SwedeSpeed - Volvo Performance Forum banner
1 - 8 of 8 Posts

·
Registered
Joined
·
59 Posts
Discussion Starter · #1 ·
Is there any brake pad sensor or wear indicator to show that we need to change the brake pad?

My front brake pad "looks like" balance 1-2 mm. The next service will be due in another 3000 miles. i just want to make sure i am good to keep moving without damage the rotor.
 

·
Registered
Joined
·
120 Posts
Let me get this straight. You have 1-2mm of pad material left and you want to stretch it out even further or are you talking about something else?

ANY pad equal to the thickness of the backing plate whether a front or rear pad should be replaced immediately. Anything less won't be able to transfer heat away from the disc and can result in warped discs when used in successive hard stops.

BTW there are no pad imdicators or wear sesnors apart from the sound of steel upon steel when all the pad material is gone.

Sent from my SM-N910G using Tapatalk
 

·
Registered
Joined
·
7,614 Posts
I don't agree there. Air is what transfers heat away from the disc, the heat does not by design travel through the pad. That's why there's vents and vanes on the disc and not the pads. You actually want the heat to go in to the rotor so you don't heat the caliper and boil fluid. That's also why there's such a small contact patch with the caliper piston, so pads don't heat it up quickly.

Your advice of replacing at backing plate thickness throws away about 10-20k miles worth of brake pad depending on pad and driving style.

These pads start at something like 10-12mm and last for tens of thousands of miles. I doubt you'll burn through 1mm in 3k. To be safe, don't delay the service though. Also, unless you checked inner and outer pads you could be fooling yourself. If you hear any increase in noise, or odd metallic noises during braking, just go get it serviced immediately.
 

·
Registered
Joined
·
120 Posts
I just don't understand that logic. The last 3-4mm can go quickly leading to a scored disc which will need to be changed in pairs and require total removal of the caliper taking a further 30 minutes per side to save 30% of the cost of a $35 pair of pads. In effect risk $50 in rotors in order to save $12 @ pro rata of pad wear.

Sent from my SM-N910G using Tapatalk
 

·
Registered
Joined
·
7,614 Posts
Well, we disagree on how fast the pads wear and that's basically it. I've never found the last part of a pad to wear any faster than the first part.

In addition to that, I've never had rotors outlast pads on a newer car, they always get a lip around the perimeter that leads to them needing to be machined or replaced, so the extra labor component isn't a factor in my reasoning either. In fact, on my V70 right now my rotors are developing a lip when the pads are still 8-10mm thick after over 50k miles. I've been absolutely astounded at how long wearing Akebono pads are. At the rate I'm going I'll need to replace the rotors before I'm even halfway through the pads.
 

·
Registered
Joined
·
856 Posts
Well, we disagree on how fast the pads wear and that's basically it. I've never found the last part of a pad to wear any faster than the first part.

In addition to that, I've never had rotors outlast pads on a newer car, they always get a lip around the perimeter that leads to them needing to be machined or replaced, so the extra labor component isn't a factor in my reasoning either. In fact, on my V70 right now my rotors are developing a lip when the pads are still 8-10mm thick after over 50k miles. I've been absolutely astounded at how long wearing Akebono pads are. At the rate I'm going I'll need to replace the rotors before I'm even halfway through the pads.
Your no dummy Lloyd.You get it.
 

·
Registered
Joined
·
120 Posts
When I said the last 3-4mm can go quickly I did intend to convey that the pad material lasts less time during that period, and this is a well known problem. There is a term called "pad fade" and is usually apparent with overheated pad materials. The metallic particles have been overheated and lose their tensile strength. Look it up if you're unfamiliar.

I mean that it's easy to forget that you're riding on the last few millimeters and then find that one of the calipers isn't sliding as well as the others in a sliding caliper or, in a twin piston design, one of the pistons can be seized leading to the braking force going to the other piston side and prematurely scoring the disc. Also pads can wear in a tapered fashion where the leading edge of the pad wears faster than the trailing edge due to binding within the caliper.

It's just safety first and nothing else.

How long do ceramic pads last anyway?? I can't see 50,000 miles out of them though I could be wrong. A lip on the rotors? Doesn't mean that the disc is undersize or there is a poor surface finish. I have a guage which can measure around the lip to see if minimum thickness is achieved and only replace rotors if:

1) minmum thickness is achieved
2) surface finish is bad and after machining them the thickness will be less than minimum spec
3) I run into a customer that insists on replacing them when there is absolutely no need to.

On my own V70 I have 80,000kms on the best rotors I ever used. The first set of pads were rock hard and had no feel and no braking power. The second set have perfect feel and of course far more brake dust



Sent from my SM-N910G using Tapatalk
 

·
Registered
Joined
·
7,614 Posts
I'm pretty blown away too, usually I have to replace pads at around 30k miles. I rotate my tires summer to winter every 6-8 months and I check the pads every time, and the Akebonos are still really thick. A few weeks ago I checked the mileage and it was indeed 50k miles ago that I installed them. I mean, the car has a manual transmission so I do a lot of engine braking with light pedal assist but it's still 100% city driving. I've never seen this level of durability before myself.
 
1 - 8 of 8 Posts
Top