8.8 / Cobra brake - noise help!!

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superhuaman

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Apr 8, 2006

#1

• Apr 8, 2006

• #1

I just put in my 8.8 that I had built out of the car. It has 11.65" brakes on it with Ranger axles (used ones unfortunately) and North Cobra brackets. I also have the Ford moan braces. It replaced a 7.5" with drum brakes. I DO have a slight moan at low speeds under not-so-hard braking. I was expecting that. But, my problem is the same noise occurs when not braking, and making sharp right-hand turns about 20 mph... And whereas the moan is constant, i.e. hmmmmmmmmmm, the turning noise is over-and-over, i.e. hmmmmm hmmmmm, but it doesnt seem perfectly regular. The axle assembly has all new parts except for the axles. I ran out of money. While I was assembling the axle, I had problems with axle flange runout, because of the disc brakes, and had to get another axle, but that was on the right side. Both noises seem to come from the left side...

Please help, I don't want to touch it unless I know what I'm going after...

 

96SVTpilot

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Apr 8, 2006

#2

• Apr 8, 2006

• #2

superhuaman said:

I just put in my 8.8 that I had built out of the car. It has 11.65" brakes on it with Ranger axles (used ones unfortunately) and North Cobra brackets. I also have the Ford moan braces. It replaced a 7.5" with drum brakes. I DO have a slight moan at low speeds under not-so-hard braking. I was expecting that. But, my problem is the same noise occurs when not braking, and making sharp right-hand turns about 20 mph... And whereas the moan is constant, i.e. hmmmmmmmmmm, the turning noise is over-and-over, i.e. hmmmmm hmmmmm, but it doesnt seem perfectly regular. The axle assembly has all new parts except for the axles. I ran out of money. While I was assembling the axle, I had problems with axle flange runout, because of the disc brakes, and had to get another axle, but that was on the right side. Both noises seem to come from the left side...

Please help, I don't want to touch it unless I know what I'm going after...

Click to expand...

I just did the conversion with the North Racecars brackets over the winter. Their instructions do not mention using the ford moan braces. I didn't and I haven't had any issues. Don't know what your problem is for sure, but a few ideas off the top of my head.....

1) caliper alignment is slightly off

2) brackets are not fully seated against axle (I had this problem on one side, had to do a little grinding)

3) E-brake is partially engaged

4) E-brake cable is rubbing tire/wheel

5) wheel bearing was dinged when installing axle

Hope this helps, here are the NRC instructions in case you didn't have them.

http://www.northracecars.com/instructions/5_lug.pdf

 

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superhuaman

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#3

• Apr 8, 2006

• #3

Well, I can tell you that the e-brake cables are not installed yet...
I made sure that I didn't mess up the axle bearings or seals.
I suppose the caliper or bracket could be a little off, but that wouldnt explain the cornering noise...unles the axle had too much in-and-out play...

 

96SVTpilot

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Apr 8, 2006

#4

• Apr 8, 2006

• #4

superhuaman said:

Well, I can tell you that the e-brake cables are not installed yet...
I made sure that I didn't mess up the axle bearings or seals.
I suppose the caliper or bracket could be a little off, but that wouldnt explain the cornering noise...unles the axle had too much in-and-out play...

Click to expand...

There shouldn' be any axle play. You remembered to put the c clip back in right? Maybe the best course of action is to run it for a few thousand miles and then inspect for any uneven wear on the pads or marks from metal to metal contact or scoring.

 

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superhuaman

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Apr 9, 2006

#5

• Apr 9, 2006

• #5

Yeah, I put the C-clips in. They were new but of course the axles weren't. I think new axles are in order... North Cobra has them for $190/pair plus $30 for shipping, and they are Fox length, but have SN95 studs and hubs. Then, I wouldn't have to use hub centric rings for the rotors.

 

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superhuaman

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Apr 9, 2006

#6

• Apr 9, 2006

• #6

Also, the pads seem to only be braking with half their surface - the outer half, towards the edge of the rotor. This is probably because of the rotor runout, caused by the axle flange not being square to the axle shaft. :-(

 

Mustang5L5

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#7

• Apr 9, 2006

• #7

Is the rotor loose on the axle shaft now?

A lot of guys have about 1/4" clearance between the hub of the axle and the inside of the rotor. To fix this you need to cut a 1/4" sliver off an 2.5" ID/2.75" OD peice of pipe to use as a spacer inside the rotor

 

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superhuaman

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#8

• Apr 9, 2006

• #8

no, its not loose... i have hub rings to center the rotors

 

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superhuaman

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#9

• Apr 9, 2006

• #9

I also have the outer brake pads on each side, not completely touching the rotor, for some reason. its only using about half the pad, the half towards the rotor's edge... the inner pads are fine though...how do i fix this???

 

Mustang5L5

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#10

• Apr 9, 2006

• #10

Which caliper bridges are you using? The CObra ones which connect in the front or the GT/V6 ones which do not connect?


If 1 pad isn't touching, that means the slide pins inside the caliper bridges might be frozen solid. Take off the caliper from the bridge and see if you can easily move the pins in and out.

 

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superhuaman

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#11

• Apr 9, 2006

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I am using the Cobra bridges which connect. The slides are not frozen, they move quite freely. The calipers were semi-loaded rebuilt units from Advance (hardware, no pads). The outside pad IS touching, but only half of it. Maybe the slides have too much side-to-side play, or the two "ears" on the caliper for the outside pad are bent. I dont know... I thought the caliper hoses had something to do with it, since I mounted their brackets in the wrong place (under the axle bump stops) , and had to bend the steel parts at the ends of the hoses.

 

Mustang5L5

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#12

• Apr 9, 2006

• #12

Can you take some pics at all? If so try to get some at a few different angles close up

 

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superhuaman

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#13

• Apr 9, 2006

• #13

View attachment 478028
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View attachment 478036

 

Mustang5L5

That is…until I whipped out my Bissell

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#14

• Apr 9, 2006

• #14

Honestly everything there looks exactly how it should be. I can't see anything installed "weird".

DO the caliper hoses tug on the caliper at all??

If the problems exist on the side you did not replace the axle on then perhaps that is the case, because the rest of your hardware is fine, unless a bracket is bent.

If you spin the rotor (with the lug nuts tight) does the rotor "wobble" inside the grooves on the bridge? Does it contact?

 

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superhuaman

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#15

• Apr 9, 2006

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I did discover that the hoses were preventing the calipers from moving today, but i bent them some more and now they move freely. the rotor doesnt seem to wobble. my theory is that i didnt install the o-rings on the ends of the axles where the c-clips go, or that area is worn. this in theory would allow a bit of endplay, so that when im going in a right-hand donut about 20 mph, the axle will move and allow the rotor to touch one of the pads. the rotors DO wobble but thats only with the wheels off and no lug nuts.