GM brake rotors and an audit

[robc]

GM rep stops by this store and asks to look at 50 or so warranty brake repairs, mostly involving rotor machining. Now while I may admit that by GM's standards the dealership was over machining, here are some of the points their rep made:

Rotors can only be turned for warping or scoring. Squeals, rotor/pad replacement, and corrosion were NOT considered valid reasons to turn the rotors.

The scoring had to exceed 1.5mm and the runout had to exceed 0.025mm to be considered for turning.

And finally that every vehicle should have signs that the hub/mating surfaces were cleaned using that tool we got last year; that the rotors had to be put on the same position they were removed, and (obviously) the torque sticks must be used on the lugs.

He kept refering to some past bulletin, but I think it's been updated or superseded. Has anyone seen any recent information about brake rotors???



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** Rob, Editor WD&S **
Help is only a message post away!
robc@dealersedge.com

[Michael White]

Turning rotors is such a grey area. When is it warranty and when is it customer maintenance. Reviewing this with my DSM reveals his opinion is it is a maintenacne issue. However, it is a real customer disastisfier and creates a CSI problem. I am intgerested what other GM dealers do about warpage in rotors and brake noise complaints. It is a major concern in our area.
thanks
Mike White

[Gerry Laughlin]

Mike, In out store it pretty much seems to be, if it is warranty replace them, CP turn them. Our Service Manager seems to do a good job of winning the battles that result from this. On a personal note, I have owned 11 new GM vehicles and not once has a rotor been machined, even though I have had my share of brake problems. I personally feel that even though machining is a proper form of repair, GM does not own that however many thousands of an inch they want the tech to remove, that belongs to me. By machining the rotors under warranty they are putting me in a position that I will have to buy a pair of rotors sooner. In my mind it would be no different than removing other parts because they have failed and not replacing them. Like I said this is just my opinion,

[RMARTIN]

re: resufacing rotors..according to the technical training our techs receive: the primary cause for rotor warpage is incorrectly torqued wheel lug nuts. I have observed many techs in many shops and few actually use the torque sticks as they should. Review your brake/lube techs and others who may do tire rotation/balance/brake checks and see if you are creating this headache on your own. Also question the customer re:tire rotation and see if they have had it done at one of the mass retailers-I have been succesfull in explaining the incorrect torque cause to customers who regularly use these outlets and converting them to us permanently. Especially after they pay for a resurfacing. Consider it an opportunity to educate and capture a new customer for life!

[jrcal]

This is such a grey area!! You can make valid reasons on both sides of this issue.

In my opinion (20 years as a tech before becoming management) most rotor warping problems are a result of incorrect torque of the lug nuts and the failure to remove debris such as rust from the mating surfaces.

Having said that, I remember not too long ago when Pontiac's policy was to NOT resurface rotors but to replace them. Their agruement was much like the above posts where in the rotor thickness is compromised and the ability of the rotor to disipate the heat and resist fade was compromised (not to mention the stopping distance).

In our shop the service manager must authorize the warranty repairs for brake rotor resurfacing. We look mostly at mileage. Low mileage vehicles we replace the rotor assemblies (in pairs for each axle). High mileage with corroded mating surfaces and obvious lug nut overtorque we look at the amount of wear left on the pad. If mostly worn then the customer pays. On some occassions, as a cust satisfaction issue, we will resurface the rotors under warranty.

I expect a bulletin from GM (similar to the shocks\struts and tire balance\alignment bulletins) which will make clear GM's position. In the meantime I call them like I see them. <GRIN>

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JC

[robc]

The dealer got the final review report from their rep and sure enough the whole thing came from instructions printed in a bulletin.

Information bulletin 23-50-05B was released in November 1997 covering brake rotor service procedures and outlined everything I detailed before.

Does anyone know if there has been an update to this bulletin before I write about it????

-- Rob

[Michael White]

Rob,
Was it OK with the auditers turning rotors at 26-30K? This is where my DSM has some concerns. Taking their side, warping is a result of overheating and use, unless there is some kind of mechanical failure that caused the brakes to warp.As far as I know,certain 1994-96 Sedan Deville rear rotors have a metal/design problem that makes the rotors prone to warpage. I am not aware of any others. Now I feel the factory should step up 1 time becasue warpage is related to usage. So again, should the factory pay for turning rotors when there is pulsation or is this maintenance. As a service manager, we can make it warranty, but will the auditors allow us to keep it??


Also, the bulletin you mentioned has not been updated since 1997
Mike White

[This message has been edited by Michael White (edited 06-09-99).]

[MARY SHERICK]

THIS WHOLE ISSUE IS A NIGHTMARE. THE REP'S PERSONAL OPINION SEEMS TO DICTATE THE POLICY IN A GIVEN GROUP OF DEALERS. YES THE DEVILLES HAVE UPDATED ROTORS AND PADS AVAILABLE. WHAT YOU MIGHT WANT TO LOOK INTO IS A RELATIONSHIP WITH A DELPHI CONSULTANT GROUP CALLED MILLER CONSULTING. WE HAVE WORKED OUT A COMPROMISE. WE GET FREE NEW PARTS FROM THEM, THEY GET THE OLD PARTS IN RETURN FOR EVALUATION. THIS IS ESPECIALLY HELFUL ON THE 20-30,000 MILE CARS. THE CUSTOMER PAYS FOR THE LABOR, AND GETS 300.00 PLUS IN PARTS AT NO COST. IT HAS HELPED US IN CSI AND BRAKE CPVS ISSUES. SINCE GM IS NOT CHARGED FOR THE REPAIR,THEY CANNOT DICTATE HOW IT IS DONE. THE PARTS ARE NEW GM PARTS THAT ARE OBTAINED FROM SPO BY DELPHI. THEY EVEN DELIVER THE PARTS, AND PICK UP THE OLD ONES.

[MARY SHERICK]

JUST HAD CONVERSATION WITH OUR REP AGAIN ON THE BRAKE SUBJECT. LATEST INFORMATION FROM HIM IS "IF THE REPAIR IS DUE TO WEAR, IT IS CUSTOMER PAY, IF THE PADS ARE STILL GOOD, IT IS A WARRANTY ISSUE." HIS COMMENT WAS THAT IF GM CAUSED THE PROBLEM, THEY SHOULD FIX IT. WE WILL SEE, SINCE DEVILLES ARE OUR NUMBER ONE ISSUE, FOLLOWED BY THE CUTLASSES WITH THE TSB TO REPLACE THE ROTORS.

[MIKEA]

AS A FORMER TECH AND NOW WARRANTY ADMIN, I HAVE BECOME VERY FAMILER WITH BRAKE ROTORS. GM ROTORS (AT LEAST ON CADILLACS) WARP ON NORMAL DRIVING (NEVER MIND STS AND OTHER SPORTY TYPES) AND OR RUST FROM LACK OF DRIVING! BOTH FAULTS LEAD TO PULSATION OR GROWLING. MY DSM'S POLICY IS IF THEY NEED BRAKES ITS CP. IF THE PADS ARE GOOD THEN ITS AFA FOR RESURFACE AS LONG AS THERE ABOVE MINIMUM SPEC FRONT AND REAR CAN BE DONE AT THE SAME TIME WITH A "B" AUTH. CODE

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