Need a Brake expert

[woodnthings8]

The rotors usually have a minimum thickness dimension stamped or cast into them. You should not go below that dimension. You need to measure with a micrometer or caliper along several spots to determine the actual minimum thickness.

[hucklejack]

Originally Posted by woodnthings8

I have been using Powerslot Rotors with Hawk pads on mine, I tow a 9k trailer around and I have had the pads/rotors on for over 5 years now. Seem to be holding up fine and stop the truck great!

Have you replaced the pads since you have done the job, and about how many miles would you say you have traveled on those pads/rotors in the five years

[01F250CCLB4X4]

FMTRVT In your first post are you saying that most mistake uneven wear for warping? I had Ford's premium pads & rotors and the performance I wanted wasn't there. I switched to a high quality grey iron rotors that are precision machined. I went with a ceramic/carbon fiber pad. They had a brake in material on them and now after about a year and 10,000 miles they are wearing perfectly (look brand new actually). I do a fair amount of higher speed braking and I was looking for performance gain. Did I choose the wrong set up for my needs?

[woodnthings8]

Originally Posted by hucklejack

Have you replaced the pads since you have done the job, and about how many miles would you say you have traveled on those pads/rotors in the five years

No I haven't replaced the pads yet. I have inspected them for remaining thickness a couple times I would say they are around 40-50% remaining now. I have put approx. 40k on the truck since putting them on. I use it mostly on weekends and for pulling the RV around. But when the snow hits, I drive it most everyday. I also put a similar set-up on a dually for a friend of mine, he was having problems with Les Schwab's brake job and was complaining they had it three times and it still didn't stop or feel right. He ordered up the Powerslots/Hawks and he said all his problems went away. He has had his on probably 4 years now, and I have no idea as to mileage. But they pull a 30' horse trailer with it, so I know it gets used too.

[FMTRVT]

Originally Posted by 01F250CCLB4X4

FMTRVT In your first post are you saying that most mistake uneven wear for warping? I had Ford's premium pads & rotors and the performance I wanted wasn't there. I switched to a high quality grey iron rotors that are precision machined. I went with a ceramic/carbon fiber pad. They had a brake in material on them and now after about a year and 10,000 miles they are wearing perfectly (look brand new actually). I do a fair amount of higher speed braking and I was looking for performance gain. Did I choose the wrong set up for my needs?

The pulsation is from thickness variation in the width of the rotor. As you transition from thick to thin you get a variation in pressure and clamping force. As the rotor moves to it's thin area, the pressure drops slightly reducing the brake torque and causing the pedal to slight drop due to the caliper brake fluid volume change. As the rotor travels 90 or 180°, the rotor moves to its thick area and the wedging of the pads produces a higher pressure, an increase in brake torque and a slight pushback of the brake pedal. This is the pulsing one feels in the pedal, steering wheel (if front rotors), and in the body of the vehicle as well.

If the rotors were "warped" 0.005", wouldn't the caliper just move on the slides that amount with the rotor? What if 0.010" warp? The caliper would just move on it's slides again, but with this amount of movement and the quickness of the side to side movement with rotor rotation, the G forces tend to overwhelm the slide hystorisis and pulsing is then felt. But 0.010" runout of a rotor is rarely seen. Rarely, but not impossible.

When you wrote "Ford's premium pads" I'm starting to feel like there is counterman parts speak, like these are the Motorcraft Super Duty line of aftermarket pads, or the step below. To me, the OE pad is the "Premium" pad if I was going to use labels.

With the tire size in your signature, I would not expect any of the Ford pads to do remarkably well with the leverage of the new tire size over the brake size. You did well in your choice of going for higher friction brake pads.

[01F250CCLB4X4]

Originally Posted by FMTRVT

When you wrote "Ford's premium pads" I'm starting to feel like there is counterman parts speak, like these are the Motorcraft Super Duty line of aftermarket pads, or the step below. To me, the OE pad is the "Premium" pad if I was going to use labels.

I went back and looked at what they sold me and the receipt says part number YC3Z*2200*AA 2018 Kit - Bra. The following information was taken from a safety report from a material safety data sheet off of the motorcraft chemicals and lubricants website.The friction material includes barium sulfate, magnesium oxide and graphite (semi-metallic). According to Ford Motor Company's OASIS report #9616 it was produced to cure brake noise. That's what my local part's manager was referencing as premium pads.

[FMTRVT]

Good parts man.

That's an OE part number, the 2200 designates a rear disc pad. The AA were an modification during the maturing of the vehicle platform, utilizing a change in the noise insulator to address rear brake noise while still maintaining the original friction material.

The edge code on those pads would have been FM6091EE, designating it as Federal-Mogul's 1222-1A friction material, with a cold/hot friction rating of EE. With the 315/75 tires on the vehicle your exceeding the design parameters of the brake system, and I agree the OE material would feel lacking. You need a material preferably with an edge code of FF. (Edge codes are not the end-all of knowing how a friction material will perform, but it's the only consumer rating that materials are identified with.)

That MSDS, like all MSDS list the most worrisome chemicals without disclosing ingredients that would hurt a companies proprietary formulation. Most friction MSDS cover a range of friction materials rather then one specific one. There are about another dozen ingredients in that formula that are not disclosed.

My confusion when you stated "premium" was that you got one of the Motorcraft aftermarket pads as these two parts, as an example, typically carry these designations:

BR1266 STANDARD PREMIUM
BRSD756 SUPERDUTY

[JW350]

Great info here. I have been happy with the OE brakes on my truck. 5 years with big tires and towing heavy on weekend camping trips. No pulsation or noise. I was thinking of staying with the OE stuff, but it sounds like I'm leaving some braking performance on the table. What is recommended for my setup? I don't think my brakes need to be serviced yet, but if I can simply replace the pads now and get another 5 years out of them...

[FMTRVT]

The term "leaving some braking performance on the table" is a good one. It's not that they are horrible, but that the pedal effort is going to higher then many care for. Of course I also have '66 GT-350's with manual disc and full race metallic pads which my wife cannot even make stop at the first stop sign at 25 mph, so I'm OK with a harder feel.

But for you it would be worth investing (like I did) in a front set of Performance Friction Z pads (not Carbon Metallic) and see how they are. The bite will not be as strong until they conform to the old rotor surface, but in two weeks you should have a better feel. If you think it was a good increase, then get a rear set of pads to compliment the fronts.

It would be a good opportunity to check the caliper slides. I would recommend that you check the fitment of the pads in the brackets. Like all aftermarket pads, the steelback and paint control tolerances are not as good as OE and some people have had to do a little sanding or grinding of the tabs to get them to slide freely.

[01F250CCLB4X4]

FMTRVT: I must have pulled the wrong receipt, found the right part # 1C3Z*2001*BA. I knew you'd come in with your knowledge of friction materials and it's greatly appreciated. Those reports were for safety procedures on handling and storage hence only stating the harmful materials since I know of very few products with full disclosure. Could you explain what Average friction coefficient 0.45mm (That's stated for my rear pads, EBC's "greenstuff") and Average friction coefficient 0.5mm (front pads, EBC's "yellowstuff") means?

JW350: I would definitely take FMTRVT advice for your application. I choose racing pads and although they do have better braking performance than oem pads to get the full capability of them I have to put a bit of heat (which isn't that hard with a 8,800 lb truck) into them before they really show their potential.

[FMTRVT]

Figured you’d be back with another receipt. 01, you’ve got a good feel for friction materials.

The 1C3Z-2001-BA were the late 2001 (year) revision of the pads, 2001 (part number) being the base number for front pads. The original pads for the platform in ’99 I believe carried an F8 (1998) prefix. This was another change for brake noise, going to double stick insulators from MSC. With these pads the stainless steel heat shield is no longer used, and the MSC insulator has what I refer to as “Mickey Mouse” ears, little projections on the top of the pads that protect the piston caliper boots from rotor heat like the stainless shims were utilized for.

When these pads are utilized it’s important to serious clean the caliper piston and caliper finger surfaces so the double stick insulator will adhere to those surfaces like they would on the assembly line. I know you’re done with them, but just a public service announcement.

Friction material whether sold OE or aftermarket are required to have the edge code per several states laws. There is no federal requirement. The edge code is generated on what is known as a Chase machine (developed by Dr Chase when he was at GM) and performed under SAE J661. Geoff Nicholson was an engineer at my old company when I first started and his son has a good website that discusses the test, and why it’s not great.

Technical Reports

If you wander around the site, check out Arne Anderson’s article about rotor pulsation. Arne was the head of Ford’s Scientific Research until the latter 90’s.

And an example of the Chase test……

http://www.stopcobrake.com/en/file/en.pdf

From those tests an average cold and hot rating is determined for 250 and 650F. The alphanumeric codes equate to a friction range, i.e. E = .25 to .35, F = .35 to .45, G = .45 to .55. In some ways it can be confusing as a high EE rating is really equal to a low FF rating.

But it gets worse as Geoff alludes to. What a 1” square piece of friction material does in a drum dose not equate to what happens on a vehicle, especially with a disc brake. And it’s all about in-stop friction.

The OE pads you noted are rated an EE, and are a high EE, about .34. But a stable in-stop .34.

By law, somewhere on the pads EBC should have the two-letter friction code. So they are supplying a lower friction rear and higher friction set of front pads. But since they state an average rating, you can’t see if there is a good spread between cold and hot friction. But you’ve already stated there is, as the pads are not as effective until they see some heat. But many semi-mets do this to ‘some’ extent, even the OE material on this vehicle.

And that’s somewhat the kicker. As we get into the more “high performance” types of pads no matter what the friction range, there is a bell curve in the friction level. The bell curve is steeper with really high friction materials, and if compounded for really high temps, the cold ramp-up extends for a longer period of time. The anti-thesis for what OE brake engineers really want in their system, not only for consistent feel, but shorter stopping distance (when cold) and predictable ABS actuation.

I’m gong to go off on a tangent here, so this is not directed towards you. (Here’s where I start loosing audiences).

In-stop friction is the key to short distances. Many people rave about a friction material that really comes in at the end of the stop. The deceleration builds and you get pulled more towards the steering wheel. But if you’re making a stop from 60 mph, you’re traveling at 88 feet per second. If your pulling 15 fpsps (feet per second per second) at the start of the stop and 25 fpsps at 20 mph (~30 fps), it “really comes in”, but your distance isn’t anything special because at the beginning of the stop you’ve “left at lot on the table”. More then the width of the car you just T-boned.

88-15=73 73-17=56 56-22=34 34-25=9 9-25=0 About 4.3 seconds to stop.

With a more stable but slightly lower friction ….

88-18=70 70-20=50 50-22=28 28-24=4 4-24=0 About 4.1 seconds to stop.

But look at the speed differential at each second and think of it as energy. If the hit occurs at the start of the fourth second, the speed differential is 34 fps vs 28 fps, 23mph vs 19 mph.

A driver in a T-boned car usually dies from head trauma when hitting the door at the threshold of 25 mph from my memory.

And the total stopping distance as SWAG of the above values are 208 ft vs 186 ft. for the lower stable friction, way more then a car length although the decel rates are not that different and lower in example number 2. It’s at the start of the stop that counts. Typically the SDs with stock tires are tire skid limited at about 25 fpsps.

And for reference, the 99-04 SD’s with OE materials at 60mph generate about 170 ft stopping distance two passenger and 190 ft at GVW. The GVW tire skid threshold occurs at 55lbs Pedal Effort if the brakes are at 200°F. FM6091EE

The ‘05+ SD’s with OE materials at 60mph generate about 160 ft stopping distance two passenger and 165 ft at GVW. The GVW tire skid threshold occurs at 35lbs Pedal Effort if the brakes are at 200°F. Slightly larger rotors, larger caliper pistons, and the friction material is higher in mu (coefficient in friction) in the cold range. FM2160FE.

That is if you believe the Chase machine ……

By now someone is thinking about going back to the OE material. Not if you have experienced pulsation, and not if you have larger then OE tires on this vehicle and the brake size is easily overwhelmed with oversize wheels and tires.

I’ll throw out one more thing that is important to us that (or used to) develop brakes for vehicles. In Geoff’s Chase test information he states something that to many people defy common sense. After all, you want the most stable brakes on the planet.

“A material that does not fade when temperatures get high can be dangerous. A driver is not aware the brakes are hotter and does not adjust his driving to compensate. Brakes can get hotter and hotter until the tires burst, or the brake lining catches fire.” Or the brake fluid starts to boil.

But that’s for another tirade of mine………

An image of our caliper piston boots that burned during a brake fluid boil test. And why those heat shields or “Mickey Mouse” ears are important for those rare extreme heat conditions, like Townes Pass.

[Matt0987]

FMTRVT,

"Former Vehicle Test Manager - Friction Products"

With what company(ies)?

"The rotor situation has just gotten way overblown. People and mechanics keep using the term “warping” and equate the supposed “warp” to heat when in fact it has nothing to do with this."

I have read this, and other, posts of yours and I am still confused. Would you mind reviewing this warping again?

I have been told that the pulsating we sometime feel is warping. And, I had a regular problem of this pulsating on my Ex. With factory pads and "OEM" A/M pads. Each time I replaced the pads the rotors were turned and there would be no problem until the next time I used the brakes at the high end of use. Not a panic stop. Not where I activated the ABS. But when I would have to go from, for example, 70 to 50 under a controlled, but quick, firm, slowing. Or, as I am traveling down a hill at 40 and have to slow under a quick, firm, slow to a stop. Usually w/in the first 1000 miles of use. It did not happen sooner because, knowing of the condition, I would baby the braking system so as not to cause this "warping" to happen. Which, I believe, is not how the system should work, BTW. Then, once done, it is there until the next time I change the pads and, at that time, I have the rotors turned. Because I know that the warping will happen again and I do not have the time, nor inclination, to remove the rotors, have them turned, and reinstall them each time the "warping" occurs. Only to have them "warp" again.

So, I purchased drilled/slotted rotors and I have not had the issue since. I thought it was because of the reduction of the gases between the pad and the rotor along with better cooling aspects of a drilled and slotted rotor.

One more question..... How does one know the different quality of the products we are considering purchasing beyond the purchase price. I have learned in my life that purchase price does not necessarily guaranty quality. Without going to the local auto store and dragging the rotors, one by one, onto the floor and checking them for size and fit. Without taking the pads to a belt sander to see how long they will last or if they will squeal.

I have taken my vehicles to dealerships only to have a problem because an apprentice did the work and the work was done worse than I did. I have purchased various products from various sources in my life. I have even had an account- at one point- where the auto shops purchased the products they used. But I would still be purchasing products on a hope and a prayer that I was making the proper decision(s).

In regards to brakes rotors and pads, and keeping in mind that OEM from the dealer did not resolve my "warping" problem, how do we know that we are buying the product that we need for our application and use?

[Matt0987]

Wow! When I posted my last post I must have been taken to page 2 of the thread. A lot of good info there. Sorry, FMTRVT, to have wasted your time.

[Matt0987]

I have read "5 years" in regards to the brake life. I have had my Ex for almost 90k miles and have had new pads and turned rotors right around 20K each. 20k to 25K seems to be the life of my pads regardless of which ones I use. Which, BTW, is a lot better than the life of about 18K out of my 2 previous Suburbans. Now, when I buy pads I always ask for OEM compatable products. I tried some longer life pads once and got a lot of squeal and, since the Ex is my wife's car, so I changed the for the OEM spec. pads.

[Matt0987]

01 mentions ceramic/carbon. Is this a "better" pad? How is the squealing?