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Just how good should my brakes be ?

14K views 124 replies 31 participants last post by  cougar70 
#1 ·
65 Convertible disc/drum setup ,just had new dual reservoir m/c and booster installed , new rotors and calipers and lines ,new wheel cylinders and shoes on the back.
Struggling with long peddle travel and soft stopping. Have bled several times and adjusted the rear brakes as much as my mechanic is comfortable with. It's better now but I'm still not thrilled with the stopping ability. I don't think its air in the lines because I can't pump the peddle up. I been following a couple of recent threads with great interest.
Should I be able to "lock" these brakes up ? right now that's not possible.
Wondering if I just need to get my head around the fact that it's an old car or is there a problem?
 
#7 ·
Sounds like you need a new mechanic.
He/she shouldn't be releasing work that isn't RIGHT. (and leaving you to figure it out)

ex-Global West GM
1991-1995
 
#9 ·
Power brakes (both factory and swap kits) move the location of the pin that the actuator rod mounts to on the pedal. So if you’re putting a booster on a car that came with manual brakes, this pin needs to be relocated.

I’m no engineer, so I can’t tell you all the why’s and wherefore’s, but it is necessary on all swap kits that I’ve ever seen. Perhaps there are exceptions, but not in my experience.
 
#12 ·
Basically, yes. Or you put in a new pin.

Just to add a little more info. When I bought the car it had Non Power front disc with the large bowl single reservoir.
The brakes were not functioning when I purchased the car and had been sitting for 5 years.
As much as the peddle travel concerns me , I'm more concerned about the lack of stopping power and not being able to "lock up" the brakes.
Pedal travel can be part of that equation, though you may have other issues as well.

This is what I have, so you can see what I'm talking about.

 
#11 ·
Just to add a little more info. When I bought the car it had Non Power front disc with the large bowl single reservoir.
The brakes were not functioning when I purchased the car and had been sitting for 5 years.
As much as the peddle travel concerns me , I'm more concerned about the lack of stopping power and not being able to "lock up" the brakes.
 
#15 ·
I just think there must be a physical problem if I can't lock the wheels up during a hard stop
I think you’re right.

Residual valve can be a separate part located somewhere on the rear line or built into the master.

I don’t know this for sure, but seeing as the residual valve is there to maintain a small amount of pressure to preload the brake shoes so that there is less delay between pedal and actual braking, I don’t think it would significantly impact overall braking power. Rather, it takes less pedal to begin actuation.

Would love to know if I’m wrong though if any hydraulics experts know better.

I do like the idea of checking the adjusters in the rear.
 
#19 ·
The '65/'66 cars did not have different pedals for manual and power brakes. For power brake cars there was an adapter that went between the firewall and the booster that changed the ratio of the pedal for power brakes. You can see it in the photos of this kit.
 
#24 ·
We'll know more if you clear up what booster you have. Of course, the booster is not capable of improving braking. Boosters effect only pedal effort, not stopping. Of course, a malfunctioning booster can make things worse.

The OP keeps referring to lack of ability to lock the brakes. The ability to do this was standard equipment. The 200 I6-equipped Mustang, with 9" manual drum brakes, was capable of locking the wheels.

This means his brakes have a serious problem.
 
#27 ·
good info, but I don't think its a booster problem. It's a lack of pressure at the wheels that won't allow the brakes to lock up. So I'm leaning more to a m/c problem or the shaft between the booster and m/c.
Mechanic is supposed to be checking the pressures at the wheels today...
That should revile a lot.
 
#30 ·
ya it will reveal there's not enough pressure in the system which you already know since you can't lock up the brakes. Pushrod travel seems most likely or rear brake adjustment or air or some combination of 3 of those would be my guess. or bad MC but i think you said it's new.

Not to be a dick but I hope you're not paying much for that mechanic...
 
#29 ·
my brakes were never right until i sprung for one of these thingies. took all the guess work out of the star adjuster

 
#33 ·
ok so this is the kit I have:
mechanic added a bushing at the pedal pin to help with travel and seems much better.
However still can't lockem up
Interesting that both reservoirs are the same size, most seem to have a smaller front reservoir.
That kit has the adapter that changes the pedal ratio. The video says it needs 18" of vacuum at idle to operate the booster. Does your engine make 18" of vacuum at idle?
The reservoir size has absolutely nothing to do with stopping power. The size of the piston has everything to do with stopping power and the specs say it has a 1" piston.
When you try to lock up the wheels are you standing on the pedal with everything you have or are you expecting the booster to do all of the work for you? Maybe your engine is not making enough vacuum for the booster to do it's job efficiently and you need to apply more leg effort.
 
#34 ·
Good point , and you may be right about the leg effort.
I haven't driven an old car on a few years !
@ BlakeTX I see we have the same manufacturer but a different kit
Wonder what the differences are as far as performance and application ?
 
#36 ·
@ BlakeTX I see we have the same manufacturer but a different kit
Wonder what the differences are as far as performance and application ?
I"m confused. You have linked the Master Power brake kit, while I have the Mustang Steve power brake kit. Everything in my setup, aside from some modifications to the pedal and support is a Ford part (booster and master).

I'm not familiar with the Master Power kit, and I must say, I've never seen a master cylinder that is supposed to work with all drum, all disc, or front disc/rear drum. That's a new one for me.
 
#37 ·
Forgot to mention: If there is any chance at all, as awhtx is saying, that maybe you're just not stomping on it hard enough, that would be my first test. Take it out somewhere where you have room, and stand on that pedal like your life depends on it. If you still can't get it to lock up, then we can keep trying to diagnose.

As a potentially separate issue, the suggestions about vacuum are solid too. But again, that's about pedal effort, not stopping power. Even if you disconnect the vacuum hose from the booster, your brakes should still perform, just with more effort.
 
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