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Sorry, did not want to derail this thread, but the stone is rolling.
So the 8 piston caliper has smaller pistons that are distributed out along the back of the pads, same clamping force else there would have to be master cylender changes. Guess the next question is, if its a bigger caliper, with bigger pads, more surface area on the rotors, does that help or not? I've not been able to find any specs on the pads, just that they are "SSBC Big Bite Brake Pads 10133".
I'm beggining to guess that even if they are a little bigger, its not going to be worth the $1k price tag for the minor gain in braking performance.
Larger surface area of pads lowers the lbs/sqin loading. If you were applying 1000psi with stock size brakes and you double the surface area, it’s like applying 500psi with the stock brakes.
You generally make up for that by increasing the brake pad formulations coefficient of friction. But then, that could have been done with the stock brake size too.
COF x clamping force = .........
Edit add in,
COF x clamping force x swept radius = brake torque.
Larger surface area of pads lowers the lbs/sqin loading. If you were applying 1000psi with stock size brakes and you double the surface area, it’s like applying 500psi with the stock brakes.
You generally make up for that by increasing the brake pad formulations coefficient of friction. But then, that could have been done with the stock brake size too.
COF x clamping force = .........
Edit add in,
COF x clamping force x swept radius = brake torque.
So what your saying is, unless you're going to replace a lot of parts, stick with the stock brakes. :-)
The biggest impact is rotor diameter. But you can accomplish most of that with changes in friction material, which is way more cost effective. Increasing COF at both axles keeps brake bias in balance and doesn't shift temperatures from the back axle to front axle. Many make the mistake of increasing brake torque at the front brakes and end up with fade issues because of the work shift, what was 55/45 disc/disc now becomes 65/35 and you're fading front material or boiling fluid. A lot of work goes into brake balance now that the designers have linear output from both the front and rear brakes.
The downside of higher COF of material is how the compounder (the chef of the friction material who comes up with the ingredients, develops the best methods of mixing and adding ingredients, and comes up with the proper bake cycle - I did that for 5 years) crafts it. Is it by abrasiveness, a higher temperature range material, a higher metallic ....... everything in friction is a compromise.
From an OE development side, most of the time the design hangup is the wheel sizes, so the designer stuffs as large a rotor in there that the caliper will allow. The Superdutys have a very stiff caliper design which is good for fade resistance, one of the original goals back in '96-97, so the bridges of the calipers are thick. Compared to other platforms it also has a lot of mass in the rotors, so these trucks actually run cool in normal use then others, not only due to rotor mass but the '99-04 OE TRW rotors used a Pin Vane design for better cooling. Your '04 utilizes the Akebono design calipers, which came with a Abex/Federal Mogul friction material that has a Chase Test rating of EE for cold/hot COF. It was utilized on a different Ford platform, it worked great and it's one of my favorite friction materials from the company. But it's a mid EE material and in hind site this wasn't its best place. The Federal Mogul material that replaced it on the '05-'08 platform was a F/E rating, but the E rating is higher then the previous material's E, right at the borderline to F. '05s targeted bigger wheels, higher GVWs.
The foundation brake designers and actuation system designers come up with their work, then its up to the friction material supplier to fine tune the friction side to get the pedal efforts into compliance to some extent. You target EE in design. You can bump friction but you start to lose other characteristics like noise abatement, rotor wear and friction wear life. And throw wheel dust in their too. The aftermarket has a wider canvas. If the friction guys can't correct to the standards, then the application guys may have to play with pedal leverage, master cylinder and booster balance. Remember Mustangs with hydroboost? When all that fails it's back to the caliper guys with larger pistons, which ends up putting the application guys back to work to get the pedal effort/pedal travel to fit customer feedback and FMVSS compliance.
It's easier to hunt for a friction material that works, but may lose a little in noise, rotor or wear life. If you increase tire diameter, that's another whole level as you're increasing the leverage of tire rolling radius over brake swept radius. The '05 platform was designed to manage both the 18" and 20" tire options. Braking is a little easier with the 18".
The upside to larger surface area is a longer wear life from the volume increase and better fade resistance as the thermal conversion is done over a larger area, so Temp Delta per sqin is lower for the friction material. Temp Delta for the same size rotor is not.
What I noticed in the pricing for the upgraded brake setup in this thread is that you already have to have the larger than standard 16" rims/tires, or you need to add them to the cost of the project as well. I think I am Correct? Or will this work with the 16"?
The 14.29" rotors require the OEM 17" steel wheels or the 18" alloy wheels at minimum. Not cheap, but I will say you can get a set of new 18" or 20" take-offs for less than what you could buy the tires for. And it's not just the room for the bigger brakes; the limiting factor to braking is tire adhesion. The contact patch of the 275/65r20s is 291 cm2 compared with 259 cm2 for the original 265/75r16s. There is a reason why they (or the 275/70r18s) come on the new trucks.
Are you saying that the truck tracks better now? Is there a change in front suspension geometry? It might be worth it just for that.
BTW, I resolved the rubbing by chamfering off the bottom corner of the fender/trim with a Sawz-All. Don't worry, I made it look nice... Still rubs occasionally on my stock mud flaps though (had to trim those, too.)
Greg, sorry I neglected to respond to your post. Yes, the truck tracks better now. No, I do not think that the geometry of the twin I beam has changed. What has changed? Two possibilities. The first is just the new parts--mainly, the new ball joints that came with the spindle/knuckles but also a couple other suspension parts you change when you are doing a project like this. The other possibility is that the larger knuckles and 2" wider track have also contributed. Maybe we could ask guys who have driven both the original (when it was new) and the newer 2wd Super Duties to see if they noticed any difference.
OK, I just got the truck back after some follow-up work. All the issues have now been solved:
1. The ABS sensors? Big shout out to Jacksonville 4x4 (Jacksonville NC) who fixed this along with everything else--nothing daunted them. Retaining the original ABS sensors as the core, they just used the casings from an older generation Chevy truck as shims (some assembly required). Works perfectly and looks great. Thanks for making this unique project a reality.
2. The soft brake pedal? It just needed a good bleed. If I ever get around to changing the rears, I might go to the new 1.313" MC, but for now the 1.375" original MC works just fine.
3. Tire rub? Well, I was using the wheel spacers to make the 2017 wheels work with the 2000 front end. But of course, I now have the main parts of a 2017 front end. After removing the wheel spacers (anyone need 2x BORA 2" spacers?) the wheels are back where they belong, and do not rub at all.
I will answer the question about cost in a separate post.
Do you have any more info and pics of the ABS sensors? I've got a similar setup with 05 spindle/knuckle. Only issue is the older sensors don't fit and the truck doesnt read the newer ones correctly
Do you have any more info and pics of the ABS sensors? I've got a similar setup with 05 spindle/knuckle. Only issue is the older sensors don't fit and the truck doesnt read the newer ones correctly
+1 on this; I'm about the pull the trigger on this upgrade (I need to replace the brakes anyway).
Unfortunately, it looks like the OP has not been online here since he posted this in 2018...does anyone else have any suggestions?
Greg,
A shop did some very poor work replacing my brakes, and ended up damaging the ABS sensor (the one that was stuffed in an old Chevy housing). Anyhow, they ended up just drilling out the hole in order to mount a '99- model Ford ABS sensor. It works fine.
I'm gathering parts now for this. I'll take some measurements of the sensor and will very likely drill/bore the later spindles to do the same thing. If/when I get that I'll post the info here.
Pardon my ignorance on suspension and brake setups, but will this setup (factory 14.29" brakes) work on 4WD trucks? I understand the differences between 2WD and 4WD parts, but as a general direction. The brakes on my 2000 4WD are getting near the end of their life, and if this is a possibility, I can move my 20" wheel upgrade up the list.
Bill, Did you ever put a 2013-2016 rear end under your X?
My 2000 PSD 2wd has miles on it, original owner, and I am looking at doing your front-end mod as well as the rear end, new coil springs up front and new leafs in the rear, complete refresh.
Pardon my ignorance on suspension and brake setups, but will this setup (factory 14.29" brakes) work on 4WD trucks? I understand the differences between 2WD and 4WD parts, but as a general direction. The brakes on my 2000 4WD are getting near the end of their life, and if this is a possibility, I can move my 20" wheel upgrade up the list.
Thanks.
you would have to order the 2013+ 4wd parts, but I don't necessarily see a reason why it wouldn't work.. that said, I haven't measured anything and I'm not quite ready to pony up $800 on a kit that might not fit.
08-17-2018, 01:51 PM
Still rubs occasionally on my stock mud flaps though (had to trim those, too.)
