My DIY Brake Rotor Refinisher

[Mud]

Hopefully, the pics will save a few thousand words!

General info:
- We live in a rural area, not convenient to take rotors in to an auto parts, yet I like to have a fresh finish for new pads. Please note that since I usually don't run rotors to the core, I'm not talking about cutting them.
- I used a 1/3 hp 115/230v 1750 rpm bought new on ebay for about $40. The 1750 is a bit fast but it still works fine.
- Turntable that the rotor rests on is intended to take weight off of the motor. Came from McMaster-Carr.
- Motor is mounted on unistrut to allow it to slide to adjust bolt plate to mount to rotor.
- Frame is made from some scrap angle and a couple pieces of plywood.
- Studs are not on a dead-centered bolt circle so the rotor will wobble a bit when turning but has not been an issue.
- To use, I flip the switch, rotor spins. While it spins I take a drill with the hone brush and apply to the spinning rotor with a little back and forth motion. Only takes a few minutes per surface to get a decent fresh finish.
- Checking rotor thickness with a dial caliper shows negligible material removal.
- I've used it twice with good results. We have enough cars/trucks in the family and it was cheap enough to build that I figured it to be feasible and easy to build project.

 

[eljefino]

How would this differ from using the car's drive axle as a motive source? You could theoretically stick a front rotor on a rear drum (for RWD) with the cars own lugnuts. Set the cruise for 60 when it's up on the jack and have at it!

 

[beanoil]

Originally Posted By: eljefino

How would this differ from using the car's drive axle as a motive source? You could theoretically stick a front rotor on a rear drum (for RWD) with the cars own lugnuts. Set the cruise for 60 when it's up on the jack and have at it!

That is NOT a good idea. And if I have to explain why, all I can say is you may want to resist the temptation to service your own vehicles.
MUD, that is slick. Pretty ingenious.

 

[saberz]

If something happens while its on the jack something bad will happen(ie. car falls off jack and slides into building etc).


Smart idea though!

 

[eljefino]

Originally Posted By: beanoil
Originally Posted By: eljefino

How would this differ from using the car's drive axle as a motive source? You could theoretically stick a front rotor on a rear drum (for RWD) with the cars own lugnuts. Set the cruise for 60 when it's up on the jack and have at it!

That is NOT a good idea. And if I have to explain why, all I can say is you may want to resist the temptation to service your own vehicles.
MUD, that is slick. Pretty ingenious.


I never said it was a good idea, just asking for a comparison.

With an e-brake set on the drive wheels, and a rotor spinning with an open differential, if it slips off the jack there won't be enough traction to go anywhere.

 

[Jim 5]

Nice work!

Nobody builds anything anymore. I love seeing stuff like this. Keep them coming!

If you have a floor model drill press, you could lower the table low enough to clamp this whole device onto the table, then chuck the honing tool into the drill press and apply uniform pressure.

 

[oilboy123]

I like the idea overall. Looks like it leaves a perfect roughing up pattern. You should patent it. Being posted on this board shows that you had the idea and the date.

One little thing is it would be nice to have the studs that hold the rotor to adjust so you can run different sized bolt patterns on it. If you lived near me I would want to bring my Rotors to you. You try it on drums?

Good luck with it.

 

[Jim 5]

Originally Posted By: oilboy123
I like the idea overall. Looks like it leaves a perfect roughing up pattern. You should patent it. Being posted on this board shows that you had the idea and the date.

One little thing is it would be nice to have the studs that hold the rotor to adjust so you can run different sized bolt patterns on it. If you lived near me I would want to bring my Rotors to you. You try it on drums?

Good luck with it.


It's been a while since I studied patents, but as I recall one of the requirements of patent is that you haven't revealed your idea publicly, and posting it on this board eliminates the possibility of meeting that requirement.

 

[Mud]

thanks for your input and comments, interesting idea on the patent - one in every garage! I get so much info from BITOG though, just wanted to send something back.

I had thought about doing the adjustable studs but was limited on time, needed to get this done so I could cross off brakes from the to-do list. By concidence our crown vics and accord have the same bolt pattern so it was quicker to make the wooden plate. Next update will incorporate a slotted plate to make the BC adjustable.

Regarding use of a drive wheel, I would not want to get around anything spinning with lots of torque that I could not stop if something got caught up in it. I use my tractor at times and have a lot of respect for that spinning pto! With the 1/3 hp motor, you can stop the rotor if needed with a gloved hand (not that I would want to) and even if you apply too much pressure with the hone you can slow down the rpms.

I think that a real brake machine operates at 150 or 200 rpm so even the 1750 is pretty dang fast in comparison. I did look into a motor speed control but unless I goofed looking at info, it seemed that an ac motor speed control was very expensive and not feasible for this particular project.

That's a great idea about having a drill press sort of arrangement where you could apply constant pressure, but what I found was that just holding the drill by hand allows for a slight back and forth motion across the surface to get that circular looking finish.

 

[SteveSRT8]

X2 on the kinda fast!

Slow that down and I'll take one!

One heck of a sharp idea.

 

[UncleS2]

What? You did that without asking anyone, or getting gov't clearance, or appointing a committee, or anything?

Excellent!

 

[eljefino]

Let us know if this thing fixes a "troubled" rotor, like one that causes pedal pulsations. Not from warpage, but from uneven pad deposits or whatever they're blaming these days.

 

[Mud]

Originally Posted By: Stuart Hughes
What? You did that without asking anyone, or getting gov't clearance, or appointing a committee, or anything?

Excellent!

Yup, I expect to be hearing from the brownshirts any day now

Regarding truly bad (warped rotors), I think it may depend on how bad they are. If slight, it seems that a constant pressure with stone and/or abrasive paper may help but I don't know if that may just wind up following the warpage or not. It's worth a try since the worst is you would have to replace or get the rotor properly turned down. My main goal was to get a clean prepped surface for basic pad replacement on rotors in good shape - for me, that is the situation on 99% of the brake work I do.

 

[oilboy123]

Dang.....you're halfway to making a brake lathe. That should be your next project.

An affordable home brake lathe/surface finisher.

 

[Ducked]

Originally Posted By: eljefino
Originally Posted By: beanoil
Originally Posted By: eljefino

How would this differ from using the car's drive axle as a motive source? You could theoretically stick a front rotor on a rear drum (for RWD) with the cars own lugnuts. Set the cruise for 60 when it's up on the jack and have at it!

That is NOT a good idea. And if I have to explain why, all I can say is you may want to resist the temptation to service your own vehicles.
MUD, that is slick. Pretty ingenious.


I never said it was a good idea, just asking for a comparison.

With an e-brake set on the drive wheels, and a rotor spinning with an open differential, if it slips off the jack there won't be enough traction to go anywhere.


The only explanation offered so far for this non-specific put-down is that you shouldn't do maintenance because it's bad if your car falls off the jack??

No kidding.

I've done disk clean-up using the car engine. I use an axle stand, as I do for any wheel-off procedures. The engine is at idle so its a bit slow. It doesn't seem to be especially unsafe, but of course you have to be careful when you have your hands near a spinning hub.

Access isn't very good to the rear of the disk but I havn't tried disk-flipping, which would be awkward on this car.

In this vid (not me) seems to wobble quite a lot with them flipped.

https://www.youtube.com/watch?v=RdMFpuLCcxA