Lets Talk Full Floater

[ntsqd]

Truck is an Auto trans and that won't be changing, so while I prefer to first set the p-brake, the trans' Park function will back it up. I try not to be pulling the trans out of Park while it is under a load even if it is designed to allow that.

I do have a Jamar "Park-Lok" that was intended to be put in the avatar, but that never happened. Seemed like a good idea at the time of purchase, but it proved to not be needed in the buggy.

Brake torque is calculated from the coefficient of friction, the clamping/driving force (self-energizing drum brakes make this a fun one!), and the radial distance of the contact patch. In the case of a disc brake that would be the radial distance of the centroid of the pad's contact area. Drums I'm far less familiar with, but my best guess is that it is the radial distance to the drum's wear surface. Same force applied at a larger ID will be an increase in brake torque.
The area(s) in contact aren't part of the torque equation. Pad area and pad thickness are factors in wear life only. I would assume that shoe area and shoe thickness in drums have the same effects. I do know that leading shoes have different areas than trailing shoes in service brakes, but that has to do with the self-energizing function as I understand it.
I would expect that the F-150 drum surface has a larger ID than the Exploder drum, and that the F-250 drum surface would be larger than the F-150's.

Perhaps we should petition to have this brake discussion be moved to a new thread? Mods, what say ye?

[Wrightracing.net]

I am considering the 1999 F350 rear brakes on my Full Floater 9". I am thinking Of Dana 60 snouts on my 9" with custom hubs to widen the axle and use the stock 8 on 170mm lug pattern. Then I can swap on a spare from the F350 if needed.
I am still on the fence with that, because I did have issues with the E-Brake on my F350 since I had a friend drive it with the brake on for several miles. But I think with a hand brake and new shoes, I can get it to work much better on the lighter Bronco.

The stock rims on the F350 were 16", but I have beadlock 16.5" rims now. That way, I am not worried about the brake size, but I won't be able to run the 15" wheel's anymore. So then I will sell off my Craigar soft 8 rims. I have 4 that are on the Bronco now and 4 new ones in the box in my Garage. That is a ways off right now.



David Wright

[ntsqd]

Since you are building the axle housing from parts I would go with the 14bolt FF spindles for several reasons. The wall thickness of the spindle is thicker under the inner bearing and they fit a 35 spline drive axle w/o mods. That thinness under the inner bearing is my biggest concern with choosing the lighter D60 over a 14bff. As I'm not hucking this truck into the air or using it as a full throttle pre-runner I am hopeful that it won't become a problem.

The other option would be to harvest some 10.5" spindles or graft the 10.5"s tubes into a 9" housing. For that matter, what about just running the 10.5"?

[Wrightracing.net]

Since you are building the axle housing from parts I would go with the 14bolt FF spindles for several reasons. The wall thickness of the spindle is thicker under the inner bearing and they fit a 35 spline drive axle w/o mods. That thinness under the inner bearing is my biggest concern with choosing the lighter D60 over a 14bff. As I'm not hucking this truck into the air or using it as a full throttle pre-runner I am hopeful that it won't become a problem.

The other option would be to harvest some 10.5" spindles or graft the 10.5"s tubes into a 9" housing. For that matter, what about just running the 10.5"?

I have seen the options for 10.25 and 10.50 snouts. Sourcing the 10.50 hubs in aluminum may be pricey. With Steel ones, I can modify them and turn them for my tubes on the 9".
If I found a 10.5 hub, I would remove the lug plate and weld in a new one with the correct pattern and spaced out if needed to achieve a wider axle. I read somewhere that I can get spindles that would make the axle wider by 2.5" per side. Then I may have to move the hub wheel mounting surface out by 1.5 in, to give me 4 in on either side of the axle. I am still torn whether or not I want to widen the Bronco by 3 or 4.5 in.

I have so many options Running around in my head it's kind of crazy.

David Wright

[ntsqd]

I recognize the economics of using/modifying an existing housing, but I don't think that it is the right way to go about widening a rear axle. If you re-tube your existing housing or start from scratch to be the right width then you can use off the shelf OEM type wheel hubs, brakes, etc., etc., etc. Then, less whatever the drop-out is, you only have three custom parts to worry about for spares. The housing and the drive-axles. Everything else is COTS parts that you hopefully can find in Manhattan, NV or BoLA, Baja if need-be.

Dutchman had no added cost for a large range of drive axle lengths, no change in cost there. Being able to use OEM wheel hubs saves a chunk of money that can be put into the housing instead. I started down the road of building a custom housing and realized that the cost/benefit wasn't there for me and that a whole axle would be a better buy even if it wasn't technically as strong. I had to buy drive axles because the numb-nutz kid managed to loose them and a bunch of other stuff, but the price for what was there was right.

FWIW anyway, that's how I look at it.

[mobil1syn]

if you are looking into OEM parts, check out jk stuff. currie sells a re-drilled rotor for 5x5.5

i am building a custom axle and am on the fence about lug pattern. if i stay 5x5.5 i will be utilizing the f450 kit from black magic. ive driven a few jks with this kit and it works. shouldnt be hard to modify a few things and run all JK brakes.

https://www.shop.blackmagicbrakes.com/C ... MASTER.htm

https://www.shop.blackmagicbrakes.com/W ... ACKETS.htm

[PaulW]

Hub centric? To limit your choice of wheels?
Are you really locked into an old school D44?
Of course for a D44 you probably know the new m220 Spicer D44 is a bigger and stronger diff than previous D44s.
Lug pattern? lots of choices for wheels if you choose a 6 bolt chevy pattern

[mobil1syn]

Hub centric? To limit your choice of wheels?
Are you really locked into an old school D44?
Of course for a D44 you probably know the new m220 Spicer D44 is a bigger and stronger diff than previous D44s.
Lug pattern? lots of choices for wheels if you choose a 6 bolt chevy pattern

im confused ... im not building a jk axle. i making a suggestion to ntsqd to check into JK stuff because you can get an OEM rear disc setup with an ebrake and if hes married to the 5x5.5 bolt pattern.


my rear axle is the following parts
- tundra 10.5 center section with an ARB
- custom housing
- spridertrax unit bearings
- OEM brakes with a drum in rotor ebrake, lug pattern and actual parts TBD. have a few ideas just need to finish my bathroom remodel so i can sort out the details.

[ntsqd]

I already have a rear D60 from a mid 70's F-250 (I *think*), 4.56 gears, bearings (diff & wheel), Mark Williams bearing caps, Dutchman drive-axles, an Explorer RDB kit, and an OX locker (air, not cable). It will stay 8 lug and I now have five 17x8.5 8 lug wheels (3.5" BS) and 315 R17 BFG A/T's. I've modified the housing for the stock VSS ('96 Bromco) and have a D60 tone ring. I'll need to reprogram the speedo, but that's only been done once so there's still some spots left.
The front is going to be GM 3/4t front brakes (COTS/OEM 12.5" rotor brake system) and those are also staying 8 lug. Tundra front fixed calipers might happen at some time in the future. Changing to 5x5.5 isn't really feasible with the pieces that I've chosen, and that doesn't bother me. I just need to find some 9/16" rear wheel studs to match the fronts that will work with everything else! I may just use that same stud everywhere. If it were longer I'd already have them.

When I looked at building up a whole rear axle it suddenly got into deep money and didn't make sense for my goals. Which are pretty simple: stronger than the 8.8 under there now, full float, and least gain in unsprung weight as I can figure out w/o getting into spending cubic dollars. From the weights posted on the net it would appear that a FF D60, less it's typical drum brakes. isn't too much heavier than the 8.8 with it's drum brakes. By going Explorer rear discs I'm hoping to keep the weight gain from the brakes to a minimum.

Using the Tundra diff wasn't an option that I'd thought of, that's interesting! An electric locking Tundy diff would be really cool!

[mobil1syn]

ooh i didnt realize you were that deep into it, theres no turning back now

[ntsqd]

Thanks for the thought anyway!

[toddz69]

my rear axle is the following parts
- tundra 10.5 center section with an ARB
- custom housing
- spridertrax unit bearings
- OEM brakes with a drum in rotor ebrake, lug pattern and actual parts TBD. have a few ideas just need to finish my bathroom remodel so i can sort out the details.

Tell us more about the Spidertrax unit bearings and OEM brakes will fit together. Which OEM brakes are you referring to? I haven't seen a setup that uses the Spidertrax FF set with drum-in-rotor e-brakes.

Thanks,
Todd Z.

[mobil1syn]

Thanks for the thought anyway!

looks like chevys were drum in rotor for the 00-07 2500hds

https://www.youtube.com/watch?v=DnfG9QTBX9g

[ntsqd]

Looks like a very big caliper for the rear of a Bronco, even a full sized one. When the bed is empty I'll bet the ABS system dials those down to almost no pressure to keep from locking up the rear tires.

[AussieRod]

I already have a rear D60 from a mid 70's F-250 (I *think*), 4.56 gears, bearings (diff & wheel), Mark Williams bearing caps, Dutchman drive-axles, an Explorer RDB kit, and an OX locker (air, not cable). It will stay 8 lug and I now have five 17x8.5 8 lug wheels (3.5" BS) and 315 R17 BFG A/T's. I've modified the housing for the stock VSS ('96 Bromco) and have a D60 tone ring. I'll need to reprogram the speedo, but that's only been done once so there's still some spots left.
The front is going to be GM 3/4t front brakes (COTS/OEM 12.5" rotor brake system) and those are also staying 8 lug. Tundra front fixed calipers might happen at some time in the future. Changing to 5x5.5 isn't really feasible with the pieces that I've chosen, and that doesn't bother me. I just need to find some 9/16" rear wheel studs to match the fronts that will work with everything else! I may just use that same stud everywhere. If it were longer I'd already have them.

When I looked at building up a whole rear axle it suddenly got into deep money and didn't make sense for my goals. Which are pretty simple: stronger than the 8.8 under there now, full float, and least gain in unsprung weight as I can figure out w/o getting into spending cubic dollars. From the weights posted on the net it would appear that a FF D60, less it's typical drum brakes. isn't too much heavier than the 8.8 with it's drum brakes. By going Explorer rear discs I'm hoping to keep the weight gain from the brakes to a minimum.

Using the Tundra diff wasn't an option that I'd thought of, that's interesting! An electric locking Tundy diff would be really cool!

If you find a source for the front 3/4 ton chevy stuff, let me know. I'd be interested in the spindles, 8 lug hubs, backing plates, outer axles, etc. Bearings, calipers, rotors, etc I can source locally, but the main stuff I need to convert mine. That way, I can fit the D60 to mine and just have one spare, rather than carrying two.

[mobil1syn]

Tell us more about the Spidertrax unit bearings and OEM brakes will fit together. Which OEM brakes are you referring to? I haven't seen a setup that uses the Spidertrax FF set with drum-in-rotor e-brakes.

Thanks,
Todd Z.

all just a theory right now, waiting on my housing to show up and got some honeydo's to handle before diving in. rotor works, caliper integration is easy, the backing plate is the unknown.

Looks like a very big caliper for the rear of a Bronco, even a full sized one. When the bed is empty I'll bet the ABS system dials those down to almost no pressure to keep from locking up the rear tires.

you are sticking a 1-ton axle under a bronco, of course its a large caliper. if its a concern you can always run a different caliper and mount.

[mobil1syn]

MANAGEMENT ... CAN WE PLEASE GET AN EDIT BUTTON

Looks like a very big caliper for the rear of a Bronco, even a full sized one. When the bed is empty I'll bet the ABS system dials those down to almost no pressure to keep from locking up the rear tires.

additionally as long as the front is matched to the rear, it would be a balanced setup.

[ntsqd]

Rod, the backing plate will be the hardest part to source outside of a yonke. I've come across the wheel hubs, stub spindles, and the outer axles in various places on the net. Used to be that you could find the brackets on ebay, but I've had no luck this morning. You will need D44 TTB 6 bolt knuckles with the OEM caliper mounting ears cut off. The caliper brackets will then need 6 new holes drilled between the existing holes to clock the caliper so that it clears the knuckle. I eyeballed the rotation to be centered between the existing holes and used a spindle clamped to the bracket with the transfer punch to mark the new hole locations. In small parts you'll also need the 3/4t GM spindle to knuckle bolts as they are longer than the TTB spindle bolts because the caliper bracket sits on top of the spindle's mounting flange. I bought these new, complete with prevailing torque lock-nuts, off ebay.

Mobile, Even with a complete system transfer (Master cyl - booster, ABS, calipers & rotors), into a Bronco it won't work the same way because of how different the Bronco is from a full size pick-up. From my experience in designing and installing brake systems it is pretty easy to get too much rear brake. At GVW the pick-up can use that much rear brake because there is enough weight on the axle. The rest of the time the ABS system is dialing the pressure in the rear brakes way down. From observation of aftermarket kits and brackets they all are too large. In my mind a truly balanced system doesn't need a proportioning valve (or ABS!) when the rear axle load is consistent, it only needs a delay valve to slow the actuation of the rear brakes during a panic stop.
As for changing the rear caliper to one with a smaller piston. It usually isn't that easy as it's not just a simple bracket that they're bolted to. With a drum in hat p-brake the backing plate for the drum brake is also the caliper bracket. Most of those are a fairly complex piece. Better to start with an appropriately sized assembly and adapt it to the axle of choice. Arguably I'm leaving some braking performance on the table by using the easy to acquire Explorer RDB system instead of the slightly larger and likely closer to ideally sized Expedition RDB system. Overall the improvement will still be significant enough that I'm not too concerned about not optimizing the rear brakes.

I didn't really deal with ABS because the forum's focus doesn't include that tech, AND I'm not really qualified to discuss it in depth, but I condensed most of what I've written on the topic into this thread: https://forum.ih8mud.com/threads/commen ... es.256361/

[AussieRod]

Rod, the backing plate will be the hardest part to source outside of a yonke. I've come across the wheel hubs, stub spindles, and the outer axles in various places on the net. Used to be that you could find the brackets on ebay, but I've had no luck this morning. You will need D44 TTB 6 bolt knuckles with the OEM caliper mounting ears cut off. The caliper brackets will then need 6 new holes drilled between the existing holes to clock the caliper so that it clears the knuckle. I eyeballed the rotation to be centered between the existing holes and used a spindle clamped to the bracket with the transfer punch to mark the new hole locations. In small parts you'll also need the 3/4t GM spindle to knuckle bolts as they are longer than the TTB spindle bolts because the caliper bracket sits on top of the spindle's mounting flange. I bought these new, complete with prevailing torque lock-nuts, off ebay.

Yep, I've noticed that, too. IF I was able to travel to USA, I'd be over in a flash, source a 10 bolt 3/4 ton and scavenge what I need to send home with all new consumables. I have a comprehensive list of all the parts required, including part numbers for new available parts and year models to source the unavailable new bits. It also gives details of the mods required for the knuckles and backing plates, etc. I'm fully aware what it needed and have a heap of stuff on my watch list on ebay for the easy to get parts. I'm more curious that if you find a source for say, a complete front 10 bolt from a 3/4 ton and there is more than one, I'd be interested in obtaining what I need.

[ntsqd]

I do need to head out to the yonke, hopefully this weekend, to see if I can score some TTB beams for cores. I'll have a look for that front axle too and if I see anything I'll pull what's there. I'm in the Lower Left Coast though, odds are very low of any yonke close to me having anything that old.