Upgrading to 11.75” discs on the front?

[71DodgeDemon340]

Im running 11” ssbc rotors up front with the slider type calipers. I would like to upgrade to the 11.75” rotors but seems the larger caliper brackets are hard to find?

If i find the larger brackets i will need to use larger dust shields as well correct?

also i already have the spindles that accept the lbp 11” rotors as found on the 79 volare, will the larger rotors fit my spindles?

ive read that both the 11” and 11.75” rotors used the same brake pads is this true?

anything else i need to consider?

im also looking at going this route

Wilwood Mopar 11.75" Front Disc Brake Kit (Stage 2 Plus)

 

[72bluNblu]

Im running 11” ssbc rotors up front with the slider type calipers. I would like to upgrade to the 11.75” rotors but seems the larger caliper brackets are hard to find?

To clarify, you are using stock sliding calipers? Not an SSBC conversion kit?

The 11.75" slider caliper brackets are reproduced. DoctorDiff is currently out of stock, but I'm sure he has an idea of when they'll be available. Supply chain issues have been affecting pretty much everybody in this industry
Mopar 11.75" Disc Brake Slider Caliper Brackets

If i find the larger brackets i will need to use larger dust shields as well correct?

DoctorDiff sells dust shields that will work with the 11.75" rotors. But dust shields in general are pretty useless, they do a better job of trapping brake dust and heat close to the rotor than anything else.

also i already have the spindles that accept the lbp 11” rotors as found on the 79 volare, will the larger rotors fit my spindles?

The 11.75" rotors use the same wheel bearings as all of the 73+ 10.95" rotors. If you have 73+ A/B/E/F/M/J/R spindles you can use 11.75" rotors as long as you get the 11.75" caliper brackets.

ive read that both the 11” and 11.75” rotors used the same brake pads is this true?

Yes. They use the same calipers, so the pads are the same. The only difference is that the factory '73-75 A-body slider calipers used 2.6" diameter caliper pistons. In '76 the A-bodies started using the same 2.75" pistons that the B/E bodies were already using. From there forward all the calipers had 2.75" pistons. As long as you match the type of caliper (slider vs pin type) to the style you already have, all you have to do is install the larger rotors and caliper brackets.

im also looking at going this route

Wilwood Mopar 11.75" Front Disc Brake Kit (Stage 2 Plus)[/QUOTE]

I mean, I suppose. If I was going to spend $750 (just for calipers, brackets and rotors) though I would probably go with a kit that had a larger diameter rotor. For about another $100 you can run the 13" cobra style kit.

You can get a pair of plain 11.75" rotors for a little over $100, plus another $90 for the 11.75" brackets. Using your current slider calipers and volare spindles you've got 11.75" brakes for about $200. And the 11.75" brakes and stock calipers work pretty well, I ran 11.75" rotors and a set of E-body pin style calipers with the 2.75" pistons on my Challenger for like 70k miles, they worked great and still stopped the 275/40/17's I ran on that car.

 

[71DodgeDemon340]

To clarify, you are using stock sliding calipers? Not an SSBC conversion kit?

The 11.75" slider caliper brackets are reproduced. DoctorDiff is currently out of stock, but I'm sure he has an idea of when they'll be available. Supply chain issues have been affecting pretty much everybody in this industry
Mopar 11.75" Disc Brake Slider Caliper Brackets

DoctorDiff sells dust shields that will work with the 11.75" rotors. But dust shields in general are pretty useless, they do a better job of trapping brake dust and heat close to the rotor than anything else.


The 11.75" rotors use the same wheel bearings as all of the 73+ 10.95" rotors. If you have 73+ A/B/E/F/M/J/R spindles you can use 11.75" rotors as long as you get the 11.75" caliper brackets.



Yes. They use the same calipers, so the pads are the same. The only difference is that the factory '73-75 A-body slider calipers used 2.6" diameter caliper pistons. In '76 the A-bodies started using the same 2.75" pistons that the B/E bodies were already using. From there forward all the calipers had 2.75" pistons. As long as you match the type of caliper (slider vs pin type) to the style you already have, all you have to do is install the larger rotors and caliper brackets.



Wilwood Mopar 11.75" Front Disc Brake Kit (Stage 2 Plus)

thanks blu i was expecting you to stop by lol. im only running the ssbc rotors, stock style brackets and calipers. car stops about as well as i can ask for manual brakes but seems like its lacking some, they arent really spongy that i can tell. im running a 1-1/32” bore master which i now discovered from reading and talking to cass at dr diff probably should have been a 15/16” bore but the pedal really doesnt seem that hard to press to me. Is the larger bore master hampering my braking? I know either way i need to correct my calipers being upside down and swap them side to side so i can get the bleeders at the top. I bled them off the car but due to not having the right hoses i had to mount the calipers upside down. They never have been bled since which was about 8 years ago so they may have developed a tiny air pocket. Either way i plan to fix the calipers by swapping them back to the correct position and order correct hoses. Im just trying to decide the best route. So is there really no need in going to drilled/slotted rotors on a street car?

 

[Demonic]

They never have been bled since which was about 8 years ago

Brake fluid gets "stale" - rust, moisture from the air. Just freshening the fluid every 2 years can make a difference in pedal feel.

Many say that driller/slotted rotors are overkill on the street, unless you're road racing. If they don't get that hot, why reduce the contact area w holes?

 

[Kendog 170]

Good info Blu. Thanks

 

[72bluNblu]

thanks blu i was expecting you to stop by lol. im only running the ssbc rotors, stock style brackets and calipers. car stops about as well as i can ask for manual brakes but seems like its lacking some, they arent really spongy that i can tell. im running a 1-1/32” bore master which i now discovered from reading and talking to cass at dr diff probably should have been a 15/16” bore but the pedal really doesnt seem that hard to press to me. Is the larger bore master hampering my braking? I know either way i need to correct my calipers being upside down and swap them side to side so i can get the bleeders at the top. I bled them off the car but due to not having the right hoses i had to mount the calipers upside down. They never have been bled since which was about 8 years ago so they may have developed a tiny air pocket. Either way i plan to fix the calipers by swapping them back to the correct position and order correct hoses. Im just trying to decide the best route. So is there really no need in going to drilled/slotted rotors on a street car?

So first off, yes, you definitely need to get the bleeders on the calipers facing up and re-bleed the brake system. That would also be a good time to flush out the old brake fluid and replace it, Demonic is right about that. Brake fluid will absorb moisture over time and it does need to be replaced.

So, using the 15/16" master cylinder would actually increase your brake line pressure, which will increase your clamping force at the calipers. If you use a 70 lb force applied to the brake pedal, consider the 6.5:1 pedal ratio on an A body, and calculate the brake line pressure with a 1-1/32" MC you get 545 psi. If you use the same applied force and ratio but with a 15/16" master you end up with 659 psi. If you take that through to the clamping force at the rotors using a 2.75" piston caliper, you get 3,236 lbs for the 1-1/32" MC, and 3,915 lbs of clamp force with the 15/16" MC, with everything else being the same. So the 15/16" master cylinder will increase your braking power and give a little more brake pedal travel, which will make the pedal feel easier to push.

As for the drilled/slotted rotors I wouldn't say there's no need. It depends on how you drive your car and how hard you are on your brakes. If you do a lot of "spirited" driving on winding roads, or have a lot of long downhill grades where you need the brakes for long periods of time you might benefit from them. But I would say that the way most of these cars get driven most of the time the drilled/slotted rotors are overkill. Let's put it this way- if you've never had brake fade with the plain rotors, you don't really need the drilled/slotted rotors. They still might lower your brake temperatures a little, but if you're not getting to a place where you've noticed brake fade from heat they're not a "must have" item.

Brake fluid gets "stale" - rust, moisture from the air. Just freshening the fluid every 2 years can make a difference in pedal feel.

Many say that driller/slotted rotors are overkill on the street, unless you're road racing. If they don't get that hot, why reduce the contact area w holes?

Definitely agree with changing the fluid!

Although I would say most folks don't need the drilled/slotted rotors, I would also say that the area reduction from the holes/slots is pretty darn minimal. Like not really worth considering. You also don't need to be road racing to benefit from the drilled/slotted rotors, the brakes don't have to glow red for you to benefit from having the drilled/slotted rotors. That said, like I said above unless you're pretty hard on your brakes I agree they're probably overkill.

 

[DionR]

My understanding was the when cars started leaving the factory with the 11.75" rotors, the dust shields didn't change. So no reason to look for something that isn't any different than what you already have.

That said, I agree with Blu that they don't do much good.

 

[71DodgeDemon340]

Thanks for the replies guys, much appreciated. Is the 15/16 master worth the hassel of swaping it out? My 1-1/32 master feels good to me, not sure what size pistons my calipers are, i will deff plan on changing the brake fluid, i was also thinking about using braided hoses on the front? Also is there any benefit in going from the single piston to 4 piston wilwoods

 

[71DodgeDemon340]

My understanding was the when cars started leaving the factory with the 11.75" rotors, the dust shields didn't change. So no reason to look for something that isn't any different than what you already have.

That said, I agree with Blu that they don't do much good.

thats what i thought i read somewhere, so are the dust shields the same?

 

[71DodgeDemon340]

Also is the offset on the hub on the 73’ a body 11” rotors the same as the 78 cordoba 11.75” rotors?

 

[DionR]

thats what i thought i read somewhere, so are the dust shields the same?

That's my understanding.

In fact, that's one way I check cars when looking for the adapters. If the rotor overhangs the dust shield a little, it has the 11.75" rotors. If not, I don't bother to look any further.

 

[DionR]

Also is the offset on the hub on the 73’ a body 11” rotors the same as the 78 cordoba 11.75” rotors?

Offset is the same.

 

[71DodgeDemon340]

Offset is the same.

is the hub register the same diameter as well?

 

[72bluNblu]

Thanks for the replies guys, much appreciated. Is the 15/16 master worth the hassel of swaping it out? My 1-1/32 master feels good to me, not sure what size pistons my calipers are, i will deff plan on changing the brake fluid, i was also thinking about using braided hoses on the front? Also is there any benefit in going from the single piston to 4 piston wilwoods

I think it's worth swapping the master cylinder to 15/16", I've swapped both my Duster and my Challenger over. But if you're happy with the pedal feel on the 1-1/32" then you can leave it alone.

I'd check the piston diameter as well, if you have the 2.6" pistons going to the 2.75's is also a nice upgrade. If you go from the 10.95" rotors to 11.75's with 2.75" pistons it will be a nice upgrade in braking.

Braided hoses are nice, they have a little less flex in them so you get a little stiffer pedal if you do it all the way around. Plus the quality of the plain rubber hoses has taken a nosedive, seems like they don't last very long at all anymore. The braided hoses tend to be a higher quality. That's the reason I use them, they hold up better than the rubber hoses.

So, the 4 piston wilwoods are a fixed caliper. If you run the clamping force numbers compared to a set of 2.75" piston stock calipers you actually find that, in theory anyway, the factory calipers have a higher clamp force. But, because they're a single piston floating caliper you get more losses than a fixed 4 piston caliper would have. The factory calipers are less efficient because they can flex more, get hung up on the sliding mechanisms, etc. so even though the math shows a higher clamp force the actual force transmitted to the rotors might be lower. You would also likely have some better brake pad choices with the wilwoods. And the wilwoods are aluminum, so they're lighter. But it really depends on a lot of things. For a street car I would have no problems running the factory 2.75" calipers, they work well. As I said, I did like 70k miles in my Challenger with a set of 11.75" rotors and factory calipers, they work really well. The wilwood calipers might work better, but for the price tag (an extra $750) I'm not sure they're worth it. Like I said before, if I was going that far I'd probably just go to the 13" rotor brake kits, although they take larger diameter wheels.

Also is the offset on the hub on the 73’ a body 11” rotors the same as the 78 cordoba 11.75” rotors?

Yes

is the hub register the same diameter as well?

It should be. Comparing between different manufacturer's, brands etc it might be a little different. But the specs are the same so any differences would be in the production of that particular set of rotors, basically they shouldn't be different by more than production tolerances.

 

[71DodgeDemon340]

Any reason why i should worry about the wilwoods not having dust boots? My car never sees rain or snow

 

[71DodgeDemon340]

For now im going to stay with my 1-1/32 master. Ok heres my options.

1. buy the complete stage 2 plus kit from doctor diff. $850

2. Upgrade to the larger piston calipers, braided hoses and buy the 11.75 caliper brackets along with wheel bearings and 11.75 rotors/pads. $450

3. Upgrade to the wilwood 4 piston calipers, braided hoses, wilwood caliper 11.75 brackets along with wheel bearings and 11.75 rotors/pads. $700

4. leave my current calipers (not sure if they are 2.75 pistons will have to check) upgrade to braided hoses, get the 11.75 caliper brackets along with wheel bearings and 11.75 rotors/pads. $380

 

[1971 CY Dodge Dart]

I run the Wilwood brake kit on my Dart. That includes the rotors, calipers, and master cylinder. I bought the car with the setup. The biggest issue with the Wilwood system is it severely limits what wheels you can run. The rotors use a 3.1" hub bore and that alone makes wheel choices difficult.

 

[1971 CY Dodge Dart]

I have 6 piston on the front.

 

[autoxcuda]

For now im going to stay with my 1-1/32 master. Ok heres my options.

1. buy the complete stage 2 plus kit from doctor diff. $850

2. Upgrade to the larger piston calipers, braided hoses and buy the 11.75 caliper brackets along with wheel bearings and 11.75 rotors/pads. $450

3. Upgrade to the wilwood 4 piston calipers, braided hoses, wilwood caliper 11.75 brackets along with wheel bearings and 11.75 rotors/pads. $700

4. leave my current calipers (not sure if they are 2.75 pistons will have to check) upgrade to braided hoses, get the 11.75 caliper brackets along with wheel bearings and 11.75 rotors/pads. $380

if you like your current pedal feel I’d go #4 for just aggressive street cruising.

both my abodies have just 11.75 rotors with factory calipers.

I manage out at Willow Springs with that setup. But repeatedly slowing at the end of the long straightaway from 110+ mph to make a 50 mph curve could use better brakes.

 

[71DodgeDemon340]

if you like your current pedal feel I’d go #4 for just aggressive street cruising.

both my abodies have just 11.75 rotors with factory calipers.

I manage out at Willow Springs with that setup. But repeatedly slowing at the end of the long straightaway from 110+ mph to make a 50 mph curve could use better brakes.

I mean is there anyway the 4 piston calipers wont stop better than the factory style?

 

[71DodgeDemon340]

I run the Wilwood brake kit on my Dart. That includes the rotors, calipers, and master cylinder. I bought the car with the setup. The biggest issue with the Wilwood system is it severely limits what wheels you can run. The rotors use a 3.1" hub bore and that alone makes wheel choices difficult.

View attachment 1715687374

how many miles have you put on them? Do they have the dust boots? I know the dust boots help protect the pistons but are they even needed with stainless pistons?

 

[autoxcuda]

I mean is there anyway the 4 piston calipers wont stop better than the factory style?

should stop at least same or better. But might not be noticeable on street. That’s IF the master cylinder bores are correct diameter. That might take some trial and error or find someone with same setup.

 

[71DodgeDemon340]

should stop at least same or better. But might not be noticeable on street. That’s IF the master cylinder bores are correct diameter. That might take some trial and error or find someone with same setup.

im running the 1-1/32 bore master

 

[autoxcuda]

im running the 1-1/32 bore master

I never ran Wilwood stuff on my personal cars. So I don’t know what master works for that setup.

Does Dr Diff make the disk brake spindle to Wilwood caliper adapters ?? If so he would know. Or maybe whomever makes it.

 

[1971 CY Dodge Dart]

how many miles have you put on them? Do they have the dust boots? I know the dust boots help protect the pistons but are they even needed with stainless pistons?

I've put maybe 30 miles on the car which was just the ride home after purchasing it. By the time I got it registered it was time to put the car away for the Winter. I do have the dust boots but I'm not convinced they're necessary.