Cobra brakes installed... Doesn't stop well at all...?

C

cobracoupe

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Apr 21, 2008

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Apr 22, 2008

#1

• Apr 22, 2008

• #1

Just got done doing a 5 lug conversion and sn95 cobra brakes on all fours of my 89 coupe...when i apply the brake you here a hissing from my brake booster and it doesnt feel like its stopping well at all (like the calipers are not getting much presure) pluss if i push real hard it will just go to the flore slowely. Is it common for thoughs boosters to go out, and if so is their a better one on the market, like upgradeing to a sn95 booster or something?...
....AND YES I DID BLEED THE BRAKES.....
Thanks

 

cenok is family

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Jun 25, 2003

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Apr 22, 2008

#2

• Apr 22, 2008

• #2

did you bleed the brakes?


i don't have all wheel disc, but from what i've seen and read, aren't you supposed to change to the sn95 booster, master cylinder and prop valve when you go all wheel disc? and by you saying "should i upgrade to an sn95 booster" i would assume you still have the original 89 stuff. someone else with more knowledge will chime in on this.

 

stykthyn

I want to measure mine. It doesn't look that tall.

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gainesville

Apr 22, 2008

#3

• Apr 22, 2008

• #3

a 93 cobra master cylinder is what you want to really get the most out of those brakes.it fits better than the sn95 mc. It also sounds like you did not bleed your brake system, or if you did, you still have a lot of air left.

 

SuperStang83

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Apr 22, 2008

#4

• Apr 22, 2008

• #4

It sounds like you need to bleed your brakes. I have a 93 Cobra master cylinder on my car with SN95 brakes all around and it does a great job.

 

trbkrb

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Jun 4, 2001

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Apr 22, 2008

#5

• Apr 22, 2008

• #5

A hissing booster is usually a sign it is going out. Did you change the MC? If so, did you bench bleed it to remove the air before installing it? Is it a new one or used one? If it is used, it could have worn internal seals and be bad too.
Is the pedal soft or hard? What all else have you changed and was it new or used?

Based on what you have described, a hissing booster and a pedal that goes to the floor slowly with a lot of pressure on it, sounds like a bad MC and a failing booster to me.

 

Mustang5L5

That is…until I whipped out my Bissell

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Feb 18, 2001

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Apr 22, 2008

#6

• Apr 22, 2008

• #6

What MC are you running?

 

C

cobracoupe

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Apr 21, 2008

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Apr 22, 2008

#7

• Apr 22, 2008

• #7

Sorry i forgot to say I have a sn95 MC....also along with the hissing with my brake booster when i push it. My idle sometimes will fluctuate up and down almost to the point that it wants to die then i push the brakes till the hissing stops and the idle smoothes out (sounds like i need to change the booster)..

I think what im going to do is buy a 93 cobra MC, and a new brake booster, and do a good job bleeding the brakes. Sounds like from what you guys are saying my brakes should work great if i do this set up...

 

88mouse

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Apr 18, 2007

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Apr 22, 2008

#8

• Apr 22, 2008

• #8

If the booster is making a hissing sound it is bad. Change it and to a 93 cobra and you will be set.

 

Mustang5L5

That is…until I whipped out my Bissell

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Apr 22, 2008

#9

• Apr 22, 2008

• #9

Sounds like a bad booster or a serious vacuum leak somewhere. Did your booster work fine before the swap? Have a buddy mash the brakes and poke around with your ear on a peice of fuel line and see if you can pinpoint the hiss.

The Sn95 MC should work fine. It's what I have with my setup. It's what the car comes with stock basically If anything, try a '93 Cobra booster if you end up replacing yours

 

SVT32VDOHC

waiting for the next hack atta

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Apr 22, 2008

#10

• Apr 22, 2008

• #10

I put the Cobra brakes on mt 95GT once, and they sucked too!! According to my computer at work, the 94-95 GT's and Cobras used the came booster, but their master cylinders are different. So, if you go with an SN95 M/C, try to get on for a Cobra.

Good Luck man. They look cool, but it would be better if they stopped well....obviously.

 

mustangfan1990

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Apr 22, 2008

#11

• Apr 22, 2008

• #11

The hiss could be its way of saying you need a 93 COBRA boost LOL

 

Mustang5L5

That is…until I whipped out my Bissell

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#12

• Apr 22, 2008

• #12

lol

 

Prime Lord

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Apr 23, 2008

#13

• Apr 23, 2008

• #13

I'm agreeing on the booster being the culprit. If your MC is completely shot, then you'll hear some hissing. But if its LOUD and obvious, then there is a serious problem w/ the booster.

Does the pedal still go to the floor when the car is off? I had to replace my booster about a year before I did my 5-lug swap and when the engine was off, I could still push the pedal down REALLY easily.

If you replace the booster, definitely get the '93 Cobra part. Its a hell of a lot easier to get in that thing in there.

 

C

cobracoupe

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Apr 21, 2008

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Apr 23, 2008

#14

• Apr 23, 2008

• #14

LOL......thanks alot, ill try changeing the booster and MC....

 

Shakerhood

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Oct 28, 2004

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Apr 24, 2008

#15

• Apr 24, 2008

• #15

When you bleed the rear brakes make sure you have your adj prop valve set to full pressure to the rear.

 

white 89 GT

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Apr 3, 2003

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Apr 24, 2008

#16

• Apr 24, 2008

• #16

http://svo73mm.cjb.net/
This may help, also did you have to reset the rod end for free play.

 

Prime Lord

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#17

• Apr 24, 2008

• #17

Oh, one more thing I thought of. The rear brakes take FOREVER to bleed correctly. the position of the bleeder is really poor and you either have to bleed it a lot really fast (push down on the pedal quickly) or tap them w/ a rubber mallet while they're being bled so that the air actually goes where its supposed to.

 

C

cobracoupe

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Apr 21, 2008

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Jan 21, 2009

#18

• Jan 21, 2009

• #18

Works perfect noe i just had to instal a new Brake Booster, Thanks.

 

R

Rick James

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May 13, 2007

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Jan 21, 2009

#19

• Jan 21, 2009

• #19

what booster did you use?

 

C

cobracoupe

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Apr 21, 2008

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Jan 22, 2009

#20

• Jan 22, 2009

• #20

I just used a oem new brake booster, I tried to use one from a 93 svt cobra but it was to tight of a fit to get it in between the strut tower and fire wall for some odd reason. I guess their strut towers are further forward.