Thanks for pointing me in the right direction. Hopefully this stuff will work, I actually looked at this last time I was at Advanced Auto.
Brake pad wear
- Thread starter Ben's LS
- Start date
Thanks for pointing me in the right direction. Hopefully this stuff will work, I actually looked at this last time I was at Advanced Auto.
joegr
Dedicated LVC Member
The spray is what I have at the moment bc my one friend said to use it, so obviously he doesn't know what he's talking about
The best advice I can give you is to replace those pads and deglaze/clean the rotor and try bedding them in again. Those brake pads don't look like they are anything super expensive. I am guessing somewhere in the $40 range? The rotor is what you want to worry about saving here.
If you want to use anti-squeal spray, only coat the very back of the pad. Take extra measures to make sure the friction material on the pad and the rotor stay as dry and clean as possible. Buy lots of brake cleaner and use it liberally, allowing time for it to dry.
As far as deglazing and prepping the rotor, I would do the following:
1) Buy a big can of WD40 and one (or two, they are handy!) of those 3M roloc "surface refinishing" wheels
2) Mount wheel to drill or die-grinder
3) Spray one side of rotor liberally with WD40
4) With light pressure, go around the face of the rotor in small circular motions making sure to not hold the thing in one place. You are literally honing/sanding the face of the rotor. You want it to be as even as possible.
5) Every lap you make around the face, spray it down liberally with more WD40 to wash the old stuff off. Might have to make 2-3 passes to clean it up.
6) Flip rotor over and repeat steps 2-5 for other side.
7) Using the big cans of brake cleaner you bought, clean the hell out of the rotor! If not using right away, then lightly re-coat with WD40 and put in a bag on a shelf until you are ready for them.
Try to keep the rotors clean. What I always do is once they are up on the hub is spin them while spraying the front and back with brake cleaner, then wipe them down with a paper towel. Maybe that's anal retentive, but it only takes 2-minutes and costs me 25-cents worth of paper towels and brake cleaner. Just make sure you don't grab them by the rotor when jerking around with the brakes.
And I still wouldn't use that anti-squeal spray. Just get pads that include the squeal shims already on them. I am surprised those pads you bought didn't have them. The anti-squeal stuff is crap IMHO. Your mileage may vary.
Here's the 3M disc I am talking about: Amazon.com: 3M 07480 Roloc 2" Coarse Surface Conditioning Disc: Automotive
There are a lot of different versions by other companies though. If you go into a decent autoparts store like a Napa or something, describe what you are doing, and tell them about the disc, they should know what to get you. If they don't, try another parts guy or store.
2000sport
Dedicated LVC Member
One time I got ceramic pads from autozone, got home and opened the box and turnkey someone already had them, put grease on the pad material, found out they screwed up, and returned them. I was pretty shocked that autozone didn't notice when they took the return.
I'm hoping you took them back and didn't use them lol
cirelle
Active LVC Member
In days gone by, brake pads used to come with a tube of goop that was supposed to be placed on the backs of the pads, not the brake surface, to prevent squealing. Has this changed (technology and all)?
joegr
Dedicated LVC Member
Not really. Many now come with a stick on patch that takes the place of the goop.
Right on the Mark
Dedicated LVC Member
There where coated from the factory. There was nothing wrong with them. Just some kind of new coating. They worked fine on what I put them on. Just was weird never seen it again.Opps sorry wrong post disreguard. LOL
Hey Cirelle what color is your ls?
+1. They call them "Shims" on most parts listings. It's just a rubber-coated piece of metal with some glue on one side to hold it in place.
oddball
Dedicated LVC Member
FWIW, I prefer the disk brake spray from CRC above the goop bottles for the pads. If it's the correct stuff, then it's fine.
Make sure to lube the guide pins with brake grease. That comes in a little bottle. Totally different stuff than disk brake quiet.
Note that semi-metalic pads are well known to squeak on the LS. If you want quiet brakes, get ceramic.
Ok so i read this whole thread so far and i had all these issues with the squeel tried all the goops etc. DID NOT WORK at all well it did but not for long, so i purchased the oem brake pads with the correct shims.
Installed everything and the no more squeel at all, I think the shims and clips have alot to do with it.
Installed everything and the no more squeel at all, I think the shims and clips have alot to do with it.
TooManyToys
Well-Known LVC Member
I’ll throw a few things out here based on my past career.
Those chamfers had to be on the pads when installed, if that is what you are talking about. They look to be about a 25 or 30° chamfer, physically impossible to have worn when installed due to the physical geometry within the caliper assembly.
Chamfers are misunderstood in the aftermarket and general population. They are not there to provide a lead-in but are used to alter the width of the pad as to not achieve a natural harmonic to the rotors nodes. If you tap on a rotor it will produce its natural frequency, along with sympathetic frequencies. As an example it might have a dominant frequency of 5k Hz, and sympathetic frequencies of 10k and 15k. If you look at a laser image of the rotor these vibrations show up making the rotor look like a wave washer. And if the pad width bridges the peaks of these nodes, noise can occur. So if this happens to be one of the many reasons that noise occurs, then altering the width of the pad eliminates the issue.
This works with the production setup as the pads and rotors are static from the same supplier sources, but in the aftermarket things change. The aftermarket rotors will have a different frequency as no aftermarket company tries to match the OE rotor suppliers’ vanes, vane count or rubbing disc thickness, so you are dealing with a different natural frequency. And I’ve never found an aftermarket pad company to exactly change the chamfer grinding equipment on the production line to match the OE. They will just make a “lead-in” edge.
The natural frequency of the pads also changes as it wears, and sometimes you can get away with the tapered chamfer you are used to seeing, but in some cases you need to maintain the pad width, such as these pads on the Ford Superduty. Ain't no "lead-in" here.
Noise insulators attached to the backs of the pad steelbacks are also highly refined at the OE level. Some are single constrained layer and other double (layers of stainless steel). They can also be what are known as “double stick”, where there is a secondary silicone adhesive backing uses to attach the pad to the caliper fingers and pistons. Companies such as MSC develop the noise insulators based on the frequency of the noise need to be abated. The viscosity and thickness of the silicone adhesive is altered to achieve this at the temperatures that noise occurs in. As the temp goes up, the silicone changes its viscosity meeting the requirement.
Aftermarket insulators are there with a hope and prayer that they will do something. No aftermarket company spends the money to develop a specific insulator for an application. And the OE product is sanctified with the OE contract, not that it matters as brake noise is also dependent on the friction material compound, both by its friction level, weight and porosity. So what insulator works with one friction material compound may not work with another, or it's different geometric shape (chamfer).
Using the aftermarket “Disc Brake Quiet” is really a poor attempt at achieving what the silicone adhesive does, although in some cases it works for a time. Another approach is to use what many of the Asian manufactures like Honda and Toyota do, using a moly filled viscous silicone grease on the backing plates to prevent the pad vibrations from transferring to the caliper, caliper bracket and knuckle, another source of brake noise transmission. It really depends on the vehicle.
It’s hard to tell in these pictures but while the pads look shiny, I don’t think they are glazed. Below are examples of glazed pads from a test.
Glazing occurs when the organics in the friction compound vaporize and deposit and the rubbing surface requires a good amount of heat. With a higher organic level at the rubbing surface, you generally develop a lower level of friction, but no so much noise. The sanding of the pads and rotor surface does remove the glazing, s will about a dozen or two of low temperature brake stops, but the reduction in noise is generally due to the rough pad and rotor surfaces now having less brake friction now that they are “green”, transferring the work to the opposite axle. Once the pads and rotors are smoothed from braking activity and friction material transfer to the rotors surface re-establishes (which is normal), the friction returns and often so does the noise.
These pads may be normally shiny due to their density and lack of porosity. We would alter a pad formula’s porosity during manufacture to reduce noise development, but with rotors that have slots you need the denser, stiffer pad to prevent the friction material from wearing excessively as the slots wipe across the pad rubbing surface, basically shearing off material.
Those chamfers had to be on the pads when installed, if that is what you are talking about. They look to be about a 25 or 30° chamfer, physically impossible to have worn when installed due to the physical geometry within the caliper assembly.
Chamfers are misunderstood in the aftermarket and general population. They are not there to provide a lead-in but are used to alter the width of the pad as to not achieve a natural harmonic to the rotors nodes. If you tap on a rotor it will produce its natural frequency, along with sympathetic frequencies. As an example it might have a dominant frequency of 5k Hz, and sympathetic frequencies of 10k and 15k. If you look at a laser image of the rotor these vibrations show up making the rotor look like a wave washer. And if the pad width bridges the peaks of these nodes, noise can occur. So if this happens to be one of the many reasons that noise occurs, then altering the width of the pad eliminates the issue.
This works with the production setup as the pads and rotors are static from the same supplier sources, but in the aftermarket things change. The aftermarket rotors will have a different frequency as no aftermarket company tries to match the OE rotor suppliers’ vanes, vane count or rubbing disc thickness, so you are dealing with a different natural frequency. And I’ve never found an aftermarket pad company to exactly change the chamfer grinding equipment on the production line to match the OE. They will just make a “lead-in” edge.
The natural frequency of the pads also changes as it wears, and sometimes you can get away with the tapered chamfer you are used to seeing, but in some cases you need to maintain the pad width, such as these pads on the Ford Superduty. Ain't no "lead-in" here.
Noise insulators attached to the backs of the pad steelbacks are also highly refined at the OE level. Some are single constrained layer and other double (layers of stainless steel). They can also be what are known as “double stick”, where there is a secondary silicone adhesive backing uses to attach the pad to the caliper fingers and pistons. Companies such as MSC develop the noise insulators based on the frequency of the noise need to be abated. The viscosity and thickness of the silicone adhesive is altered to achieve this at the temperatures that noise occurs in. As the temp goes up, the silicone changes its viscosity meeting the requirement.
Aftermarket insulators are there with a hope and prayer that they will do something. No aftermarket company spends the money to develop a specific insulator for an application. And the OE product is sanctified with the OE contract, not that it matters as brake noise is also dependent on the friction material compound, both by its friction level, weight and porosity. So what insulator works with one friction material compound may not work with another, or it's different geometric shape (chamfer).
Using the aftermarket “Disc Brake Quiet” is really a poor attempt at achieving what the silicone adhesive does, although in some cases it works for a time. Another approach is to use what many of the Asian manufactures like Honda and Toyota do, using a moly filled viscous silicone grease on the backing plates to prevent the pad vibrations from transferring to the caliper, caliper bracket and knuckle, another source of brake noise transmission. It really depends on the vehicle.
It’s hard to tell in these pictures but while the pads look shiny, I don’t think they are glazed. Below are examples of glazed pads from a test.
Glazing occurs when the organics in the friction compound vaporize and deposit and the rubbing surface requires a good amount of heat. With a higher organic level at the rubbing surface, you generally develop a lower level of friction, but no so much noise. The sanding of the pads and rotor surface does remove the glazing, s will about a dozen or two of low temperature brake stops, but the reduction in noise is generally due to the rough pad and rotor surfaces now having less brake friction now that they are “green”, transferring the work to the opposite axle. Once the pads and rotors are smoothed from braking activity and friction material transfer to the rotors surface re-establishes (which is normal), the friction returns and often so does the noise.
These pads may be normally shiny due to their density and lack of porosity. We would alter a pad formula’s porosity during manufacture to reduce noise development, but with rotors that have slots you need the denser, stiffer pad to prevent the friction material from wearing excessively as the slots wipe across the pad rubbing surface, basically shearing off material.
oddball
Dedicated LVC Member
Wow, thanks! That was a good read.
And while we have an expert on the line, what is your professional opinion of semi-metallic vs ceramic, and blanks vs drilled vs slotted vs combo? I'm always up for learning something new. I always knew the chamfer was for squeal, but never knew exactly why, and now I do!
TooManyToys
Well-Known LVC Member
While I accepted the "expert" phrasing about a dozen years into my career, 30 years teaches you more humility. There is no perfect friction material, and whatever you are using can have a completely different personality with what is used on the other axle or physical changes, even to the point of wheel size.
I may have answered you questions in another thread:
http://www.lincolnvscadillac.com/showthread.php?t=78128
I may have answered you questions in another thread:
http://www.lincolnvscadillac.com/showthread.php?t=78128
An expert is one who has a skill or knowledge on a given subject in excess of those around him. So while you might choose to humble yourself for posterity, it does not diminish your obvious expertise on this subject in this setting.
That being said, it is nice to understand the theory behind a few "rules of thumb" I had learned over the years, and confirming some other suspicions. Thanks for the info
Perhaps a discussion for a different post, but I wouldn't mind hearing your thoughts on the 320mm front brake upgrade I did on my LS, both good and bad. Would you have found it a worthwhile upgrade to the LS? Or overall have a minimal effect on the handling? Pad and caliper are the same type, just an extra 20MM of rotor from a Jag S-Type and a different backing bracket from the same car. If you have time, the thread detailing all of that is over here: http://www.lincolnvscadillac.com/showthread.php?t=75235&highlight=upgrade
Put the disc brake quiet on my pads today, but I'm not gonna be out driving til tomorrow. Keep everyone posted