Boss T/A front brake upgrade (Lincoln/Tbird calipers) thread

[Rusty67]

I am just starting to learn suspension, but this sounds like the way to go in my newbie-like opinion on the subject.

You are saying that 68 Bird spindles will fit our cars (with the exception of the ball joint size), correct?

Then with the spindles adapted, you should be able to use all the factory hubs, rotors, brackets, calipers, etc...

You can't beat that.
Spacers for the joints should be no problem.
Who's to say that you can't just use the Bird ball joints bolted into our control arms???
Any comment on that idea?

The main issue I see with using the tbird spindle is that it very well could change the track width of the car. I doubt it would narrow the track width either. If it makes the track width wider, then we will all have to be careful when using larger wheels/tires because it will push them further out and may cause quarter pannel interfierence.

Chaning the upper ball joint to match the tbird might not be all that hard. ACDELCO Part # 45D0015 or #88911386 would give you a 4 bolt Mustang upper ball joint to compair against. Kragen lists Rare Parts Upper Ball Joint P/N 10131. Unfortunately they don't have a picture. I don't know if that is a 3 or 4 hole ball joint or what.

The lower arm is where it becomes a pain in the ass. I would imagine you would provably need to remove the lower ball joint, remove the stocket for the lower ball joint, weld in a new socket for the ball joint the correct size for the Tbird ball joint and then find a lower ball joint the right size which provably wont be easy. Apparently there is a left side and right side for the ball joints.... Kragen lists Rare Parts PN 10132 Lower Ball Joint Right and P/N 10133 Rare Parts PN 10132 Lower Ball Joint Left. Each of those 4 ball joints is about 100 bux each so now we are talking labor plus 400 bux. At that point just buy the Cobra Automotive bracket... it would end up being cheaper due to labor costs.

Another option may be to go with screw in lower ball joints and try to find one with the correct taper for the Tbird spindle. It would be as much trouble initially but finding the right ball joint would be provable. Again, this is going to make for some high expense in control arm modification.

Yet another option is to use an adaptor (like was mentioned) because I think the ball joint on the Tbird is bigger. You would only need 1 adaptor if you changed the upper ball joint, again the expense may not be worth changing the upper and just using adaptors/spacers all the way around.

The 1968 Ford Full Size rotor (Raybestos 6008) is not a "drum hub type". It mounts, like all 60's Ford disc/hub assemblies, to the back of disc hubs, which are different from drum hubs.

An alternative is to use Rabestos rotors and aluminium hats in combination with drum hubs. A little more expensive (2 x $75 for the hats and 2 x $50 for the rotors), but significantly lighter. This is similar (or actually identical) to the Cobra Automotive kit.

I'm not exactly sure what you mean. Why wouldn't it work ? Using the drum hub is the same thing that all the kits puting late model Cobra brakes on the classics do. I think I'm just not understanding it. Can you give some part numbers for the hats/rotors you are talking about ?

i don't even know anyone that has one of the brackets to get the drwaings from, nor do i have any of the parts to even get a rough estimate from. so far i have a set of stock 69 drum spindles and a set of original 69 disc brake hubs.

the drawback to this system is that it's really very heavy, though it still works quite well, even today.

one of these days if ever get rich, i'm going to buy me a bridgeport and build my own billet aluminum version of these calipers, don't see that happening anytime in the near or even nearly distant future though.

I know for a fact one of the members on this message board has a set of the brackets waiting to be installed. An aluminum of these would be badass, but I would like to see the calipers use an internal cross-over if possible. The external cross over kind of annoys me.

 

[iapexl8r]

Carl Vogt at cobra automotive told me that the t-bird spindles will not work due to geometry issues, thats why none of the trans am teams used them.

 

[Helmantel]

I'm not exactly sure what you mean. Why wouldn't it work ? Using the drum hub is the same thing that all the kits puting late model Cobra brakes on the classics do. I think I'm just not understanding it. Can you give some part numbers for the hats/rotors you are talking about ?

My bad, I meant to say that you could use Wilwood (not Raybestos like I wrote earlier) hats and rotors. They would slip on the drum hub, just like Cobra Automotive kit. I believe a 1.59" offset hat is needed, but they offer them in several sizes. For part numbers, check the Wilwood site.

The 68 Ford rotor mounts to the back of a disc brake hub, not to the front of a drum brake hub.

 

[bnickel]

My bad, I meant to say that you could use Wilwood (not Raybestos like I wrote earlier) hats and rotors. They would slip on the drum hub, just like Cobra Automotive kit. I believe a 1.59" offset hat is needed, but they offer them in several sizes. For part numbers, check the Wilwood site.

The 68 Ford rotor mounts to the back of a disc brake hub, not to the front of a drum brake hub.

you are correct, i had forgotten about the disc and drum hubs being different but honestly can't remember what the differences are right now. i knew there was a reason i was saving my original 69 disc hubs though.

hmmm, well this changes things a little, it's also probably why CA has made changes to their bracket from the original DOZX bracket since they do use the drum hub on their kits. i'm sure there must be another 12" rotor that would work with the drum hubs though. could even be a mopar rotor for that matter since they use the same 5x4.5 bolt pattern or even redrill something else to fit. then again my idea of using some kind of one piece rotor from a 72 t-bird or a 70-72 LTD (they have different hat heights) could work well too.

do you know the exact height dimensions of the hub/rotor combo? if so i could probably find a one piece rotor that would work.

 

[bnickel]

ok got some height measurements from napa online.

68 LTD rotor (this is the rotor used on the DOZX kit) height 2.31, this does not include the added height of the hub which is right at 2" which comes out to 4.31"

72 ltd one piece rotor-height 4.525"

72 t-bird one piece rotor-height 4.807"

these are all 12" rotors (actual 11.72") so they are all identical in that dimension and all are 1.8" thick as well. they vary in price from $93 for the 72 ltd rotor to $155 for the 72 t-bird rotor and the 68 LTD rotor comes in in the middle at $125.

i think our best bet is the 72 LTD rotor which has the closest dimensions to the 68 rotor and hub combo and is also the cheapest price wise, there is also a company on Ebay called rotor pros that has the 72 ltd rotor in a drilled and slotted version for $94 for the pair. i think that would be the best bet right there, drilled and slotted 12" rotor that will work on the mustang drum spindle and use the big 4 piston calipers, it also uses the same wheel bearings as the 70 mustang which also means that you can use the 67-69 bearings in these rotors by changing the races just like any other mustang rotor. this "SEEMS" like it would be the best option for a drum spindle without having to try to hunt down the "correct" rotor and disc hub plus it's cheaper and is available in drilled and slotted to boot.

it can also still be used with 15" wheels for those of use are hold outs from the stone age.

BTW, i'm fairly certain that the SSBC big force 10 4 pistons caliper is an aluminum copy of the big K/H 4 piston caliper and it does have internal crossovers as well for anyone that wants to pay the bucks for them, however they could also be copies of the 4 piston vette caliper as well, can't say for certain.

 

[Rusty67]

I looked again at the CA kit and I was wondering why it looked like they were using non-OEM type rotors. Apparently they are selling Wilwood stuff or possibly another brand. They do look strikingly similar to Wilwood parts tho.

The Speed Parts International kit used Ford rotors and 70 Mustang hubs.
http://www.speedpartsinternational.com/transambrakekit.html

I think you are right about the rotor mounting behind the hub instead of infront. I downloaded the picture of it installed and zoomed in on it, looks like the hub is actually in front of the rotor.

I would imagine that there is a 12" rotor that would mount to a drum hub out there. This would be the most cost effective solution for most people I would think. The Wilwood parts are not terribly expensive but it definately adds to the expense.

 

[bnickel]

I looked again at the CA kit and I was wondering why it looked like they were using non-OEM type rotors. Apparently they are selling Wilwood stuff or possibly another brand. They do look strikingly similar to Wilwood parts tho.

The Speed Parts International kit used Ford rotors and 70 Mustang hubs.
http://www.speedpartsinternational.com/transambrakekit.html

I think you are right about the rotor mounting behind the hub instead of infront. I downloaded the picture of it installed and zoomed in on it, looks like the hub is actually in front of the rotor.

I would imagine that there is a 12" rotor that would mount to a drum hub out there. This would be the most cost effective solution for most people I would think. The Wilwood parts are not terribly expensive but it definately adds to the expense.

actually at 94 bucks a PAIR i think the drilled and slotted rotors from RotorPros on ebay would be the most cost effective solution, provided they'll work which i'm fairly certain they will. i will probably try going that route myself eventually. i also kind of like the fact that these rotors are a one piece design for ease of maintenance as well. i just keep hoping Degins will change his mind about incorporating a caliper bracket cast into his drop spindle so i can use his spindle with these brakes.

 

[rbohm]

now if someone would replicate the bracket that allowed the use of the stock mustang front caliper on the rear end, you would have the complete system that was used in the trans am cars.

 

[Rusty67]

I'd like to talk about the rear setup as well but the thing I don't like about the rear setup is that there was no parking brake.

According to the Boss 302 chassis book I've got, the rear setup was not just brackets. There were special axles and I don't have any idea what rotor was used.

I think there are other Ford parts which might be a better choice for street cars (like a Crown Vic setup). If you wanted to do a vintage race legal type thing then I suppose using the rear TA kit would be the wepon of choice.

 

[bnickel]

I'd like to talk about the rear setup as well but the thing I don't like about the rear setup is that there was no parking brake.

According to the Boss 302 chassis book I've got, the rear setup was not just brackets. There were special axles and I don't have any idea what rotor was used.

I think there are other Ford parts which might be a better choice for street cars (like a Crown Vic setup). If you wanted to do a vintage race legal type thing then I suppose using the rear TA kit would be the wepon of choice.

the rear disc kit used the stock front calipers and rotors after you had removed the hub.

the rear caliper bracket could very easily be made from a piece of 3/8" steel and welded on the housing or bolted to the housing flange

 

[Helmantel]

Keep in mind that the Trans Am rear setup lacks any parking brake provisions.

 

[Helmantel]

Does anybody know the center to center distance of the mounting ears of the small K/H four piston calipers?

Here's a picture of the bracket:

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The vertical distance of the mounting holes on the spindle is 2.5" and judging from the picture, the caliper mounting holes are only a little further apart. Maybe 2 3/4"?

The reason I'm asking is that mounting holes of the big K/H calipers are 4 7/8" apart. So, if the caliper would clear the stock disc brake bracket, you could make a simple bracket that bolts to the small caliper bracket, to which you can mount big caliper. It would consist of the (blue) 1" wide, 1/2" thick and ~6" long piece of steel with holes for the caliper (4 7/8" apart) and holes for the caliper bracket (say 2 3/4" apart) This part would then be moved inwards by a (red) 4" long piece of steel of apropriate thickness, also with mounting holes 2 3/4" apart. The caliper mounting ears would then sit on the outside of the bracket (instead of to the inside, like both the small and the big K/H).

This is actually an advantage, because this is how it is mounted to the spindle on Thunderbirds etc. If you want to mount the big calipers to the Cobra Automotive or DOZX brackets, you need to drill out the threaded holes and spot face the new mounting position on the other side of the mounting ears (it's rough and not very even). With the above mentioned bracket, the caliper would bolt right on with not machining. It all depends of course on if the caliper clears the regular stock caliper bracket. And, great for bnickel, this method may even work with degins cast-in K/H mounting brackets on the new spindle

 

[Rusty67]

That is an interesting idea. I'd prefer to have a 1 piece bracket tho. What I was considering doing is using the original bracket from my smaller K/H calipers as a reference point to build new brackets for the bigger calipers.

 

[bnickel]

Does anybody know the center to center distance of the mounting ears of the small K/H four piston calipers?

Here's a picture of the bracket:

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The vertical distance of the mounting holes on the spindle is 2.5" and judging from the picture, the caliper mounting holes are only a little further apart. Maybe 2 3/4"?

The reason I'm asking is that mounting holes of the big K/H calipers are 4 7/8" apart. So, if the caliper would clear the stock disc brake bracket, you could make a simple bracket that bolts to the small caliper bracket, to which you can mount big caliper. It would consist of the (blue) 1" wide, 1/2" thick and ~6" long piece of steel with holes for the caliper (4 7/8" apart) and holes for the caliper bracket (say 2 3/4" apart) This part would then be moved inwards by a (red) 4" long piece of steel of apropriate thickness, also with mounting holes 2 3/4" apart. The caliper mounting ears would then sit on the outside of the bracket (instead of to the inside, like both the small and the big K/H).

This is actually an advantage, because this is how it is mounted to the spindle on Thunderbirds etc. If you want to mount the big calipers to the Cobra Automotive or DOZX brackets, you need to drill out the threaded holes and spot face the new mounting position on the other side of the mounting ears (it's rough and not very even). With the above mentioned bracket, the caliper would bolt right on with not machining. It all depends of course on if the caliper clears the regular stock caliper bracket. And, great for bnickel, this method may even work with degins cast-in K/H mounting brackets on the new spindle

hmmm, interesting idea. would definitely be worth checking into for sure.

 

[Rusty67]

bnickle, do you think you could find a 12" rotor that would work with a standard drum hub ? Let me know.

Also, does anyone have an autocad (or anything else) drawing of a stock drum or disc hub ?

 

[rbohm]

bnickle, do you think you could find a 12" rotor that would work with a standard drum hub ? Let me know.

one more time. the stock 68 tbird rotor uses the SAME wheel bearings at the 65-69 mustangs, thus they go on the stock 65-69 V8 spindles.

 

[Rusty67]

one more time. the stock 68 tbird rotor uses the SAME wheel bearings at the 65-69 mustangs, thus they go on the stock 65-69 V8 spindles.

Check my original post and you will see that the 68 Tbird rotor interchanges with the 68 LTD rotor. These rotors mount to the back side of a disc hub, not the front size of a drum hub. Please correct me if I'm wrong here. I would love to find a set of rotors that will work so I can go buy one to start the mock up. I also need a caliper, someone out bid me on ebay =(

The reasons I want to use a drum hub with a front mount rotor are simple. First, it is easier to service. Just pop the rotor off, no reason to remove the front hub or involve a press to remove/change the rotor. Second, the drum hubs are easy to find and cheap as well.

I don't want to use an integrated hub/rotor combo because it will most likely be more expensive in the long run. Every time you go to replace your rotors you have to pay for the rotor and a new hub. The new hub will need a set of races, seals and bearings. At a minimum you have to have the race pressed in so you have to pay for that at a shop (unless you have a press at home).

 

[bnickel]

Check my original post and you will see that the 68 Tbird rotor interchanges with the 68 LTD rotor. These rotors mount to the back side of a disc hub, not the front size of a drum hub. Please correct me if I'm wrong here. I would love to find a set of rotors that will work so I can go buy one to start the mock up. I also need a caliper, someone out bid me on ebay =(

The reasons I want to use a drum hub with a front mount rotor are simple. First, it is easier to service. Just pop the rotor off, no reason to remove the front hub or involve a press to remove/change the rotor. Second, the drum hubs are easy to find and cheap as well.

I don't want to use an integrated hub/rotor combo because it will most likely be more expensive in the long run. Every time you go to replace your rotors you have to pay for the rotor and a new hub. The new hub will need a set of races, seals and bearings. At a minimum you have to have the race pressed in so you have to pay for that at a shop (unless you have a press at home).

most rotors come with races installed and you can use the old bearings if they're in good shape, no need to change them and since the rotor should have new races already installed you don't have to worry about a wear pattern. also even if you do have to install new races you can buy them seperately and install them with a brass punch or drift, or even a steel punch or drift in a pinch. i have never used a press to install races, not even once.

 

[rbohm]

most rotors come with races installed and you can use the old bearings if they're in good shape, no need to change them and since the rotor should have new races already installed you don't have to worry about a wear pattern. also even if you do have to install new races you can buy them seperately and install them with a brass punch or drift, or even a steel punch or drift in a pinch. i have never used a press to install races, not even once.

that, and by the time you are ready for new rotors, or resurfacing the rotors, you should be cleaning and repacking the wheel bearings anyway.

 

[Helmantel]

I wouldn't worry too much about ease of maintainance. A decent quality rotor should last a long time, even on a daily driver and about forever on a weekend driver. If you plan on a lot of open track weekends of other sorts of racing, then I can understand that it becomes more important.

Anyway, here are some pictures and a drawing of the Cobra Automotive brackets. With a disc brake hub and a Raybestos 6008 rotor (68 Full Size Ford), and after I spot faced the mounting surface on the mounting ears of the caliper, I needed to move the caliper ~1/8" inboard with spacer rings, so the offset of the caliper mounting ears was not quite enough. They are probably correct for Cobra Automotive drum hub and Raybestos hat+rotor combo.

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