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Quote:
Originally Posted by Willcox Corvette
What is sad... The 1.215 is stamped in all the factory rotors.... how could you be in this business and not know that.
Ernie
Originally Posted by DUB
I know... and what blows my mind is that they wanted to argue the facts out of the service manual.
Quote:
Originally Posted by Willcox Corvette
What is sad... The 1.215 is stamped in all the factory rotors.... how could you be in this business and not know that.
Ernie
Originally Posted by DUB
I know... and what blows my mind is that they wanted to argue the facts out of the service manual.
DUB, seems as though this thread took a left turn on you. Go figure.
I read it, saved it for future reference (and for the tool name) Thanks for the tips.
YES it did.
I clearly see that somethings do not change and thus...I guess that is how some people want it..
And what is really funny...if I logged in as a new member and tried to pass this information along...THEN many people would then tell me that I only made one post and they are supposed to believe it.... and what I am REALLY doing is trying to damage 'that companies' business.
Thanks for the warning / heads up Dub. Easy to forget to check parts when they're ordered from supposedly specialist vendors. Hope you stick around, I (and I dare say most of us) greatly appreciate you sharing your knowledge and experience.
Just take Dub's warning as just that, it's a warning for the buyer to beware. Normally, if rotors aren't grooved or badly warped, it doesn't require taking off a ton of metal to get them true. I'm guessing they had an inexperienced person machine these rotors. A brake lathe is easy to use and can it's use can be taught very quickly. Judging a rotor's condition and machining off the bare minimum takes experience.
They may very well have assumed that the customer wouldn't check the thickness and didn't know what the thickness was at when they were shipped. If they called the customer, and legitimately couldn't clean them up within the "machine to" tolerances, I think most customers would call BS and get upset. It's just the nature of most customers, especially in the DIY hobby.
In today's business environment the customer is constantly pushing for lower prices. It takes real skill to sell quality. Look at all the Chinese products sold everyday, we all know how hard it is to buy anything made in the USA.
I think they should have caught it and given the customer the option to purchase new rotors, but I'm of the opinion that sloppy machining is the cause. Having read many of Dub's posts. I'd guess he'd recognize unsalvageable rotors.
I am NOT going to give the name of the company that did this service...becasue all I am trying to express is that you should NEVER assume anything...regardless on who it comes form...and you will shorty read why this is true.
These are FACTS and not my opinion on this matter and unless a person chooses not to acknowledge GM's service information...then I guess that person will want to debate this.
First off...read this out of the GM Corvette service manual.
it CLEARLY states that when a rotor is being turned down...it CAN NOT be surfaced thinner that 1.230". So,,,turning it to 1.228" is not good or any thickness under the 1.230"
I customer of mine sent his two trailing arms out for rebuilding at this company because the costs were cheaper than if I did it. There was an extra charge for indexing the rotors to the spindles and I told him I DID NOT want the rotors riveted back on due to it is not required.
The company that he sent them to, who I know should do a good job due to being in business a very long time. When the trailing arms came in the trailing arms looked very good. And the rear wheel bearings were also done correctly.\
But here is where the problem begins. The rotors were machined BELOW the minimum of 1.230 when completed.
These two photos show what they measured at.
1.219"
1.218"
Not that this was bad enough...that these rotors are now about .003" to .004" of an inch from discarding them....because if you remember...in rotor information above...it clearly states that discard is at 1.215".
The sad thing about this is that the rotors that were sent with the trailing arms where at 1.247" and 1.245" respectively. If I still had them at the shop I could have saved them and not needed to cut them down as badly as they had. I assumed they knew what they were doing... a big error on my account for assuming that.
Also it is a crying shame that this company has not figured out how to use the shims that are available ...even if they rivet the rotor back on so they do not have to machine off so much metal....OR...realize that they are turning rotors down too far.
Thank goodness I did not have the rotors riveted back on because when I went in and installed brand new rotors and indexed them by using shim material as needed. I also noticed that the adjuster on one trailing arm was not installed correctly and it needed to be corrected. because its position is critical in order to follow GM's outline on how to tighten up the parking brake shoes for adjustment. IF these rotors were riveted back on..it would have been a waste of time and money.
Correct procedure to using the screwdriver on the adjuster.
Clearly stated in the fifth paragraph. Your hand raises up when tightening the park brake shoes. One trailing arm was backwards and I had to go down with the screwdriver. Something that should NOT have been overlooked if they were paying attention....or trying to do so much for so little money.
Lastly here is the written text that states the rotors do not need to be riveted back on. People can do as they wish in this area...but I prefer not to for making it easier on some service operations.
So...just because your trailing arms come in looking great may still make them not right.
DUB
So were the rotors true, and above the min. thickness?
So were the rotors true, and above the min. thickness?
They were above 'discard' thickness. And that's my big issue with all this....they're not at throw away thickness. Do I understand DUB's perspective? Yes, I do.
Funny thing is if the rotors had worn on their own to that thickness it wouldn't be a problem.
I for one am thankful for the post. I did not, by practice, use calipers to verify the thickness of rotors I put on my cars, but I certainly will do so now. I have new rotors in the box set to go on my 69 rolling chassis and guess what I will be doing this afternoon? You bet I will. Thank you Dub, regardless of the supplier I will take the warning and protect myself from such an error and take it up with the supplier should it ever happen to me. Appreciate the continued support. Keep it coming.
Best regards,
David Howard
AllVettes4Me
They were above 'discard' thickness. And that's my big issue with all this....they're not at throw away thickness. Do I understand DUB's perspective? Yes, I do.
Funny thing is if the rotors had worn on their own to that thickness it wouldn't be a problem.
The reason I asked is I will take them if you are throwing them away. I'm positive they will work just fine on one of my cars.
I think Dub's post is indicative of his high level attention to detail that he puts into his work. Which is exactly the kind of guy I and many others on this forum would want to work on our cars. Let's face it, many of us don't have that level of focus when we do our own repairs on our own cars. This guy is looking at things I don't even think about, and I learn from his post. I hope he doesn't leave this forum.
Because of the way GM originally installed these an almost perfect rotor at 1.250 may have to be turned over .010 on each side just to get a clean surface on both sides after bolted up to the true surface of the lathe. They were riveted to a not perfectly concentrically machined outer axle then trued 90 degrees to the centerline hence the need for shims once rivets are removed. If you are working on a very small margin I somewhat understand the reasoning of the vendor. The customer should have been contacted about purchasing new rotors.
Guys, a similar thread got so derailed by people guessing who the vendor was it got closed. I'm posting this in an attempt to keep that from happening here, because there's still good information being exchanged.
Please don't bring up who the vendor is any further. Also, please do not bring up the OPs decision not to name the vendor again. He's chosen not to name them, and if he did the thread would belong in Transactions Feedback. The OP can start such a thread there anytime he chooses. Thanks.
It is pointless to involve the company by linking them to this thread....they will do as they wish and nothing is going to change that. They should already observe specifications that can not be debated or dismissed...unless a person just can not read and comprehend what was written. I did my best.
The rotors are being disposed of and recycled.
I did not check to see if the rotors where 'true'...because they failed the test of measuring them AFTER they had been machined. Simply put....if they are turned down BELOW 1.230"...they are junk....regardless if they are indexed perfectly. Because doing anything otherwise...is contradicting what GM wrote in the service manual ....and that 'MINIMUM AFTER REFINISHING' can not be interpreted in any other way.
I get rotors that are at 1.220 ( for example)...which is still above discard thickness 1.215")...BUT...I can not turn them. Because they are already BELOW the minimum thickness of what GM has outlined. Now...others here can do as they wish...and I do not care what you do on your own car...but trust me....I have to follow certain procedures very precisely..ESPECIALLY BRAKES..and if people have gotten so tight and cheap with their Corvette that they can not afford to repair it correctly....then they need to sell it and buy something they can afford to maintain CORRECTLY. Its one thing to put some black duct tape on your seat cover to hide a tear...but 're-inventing the wheel' and doing whatever someone feels is okay when working on your brakes is just plain insane....no matter how you slice it. THAT is my opinion. If any of this has offended anyone...then that should be telling them something. Keep in mind I DID NOT direct this at anyone. It has come from over 30 years of dealing with some customers who think they know more than me, but yet, do not know how to do what they are telling me to fix on their car. Go figure.
For what this is worth: There is a way to use the rotor shims and index the rotor PRIOR to it being riveted on if desired...but I can not help this company or any other that does not know how to do this. And by not knowing or spending the time to do so..they remove so much material..is a crying shame. By getting the rotor indexed correctly or so close that only a very few thousandths have to be machined off....will result in a new rotor that is still way above the minimal thickness AFTER refinishing. How do I know this...because I have done it...but what it does... it causes the cost of the job to increase... thus...does not make the attraction of getting a restoration service on your trialing arms with rotors riveted on so 'tasty' when it is advertised at an affordable rate.
I am done here...all I wanted to do was to do as the thread stated...BE AWARE of what you buy...and not mentioning who it is does not matter...because IF I did...some of you would never let it go....and it just is not worth it.
Thank you to all of those who 'get it'. All I wanted to do is pass along something I thought was important...and I see how it went sideways really fast...and that is truly sad.
'Vettebuyer6369',
If you fell the need to...you can shut this one down if you want. I am leaving that choice up to you.
Thank you Dub. David 
