power brakes

[69 red fastback 20]

I was hoping you guys could help me with my brakes.

The problem is that my brakes aren't the best, I've put a disc brake conversion on the front, new mc, booster, and lines. I've bled the brakes at least 4 times, but they still don't feel the best.

My other thing is vacume, I built the 302 that's in it to a 306 roller with the cam being 214./224 @ 50 with lift at 472./496. with a 112 lobe. Would it help to put a vacume reserve canister on for the extra vacume.

Any help would be greatly appreciated

[Rsmach1 71]

Is your pedal hard or mushy? As far as vacuum for the booster have you checked your engine vacuum with a gauge? Boosters need around 16in+ to work best.

[69 red fastback 20]

Thanks for the reply, the pedal doesn't feel bad, they just don't have good stopping power like they should, and yes I did check the vacume and the best that I could get was 12-13 at idle, so I was thinking a vacume canister might help, just not sure!!

[barnett468 418]

hello;

 

advance your timing as much as your engine will tolerate it if you have not done this yet. then reset you idle and you will have more vacuum.

 

if you can't get more than that then you need an auxiliary vacuum canister or vacuum pump.

 

also, your brake pads might be cheap organics. hawk pads are good.

.

[69 red fastback 20]

Thanks for the info, yes I've already done all of that, so it sounds like I will be getting a canister and see if that helps

[MikeStang 247]

You shouldnt need a canister.

My 408 has a much larger cam with same vac readings as yours and I also did a Granada brake swap and my power brakes are awesome.

 

1. Do you have an adjustable pushrod from the master Cyl to the booster? If so be sure its right.

 

2. With the master and booster mounted on the car remove the lines and bleed the master cyl with a master cyl bleeding kit from auto zone, they are like 10 bucks.

 

3. Re-Bleed your brakes starting on the pass rear then the driver rear then the pass front and finally the driver front...

 

Once you do all that then report back.

My brakes are soft for about 1/4 of the pedal travel but when you pass that they hit pretty hard and I dont even have my rear pressure turned up so it would be easier to do burn outs with no damage to rear shoes haha

[69 red fastback 20]

MikeStang

 

Yes I have already done all of that, but it sounds like my brakes are just like yours.It has been 4 years restoring it so maybe I just forgot how they were.

 

Thanks for the info

[MikeStang 247]

No Problem.

Have you driven the car yet? or is this just pedal feel while sitting still?

My friend has Manual SSBC Disc brakes on his car and I know my power disc/Drum combo stops better lol plus its easier to operate.

Have you rented a guage to check the pressure at the calipers?

 

I would still Re-Bleed the master and all Brakes....Tap on the master a bit when its being bled. When I did mine it made a world of difference.

 

Also be sure that you don't have any leaks anywhere.

I do fine in traffic and brakes are easily strong enough to hold the car to start a burn out lol.

 

I have been 5 years doing mine so I know the feeling.

Drove it to work only for it to die on me after Installing a new Aeromotive pump and regulator, so I was under the hood this morning in a parking lot with my phone as a flash light wrenching on it... Turns out my float was sticking closed and not allowing fuel in...Just raised the float level and it seemed to cure it....Time to rebuild carb I suppose.

[1969_Mach1 333]

Did you do a power brake conversion? I have seen a conversion where somebody tried to reuse the brake pedal for manual brakes with power brakes. It simply didn't work correctly, a lot of pedal travel. Is it possible the wrong brake pedal is installed?

[69 red fastback 20]

MikeStang

 

Yes I have driven the car, it stops alright they just don't feel right, I will bleed them again and see what happens

 

Thanks ago for the info

[69 red fastback 20]

1969 Mach 1

 

Yes I did do a disc brake conversion, but it already had power brakes, I did think about that though so I called the place where I got the conversion kit from and they said that everything was good as far as the pedal.

 

Thanks for the info

[Max Power 74]

1969 Mach 1

 

Yes I did do a disc brake conversion, but it already had power brakes, I did think about that though so I called the place where I got the conversion kit from and they said that everything was good as far as the pedal.

 

Thanks for the info

 

So, it had power drums? I'm confused.

 

FWIW, when many people convert to power brakes from manual, and don't change to a power brake pedal, the brakes are quite grabby. The manual brake pedal is pivoted to apply much more leverage to compensate for lack or power assist, so when people do the conversion without changing the pedal, the complaint is that the brakes are too touchy, rather than the other way around.

[69 red fastback 20]

Max Power

 

Yes it did have power drums

and I changed the front to disc

 

Thanks for the info

[1969_Mach1 333]

You are correct, Max Power. I didn't even consider that aspect. I can see where the increased leverage from a manual brake pedal would cause brakes to be too touchy on a power brake system. Also, though its been a while since I compared the two pedals, I think based on geometry, the pedal pad on a manual brake pedal will travel further than the pedal pad on a power brake pedal to obtain the same amount of rod travel.

Edited October 15, 2014 by 1969_Mach1
errors

[magician 13]

What are you using for a p_valve ?

[Max Power 74]

Max Power

 

Yes it did have power drums

and I changed the front to disc

 

Thanks for the info

 

Wow, I am not sure I have ever seen a power drum 69 before. That's pretty rare.

[69 red fastback 20]

Magician

 

Sorry I'm new to this, but if you're asking about what proportioning valve it is an SSBC

[magician 13]

What happens when you ajust the valve...can you tell any difference.?

[69 red fastback 20]

Magician

 

Actually I haven't tried adjusting it but I'll give it a try and see if that makes a difference.

 

Thanks for the info

[MikeStang 247]

Be sure the rear brakes are adjusted correctly.

I usually adjust the shoes till I can just wiggle the drum on and it makes a good fit, then I put it in Neutral and roll the tire and feel for resistance.

My car was a power Disk/Drum car and I wanted the somewhat larger Granada brakes, plus it was cheaper to buy it as a kit than rebuild my old crap.

are you also using the old Brass Prop valve that ties in all the lines and then an SSBC valve for the rear only?

[69 red fastback 20]

MikeStang

 

I'll adjust my rear brakes and see if that makes a difference, and yes I'm still useing the old distribution block with the ssbc valve after that.

Thanks for the advice

[MikeStang 247]

Yeah Im using same as you.

I mounted the rear valve in the back of the car right in front of the axle just b4 the line splits...its a PITA to get to but i figure why not get max pressure all the way back then adjust.

[69 red fastback 20]

I put mine right after the dis block right where the line turns and goes down the tranny tunnel

[69 red fastback 20]

MikeStang

 

Maybe that's my problem, I may not be getting enough pressure back to my rears, I bet if I turn the valve up that will make a difference. Thats the reason I put mine where I did so I could get to it easier.

 

Thanks for all of the advice

[MikeStang 247]

No problem bud.

Clockwise increases the pressure if i recall