Brake Disk Life/Pad replacement


#1

My wife drives a 2002 New Beetle. We bought the car at 18000 milews in 2005. At 23000 miles the rotors were warped (felt like the bug would jump off the road while braking) and the rotors but, not pads were changed. After complaining that this is early for rotors to be worn out, I was told this was normal for the originally mounted disks on Beetles and that the replacement was likely to last longer. Now, at 46000 Miles the check brakes light went on and I assumed that the pads were worn and my wife brought it in to check. When she wanted to pick up the car, turns out they changes the pads and the rotors again because they were “close to specs”.

Whats going on ?




#2

First of all, don’t ever take your car to the corner, convenience, franchise shop. Their product will always be as good as the mechanic they hire, and with all their overhead, the first place they are going to reduce overhead is on wages. I bet you if you take your car to the same franchise shop in a different town they’ll sell you rotors and pads again.
“Close to specs” is a pretty convenient, and well rehearsed answer. I have 225000 miles on original Ford rotors - but, I have always had the rotors “Turned” and never let the rivets of the brake pads get to the rotor. It isn’t uncommon for rotors to have to be replaced if they become out-of-round or one waits too long to change the brake pads. Basically that means that if the brake pad rivets touch the rotors you are looking at machineing (+).030 off of the rotors compared to .010 machined off. Per manufacturer, any more than .030 will make the rotor less tolerant to stress (Heat) and will shatter (This is what they meant by “Close to specs.”). If you lived in Colorado I could refer you to a good, honest shop.


#3

all was done at the dealership. they also told me that vw’s and audis disks cannot be resurfaced or turned but are “throwaway”.


#4

For something as simple as routine brake work, I prefer taking my car to the corner, convenience, franchise shop. I’ve not had any bad experiences with them. Of course, I know why am there – brake pads, rotors, or both.

On your first visit you were treated well. The rotors needed replacement as you well knew. There was plenty of life left in the pads and the shop made no attempt to sell you unnecessary parts and service.

We cannot criticize your results from the second visit. Clearly you needed new brake pads and so you got them. As for the rotors, who can tell? It is possible you were previously sold cheap aftermarket replacements that were intended for single usage only. Many new cars even come that way so again we cannot necessarily fault the shop. In short, we simply cannot assume you were ripped off.


#5

"all was done at the dealership. they also told me that vw’s and audis disks cannot be resurfaced or turned but are “throwaway”

Modern car design calls for lighter wheels and that includes lighter rotors. They are really designed to last through about one set of pads. How long that is or how well they match a set of pads has a lot to do with how you drive. I have the original pads and rotors on my 2002 NB with over 70,000 miles and going strong. I drive like a little old lady, so I get more MPG and less brake wear than most. The cost of modern disk is less and after you consider the cost of machining the old disk you are usually better off replacing them.

   Dealers are no better (or worse) than independent mechanics for almost anything you might need done on your car.  They will almost always charge more per hour and often more for parts and supplies.  They also tend to look at repairs a little different than the independent. 

A dealer may well recommend work that strictly may not be needed, but could be connected to the problem or maybe replace a part when a little repair would fix it ALMOST as good a new.  

I suggest that most people would be better off finding a good independent (Not working for a chain) mechanic.

#6

Many cars recommend that the rotors be replaced with every set of pads, the life of the pads depends on driving conditions. Personally, I would not have replaced the rotors without the pads regardless of condition (pads are cheap). Now that you have a new set of rotors and pads, you will get a good idea how long they will last for you.


#7

to recap: you got 46 K out of the original pads. WOW, good going!!

you got 23K out of the replacement disks. Hmm, well, i’ve seen better, BUT… i’ve seen a whole lot worse.

so all in all, you didn’t do too bad. now you should’nt need a brake job until around 70K or 80K.

in the future when you go in for brakes just tell them Pads AND Rotors. do both at the same time.


#8

For a data point, VW Passat 03 54k miles. Replaced the rear pads (and rotor) at 40k, still original fronts.


#9

The thickness of the rotors have not changed since pads do not wear metal off the rotor (unless it’s down metal to metal). If the rotors are severly warped then it will require a lot of metal to be removed to back true and straight. Since manufactures have to lighten up the entire vehicle they make thinner rotors & therefore they do not last as long.


#10

“The thickness of the rotors have not changed since pads do not wear metal off the rotor (unless it’s down metal to metal).”

Not true, the rotors also wear. After about 40K miles (when my front pads are down to about 20%) my rotors have a small ridge along the out side edge where the pads don’t contact them (maybe 1 mm). I usually replace my rotors with every second pair of pads.


#11

Well thats a good point but I guess I should have clarified that the pads don’t wear off several thousands of an inch off the rotors.

Also consider this… On several of the brake jobs I have performed this lip of metal at the edge of the rotor is nothing more than “stuck on” rust that breaks off easily leaving virtually no lip.


#12

The rotors do normally get used up (more than several .001s of an inch), and there is a minimum thickness specified for replacement. The amount of rotor material lost has a lot to do with the type of brake pads you are using. My experience is that after two sets of pads (about 80K miles in my case), the rotors are obviously worn to the point wear they should be replaced (maybe a 2-3 mm lip). On my car, the fronts need to be replaced about twice as often as the rears. My front rotors last about 2 years (80K miles). I would expect the life of both rotors and pads to vary significantly between cars and drivers.


#13

I would expect the life of both rotors and pads to vary significantly between cars and drivers.

You got that right!!! I used to have a job in which I drove about 700 miles a week. Since I replaced pads very often I never spent the money on turning the rotors but when the rotors got so warped I could not stand it, thats when I replaced them.


#14

I agree, I would never bother turning rotors, they are either good or they need to be replaced. What’s the point of messing around with used rotors?