@TooManyToys

 

Good evening,

My 99 E350 SD DRW is in need of brakes all the way around. I have been lurking your past posts regarding blank rotors over drilled and slotted. I have been trying to source OE rotors and pads to no avail. Are the Powerstop Kits a good option? I would like to "buy once, cry once."

Regards,
Tibursky

I have an 05 350 and will be doing powerstop drilled and slotted. I've always thought slotted is fine but drilled becomes a problem because of cracking? Idk. I'm interested in hearing what Jack has to say as this was his career.

 

EBC makes some pretty good solid rotors that are easy on the wallet. They also have slotted as well as dimpled and slotted. Hawk pads would be my choice if OEM were not available. Drilled are not the correct choice for a truck IMHO. I too am interested in what Jack has to say.

 

I want to say while drilled rotors can serve a function, there's a weaker surface area than cannot sustain the severe stress and heat for long. On a little sedan drilled rotors could be a huge gain, while on a 8k truck loaded up with a 15k trailer you need material to help absorb heat.

 

Formula Truck brakes are not drilled. That should tell ya something.
If you’ve never seen the truck races then you are missing out.

 

Geeze, no pressure here.

I wrote this last night but did not post.

Drilled rotors were born out of autocross for weight reduction. Slots remove gases when the brake pads degas, which is the high-temperature range for the binders and organics in the friction material formulation.

For an average OE friction material across all platforms, the materials are formulated and processed for a higher temperature range. We would run fade tests on the materials during development and production. You have to be pretty radical to get degassing out of them.

There are different types of fade, BTW. The pedal stays high when you have degassing fade; a film of decomposition gasses prevents the friction material from fully contacting the rotor. This can happen if the material is not processed well enough, and during the initial use of new brakes, you get the gassing that would occur in the ovens for an OE friction product. You can also have this gassing if the organic materials chosen (including the phenolic binder) are not selected due to the cost for the higher heat. You can see this in the aftermarket more often. This situation usually has a long pedal as the friction material is excessively compliant (mushy). Even with OE, you can have this when some brakes are not working correctly, or trailer brakes are not doing their part.

A general guide is when you can smell brakes, the friction material is around 500ºF, and when you see smoke, it's around 800ºF. Rotors typically run about 100ºF hotter than the friction material.

Another is brake fluid boil fade when the pedal goes to the floor. This is the primary reason why the industry got away from metal caliper pistons. Phenolic pistons insulate the brake fluid better, but there is a point.

I could go and see what fade test graphs I have locked away. Right now, it's been a long day; maybe tomorrow.

The cliff notes version is that if you are using a good, proper friction material, consumer and commercial vehicles should not need holes (which do crack) or slots. One issue with slots is you need a stiff, hard friction material to bridge the slot or the friction material wears out quicker due to "slicing" a little bit of the friction material with every pass. Okay on a track. But hard friction material without any compliance results in heat banding and hard spots. And hard spots eventually get you into pulsation and steering wheel shake - the cause being the rotor surfaces not parallel, but transitioning thick to thin. The thick areas are that way because the hardened surface does not wear at the same rate.

This AM, I grabbed some data.

First, if you use a good friction material, you won't fade. Secondarily, in 1997 some of the criteria Ford set down for the upcoming Superduty was to reduce the issues present in the OBS vehicles, which would crack front rotors due to the excessive heat, and reduce the possibility of brake fluid boil. A disc/disc vehicle shares the load better and disc/drum. Brake fluid boil was more of an issue with trucks that used steel pistons in the late 80s to early 90s. But the 1999 to 2004 platforms with the Akebono brakes were the most balanced front to rear and incorporated more extensive thermal solutions for brake fluid boil (that were over the top).

I always try to use assembly line rotors, and within the Ford lineup, that also means not the Motorcraft service line, which my old company makes for Ford. Note the durability test day where at GVW normal highway (open two lane road with traffic lights) the brakes are running around 200ºF AT GVW.

You will always have some loss of friction with high temps unless you go with a good quality high metallic, and then cold friction is lower (bell curve of all friction material). If you are fading with OE, there is usually something else going on unless you are exceeding weight or speed. Double speed quadruples energy; speed is logarithmic.

Aftermarket companies reduce costs by not doing the extensive baking done with OE products or the more expensive aftermarket products (those are getting rare). They have you do a "burnishing" after putting on new pads, although it's not as extensive as a "Fade Sequence". You can still have a fade issue the first time you push into a high-stress situation.

 

Geeze, no pressure here.

I wrote this last night but did not post.

Drilled rotors were born out of autocross for weight reduction. Slots remove gases when the brake pads degas, which is the high-temperature range for the binders and organics in the friction material formulation.

For an average OE friction material across all platforms, the materials are formulated and processed for a higher temperature range. We would run fade tests on the materials during development and production. You have to be pretty radical to get degassing out of them.

There are different types of fade, BTW. The pedal stays high when you have degassing fade; a film of decomposition gasses prevents the friction material from fully contacting the rotor. This can happen if the material is not processed well enough, and during the initial use of new brakes, you get the gassing that would occur in the ovens for an OE friction product. You can also have this gassing if the organic materials chosen (including the phenolic binder) are not selected due to the cost for the higher heat. You can see this in the aftermarket more often. This situation usually has a long pedal as the friction material is excessively compliant (mushy). Even with OE, you can have this when some brakes are not working correctly, or trailer brakes are not doing their part.

A general guide is when you can smell brakes, the friction material is around 500ºF, and when you see smoke, it's around 800ºF. Rotors typically run about 100ºF hotter than the friction material.

Another is brake fluid boil fade when the pedal goes to the floor. This is the primary reason why the industry got away from metal caliper pistons. Phenolic pistons insulate the brake fluid better, but there is a point.

I could go and see what fade test graphs I have locked away. Right now, it's been a long day; maybe tomorrow.

The cliff notes version is that if you are using a good, proper friction material, consumer and commercial vehicles should not need holes (which do crack) or slots. One issue with slots is you need a stiff, hard friction material to bridge the slot or the friction material wears out quicker due to "slicing" a little bit of the friction material with every pass. Okay on a track. But hard friction material without any compliance results in heat banding and hard spots. And hard spots eventually get you into pulsation and steering wheel shake - the cause being the rotor surfaces not parallel, but transitioning thick to thin. The thick areas are that way because the hardened surface does not wear at the same rate.

This AM, I grabbed some data.

First, if you use a good friction material, you won't fade. Secondarily, in 1997 some of the criteria Ford set down for the upcoming Superduty was to reduce the issues present in the OBS vehicles, which would crack front rotors due to the excessive heat, and reduce the possibility of brake fluid boil. A disc/disc vehicle shares the load better and disc/drum. Brake fluid boil was more of an issue with trucks that used steel pistons in the late 80s to early 90s. But the 1999 to 2004 platforms with the Akebono brakes were the most balanced front to rear and incorporated more extensive thermal solutions for brake fluid boil (that were over the top).

I always try to use assembly line rotors, and within the Ford lineup, that also means not the Motorcraft service line, which my old company makes for Ford. Note the durability test day where at GVW normal highway (open two lane road with traffic lights) the brakes are running around 200ºF AT GVW.

View attachment 782116 View attachment 782117 View attachment 782118
View attachment 782119


You will always have some loss of friction with high temps unless you go with a good quality high metallic, and then cold friction is lower (bell curve of all friction material). If you are fading with OE, there is usually something else going on unless you are exceeding weight or speed. Double speed quadruples energy; speed is logarithmic.

Aftermarket companies reduce costs by not doing the extensive baking done with OE products or the more expensive aftermarket products (those are getting rare). They have you do a "burnishing" after putting on new pads, although it's not as extensive as a "Fade Sequence". You can still have a fade issue the first time you push into a high-stress situation.

I never even thought about how the slots would “cut” into the pads. I think I’ll be staying away from drilled and slotted. Our trucks already eat pads like it’s nothing lol

Where do you get your rotors and pads?


Sent from my iPhone using Tapatalk

 

 

@TooManyToys in other words sourcing good pads and rotors has proven to be difficult if not impossible.

Whats the next option? Motorcraft blanks and Superduty Pads?

would turn my rotors but with all the corrosion that may not be an option.

with 242k on the odometer is it wise to go ahead and replace calipers and brake hoses as well?

This is a utility body van that gets weighed down and also tows.

Im honestly leaning towards Bosch or the Motorcraft at this point.

 

@Tibursky Welcome to my world. I just picked up new rotors and pads all around while I'm sitting at 201k. I replaced the factory stuff at like 100K+. I'm going to replace the brake hoses front and back, along with flushing the brake fluid.

I bought all OEM stuff from the dealer. I'm sure I could have saved a few bucks elsewhere but I wanted to be sure I was getting the right stuff.
I don't see a need for new calipers right now.

 

Powerstop or brembo blanks, cheap and run true for a long time. Pads I have been using autozone for 18 years and have been happy with every set I installed. If I want something better Hawk.

 

Jellybean, when we were supplying private label pads to Autospecialty, we showed them the concern on dyno tests.

There are a lot of nuances within the braking spectrum, a lot of trade-offs. It becomes what size of the pie is most important to you.

I get about 100k out of a set of OE pads with the Superduties based on my use. With Hawk LTS higher metallic pads, I get about 80k. Out other vehicles do not do as well. With my 2001 and 2003, I moved from the OE to both PFC and Hawk because the friction material we supplied as OE from '99 to '04 was a little under what I would have wanted; lower in friction and not as rotor abrasive. But a great material in other applications where it was used. The 2005+ materials my old company supplied, if they were available for the earlier brake system, I would have stayed with. Another option would be the Motorcraft "Super Duty" pads if they are the same as they were over 10 years ago.

Tibursky, I still have OE rotors in boxes for my truck from when the company closed my test facility. But I typically buy at least one set of new OE rotors and pads when we get a new vehicle so I'll have them when needed. If I really have to, and sometimes I do, I'll get aftermarket rotors from a company that also supplies OE. They still will not be as good.

If you have good friction materials, you don't need rotor "enhancements". I prefer to have as much mass in a rotor as possible. During a panic stop, the majority of the energy is absorbed by the rotor, and not really dissipated to the air - declining speed (air movement) and a short time.

 

I would second OEM rotors for the superodutys. I purchased my 1999 7.3l in 2016 with 120k and it had the original rotors and they were NASTY.... But the owner was the original old lady and only had pads replaced. I put powerstops drilled/slotted rotor and pad kit and the rotors are MEH... I really like their brake pads though. They are extremely low dust and boy do they grab compared to even higher end ons from napa, autzone and OEM.

Currently I still have the powerstop pad/rotor kit from 2016 but will be going with OEM rotors by summers end. I have had similar experiences with subaurs, toyota cars and trucks, Jeep wranglers, and other half ton chevy/ford trucks. Powerstops performace pads have been incredible but OEM rotors for sure.

I have had a 70/30 bad experience with autozone rotors. 2 vehicles had good experience but all the others I swapped out the rotors within a hundred miles or less. I stand by powerstops pads but their rotors are nothing special just not bad but not amazing either.

 

Having replaced OEM rotors calipers and pads @ 46K mi, I then installed Callahan replacements, 50K Mi later, they were shot too. Now the 2012 350 DRW has Power Stop Z36.

Direct comparison to OEM, yes, they are drilled and slotted what does that mean... if I were racing, I'd want as contact as I could get, so a perfectly flat surface, and I'd replace the entire set every race due to heat damage. For real world day to day, I'd rather have the drill hales and slots. The slots keep water away from braking surface and the holes keep the brakes cooler. The holes won't cause cracks if drilled properly (every hear about drill stopping cracks). Cracking isn't caused from holes; they are caused from exceedance of material properties (failing to yield) at sharp points in surface. the hole actually reduces the focused stress. Besides Power Stop has them coated, so no rust issues in the vented areas.

The calipers are all factory rebuilds. the pads are carbon ceramic. So, the braking action seems good.

I my use, I've gone over the scales hauling gravity wagons at just shy of 40,000 Lbs. GCW (Truck, trailer(s) and grain). So, I'm pretty hard on them, but so far, they haven't let me down, (and you can only go about 20 MPH moving them) Gotta love farmers...

The biggest issue I've seem is the calipers ceasing keeping the brake pads in contact with rotors. I've personally taken on annual inspection / lubrication of the braking system.

In either case you can't go wrong.

 

The slots clear the rotor adhered water for the first revolution, ~9ft distance tire diameter dependent, then the rotors are clear due to centrifugal force and heat. At 60mph, that's 88 ft/sec, so not a lot of time.

Holes drilled properly means a chamfer. How is that done on the vane side of the rubbing discs? OE gets that done by casting in the holes, aftermarket drills.

The brake industry has gone to great lengths to maintain approximately 0.005" clearance between the pads and rotors to prevent off-brake rotor wear, which causes non-parallel surfaces, the reason for pulsation. But, I guess hundreds, if not thousands, of engineers and tests were wrong.

 

Huh, So the 350's brake pads are almost perfectly parallel. Certainly not true of the civic I once owned. But the dual piston seems to be doing a good job. Worn, but flat.

 

The pads leave the factory parallel steelback to the rubbing surface and certainly don't stay that way, with any vehicle. But I did not say anything about pad parallelism.