What should my rotors look like?

jhaynie · #1 (**permalink**) 03-24-2003, 02:50 PM

I knew my car has never had outstanding brakes (after 1400 miles of use, 2400 total miles). I took my wheels off today for the first time since I have owned the car and it was odd to me that the front rotors have absolutely no signs of wear. They are as slick as brand new rotors and the "swirl" marks from the factory are still plainly visible. Should there be some radial marking from the pads or something after 2400 miles?

Wild Cobra · #2 (**permalink**) 03-24-2003, 03:19 PM

Depends how you drive. If you drive on breaks or clutch for that matter they will wear off within couple of thousand miles, driven on gas instead of breaks will last a long time.

Mr.Fixit · #3 (**permalink**) 03-25-2003, 01:13 PM

Get harder pads, the rotors will go away quicker for you, if that's what you prefer.

excelguru · #4 (**permalink**) 03-25-2003, 05:40 PM

"Radial" is the wrong term. I think you mean "concentric". I looked at mine after our phone conv and mine have the concentric wear pattern. Either you have really soft pads or your fronts aren't being used enough. My money is on the brake bias adjustment.

Sorry my phone cut out the other day. I drive through the middle of nowhere on my way home. No signal.

Keith

Steve R · #5 (**permalink**) 03-26-2003, 09:54 AM

Drive the car, lock it up in a skid. Look at the skidmarks and determine which wheels are locking. Do the rears lock up before the fronts?

xlr8or · #6 (**permalink**) 03-26-2003, 01:59 PM

It may be an issue with needing to bleed the brakes as well.
If you have air in the front lines or calipers you will not get the line pressure required to use the brakes effectively.

I would go with a good bleeding first before messing with the brake bias. Otherwise you'll just have to go through adjusting it again later when you change brake pads and bleed them properly.

Scott

scottj · #7 (**permalink**) 03-26-2003, 02:22 PM

Did you bed the pads?

The most common visual indicator of pads that aren't bedded properly are rotors that are showing no wear.

Scott

jhaynie · #8 (**permalink**) 03-27-2003, 07:20 AM

ok, I'll bleed the brakes before I adjust the bias. Scottj, How do you bed the pads? This car wasn't driven much for around a year (only 1200 miles) and I don't know if the pads were bedded or not.

computerworks · #9 (**permalink**) 03-27-2003, 07:34 AM

Quote:

Originally posted by Steve R

Drive the car, lock it up in a skid. Look at the skidmarks and determine which wheels are locking. Do the rears lock up before the fronts?

...isn't it easier to see if the front calipers are working at all; jack up a front wheel, give it a spin and depress the brake pedal?

How do you test shocks, Steve? ...jump a row of school buses?

(..btw, Steve, what are you thinking of trading for? ...and how've you been?)

scottj · #10 (**permalink**) 03-27-2003, 08:11 AM

Pad bedding is accomplished by SLOWLY heating the pads until the entire thickness of the pads are hot. Then let the pads cool completely. This cures the pads and releases gases that are trapped in them during manufacturing.

Drive slow, alternate 3 seconds on the brakes, 3 seconds off, 3 on, 3 off, until the brakes are hot and then let them cool completely.

If pads aren't bedded, and you make aggressive stops, the surface of the pad will glaze. This will then prevent the pads from bedding, reduce their coefficient of friction, make the pedal hard and reduce stopping power.

The degree to which braking performance is reduced by not bedding will vary depending on pad type, compound, manufactuer, etc.

I fought a hard pedal, and no stopping power combined with zero rotor wear until a guy from one of the brake companys said, "you are bedding the pads correctly, right?" And I went, "huh?"

Now, regardless of pad type, I bed them.

Scott

jhaynie · #11 (**permalink**) 03-27-2003, 10:49 AM

If the pads are already glazed, is it too late to bed them? I would hate to have to change all of the pads, they are barely used.

scottj · #12 (**permalink**) 03-27-2003, 02:35 PM

If they are glazed they will look shiney. Just take a piece of sandpaper and lap the pads on a flat surface.

Usually normal street driving will bed the pads. Unless you do what I did and go out and hammer on new brakes to adjust the bias.

Steve R · #13 (**permalink**) 03-27-2003, 04:59 PM

Ron,
I guess we have a different philosophy on how to approach this question. The way I see it is:
#1. If you can hurt your car by skidding it a short distance, it probably shouldn't be on the road.

#2. The skid is the most direct way I know of to see if the brakes are working. Why ***** foot around?
Now that I have brought you over to the dark side, give me a call when you are ready to test the brakes on that beautiful Kirkham of yours

Steven
P.S. Forget schoolbuses, We jump over BBQ's down here in Texas.

Steve R · #14 (**permalink**) 03-27-2003, 09:59 PM

All this talk of bedding at pads brings me back to my youth