
Arizona
May 23, 2004
#4
  • May 23, 2004
  • #4
monk302 said:
Just put in the Granada swap with 74 Maverick MC non power or booster. Here is my question. My brakes are very spongy. In order to get some pressure you have to pump the brake pedal several times. At that point the pedal will become a bit more stiff. However, if I don't pump the brakes for a minute, that pressure that just built up will fade and the pedal will hit the floor. Also, now when I bleed the brakes there is no air in the tubing coming from the speed bleeder. I used a suction unit to the bleeder and was pulling the fluid out with the pump from the driver front wheel and when it comes out under pressure somewhere bubbles are getting into the line. I am thinking there is a small leak but I can't figure it out. What do you guys think?
Click to expand...

I had the same thing after swapping out my drums for discs from a '79 Granada and a power booster setup. I finally took it into a brake shop and was informed that I needed to "Bench Bleed" the new master cylinder before installing it or would still have air in the lines even after bleeding at the calipers for what seemed like hours! Worked great after the break shop did a vacuum bleed...

Also, it sounds like you could have a leak somewhere - be sure to check all connections for leakage.

Good Luck!
 

monk302

Founding Member
Apr 18, 2001
742
2
16
New Jersey
May 23, 2004
#5
  • May 23, 2004
  • #5
68keyblr said:
I had the same thing after swapping out my drums for discs from a '79 Granada and a power booster setup. I finally took it into a brake shop and was informed that I needed to "Bench Bleed" the new master cylinder before installing it or would still have air in the lines even after bleeding at the calipers for what seemed like hours! Worked great after the break shop did a vacuum bleed...

Also, it sounds like you could have a leak somewhere - be sure to check all connections for leakage.

Good Luck!
Click to expand...


I have bled all four wheels. How long does that vacuum bleed take. I think I may get that done soon. I want to get this damn car on the road, the weather is way to nice for it in the garage.
 

Max Power

Active Member
Jul 31, 2003
1,774
1
36
St Paul
May 23, 2004
#6
  • May 23, 2004
  • #6
Sounds like a master. If your pedal is hitting the floor, and there are no external leaks, your master is probably bypassing. Is it new? You haven't answered any questions about it.
 

68keyblr

20+ Year Stangneter
Mar 17, 2003
946
20
49
Arizona
May 23, 2004
#7
  • May 23, 2004
  • #7
Vacuum Bleed

The local brake shop here did the vacuum bleed in less than 30 minutes. Only cost me like $60...

Good Luck!
 

monk302

Founding Member
Apr 18, 2001
742
2
16
New Jersey
May 23, 2004
#8
  • May 23, 2004
  • #8
Max Power said:
Sounds like a master. If your pedal is hitting the floor, and there are no external leaks, your master is probably bypassing. Is it new? You haven't answered any questions about it.
Click to expand...

The master cylinder is brand new. The brakes are working however the pedal still feels really spongy and you have to push it down farther than in the past to have it engage. I am not hitting the floor as of this afternoon with the pedal, but still it feels a bit spongy. I am going to take a look at it now and see if I can figure out anything new.
 

68GEETEE

5 Year Member
Nov 21, 2003
481
5
38
Texas, USA
May 23, 2004
#9
  • May 23, 2004
  • #9
make sure the calipers were installed with the bleeders at the top, 12 o'clock position. Mine werent and as a result I could never bleed all the air out, till I realized the calipers were on the wrong wheels!
 

Max Power

Active Member
Jul 31, 2003
1,774
1
36
St Paul
May 23, 2004
#10
  • May 23, 2004
  • #10
Also make sure your rears are adjusted properly.
 

monk302

Founding Member
Apr 18, 2001
742
2
16
New Jersey
May 24, 2004
#11
  • May 24, 2004
  • #11
Backed the car out onto the driveway yesterday afternoon and this is what I found. The car will stop but the brakes in order to work need to be pumped several times. Though I stopped it at a 5mph stop, I would not trust it at a 25mph stop at the current setup.

68GeeTee, I will take a look at my bleeders. Right now they are at the top but pointing out at an angle, not straight up. Isn't there only one way you can put on these Granada calipers?

Max Power, my rear brakes were fine when I took off the original drums from the front. Would they have to be readjusted to accomodate the Granada disc's up front?
 

68GEETEE

5 Year Member
Nov 21, 2003
481
5
38
Texas, USA
May 24, 2004
#12
  • May 24, 2004
  • #12
monk302 said:
Backed the car out onto the driveway yesterday afternoon and this is what I found. The car will stop but the brakes in order to work need to be pumped several times. Though I stopped it at a 5mph stop, I would not trust it at a 25mph stop at the current setup.

68GeeTee, I will take a look at my bleeders. Right now they are at the top but pointing out at an angle, not straight up. Isn't there only one way you can put on these Granada calipers?

Max Power, my rear brakes were fine when I took off the original drums from the front. Would they have to be readjusted to accomodate the Granada disc's up front?
Click to expand...

Sounds like they are on correctly, my bleeders point to the side too, and their location is at the top of the piston chamber 12 noon. It is possible for left and right calipers to be installed on the wrong wheels, but from your description it sounds like you got them on right. Does the car have a small cigar shaped valve next to the distribution block? Mine did, and it was bad. Its called a residual pressure valve, and its designed to keep about 10psi of pressure on the rear brake line to increase pedal firmness. You might see if there is one on your Stang. Master Power brakes sells a 10psi replacement valve for about $30.00
 

monk302

Founding Member
Apr 18, 2001
742
2
16
New Jersey
May 24, 2004
#13
  • May 24, 2004
  • #13
There is no cigar shaped valve next to the distribution block. Actually I got rid of the distribution block and have replaced it with a Wilwood proportioning valve to the rear with the front lines breaking apart to each wheel with a T-block.
 
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