Problem: Rotors returned by shop with Runout
11-14-2010, 02:54 AM
#1
Melting Slicks
Thread Starter
Problem: Rotors returned by shop with Runout
I was doing a complete front-end rebuild and took all my parts to a corvette only shop (Corvette Care in Rancho Cordova CA) to be sand blasted. The car only has 40,000 miles on it...the only reason I had to do the front-end job was the bushings were rotten and falling out of the control arms.
When they returned my rotor/hub assemblies they made me sign a document indicating that the rotors had a .02" runout. Sure enough...I mounted the rotor/hubs and they wobble. They didn't do that before and the rivets were not removed that I can tell, so they definitely turned the rotors with the rivets still attached.
How do I fix this? I've seen that Ironcross says to machine them while still on the hub, but that was apparently already done. I've seen others say to remove the rotor from the hub and they link to a web site at http://brakealign.com; however, that website says machining while the rotor is on the hub is not the way to do it...and says to use shims...but they are apparently out of stock. I don't know about anyone else, but it seems ludicrous to trust a company that does nothing but sell shims and calls it a "system" like there's more to it than just the shims.
And, another thing is that with all the problems why isn't one of our excellent vendors selling the rotor/hub already machined and assembled? It would solve 1/2 the threads related to brakes wouldn't it? To top it off all the vendors are selling rivets...aren't they hot rivets? I don't see any home mechanic able to use those rivets...I have a rivet gun for pop-rivets. What gives?
I don't want to cut off the rivets because I won't be able to put them back on properly. On the other hand, if I cut them off it doesn't look like I really need to do anything more than just stick them back in there with a little tack to hold them in place.
This is just a theory, but I'm guessing that the machine shop which turned my rotors left them on the hub and used a brake lathe which clamped the hub inner and outer facing together i.e. didn't align the inner machined area of the hub with the brake lathe and didn't use any shims to align the rotor with the lathe. Is this super ignorant of them? I had these done years ago...and my mother paid for it and not me and she refused to complain to them, so that bridge has already burned...I have to deal with them as is.
If I take the rotors to another shop will they be able to do it right? Now that I have the money to pay for it myself at least I could complain in court if they don't do it right and at least get my money back...but would most likely be left with rotors that are too thin which would mean I would need to buy new rotors and would be back to square one by having to either attach the hub to the rotor and try to find someone that could machine them properly or do the shim thing.
Should I take the rotor off the hub and shim it and "fake" the rivets back in? Should I take the rivet and hub to a shop that has a hot rivetter?
That brakealign.com website was talking about an on-car brake lathe...does such a thing exist? Would that be a better way to go? But, wouldn't that just be compounding the problem and taking more material off the rotors than is necessary? I've tried to find an on-car brake lathe, but couldn't find one...is this like a left-handed monkey wrench, elbow grease, sky hook, etc. and it doesn't exist? I've actually almost decided to buy a metal lathe and either build an on-car brake lathe or just try to turn the rotors true on my own.
Why isn't there a vendor stepping up to fill this crucial need?
When they returned my rotor/hub assemblies they made me sign a document indicating that the rotors had a .02" runout. Sure enough...I mounted the rotor/hubs and they wobble. They didn't do that before and the rivets were not removed that I can tell, so they definitely turned the rotors with the rivets still attached.
How do I fix this? I've seen that Ironcross says to machine them while still on the hub, but that was apparently already done. I've seen others say to remove the rotor from the hub and they link to a web site at http://brakealign.com; however, that website says machining while the rotor is on the hub is not the way to do it...and says to use shims...but they are apparently out of stock. I don't know about anyone else, but it seems ludicrous to trust a company that does nothing but sell shims and calls it a "system" like there's more to it than just the shims.
And, another thing is that with all the problems why isn't one of our excellent vendors selling the rotor/hub already machined and assembled? It would solve 1/2 the threads related to brakes wouldn't it? To top it off all the vendors are selling rivets...aren't they hot rivets? I don't see any home mechanic able to use those rivets...I have a rivet gun for pop-rivets. What gives?
I don't want to cut off the rivets because I won't be able to put them back on properly. On the other hand, if I cut them off it doesn't look like I really need to do anything more than just stick them back in there with a little tack to hold them in place.
This is just a theory, but I'm guessing that the machine shop which turned my rotors left them on the hub and used a brake lathe which clamped the hub inner and outer facing together i.e. didn't align the inner machined area of the hub with the brake lathe and didn't use any shims to align the rotor with the lathe. Is this super ignorant of them? I had these done years ago...and my mother paid for it and not me and she refused to complain to them, so that bridge has already burned...I have to deal with them as is.
If I take the rotors to another shop will they be able to do it right? Now that I have the money to pay for it myself at least I could complain in court if they don't do it right and at least get my money back...but would most likely be left with rotors that are too thin which would mean I would need to buy new rotors and would be back to square one by having to either attach the hub to the rotor and try to find someone that could machine them properly or do the shim thing.
Should I take the rotor off the hub and shim it and "fake" the rivets back in? Should I take the rivet and hub to a shop that has a hot rivetter?
That brakealign.com website was talking about an on-car brake lathe...does such a thing exist? Would that be a better way to go? But, wouldn't that just be compounding the problem and taking more material off the rotors than is necessary? I've tried to find an on-car brake lathe, but couldn't find one...is this like a left-handed monkey wrench, elbow grease, sky hook, etc. and it doesn't exist? I've actually almost decided to buy a metal lathe and either build an on-car brake lathe or just try to turn the rotors true on my own.
Why isn't there a vendor stepping up to fill this crucial need?
11-14-2010, 07:11 AM
#2
Melting Slicks
Member Since: Jan 2003
Location: Doha
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St. Jude Donor '08
how much they run-out now? , if its in the region of .006 or so then I would just put a set of O-rings pistons and forget about it, other wise, take your car to someone that has the machine that can surface the rotors while they are fitted in the car.
And speaking about the shims, I used a peaces of a coke can as shims and my rotors now has less than .001 run-out, still good after about 3 years.
And speaking about the shims, I used a peaces of a coke can as shims and my rotors now has less than .001 run-out, still good after about 3 years.
11-14-2010, 07:26 AM
#3
Team Owner
I don't know everything. But I've only seen machines that can turn rotors when the rotor is free of everything. Which requires removal of the rivets. Why would you want the rivets anyway?
Why don't you just call and talk to the shop and ask them how they machine rotors and then if they machined yours?
Shimming rotors is a common practise.
Why don't you just call and talk to the shop and ask them how they machine rotors and then if they machined yours?
Shimming rotors is a common practise.
11-14-2010, 08:06 AM
#4
Race Director
What is the present thickness of your rotors ?
When I turn front rotors I mark the high and low on the rotor and make sure when they go on the machine the highs and lows are at the same spots.
If you dont do this you can do more harm than good.
Sounds like your shop just threw them on the lathe and turned them.
When I turn front rotors I mark the high and low on the rotor and make sure when they go on the machine the highs and lows are at the same spots.
If you dont do this you can do more harm than good.
Sounds like your shop just threw them on the lathe and turned them.
11-14-2010, 10:01 AM
#5
On car brake lathe:
http://lmgtfy.com/?q=on+car+brake+lathe
Why did you have the rotors turned in the first place? Are you sure they were turned at all if you just asked for 'sandblasting'.
Sounds like you jumped in the water without first looking.
http://lmgtfy.com/?q=on+car+brake+lathe
Why did you have the rotors turned in the first place? Are you sure they were turned at all if you just asked for 'sandblasting'.
Sounds like you jumped in the water without first looking.
11-14-2010, 12:06 PM
#6
Burning Brakes
I don't know everything. But I've only seen machines that can turn rotors when the rotor is free of everything. Which requires removal of the rivets. Why would you want the rivets anyway?
Why don't you just call and talk to the shop and ask them how they machine rotors and then if they machined yours?
Shimming rotors is a common practise.
Why don't you just call and talk to the shop and ask them how they machine rotors and then if they machined yours?
Shimming rotors is a common practise.
When the rotor is still attached to the hub you use the bearing race to mount properly. If the shop turns the rotor correctly to the bearings there is no runout. But this subject always receive a lot of different ways to do the job but just turn the rotor correctly to the bearing and you are good to go.
11-14-2010, 12:29 PM
#7
Race Director
Many shops I have seen have brakes lathes that are 30 years old and in need of serious rebuilding.
Even shops with "in spec" lathes have operators that have no more business turning rotors than a grocery store clerk.
First the bearing races must be installed properly, mounted on a good brake lathe and fine minimal cuts made with the rotors still rivited to the hub. A lot of shops to save a lot of time take huge cuts, not the right way.
That is by the most accurate way to have the fronts turned.
Hopefully you have enough meat left for a proper turning.
Next time ask to see the lathe, ask to watch, and ask how much runout they guarantee. You should be able to achieve almost immeasurable runout.
If your last resort is to get new rotors because too much has already been turn away, then permanently mount them to your existing hub after prepping both mating surfaces.
Here is a process for that, once done they can be turned properly to adjust for runout. Turning when possible, is always preferred to shimming. You can search for other posts by Gary, he does his properly, but I don't know if he has a lathe capable of rotors.
Even shops with "in spec" lathes have operators that have no more business turning rotors than a grocery store clerk.
First the bearing races must be installed properly, mounted on a good brake lathe and fine minimal cuts made with the rotors still rivited to the hub. A lot of shops to save a lot of time take huge cuts, not the right way.
That is by the most accurate way to have the fronts turned.
Hopefully you have enough meat left for a proper turning.
Next time ask to see the lathe, ask to watch, and ask how much runout they guarantee. You should be able to achieve almost immeasurable runout.
If your last resort is to get new rotors because too much has already been turn away, then permanently mount them to your existing hub after prepping both mating surfaces.
Here is a process for that, once done they can be turned properly to adjust for runout. Turning when possible, is always preferred to shimming. You can search for other posts by Gary, he does his properly, but I don't know if he has a lathe capable of rotors.
I might be of help here. Center punch and drill into the rivet shaft with a 5/16 Bit. Then use a cold chisel to cut across the diameter of the "dime", a couple of good wacks and the flat will split and leave the shaft, then drive it out. If you want to get fancy, what I do to dail them in is to countersink the rotor and tap the rivet hole 3/8-24 and use socket flat heads.....
Gary
Gary
11-14-2010, 12:40 PM
#8
Race Director
When the rotor is still attached to the hub you use the bearing race to mount properly. If the shop turns the rotor correctly to the bearings there is no runout. But this subject always receive a lot of different ways to do the job but just turn the rotor correctly to the bearing and you are good to go.
11-14-2010, 06:43 PM
#9
Race Director
My hub is out, it is the part that has the runout, my rotor is fine so after trying to fix the runout on the rotor for sometime I bought O ringed calipers and have a couple of Coke can shims in there for good luck and I haven't had a problem in 2 years now
11-15-2010, 09:15 AM
#10
Supporting Vendor
As soon as a certain company finishes their production of new hubs there will be hub/rotor assemblies available, but until that time it will be difficult to come up with hubs. Here at our shop we can and do machine the rotors both ways: on-car and off-car. We do have an on-car lathe, and that works wonderfully. We also can machine the rotors off-car with the hubs in them. If the hub is out of round we can machine the hub face to true to correct for run-out. I cannot fathom why any shop would not or could not correct .02" (TENTHS!) run-out. That much run-out is dangerous, and can cause brake failure in a car with lip seals.
11-15-2010, 09:33 AM
#11
Burning Brakes
Member Since: Dec 2007
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Where do the coke can shims go? Between the hub and rotor to fix the runout???
11-15-2010, 09:42 AM
#12
Safety Car
so many shops don't even turn rotors and drums anymore, easier and cheaper to just replace them. if I took my rotors to a shop, I bet 95% of them would tell me that they could not machine them down enough and still be in spec ( not too thin). I used to work on brakes in a shop and this is amost always what we told our customers.
yes, find a shop that does this and has the proper equipment, and the proper training to use the equipment. They should be able to tell you exactly what the spec is. But expect to pay for it too.
alot of people will tell you that even new rotors are delivered out of spec.
anything above even minimum bearing play will cause wobble. if the problem is in the rear then you need specific expertise to set up the bearings, escalating your costs.
I have struggled with this also..I am on my 3rd caliper and 1 new rotor. They start to pump air after either a long drive or a year of time. my next step is o-ring calipers.
yes, find a shop that does this and has the proper equipment, and the proper training to use the equipment. They should be able to tell you exactly what the spec is. But expect to pay for it too.
alot of people will tell you that even new rotors are delivered out of spec.
anything above even minimum bearing play will cause wobble. if the problem is in the rear then you need specific expertise to set up the bearings, escalating your costs.
I have struggled with this also..I am on my 3rd caliper and 1 new rotor. They start to pump air after either a long drive or a year of time. my next step is o-ring calipers.
11-15-2010, 10:46 AM
#13
Team Owner
When the rotor is still attached to the hub you use the bearing race to mount properly. If the shop turns the rotor correctly to the bearings there is no runout. But this subject always receive a lot of different ways to do the job but just turn the rotor correctly to the bearing and you are good to go.
11-15-2010, 11:02 AM
#14
Race Director
.02" Wow I misread that one too, hate to have that shop build a motor for me " Sign on this line here stating you are aware the crank is not straight by 1/4 of an inch, should run fine though"
you could get into some serious trouble with runout approaching 1/4 of an inch
11-15-2010, 11:40 AM
#15
Race Director
Yes that is where I put them, only on 3 studs, 1 shiim on the two outside and 2 shims on the stud in the middle. I did buy the 0 ringed calipers at the same time so who knows if the shims worked. They didn't work with the lip seal rotors
.02" Wow I misread that one too, hate to have that shop build a motor for me " Sign on this line here stating you are aware the crank is not straight by 1/4 of an inch, should run fine though"
you could get into some serious trouble with runout approaching 1/4 of an inch
.02" Wow I misread that one too, hate to have that shop build a motor for me " Sign on this line here stating you are aware the crank is not straight by 1/4 of an inch, should run fine though"
you could get into some serious trouble with runout approaching 1/4 of an inch
Car would probably have lost a wheel by the time the runout was 1/4", or worse.
11-15-2010, 09:01 PM
#17
Race Director
11-16-2010, 07:01 AM
#18
Melting Slicks
Thread Starter
Thanks for the responses. I have yet to measure the run-out myself...a precision dial indicator is next on my list of tools. But, I don't need a dial-indicator...I can visually see the rotor wobble...I can also feel it by spinning the rotor while squeezing the brake pads onto the rotor. I suspect the run-out is a lot more than .02"...it's more like .1" but not .2". Using the rotors in their current condition would be suicidal.
The rotor was turned because that's what the shop said was done...and it was obvious from the condition of the surface. But, the shop didn't do it themselves...they don't have the equipment...they sent them out to have them done and wouldn't say where they sent them...simply someone that they always use.
I was very upset because the rotors had less than 50,000 miles on them and had never been turned before...based on the condition of the rotors and the previous owner gave me all of his repair receipts. The races were new...I personally replaced them just the year before along with new bearings and the brakes were solid...there was absolutely no detectible run-out...I could hold the pads to the rotor and spin the rotor and there was uniform braking all around the rotor. The rotors still have a lot of material left...the outer disk is .3" on both...the inner disk on one of them is .27" while the other is .24"...which I gather is due to the shop trying to "fix" the run-out without knowing what they are doing. I can see that the run-out is in the hub though...because the whole rotor wobbles. If the shop used the race then there would not be any run-out. Actually, if the shop knew what they were doing they would have just taken one look at the rotors and taken a piece of fine sandpaper to the surface and charged me for a complete lathe job.
The problem I've seen in many shops is the hiring of in-experienced people to do the actual work. I worked as a fleet mechanic for a wholesale gift & jewelry business that had a fleet of vans and vehicles to sell as State Fairs. When I first started the owner wanted me to take the vehicles to a local Firestone repair shop if it required jacking the cars up because he didn't want me getting hurt. I had them replace the shocks on a station wagon. When I dropped it off the "mechanic" who I was told would work on the car was like 16 years old...they assured me that they would inspect his work. I drove it back to my shop and checked the workmanship for myself. I found a nut loose and almost about to fall off. The owner bought me a floor jack and jack stands that same day.
So, it's my guess that someone that didn't know what they were doing cut my rotors up. There's just enough material left for a proper turning, but I wouldn't risk a 2nd turning after that. The only other reason would be rediculous to believe that the shop purposefully created the run-out...but then again...why did they return them to me with the run-out instead of just asking me if I would like them to be shimmed or whatever. In other words Corvette Care never offered to get it fixed...they just wanted me to sign a statement saying that they were informing me that the rotors had a .02" run-out.
The rotor was turned because that's what the shop said was done...and it was obvious from the condition of the surface. But, the shop didn't do it themselves...they don't have the equipment...they sent them out to have them done and wouldn't say where they sent them...simply someone that they always use.
I was very upset because the rotors had less than 50,000 miles on them and had never been turned before...based on the condition of the rotors and the previous owner gave me all of his repair receipts. The races were new...I personally replaced them just the year before along with new bearings and the brakes were solid...there was absolutely no detectible run-out...I could hold the pads to the rotor and spin the rotor and there was uniform braking all around the rotor. The rotors still have a lot of material left...the outer disk is .3" on both...the inner disk on one of them is .27" while the other is .24"...which I gather is due to the shop trying to "fix" the run-out without knowing what they are doing. I can see that the run-out is in the hub though...because the whole rotor wobbles. If the shop used the race then there would not be any run-out. Actually, if the shop knew what they were doing they would have just taken one look at the rotors and taken a piece of fine sandpaper to the surface and charged me for a complete lathe job.
The problem I've seen in many shops is the hiring of in-experienced people to do the actual work. I worked as a fleet mechanic for a wholesale gift & jewelry business that had a fleet of vans and vehicles to sell as State Fairs. When I first started the owner wanted me to take the vehicles to a local Firestone repair shop if it required jacking the cars up because he didn't want me getting hurt. I had them replace the shocks on a station wagon. When I dropped it off the "mechanic" who I was told would work on the car was like 16 years old...they assured me that they would inspect his work. I drove it back to my shop and checked the workmanship for myself. I found a nut loose and almost about to fall off. The owner bought me a floor jack and jack stands that same day.
So, it's my guess that someone that didn't know what they were doing cut my rotors up. There's just enough material left for a proper turning, but I wouldn't risk a 2nd turning after that. The only other reason would be rediculous to believe that the shop purposefully created the run-out...but then again...why did they return them to me with the run-out instead of just asking me if I would like them to be shimmed or whatever. In other words Corvette Care never offered to get it fixed...they just wanted me to sign a statement saying that they were informing me that the rotors had a .02" run-out.
11-16-2010, 12:21 PM
#20
Race Director
It was a Corvette Shop ? I had a terrible time with a Corvette Shop that was in business for over 20 years. Bolts not tightened down on my rear spring, opened the garage and the Vette was leaning to one side because the strut rods weren't tightened, 2 different springs on the front etc.
Anyway, all I asked him for was a spring that would match the one with the correct height he installed and he refused to give it to me. I have no idea why this POS would do this as I was kind and courteous, didn't bother him and just waited for a phone call when it was done.
This was in 1995 and I know many many Corvette owners I have steered away from him that he has lost so much money over a $20 spring he could be retired now.
This was the reason I began doing everything myself. I now have a pretty well equipped garage with tools I have bought over the past 15
years. I can do almost anything to my Vette at home so no one with a "Vette Shop" gets their hands on it.
Post the shops name and address that butchered your rotors
Anyway, all I asked him for was a spring that would match the one with the correct height he installed and he refused to give it to me. I have no idea why this POS would do this as I was kind and courteous, didn't bother him and just waited for a phone call when it was done.
This was in 1995 and I know many many Corvette owners I have steered away from him that he has lost so much money over a $20 spring he could be retired now.
This was the reason I began doing everything myself. I now have a pretty well equipped garage with tools I have bought over the past 15
years. I can do almost anything to my Vette at home so no one with a "Vette Shop" gets their hands on it.
Post the shops name and address that butchered your rotors