Hello everyone this is my first post so please bear with me. I need to install a new front rotor on my 1993 f250 4x4 and I am puzzled by the auto parts store. When i went to get a new rotor, the clerk told me that the new one would need machining. Here is the actual quote from the rotor description: "Front; 4WD; Disc only - Machine rotor after re-hub so rotor is true to center line of hub." Can anyone explain this to me? I look forward to hearing from everyone and thanks for the great site.

 

Your going to separate the hub and rotor from each other by knocking all the studs out after you remove it from the truck.

Use a press, a brass drift, put a lug nut on backwards, buy two nuts at the hardware store and tighten them against each other at the very end etc etc, whatever you have available to you to protect the threads while you pound each of them out the back side of the hub.
You can just replace them all but that would be expensive! lol

Then clean the mating surface, scrape and wire brush it until its clean and flush, put the new rotor on lining up the stud holes, drive all the studs back in from the back, use a nut and a couple flat wasters to draw the stud in until they are fully seated locking the hub and rotor tight together.

Then take the assembly to an auto parts and have the rotor trued to the hubs center line. They won't remove much depending on the quality of the parts, just enough to remove any "run out", say like adjusting bicycle spokes so the rim is "true".

Do not remove the bearing raceways, they need to be in place when the rotor is turned, doing so will not damage the race's.

 

very good explanation, danr1.

 

Thanks quicklook2,

I tried not to be to "wordy" at it.

 

Just to add to danr1s great answer, if you've never done it before getting the studs in and out can be a pain in the thumb. A good machine shop will do it for ya for a few more bucks then turn them and give'em back clean and good to go. They will also do it "right", technicaly the studs are supposed to be swedged when installed but I never saw the point.

 

"swedged"?

 

"Swedged" let's see if I can explain. It's like a rivet, the top (wheel side) off the shoulder is expanded over the rotor. This is done on a press with a tool that just fits over the threads and alot of pressure. It serves the purpose of locking the rotor very securely on the hub and prevents the stud from coming out the back when the wheel is installed. This swedging is a hude part of why these studs can be hard to pound out with a hammer. (but that is still how I did it when working at a machine shop, two hammers one brass on top of the stud and hit it with a 3 pound mini sledge) It is always best to swedge them but in many cases is unnessasary because the studs are a tight press in the rotor, if they are not tight in the rotor swedging becomes more important so that the rotor will stay true and you can install the wheel without the studs falling out the back.

 

Thank you to everyone who has replied to my post. Sorry for the delay in posting thank yous.