Turning Roters

[MuddFlapp]

In past posts I've read that it is recomended to turn the roters on my 4X6 while they're on the truck. Anyone want to tell me why and what the results would be if I remove them & have them turned. Try & find someone to turn them on the truck in my area of the world.



Thanks,



Gene Earl.

 

[illflem]

Gene, the only reason to turn your rotors is if they are scored. If you are only changing pads just lightly sand the glaze off with emery cloth. If they are warped replace them, I've found that on warped rotors the warp usually returns if they are turned. If you do have them turned make sure it's by someone who knows what they're doing. I let my OEM pads wear down too much and scored the rotors, took them to my local NAPA, who usually does an excellent job, and they ruined them. They replaced them with Bendix rotors for free, only $52 each new anyways. Those same rotors now have over 100k on them. The Dodge rotors are very hard, few folks can turn them correctly. My closest dealer can only turn them on the rig, they don't have a machine to do it any other way, still doesn't mean I'd trust them to do it though.

 

[1tuffram]

Illflem,



Do you know the specific reason for turning the rotors on the truck as opposed to removing them? Wasn't there an article in a previous TDR issue talking about it and saying turning the rotors on the truck is what Dodge is recommending now. I can't remember the rational for turning the rotors on the truck.

 

[tgbol]

The best reason for turning the rotors on the truck is you get a truer cut. When mounting the rotor on a drum lathe it can be quite a job to get the rotor true. Causing some problems when put back on. 4x4's are the hardest to mount on the lathe. I won't cut my discs unless it is deeply scored or warpped

 

[Shovelhead]

Turning rotors

The main reasons for turning the on the vehicle would be to avoid the rotor being placed on the turning lathe incorrectly (too much runout, cocked to one side, or clamped too tight) causing even more problems when reassembled. Also takes less time than removing the rotor, caliper, and prevents damage to the brake line from the mech. letting the caliper hang by the hose.

Also might be a reciprocating mass balancing issue.





JMHO





Dang ... I hope I spelt that write

 

[Joe G.]

Gene,



I agree with illflem about turning the rotors. There is barely enuff metal to start with so if you remove any the rotors will have a shorter life. As long as they are in spec for run out just sand the glaze off. In fact, if my rotors need turning one of these days I'll replace them. 171K miles on the stock rotors so far.

 

[1tuffram]

I'M getting ready to do a brake job. I notice on my rotors there is a "lip" around the outer edge where the pads do not touch, the surface where the pads touch/brake is smooth. Do my rotors need to be turned or replaced? I've always been under the impression when installing new pads & shoes you want a "new" surface for the pads or shoes to wear into.



Also I read about sanding the glazing off the rotors. What are you guys using. I saw a Shade-Tree Mechanic episode where they used a special kit with Scotch-Brite looking drill attatchment things from 3M to remove the glazing. I have seen some similar Scotch-Brite looking things at Sears, would these work? Also what "grit" so to speak do you need for removing the glazing??

 

[Joe G.]

Actually I don't know what grit I used. It was pretty rough. I just used what was on a sanding disk I had for my drill. The rotors are pretty hard so it still takes some work to affect the glaze. The run out spec is . 005". Mine were . 002" on the worse side. I think the milage on them when I did the brake job was somewhere around 150K. I cut the little ridge off with the sanding disk. There were a few small rock gouges but nothing to get excited about.

 

[MuddFlapp]

Roters

OK, the reason I'm asking about turning my roters is because I feel like one or both are warped or have a hot spot that has gotten hard leaving a high spot on the roter. I can feel it when I stop (especially hard stops) "shaking" the steering wheel back and forth. I had this problem with my '85' D-150 until I replaced the roters on it.



Soooo! If new roters are only $52 each, the heck with turning, I'll replace them.



Thanks for all the help.



Gene Earl.

 

[Extreme1]

I would still turn 'em...

Look closely at the proceedure to remove them. The've been there for many years and won't come apart easily. I have replaced a cracked one and then had both turned a couple years later. If you take it apart far enough to replace the rotors, replace the axle u-joints and both ball joints too. This is one operation where the labor time is huge.



Good Luck with what ever you end up doing.

 

[SMorneau]

I will summarize the results of mine that were published in an old TDR. For my 96 4x4"



Rotors turned off of the truck had about . 025" runout ( This is 5 x spec and they shook like crazy)

Rotors turned on the truck had about . 0005 (1/10 of the spec)



The reason is the bearing assembly my not be true to the axis that a brake lathe will find. It won't matter if the person doing it is excellent or not. They are not physically the same centers.



You should measure them with a dial indicator and, as others have stated, not turn them unless necessary. Also, I have had the rear drums give symptoms that can be mistaken for front disc problems.

 

[BC]

MuddFlapp,



I had my rotors turned last week. Got new brake pads, replaced the brake fluid, and adjusted the rears as well.



I got a lot of info, as well as ordered the brake pads from Sam Peterson, who's on this board. Went with Carbomet pads (I think that's the name). Anyway, do a look up.



I did the rotors for the same reason you are doing them, I had a bad shimmy in the wheel when I was coming to a stop. I thought I was leaving for Wyoming this past Sunday and didn't want any brake problems.



Everyone told me to have the rotors turned IF I was having the shimmy. The advice was varied about whether to turn rotors everytime you replace the brake pads. Sam Peterson, who does brakes for a living, said it was best to turn rotors everytime you put on pads. Again, email or call him, he has good advice. I'll stick by his advice unless I learn something different.



I had my brake job (he didn't have the equipment to turn the rotors on the truck) done by a local guy who let me watch and help. I don't know the first thing about brakes. It was about impossible finding someone who could turn the rotors while they were still on the truck. I ended up going to Dodge. I asked for the most experienced brake guy. He did a good job. Last year I had lots of brake work done and they did a crappy job... I learned to ask for a certain person to do my brakes at the dealership.



Just got back from the Smokey Mountains. One of the roads we traveled was hwy 129. Real twisty-turney and up and down. No problems, no more shaking in the wheel.



Hope this helps.



Bill Cook

 

[SMorneau]

BC, Did you actually put an indicator on the rotors? It is possible that your rotor/bearing assemblies had "centers" that were close and they turned just fine on a brake lathe. Measuring the runout is the only way to know.



After seeing 0. 0005" of run-out I will ALWAYS have my rotors turned on the vehicle. This is very low.

 

[BC]

SMorneau,



Sorry, I can't answer your question. I wasn't allowed in the Dodge shop where the rotors were turned. Bummer.



Also, your question is over my head. I don't know what "rotor/bearing assemblies have "centers"" means. I also don't know what "run-out" means.



Can you educate me a little?



Also, I did buy a Haynes book about brakes. Haven't had a chance to read it yet, but will in the up coming weeks. Hopefully I won't stay ignorant.



SMorneau, have several other questions for you, if you don't mind.



First, I just installed the Rancho RS 9000s on my truck. I was wondering if I need to replace the stearing stabilizer. I see that you have a RS5000. How did you know it was time to replace the stock? I have 123,000 miles and pull heavy (12,000 plus pounds) 5 to 8 times per month.



Second, I had decided to add airbags, because I often pull heavy. After adding the 9000s I decided I didn't need them. You have both. What do the air bags do for you that the 9000s by themselves don't?



Thanks for any info.



Bill Cook