Brake Disk Refurb?

[Guest]

I bought a used front brake rotor for the GS550, and it has a few grooves. I'd like to get it ground flat. Local car places won't touch it. My local machine shop guy says it has to be ground flat and he doesn't have the right equipment.

Does anyone know a place within 100 miles of Providence, RI where I could get this rotor refurbished?

Thanks.

[7981GS]

If you really want to, any place that surfaces flywheels can do it.

On the 1200G project, I just used rolox pads on an angle die grinder and worked it around until the grooves
were to a uniform depth. (light record grooves)
Then, installed new pads and applied the brakes repeatedly going down the road until they seated.
So far so good.




Daniel

[FiremanBob]

Thanks. I found an automotive machine shop that does flywheel grinding. They said they did one other motorcycle rotor and it was expensive. Apparently the hardness of the steel requires a very long time on the grinding machine to produce a smooth surface, and the job could cost as much as $125. They are going to give it a try on Monday to see how bad it would be.

I'll update then.

[bwringer]

You're much better off to simply live with a few harmless grooves.

In other words, grinding or resurfacing motorcycle rotors is a Very Very Bad Idea.

Measure the thickness, then compare that to the minimum thickness marked on the rotor. You'll find that there's little to no room to remove material and be left with a usable rotor.

[hampshirehog]

Sound advice from Brian. If it's been run for a while with knackered pads (ie no material, just the metal backing) then it could be a throwaway. So what I'm saying is it depends how bad the grooves are.

If not too bad and it measures up ok it'll be fine - the pads will quickly wear to suit the grooves. If you're looking for a cosmetic improvement you can sand with an orbital sander, with ,say, a 120 grit disc, and as long as you're not hanging off the thing for half a day you can tidy a disc up nicely without ruining it.

[Flyboy]

+1 ^^^^ There is not much to play with, I don't know about the 550, but on my 1000G the discs come from the factory at 5mm and the minimum thickness is 4.5mm, so only .5mm from full thickness to scrap.
I would just live with the grooves.

[FiremanBob]

Just got the machined rotor back from the shop. It has a beautiful finish and mikes at 6.8mm, so there is plenty of meat on it. The work wasn't cheap at $75, but a new EBC rotor is $215 so I'm still in at less than half the cost of a new part.

Here's the pic:

[Road_Clam]

I bought a used front brake rotor for the GS550, and it has a few grooves. I'd like to get it ground flat. Local car places won't touch it. My local machine shop guy says it has to be ground flat and he doesn't have the right equipment.

Does anyone know a place within 100 miles of Providence, RI where I could get this rotor refurbished?

Thanks.

The correct way to re-machine rotors is by surface grinding. You can machine rotors in a lathe, but it's difficult and very time consuming. I turned my rotors on my GS1100 (they both were warped. I was able to get them to within .009 runout. The problem is you inherantly get tool insert "chatter" because of the interrupted cut from the drilled holes in the rotor surface. Machining rotors can also become a liability issue as all rotors have a stamped "min thickness" dimension.

[FiremanBob]

Let me be clear: the surface was ground with a stone. It was not cut. The thickness is still .8mm greater than the service limit per the manual.