Caliper upgrade???

I'm getting my 73 dart up to "my wife being ok taking our son in the car" level, but I know nothing about brakes. Well not nothing, because I know my front brakes aren't working. Originally I was just planning replacing the rotors, calipers, and pads, but now I'm wondering about upgrading. So here's the question: what is involved with upgrading the calipers to something bigger?? is there something that bolts on, or do I need an entire kit??

Thanks as always

Being a disk brake car already, all you need is the bigger caliper bracket and the bigger disk.

you can get the larger pin or caliper bracket that already matches your caliper either being pin or slider type so you wouldn't need to change them just a bolt on upgrade... there are many write-ups here on FABO and FBBO if you search, I think there is even a sticky on the subject.

here's a thread I contributed what I could too: HELP! 11.75" Disc Conversion - Bearings, Seals Etc

Would upgrading to the 11.75 require changing the wheels?

Futzy1 said:

Would upgrading to the 11.75 require changing the wheels?

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yes minimum 15" rims required

So, stock it is. lol

Nothing wrong with the stock 10.87" disks on an Abody for regular day to day driving, even manual (non assist) as mine are.

Looking at what is available in 14" and 15" tires I'd move to a 17" wheel just to get better tire compounds that will have better traction, wear and price. Added benefit is you can move to a Dr Diff 13" cobra brakes and all your stopping worried will be over as long as the suspensions is sound. Talking to Dr Diff recently his brake kits (excluding OEM type kits) are design for 94-04 Mustang wheels and 17x8 wheels are very inexpensive for that platform.

Well one factor I left out, it's a 225 slant six.(stock for now) That being said, it's not like I need all that much stopping power. I think my big question is, is there a larger caliper/pad setup I can bolt on to the existing equipment?

Futzy1 said:

Well one factor I left out, it's a 225 slant six.(stock for now) That being said, it's not like I need all that much stopping power. I think my big question is, is there a larger caliper/pad setup I can bolt on to the existing equipment?

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Curb weight stant 6 2932lbs
Curb weight V-8 3130lbs

The stopping power is based on weight of the vehicle not the size of the motor. All things being equal. Stopping a 3000lbs car is stopping a 3000lbs car. It wouldn't matter the number of cylinders or displacement.

But a ton of things can influence brake selection and setup. Type an size of tires, weight transfer, suspension, vehicle usage, ability to dissipate heat, driving style, manual or automatic, tune up, federal standards, even the cost of manufacture.

If it has the original A-body calipers you can upgrade to calipers from the later F/M/J/B/R cars. As long as you get the same style (slider or pins) they'll bolt right on. It's not a huge difference, but the pistons on the later calipers are larger so they do provide some more stopping power. The A-body calipers have a bore of 2.6", the later ones are 2.75".

Well I think I'm going to keep it stock reman for now. Is there anything else I should replace at the same time? Bearings, etc? I am looking to rebuild the suspension soon as well.

Futzy1 said:

Well I think I'm going to keep it stock reman for now. Is there anything else I should replace at the same time? Bearings, etc? I am looking to rebuild the suspension soon as well.

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Then you sir are my hero. I can't seem to leave well enough alone. I always seem to think I know better than any college graduated engineer and that I can always improve upon any design. Leaving things alone is not in my genetic make up. All I need is an awesome set of tools (got them), money, and time. Seem to have those last two, but never at the same time. I'm not one for doing things twice. A lot of the stuff in the front end can be upgraded in segments thus saving money in the long run. You just have to make a few decisions first. Then plan backwards from there.

Oh and what ever you think the budget should be? Triple it.

I have A body spindles on my road runner and used calipers from a mid eighties fury cop car, they bolted on and have much larger pistons in the caliper. It made a noticeable difference.

Squire, agreed. For now I'm just looking to make her nice. I found those stock kits for front suspension, for around 200-350. It's definitely a rabbit hole, but she could use the love. The dart mostly sat for the last 10 years, (started regularly) luckily there was lizard skin, but most of the rubber is falling apart and metal rusted. So I figure if I'm lifter her up and taking the brakes apart I might add well do whatever I can. the problem is I'm learning as I go.

Having had several /6 Darts back in the day (and not sparing any of the few HP they had!), the standard front discs do quite well, so you will be fine. They have decent heat capacity for repeated stops, etc. I'd put any limited budget into reworking the whole brake, suspension, and steering systems rather than an upgrade.

Yes, on wheel bearings and races. Thay may be fine or may have a bit of rust and moisture in them. These are cheap anyway.

Since you say the front brakes do not work, that is worrying with the wife and child in the car (oh, and you too! LOL), soooo, other things to consider:
- Are you working on the rear brakes too? I tend to do the whole brake system stem-to-stern for an older car; the moisture that gets into the system effects each and every part, and you'll usually end up replacing everything in the the brake system eventually on a car this age.
- I'd replace the master cylinder too; you're gonna be bleeding it all out anyway so why not. Being this old, it may spring a leak at any time, on your carpets or between front and rear systems.
- And FOR SURE, all 3 of the rubber lines (2 front and 1 rear). They deteriorate on the inside liner first, where you cannot see it, and a chuck will fall out and lock that caliper or wheel cylinder, either off OR hard on.
- Any rust in or through any hard line is an unknown so it is hard to say what to do there; it would be reasonable to keep the hard lines, IMHO, if you are in a dry climate. If you are in the rust belt, then new hard lines are a very good idea.

FWIW: The front end kits are not something I would buy. I'd much rather go to the local NAPA store and buy individual parts. The price of the kits is no bargain, and you have less control over the parts that way, and a lot more hassle and a week+ of time wasted in getting a part exchanged if something is wrong in the kit. Either way, you will be glad you did the front suspension parts, despite the work involved!

Make sure you do all the steering linkage at some point; it is easy to do with the suspension parts: tie rod ends, idler arm, and look hard at the pitman arm joint; any motion there calls for replacement, even though it is a pain. And then there is the steering box and any slop in it. Do you have manual steering?

I know, this all adds up to a LOT. You will spend some dough doing all of this, but it will be up to snuff safety-wise, and you won't have to worry about these parts again for many, many years, and you won't waste tires from things like bad alignements.

nm9stheham said:

I tend to do the whole brake system stem-to-stern

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That is basically what ended up happening. when I got her last month, she stopped, but the pedal was a little squishy. I checked the fluid, and it was black so I replaced it. That prompted the MC to go bad (I'm assuming it was the newfound pressure in the system) so I replaced that. That prompted a failure in the rear passenger drum when the parking brake adjuster screw fell between the shoe and the drum (that was a fun sound) so I replaced the drums, shoes, Springs, and parking brake assembly. Now that the rear is taken care of it just doesn't feel like I'm getting any braking in the front and from time to time a thunk in the front driver side that sounds like the piston snapping into place). I haven't actually gotten in there, but I just figure for 150 bucks it's totally worth the cost to just replace the the calipers, pads, and rotors, and if I'm there I might as well spend an extra 20 to do the dust caps and bearings.
I've seen what to do for the outer bearings, but what about the inner bearings? or is it all part of the same assembly?

I'm surprised to hear about the kits. I've been reading good things about the PST kits. Take a look, I'd like to see what you think

Performance Suspension Technology

The big project is going to be adding air conditioning. I'm in the socal desert, and summer sees more days above 100 than below. I'm talking to the guys at classic auto right now.

Ah, there ya go LOL. Yes, that is the way it is with old braking systems. Sounds like you are getting there. BTW, if you have not replaced the rubber lines, do so ASAP. Did you replace the rear wheel cylinders? Do so; they are cheap.

Being where you are at with the dryness, the hard lines may be just fine.

Did you bench bleed the new master cylinder? If not, then there is likely air trapped still in the MC that will absolutely effect the braking.

As for the 'thunk', well, it is pretty hard to hear and feel it from this side of cyberspace, but I would be more inclined to expect a worn suspension bushing or ball joint.

For the wheel bearing, both inner and outer consist of a bearing cage assembly and a race. The races are an interference fit into the hub. Once you pull the hub the outer cage falls out, and then you remove the inner grease seal and the inner cage falls out. The races may look like part of the hub, but if you clean out all the grease, you will look through the hub and see some slots in the hub casting on the far side with a metal ring visible through the slots; this ring is the back side of the race. You put a tapered punch through the slot to the back of the race, and drive a couple of whacks on one side, and then the other side, than back and forth, and that will slowly drive the race out of the hub. Do this on both sides. Be careful to minimize any nicks in the hub's inner surface, and sand out any that you make. Then you use a narrow chisel with the end flattened and the corners smoothed (so as not to gouge into the hub), or a proper race driving tool, to slowly drive the new races into the hub, going around and around to drive them in evenly. (Sorry if you know all of this already...)

I was not thinking of the PST kits but of other cheaper kits. I'd expect PST to be good, but about the same as NAPA for the rubber parts, ball joints, tie rod ends. And the PST kit does not include the pitman arm; that is the arm that sticks down from the steering box. It has a joint at the steering linkage end that is subject to wearing out. It may have some parts you don't need like anti-sway bar end links if you don't have that on your car.

BTW, for a pure street car, I'd stick with rubber, not poly. Poly does a great job of tightening the front end up, and taking out some variableness, but it will typically beat up frame and suspension parts on a street driven car that gets lots of miles. I always used rubber in the front ends of my rally cars, for that reason; poly would have beat the crap out of everything. (Of course, rallying is a pretty severe application!) So this decision depends on what you will be doing with the car.

The dark in the old brake fluid is rust. That is why your MC failed. In VA, you should be bleeding thru new brake fluid at least every 4 years, in all your cars. Most drivers don't know that and go until they have failures. If you use DOT 5 silicone, no such worries. The factory disks in 1973+ cars are fine. Front disks were a federal mandate, mainly because clueless drivers would ride the brakes all the way down mountain roads until they overheated and went off the side. Disk rotors cool faster than drums. Even today, on the Blue Ridge Pkwy you have the aroma of FL drivers riding the brakes instead of downshifting. The tech is simple - tires stop the car. If the brakes can skid the tires, and evenly, they can do the job. If you aren't over-heating the brakes (get fade), they are big enough. You shouldn't need bigger brakes unless driving like a road racer. One clue is if you get <15 mpg since all braking is wasted energy.