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Discussion Starter #1
I put Cobra brakes all the way around on my car about a year ago and used Fast ED's brackets for the rear Cobra brakes. I bought some rotors through Wagner that cost $53 and were drilled....decent looking pieces even though I didn't really care for them being drilled. I just bought some basic replacement pads for the Tbird calipers and everything was good for a couple weeks at most.

I have a problem with the rear brakes (at least the driver's side)....because it is warped. I was just wondering if I should check to make sure everything is lined up straight and if anyone has had any problems with the relocation brackets. I don't really want to buy new rotors and mess them up too...so I am trying to work out the details now. I notice that the problem appears more when the brakes get hot and the problem almost "seemed" to go away when the winter set in. You could still feel the warped rotor when you came to a complete stop but there wasn't any noise. Any help here would be appreciated....or any advice. I think I am going to go with some better rotors next time even though I thought those looked like they would work pretty well.

Russell
 

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Russell, I am a professional mechanic and can tell you without a doubt that around 80% of the rotors I put on a car are warped right out of the box, no matter what the brand of rotor is. Think about all the rotor goes through from when it rolls (sits?) off the line, to when it gets on your car. If you are sure your problem is your rotors, I would have them machined before you buy new ones again. Any car repair shop should be able to do it, as well as some parts stores. You want to make sure the guy machining them knows what he is doing, or they can be rendered useless very easily. Also, a warped rotor won't always make noise, and will get worse with heat. Just my 2 cents. BTW, are you in Cleveland OH, or cookeville, TN. I am in Columbus, OH. I'll turn your rotors if I can drive it around the block. lol
 

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In the old days , we bought new rotors and then had them turned to true them up :) ......... not familiar with Wagner, but sounds like they arent much better then autozone ;)
 

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Well, I don't know about what everyone else is saying, but before I blame a new rotor as being warped, I would actually check if it is warped.... with a runout gauge. :D

I have cross drilled/slotted cheapo Cobra (eBay) rotors all around using FastEd's brackets and I have no problems.

I would check the hub to see if it is true, and then check the rotor. :thumbsup:

Just my .02. :thumbsup:
 

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Well, since I put on give-or-take half a dozen rotors a day, that should qualify me to have some idea of what I'm talking about. Also, since I said "if you are sure your problem is your rotors," a runout guage would be how to check them. Oh yeah, I found out where Cleveland, TN is. Guess that's a bit of a drive to Columbus.
 

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96bird said:
I put Cobra brakes all the way around on my car about a year ago and used Fast ED's brackets for the rear Cobra brakes. I bought some rotors through Wagner that cost $53 and were drilled....decent looking pieces even though I didn't really care for them being drilled. I just bought some basic replacement pads for the Tbird calipers and everything was good for a couple weeks at most.

I have a problem with the rear brakes (at least the driver's side)....because it is warped. I was just wondering if I should check to make sure everything is lined up straight and if anyone has had any problems with the relocation brackets. I don't really want to buy new rotors and mess them up too...so I am trying to work out the details now. I notice that the problem appears more when the brakes get hot and the problem almost "seemed" to go away when the winter set in. You could still feel the warped rotor when you came to a complete stop but there wasn't any noise. Any help here would be appreciated....or any advice. I think I am going to go with some better rotors next time even though I thought those looked like they would work pretty well.

Russell
When I did my Cobra rear conversion I picked a pair of used (but never turned) Cobra rotors. I had them machined before I installed them & they have been fine ever since (over a year).
 

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I've been curious. Can the drilled rotors be turned as easily as the standard rotors?
 

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Good question.. I want to know that too 'cause the
rotors I got from discbrakesrus are so damn warped it's rediculous...
Going from 50mph to 40 mph as almost scary..

I even tourqed the wheels according to specs which I've never ever
done before.. Broke them easy and all..
In less than 45 miles the steering wheel started to shake
like crazy!

//Per
 

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Thats exactly what happened to me.

I'm curious to know what the cutting bit on the brake lathe does when it hits a hole.
 

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Cross-drilled rotors can be machined just the same as regular rotors. Just make sure to clean up the holes and remove any burring if it occurs. The cutting edges on a lathe are locked down wherever they are set to cut; otherwise they would wiggle and not take out warpage (or worse corduroy the rotor). They will just skip right over the holes and continue on.
 

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Thank you much. Thats what I thought would happen, but wanted a second opinion. The holes in my rotors are chamfered so that will help some. I'll be sure to inspect them carefully when I get them back. The work will be done on Sat.
 

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Discussion Starter #12
232bird said:
Russell, I am a professional mechanic and can tell you without a doubt that around 80% of the rotors I put on a car are warped right out of the box, no matter what the brand of rotor is.

Sorry guys about not replying but it usually takes a few days for me to get access to the internet again. :D

The rotors were fine for a very little while....like Traveler said...45 miles or so. I think I am going to do like Don (94DD) said and check them with a runout gauge. It is funny that I had been wondering the same thing about turning drilled rotors on the lathe...so thanks for clearing that up. I really hate spending money on things that I am going "go bad" so quick. So....is the suggestion to true up the rotors when you buy them new? I will get these turned (if that is the problem) and then buy new rotors later on when I have the money. Thanks for the replies.

Russell
 

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Russell, when you bolt up the caliper anchors on the knuckles, are they centred over the rotors OK? That's the only thing I can think of to double-check ... with variances in the casting of the knuckles, sometimes the anchor can end up being slightly off-centre in relation to the rotor. If that is the case, thin washers can be used as shims to get it where it should be.


cheers
Ed N.
 

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Discussion Starter #14
fast Ed N said:
Russell, when you bolt up the caliper anchors on the knuckles, are they centred over the rotors OK?

cheers
Ed N.
To me it looks like it is centered but I haven't measured to make sure. I think it is just the rotors because everything else looks good to me. I don't have much money or time right now so I haven't been able to check anything out.

Russell
 

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Did any of you guys switch over from rear drum? If so/not can you tell me if the knuckles are the same on disc and drum cars?

Chris
 

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Discussion Starter #16
I switched from drum and they are different....but if I remember right you can just drill the holes on the knuckle that would locate the caliper bracket. :D I needed the calipers and the whole mess, so it was just easier for me to get the knuckles, calipers, etc all together.

Russell
 

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I just needed to know what to pull for him. I have only delt with the disc rears. I have never even seen the knuckle for the drums.

Chris
 
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