Strange Grinding

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98legacy22stick
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Strange Grinding

Post by 98legacy22stick »

Hi Everyone,

I have a 98 AWD legacy that is experiencing a strange problem after some brake work.

I put new pads and rotors on all 4 wheels. The right rear rotor required quite a few blows with a large hammer to remove. The others came off fine. Ever since changing that rotor, when making right turns at any speed higher than about 5MPH, I hear a grinding noise that sounds like metal on metal comming from that wheel. The grinding increases in severety with increasing speed and turn sharpness. The sound is not made when making left turns at any speed. I have taken the brake assembly off several times to try to determine the source of the grinding with no luck. The bearing seems fine, there is no wobble in the wheel or vibration at any speed. There are no obvious marks where contact is occurring. If anybody has any ideas as to the origin and solution to this noise, I would love to hear them.

Thanks.
Legacy777
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Post by Legacy777 »

How hard did you whack at the rotor?

I'm assuming you've tried wiggling the wheel when the car is jacked up to make sure there is no play....correct?
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98legacy22stick
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Post by 98legacy22stick »

It was very hard, with a large hammer. Hard enough to leave many large divots in the rotor. I jacked the wheel up and there is abolutely no play. In addition, the car drives perfectly straight and vibration free at all speeds.
boro
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Post by boro »

I got the same sound on my ex's 97 GT after changing the rotors and pads (all Brembo). You just need to lube the slides and put either some anti squeal on the face of the pads and/or put brake lube/anti seize on the back of the pad so it sticks to the caliper. It went away when I did that.
98legacy22stick
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Post by 98legacy22stick »

Well I figured it out. For some reason, the inside lip of the e-brake surface on the rotor was rubbing against a raised section on the plate that the e-brake hardware is mounted to. I took a chisel and knocked that area in slightly. After reassembly, the noise was present, but to a lesser degree. My guess is that I hit that area fron the other side with a hammer while removing the old rotor.

After a test drive involving some hard right turns, the noise has, for the most part, disappeared under normal driving conditions.
Bheinen74
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Post by Bheinen74 »

good mechanics don't whack stuff with large hammers.
Have you hear of penetrating oil, heat riser lube, PB Blaster??????

be patient, it will work itself loose.
98legacy22stick wrote:It was very hard, with a large hammer. Hard enough to leave many large divots in the rotor. I jacked the wheel up and there is abolutely no play. In addition, the car drives perfectly straight and vibration free at all speeds.
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98legacy22stick
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Post by 98legacy22stick »

Yes, ideally one should not apply that kind of force to remove a rotor. But when penetrating oil fails and a torch is not an option, choices are limited. Especially if you want to finish the job in any timley manner.

In the end, the heavy hammering wasn't even suffient to break the rotor free. I ended up using a 3-Jawed puller. That tool did the job better than any penetrating spray I have ever used.
mike270
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Post by mike270 »

Why did you not just use the bolt holes to push the rotor off rather than hammer on it?
98legacy22stick
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Post by 98legacy22stick »

Judging by the amount of force required to pull the rotor off, I would have broken the bolts using that method if I understand it correctly. Although I will admit that I did not try it. I worked under a master mechanic for 4 years and the hammer was always his perferred method for stubborn rotor removal when spray-can methods did not work. We did countless brake jobs together without any ill results.
555BCTurbo
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Post by 555BCTurbo »

98legacy22stick wrote: the hammer was always his perferred method for stubborn rotor removal
Yeah...umm...not such a good idea


That's what I refer to as a "hammer mechanic"

Which is not an endearing term...
Nick

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98legacy22stick
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Post by 98legacy22stick »

I would say that hammer mechanic is too general a term, perhaps in this case. The appropriate force was used when necessary in an appropriate location. It was not involved in adjusting valves or torquing cylinder heads. I would be curious to why you are against that method of rotor removal. More specifically what are the adverse effects of this method? It is a very common method which has been used by me and countless others successfully. The only adverse affect I have experiences is that I misssed with the hammer and hit something I shouldn't have causing trouble discussed in this thread.
555BCTurbo
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Post by 555BCTurbo »

I am against that method of rotor removal because it has a high probability to cause damage...just as you demonstrated.



Why not take the 5 minutes and make a puller, like I did, to use the supplied factory 12mm bolt holes to pull the rotor...it works so well and takes a negligable amount of time.
Nick

1987 Audi 4000CS quattro...soon to be 20VT
1994 Dodge Ram 2500 4x4 CTD, #11 plate, 30 psi, Scotty II intake, 4" exhaust
98legacy22stick
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Post by 98legacy22stick »

I agree that using a puller is the best method. It is what eventually got my rotor broken free. But there is nothing inherently wrong with using a hammer especially when a puller is not available and I do not have the tools at my disposal to make one, regardless of the simplicity of the design. The hammer worked without issue on the other three wheels and on countless other cars.

From my experiences, I will opt for a puller for future jobes, but if one is unavailable I will not hesitate to use a hammer. I will light the area more effectively so that I can see what I am doing so as to avoid the problem I experienced.
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