69 Brakes

[gfi 10]

Hi Folks: I just joined this forum. I need help regarding 69 mustang brakes. No metter what I do I cannot seem to get the power brakes to work.I can barely lock them up and at slow speeds it takes for ever to stop the car. I have checked to power booster and it is fine. I have replaced the master cylinder,new pads,new shoes. Really am stuck. Help would be appreciated.

 

Thanks

 

Gary

[Grabber70Mach 107]

Are your rear drums adjusted properly? Are you positive that you got all the air out of the system? The front calipers can be a pain, the bleeder screw isn't in the optimal position to get all the air out.

[foothilltom 33]

Hey gfi, welcome. There's lots of good info here on brake issues if you can master the art of searching the forums (which I have yet to do). What shape is the car in generally? In other words, are you fixing up a junker, wrenching on a driver, or tinkering with a restored beauty? It would help to know hold old and rusty stuff might be.

 

My experience would suggest you look at the wheel cylinders as they can get corroded over time. Make sure they're actually working with pedal operation. Also, agreed with Grabber...any air in your system kills the necessary hydraulic pressure to apply the brakes correctly.

 

Can you explain your process for bleeding the system? It takes 2 folks (generally) and bleeding in a "longest run first" order.

 

Let us know.

Tom

[gfi 10]

Hi Guys: I really appreciate this. I have bled the system so many times starting with the longest run first.Yes the car is a restored car. Not sure how well because I did not do it. The calipers are new,as are the rotors and the rear brake shoes are new and the drums machined. Seems to have braking similiar to manual brakes but I can't seem to get the power brakes working. The power booster does hold vaccum and the pedal does go down ever so slightly when you start the car. Really puzzling.

[Max Power 74]

Hi Guys: I really appreciate this. I have bled the system so many times starting with the longest run first.Yes the car is a restored car. Not sure how well because I did not do it. The calipers are new,as are the rotors and the rear brake shoes are new and the drums machined. Seems to have braking similiar to manual brakes but I can't seem to get the power brakes working. The power booster does hold vaccum and the pedal does go down ever so slightly when you start the car. Really puzzling.

 

One thing I have learned over the years is that the front calipers are side specific. In other words, if you put the left side on the right, the angle of the bleeder will not be at the top, and the caliper will hold air in there. Longshot, but may be worth a look.

[MikeStang 247]

Do you have enough Vac to operate the power brakes? A large Cam will kill the vac, but we just did a power install on my friends car, along with a big hyd roller cam and it only pulls about 9hg of vac and the brakes seem to do ok, but if you hit them more than about 3 times in succession you can feel them fade a little bit.....You may want to check the plunger adjustment between the master Cyl and the booster...It should just contact the inside of the master Cyl. thats the little rod that goes from t he booster into the rear of the master Cyl.

Mike

[danno 128]

It is possible that they are as good as they are going to get. I have power disc brakes in mine, and I really do not think it is possible to lock up the front wheels with a factory system. At least that is what I found. Most of us are used to the brakes on new cars, and when we compare to the Mustang brakes, we assume something is wrong with them.

 

I am in the same situation, I think that is as good as they get. I have replaced everything, and got them to be as good as they will ever get. Still not as good as my Contour.

 

The only thing that could be a problem yet is a brake hose. If these get soft, they can start expanding when you apply the brakes, similar to air in the line. If they are original, consider replacement.

[gfi 10]

I will certainly try the left side/right side specific. There is absolutely no sponge effect in the peddle. As mentioned the peddle is rock hard and the brakes work,just not well.Really have to push hard.I am having the booster checked this afternoon. Will see what they say.

[Max Power 74]

It is possible that they are as good as they are going to get. I have power disc brakes in mine, and I really do not think it is possible to lock up the front wheels with a factory system. At least that is what I found. Most of us are used to the brakes on new cars, and when we compare to the Mustang brakes, we assume something is wrong with them.

 

 

Point taken on comparing to new systems, but I have been able to lock the brakes up an every 69/70 mustang I have owned, including 6 cylinder manual drum cars.

[NJ_Bob 10]

I will certainly try the left side/right side specific. There is absolutely no sponge effect in the peddle. As mentioned the peddle is rock hard and the brakes work,just not well.Really have to push hard.I am having the booster checked this afternoon. Will see what they say.

 

I have the same problem. I had my booster rebuilt, new calipers etc. The brakes can lock up, but it needs a lot of pedal pressure. Everyone tells me that the booster isn't working right. On some forums, I've heard of people going through multiple boosters... I still am not sure what the answer is.

[Fordrevhead 29]

Surprised it wasnt already mentioned but... If it was ever converted to power brakes or someone switched it from auto to manual (messed around with pedals from a different car), etc... there's a good chance the actuator rod is the wrong length. That would cause no boost as well as not full master pressure.

[danno 128]

Hey Maxpower, maybe I could stop by your place and you could drive mine a little to see what mine feel like? I used to know a Mustang owner who lived by the Univ campus in St Paul. Is that you?

[LoneWolf2U 136]

Hi Folks: I just joined this forum. I need help regarding 69 mustang brakes. No metter what I do I cannot seem to get the power brakes to work.I can barely lock them up and at slow speeds it takes for ever to stop the car. I have checked to power booster and it is fine. I have replaced the master cylinder,new pads,new shoes. Really am stuck. Help would be appreciated.

 

Thanks

 

Gary

 

If your sure the rubber hoses are in good condition and not expanding under pressure.

What your next step should be is to check the rod lenght from the power booster to master cyl.

If the rod is too short it will not give complete pressure to wheels.

Just as if the rod is too long, it will not allow fluid to return to master after pedal is released.

As these older cars did not have antilock brakes, if you stand on the pedal it should lock up all 4 wheels.

[02Lightning 10]

If it was converted from manual to power the wrong pedal could be in the car. The pivot point is diffrent on a power vs. a manul brake car.

[Max Power 74]

If it was converted from manual to power the wrong pedal could be in the car. The pivot point is diffrent on a power vs. a manul brake car.

 

The manual lever has more leverage than the power pedal. In most cases, leaving the manual pedal in place would cause too much leverage with the power boost, and touchy brakes or premature lock up.

 

Good thought, wrong direction though.