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Old 07-10-2006, 08:10 PM
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weak brake pedal

So I have a 65 Comet that I recently did a granada brake swap on. It works okay. I have problems because the pedal has tons of travel and feels squeshy, even though I have bled it like 4 times trying to firm it up. Also the pads constantly drag. I have tried putting the stuff on the back and it works for about a week then they go back to making noise. Does anyone have any suggestions??

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Old 07-10-2006, 08:37 PM
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proportion vavle ?

Quote:
Originally Posted by comet boy
So I have a 65 Comet that I recently did a granada brake swap on. It works okay. I have problems because the pedal has tons of travel and feels squeshy, even though I have bled it like 4 times trying to firm it up. Also the pads constantly drag. I have tried putting the stuff on the back and it works for about a week then they go back to making noise. Does anyone have any suggestions??
just a guess the proportion valve ?
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Old 07-10-2006, 09:32 PM
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spunge brakes

Defective master cylinder,maybe?
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Old 07-10-2006, 09:38 PM
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You say the system is bled . OK.
Without knowing exactly what you swapped it is hard to say.

My first guess is that the pushrod is too long ,not allowing the master cylinder to be bled or retract properly. That could be why the brakes drag.

If that is not the problem then my second guess is
That the M/C is too small or the pedal ratio is wrong

Is it the old single master cylinder or is it a dual?
What diameter is the master cylinder?
Did you put a power booster in it or is it manual?
What is your pedal ratio?
Are you using the stock 65 comet pedal?
I'd assume you put granada rotors and calipers.
Did you change out the rears also?

Question, questions, inquiring minds need to know.
Mikey

Xntrik is the really the granada brake guru, where's he at?
He knows all those sizes by heart.
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Last edited by powerrodsmike; 07-10-2006 at 09:51 PM.
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Old 07-10-2006, 11:34 PM
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Sorry I was vague. I swapped the front calipers and rotors from the granada. I used a re-maned late model master cylinder out of a 86 mustang. It is manual I actually shortened the pushrod. and the pedal has no stop on it so the pushrod can come as far out until it hits the stop on the inside of the master cylinder bore. I am using the stock 65 comet pedal with the rubber bumper removed. I have a wilwood porportioning valve but it is only hooked to the back. The rear is stock. I haven't changed it yet. I don't know my pedal ratio. I don't know how to check it either I don't know the diameter of the master cylinder.
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Old 07-10-2006, 11:59 PM
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Quote:
Originally Posted by comet boy
I don't know my pedal ratio. I don't know how to check it either I don't know the diameter of the master cylinder.
Was the reman M/C from a manual or power car?

Here is something I got from the knowledge base to help figger the pedal ratio:

Calculating the Ratio of a Brake Pedal
Divide the length from the pivot point to the push rod (B) into the length from the pivot point to the center of the foot pad (A).

Example:
(B) Length from pivot point to push rod = 2.0"
(A) Length from pivot point to center of foot pad = 14.0"
14 divided by 2 = 7
Pedal ratio = 7:1

Manual brakes generally like 5 to 7 : 1
power brakes feel good with about 4 to 6 : 1

Is there another hole in your pedal about 3/4" or 1" below the original?

Oh yeah, are your back brakes adjusted right?

Here is where I got the little math thing.
http://www.outlawdiscbrakes.com/faq.html



There might be some more stuff there you can look at
mikey
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Old 07-12-2006, 08:42 PM
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Still sounds like you have air.

I have done several Granada conversions. I used all the G parts, 1" MC, combination valve, and spindles/brakes. Your car is essentially a Granada, Maverick, Mustang, unibody Fairlane, etc and everything bolts on easily and works. NO pedal ratio changes are necessary. No aftermarket proportioning valve needed. The manual disk brake pedal pressure feels just like the manual drums. Your original rear brakes are fine.

Use good pads, like Wagner Thermoquiet. Avoid the cheapo life time warranty stuff, they don't stop well.

The 79 only Mustang MANUAL brake cyinder is 7/8" and has fittings in inches instead of metric and reduces the pedal pressure but goes down another inch or so. But it is modern looking.

The G disk brake pads retract by the pressure of the piston O'ring. They might need to be rebuilt. Be sure the caliper slides easily in the spindle.

www.readershotrods.com

Last edited by xntrik; 07-12-2006 at 08:51 PM.
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Old 07-14-2006, 06:37 PM
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Okay So I checked everything else out. But I am still having problems with the pads dragging. Shouldn't there be some sort of pad retainer clips on the outside pad. Mine doesn't have any. I would think there would have to be something to hold the pad in position.
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