Brake pad measurement .

Joined
Jan 4, 2019
Messages
1,284
Location
Louisiana
Is there a standard measurement at which the pads should be replaced , or does it vary by vehicle ? My wife's CX-9 has 100k on the original pads . I had it in the shop for a brake booster replacement and the tech said that the pads were thin but not metal on metal yet . He said if we ever hear it squeal , get it in the shop immediately . I'm just curious about the actual measurement because I see it mentioned sometimes .
 
Joined
Apr 27, 2010
Messages
13,456
Location
Suburban Washington DC
I had it in the shop for a brake booster replacement and the tech said that the pads were thin but not metal on metal yet . He said if we ever hear it squeal , get it in the shop immediately ..
Find another shop. Once you hear it squeal, the rotors are scored and need machining at least, if not outright replacement. Shop want's to do more repairs for you then you would have to if you just replace the pads before they are metal to metal.
 
Joined
Apr 27, 2010
Messages
13,456
Location
Suburban Washington DC
Negative, audible wear sensors are part of some pad designs as a warning to drivers to have their brakes inspected for wear.
Not on that model.

ACT1258__ra_p.jpg
 

nomas

Thread starter
Joined
Jan 4, 2019
Messages
1,284
Location
Louisiana
Find another shop. Once you hear it squeal, the rotors are scored and need machining at least, if not outright replacement. Shop want's to do more repairs for you then you would have to if you just replace the pads before they are metal to metal.
I understand what you are saying but that's not the vibe I got from him . His point was that if I don't change them now , then do it as soon as I hear them make noise . This shop has a good rep in this town .
 
Joined
May 17, 2009
Messages
18,818
Location
N.H, U.S.A.
Is there a standard measurement at which the pads should be replaced , or does it vary by vehicle ? My wife's CX-9 has 100k on the original pads . I had it in the shop for a brake booster replacement and the tech said that the pads were thin but not metal on metal yet . He said if we ever hear it squeal , get it in the shop immediately . I'm just curious about the actual measurement because I see it mentioned sometimes .
100k gotta need a brake job. That thing may never come apart if you wait much longer.
Did you get this vehicle used? It must of had rears done once.
 
Joined
Apr 27, 2010
Messages
13,456
Location
Suburban Washington DC
I understand what you are saying but that's not the vibe I got from him . His point was that if I don't change them now , then do it as soon as I hear them make noise . This shop has a good rep in this town .
If he is sure they have the noise makers, then not a problem to wait until they make some noise.
 
Joined
Dec 19, 2018
Messages
2,617
Location
Vancouver
Find another shop. Once you hear it squeal, the rotors are scored and need machining at least, if not outright replacement. Shop want's to do more repairs for you then you would have to if you just replace the pads before they are metal to metal.

You wouldn't replace rotors with 100k regardless?
 
Joined
Dec 19, 2018
Messages
2,617
Location
Vancouver
Not always. I've seen used OE with 100K be in better condition than 1 yr old Chinesium.

New OE isn't an option?

I mean consider me crazy but there is no way I would reuse relatively inexpensive rotors with that kind of mileage unless it was a pure highway vehicle and not in the rust belt.
 
Joined
Aug 30, 2004
Messages
28,606
Location
CA
New OE isn't an option?

I mean consider me crazy but there is no way I would reuse rotors with that kind of mileage unless it was a pure highway vehicle and not in the rust belt.
I can't speak for Vancouver, but down here, I've seen many rear rotors in fantastic shape after 10 years+ and 100K. Probably comparable to stuff that is a few months old in your area. ;)
 
Joined
Nov 3, 2013
Messages
2,106
Location
Northern Utah
To get 100k miles on front pads is not unusual. I got 130k miles out of the front pads on my wife's Outback. But rear pads usually need replacement before 100k miles. Of course brake life differs greatly, depending on factors such as driving style, vehicle weight and quality of brake pads

Depending upon how many miles your wife drives each month, and how aggressive of a driver she is, will make a difference on the urgency you put into having pads replaced. Generally, 4 mm is considered a still safe and usable amount of pad. Plenty of material between the rotor and the pad backing plate. But if you are one to forget to watch maintenance items on a car, then I would replace them at 4 mm. If your brake pads are measuring 3 mm or below, start planning on getting them replaced soon. At 2 mm, get it scheduled immediately.

For reference, some states and countries where safety inspections are mandatory, will fail a vehicle at 1.5 mm.
 
Joined
Nov 3, 2013
Messages
2,106
Location
Northern Utah
You wouldn't replace rotors with 100k regardless?
With no intention of being insulting to my fellow BITOG members, I've never understood when people replace rotors at every brake job. It is rarely needed at every brake job, and often not needed even at every other brake job.

I replace rotors based upon actual measurement, and compare the measurement to the spec. When I measure, I consider how many miles I estimate to the next brake job. If I estimate that the rotor will be anywhere close to the minimum thickness spec. before the next brake job, I will replace them. But it is not unusual for rotors to last through 3 sets of pads.

That is assuming the rotors are wearing evenly and are free of damage. Heavy pitting, scoring and such, all changes that. Damaged rotors will significantly reduce the wear life of brake pads. So if they are damaged, then they need replacement, regardless of thickness.
 
Joined
Dec 19, 2018
Messages
2,617
Location
Vancouver
With no intention of being insulting to my fellow BITOG members, I've never understood when people replace rotors at every brake job. It is rarely needed at every brake job, and often not needed even at every other brake job.

I replace rotors based upon actual measurement, and compare the measurement to the spec. When I measure, I consider how many miles I estimate to the next brake job. If I estimate that the rotor will be anywhere close to the minimum thickness spec. before the next brake job, I will replace them. But it is not unusual for rotors to last through 3 sets of pads.

That is assuming the rotors are wearing evenly and are free of damage. Heavy pitting, scoring and such, all changes that.

Because they're like $75 for new, OE ones. If they are in great shape and can be turned, then by all means, do that. But that is not free either, requires additional trip(s) to a shop, etc.

But of course this is BITOG where people brag about changing oil every 2k but also about never changing brake fluid. So who knows.
 
Top