golock911

Obvious statements and mimicking ahead: If this is up for popular vote, I vote no. As long as the full thickness meets the spec. Mic at several locations around the rotor. Also, the surface should be smooth( define smooth...)

plpete84

Let's not forget that not all pads are equal. When braking you have two surfaces rubbing against one another and wear will happen - that's a given. Technically rotors are made from a much harder material and will wear slower, where as pads can be organic, semi-metallic or ceramic, to name a few. Those have different attributes and will either wear faster or slower and in some cases can cause squealing noise and varying amount of dust. From what I understand, ceramic type pads will wear rotors much more than organic or semi metallic. They all have their applications and it might just depend on the driving you do and the pedal feel you want at the brakes.

e90steve

I'm more replacing everything because I'm doing a fluid swap... not that I necessarily need new pads or rotors. I could easily get another 10k out of them, but kind of a while I'm working on it thing. I do not track my car and have only done a few mountain runs therefore I don't stress the brakes much beyond regular driving.

sgt1372

Indeed, it's basically a cost comparison issue as far as buying new or turning old rotors.

Would still opt for new on my 911 even if turning were available, because the additional cost is not that great.

However, I recently replaced the front pads on my F250 and my shop turned the rotors for me w/o my even asking and only charged me about $50/rotor. Thought that was a fair price compared w/buying new ones which I didn't think was necessary

Imo000

You just quadrupled your work. Changing the fluid is a very simple process and depending on the rims you have, might not even need to remove them. There is even a simpler way of doing it but it takes a few times before the all the fluid is clean. You just take a turkey baster and place the fluid in the reservoir. Then a month later do it again. repeat this until your fluid is clear. Usually after the 3rd time it will be.

SoCal911t

I bought this caliper from Amazon that is specifically for measuring rotor thickness and it was around $45. It's one of those tools that doesn't get used that often but I do all my own work on all five cars so I thought the cost was justifiable for the peace of mind.

DreamCarrera

I've often wondered about this turkey baster method of changing brake fluid. Does it really work? Does the reservoir hold enough fluid, in relation to the total volume of the system, to make this method viable? Do you get enough circulation through the braking system to effectively change enough of the fluid after 3 or 4 times at, say, monthly replacement intervals? I doubt I would ever try this method but it may be an effective time saver for cars that require removal of the wheels to bleed the brakes for a fluid change.

JRitt@essex

As noted by others, if the discs are in fine condition there's absolutely no need to change them. Once your new pads are in I'd suggest a good bed-in cycle to lay down a nice pad transfer layer on the discs. You can see a bed in video in our essex learning center. If you track your car, another good video to watch would be our video "How to swap between street and race pads".

996.2

Lay plastic paint drop cloth on fender, drips from turkey baster can ruin paint.

Joel987

Brake fluid doesn't circulate in our cars. You remove the old fluid with a turkey baster from the master cylinder and replace it with new fluid and then start bleeding at the calipers. That way you start drawing fresh fluid through the lines more quickly than trying to push the old fluid in the master through the lines.

Imo000

Of course it works otherwise the fluid in the reservoir would not get dirty. It's a slow process but if you keep doing it every now and then, you will always have fresher fluid that if you did a complete flush every so many years.

Imo000

If it doesn't circulate then why does the fluid get dirty? Of course it circulates and is by convection and thermal expansion.

Joel987

Are you are saying that over time eventually some of the brake fluid that gets pushed against the caliper piston makes its way back to the master? There is no pump that circulates fluid around the brake lines. Have you ever noticed how dark brake fluid in the caliper is compared to the fluid in the master cylinder?

Perhaps I misunderstood the OP's comment on circulating the fluid.

Imo000

Yes the fluid slowly circulates and don't need a physical pump for this to happen due to convection helped by thermal expansion. Go get a glass of water, put a ice cube in it and a couple of drop of food dye to see how this works.......or better yet, just watch a lava lamp after it heats up. Both of these work on the same principal but in a much faster scale. Yes, there always will be more dirty fluid in the calipers but over time if you keep swapping out the reservoir, that new fluid will make it's way to the caliper too. If it didn't, the reservoir fluid will always remain clean but it doesn't.

Joel987

Makes sense. Now back to listening to Dark Side of the Moon while staring at my lava lamp...