4 wheel disc brake conversion for a 1970 mustang

[wantahertzdonut]

I'm planning on doing a disc brake conversion this winter to my 1970 Mach 1 as I've discovered a very simple way to adapt 13" front rotors from a 1994-2004 Cobra using my drum brake spindles. I figured while I'm at it I may as well convert the rear brakes to discs as well, but I'm having trouble finding out what to use for a master cylinder. I also need to figure out what proportioning valve to use, although an adjustable one is acceptable.

I've seen mentioning of using a "corvette type" master cylinder, but no specifics as to a manufacturer, donor car, part number, etc. Can anyone recomend a specific unit and give me a lead on where I can get one?

[fuzzyonion]

The Corvette type usually mentioned is a 3rdgen version, 2 sizes available, approx from 1968-1975. Power is 1.125" bore and manual is 1" bore. To fit on your Mustang, the flange holes would need elongated, although the aftermarket 4port versions already have this done.

The ports are reversed from Ford. Front port goes to front brake.

I hope you have power brakes.

[wantahertzdonut]

I do have power brakes. In some ways I'm a little sorry I do because I want to put a big cam in eventually but I'll just run a vacuum booster if it's a problem.

Is this corvette MC basically a bolt on item then?

[race-rodz-inc]

i went through a 4 wheel disk mustang swap a few years ago, i used a non-power m/c from a 4wdisk granada....direct bolt on, i didnt know they made granada's with 4 wheel disks, and non power brakes...but i did find it in the book, im sure you could do the same. you could probably get the power m/c if you would like to retain the booster.

[fuzzyonion]

If you have a part# for a manual 4wldisc Granada, I would like to know it. The only one I can find is for hydroboost, and has an offset flange which wont work on a regular vacuum booster. I have the Granada/Versailles brakes on a '68 Fastback, currently with a 1" disc/drum master.

[DarkBuddha]

I'm in a similar situation. I'm doing the Ultrastang Lincoln Mark VII 11" rear disc conversion and am trying to decide on a master cylinder. After a couple emails with Steve (Ultrastang), I figure I've got a few choices ranging from using the Mark VII mc to my original (after removing the residual valve in the rear port) to using an aftermarket or any number of junkyard options. Apparently, the important thing is to make sure piston diameter is good size. You might check out Ultrastang's site at www.ultrastang.com .

[64Comet]

donut: I have seen someone on the internet selling a kit that allows you to bolt 13" late model Cobra rotors/calipers to classic Mustang spindles. i assume this is the same one you are using? I have tried to find the info again, but havent had any luck. Any info that you could provide would be appreciated.

[wantahertzdonut]

64Comet- The 13" cobra kit is being sold by Mustang Steve. The late model calipers and hub fit on the early model spindles, then it's only a matter of making a bracket that mounts to the spindle to hold the caliper in place. Me and a friend of mine are working on making our own bracket since Mustang Steve wants a hefty price for his, and I have access to a mill both at work and at my friend's garage. We're going to start on this in the next couple weeks, we just need to order up a set of rotors, calipers, and steel plate and we'll get started.
We also suspect there is an easy way to bolt on a late model rear disc brake the same way. Once we get the front end figured out, we'll begin work on a rear bracket that will adapt the rear calipers the same way as the front. We'll probably start selling the brackets as well if there's any interest, or at least help anyone who wants to make their own.

Race-rods inc- As for the 4 wheel granada swap, it's something I considered but with swap kits for the fronts becoming more and more expensive, for a little more we figured we can step up to the modern mustang parts.

Fuzzyonion- I didn't know they made Granadas with 4 wheel disc brakes, however if you're looking for a 4 wheel master cylinder along those lines, look for a MC from a Lincoln Versailles. A lot of guys who've done the Granada/Versailles swap use the Versailles master cylinder in their mustangs.

One thing to keep note of, a Lincoln Versailles is the same car as a Granada and most had 4 wheel disc brakes. However, the front brakes off these cars will NOT work on mustangs like the granada brakes do. Many guys who have done 4 wheel disc swaps in the past used the rear axles since they had 9" rear disc brake setups. But these cars were rare in their day and pretty uncommon now. You may find one for sale but be ready for a hefty price, but you may also luck out. Keep your eyes open and your fingers crossed!

[64Comet]

I believe, or was told, that the front spindles from a V8 are the same from years 65-70. Do you know this to be correct? I believe, or again was told, my V8 spindles that I had to purchase were from a 67. They look the exact same. I also have been trying to track down a guy that has a set of Cobra calipers, rotors and pads in good shape for $250. Are there specific years I should be looking at to get the brake parts from. I was just thinking of buying them all new from Autozone or something...may be worth it.

Since i will be going with a manual setup and disc/drum f/r, what MC should i use? Just a standard 2-chamber and proportioning valve?

Also, would be interested in the bracket. When are you going to tool with it? How much is Mustang Steve looking to get for the brackets?

[wantahertzdonut]

I'm pretty sure the spindles are all the same, at least in regards to the DRUM spindles. Disc spindles changed I think, I'd have to ask some of my more knowledgable friends to be sure. Mustang Steve's kit will fit drum spindles from 65-70, maybe 71-73 as well, but he hasn't said anything about fitting the big 'stangs yet.

$250 for those brakes sounds like a great deal. Jump on them if you can get them!

You should be able to use Cobra parts from any 94-2004 car. I would doublecheck, but they should all have the same part number. If you want to check yourself, log on to autozone.com and check part numbers for those years, they should be the same, but I have yet to verify this for myself.

You can buy a disc/drum MC for the old mustangs from any parts store, they're still readily available and rather inexpensive. Just be sure you get the disc/drum and for manual brakes. That's for Mustangs anyway, your Comet I don't know about, but once again check on autozone's website for part numbers and it'll say if it's available through them.

Mustang Steve wants $400 for his brackets alone, and $650-700 for a complete kit. We're hoping to start tooling with brackets in the next 2 weeks or so. My friend is trying to acquire a set of cobra calipers through a friend who can get them at a discount, so naturally that's taking longer than we'd like. I'd go buy a set myself new but my rent is due this week!

[64Comet]

Mine are drum spindles, so I am safe there.

$250 is a great deal...still cant get a hold of the guy though.

Comets, Falcons and Mustangs from 1964-1966 are the exact same unibodies. All parts should be interchangeable. This helps me tons since its very difficult to find parts for my rare 64 Comet. If you say "64 Comet" and they have a part for it, it automatically jumps 30% in cost. So I buy everything i can under the Mustang name.

Yeah, I just saw an ebay price of $329 for the brackets...man, thats pricey! From the looks, they should be fairly easy to duplicate. I am not taking away from his product, but it is pricey for a set of brackets. I'd swear I have seen them from a different source at $125 for the pair...wish i could find that guy again. I would pay that.

[wantahertzdonut]

I'm not sure what we plan on charging, it'll depend on material costs and how much time it takes, also depends on how we decide to finish. We will want to make them cheap enough that anyone who wants to do the swap won't be hindered by costs for a small (yet important) item. We may also make a caliper bracket that will be somewhat smaller so you can use standard GT brakes, which would be much less expensive.

I hear ya on parts being expensive for less common cars. Consider yourself lucky that there's a large mustang market out there!

I'm not surprised the brackets on ebay are going for that much, afterall they are the key to making the whole setup work. If you look at the price of the kit which includes the calipers, rotors, brackets, and hardware, it's much less expensive than if you bought the parts from a dealer/parts store and then the bracket only. It takes out that chance for savings by gathering the parts yourself. Kind of a bummer but he does have a monopoly on the market right now.

[64Comet]

Problem is, you can buy a reputable setup for the same amount in any magazine and it comes complete with everything you need. I think I saw him sell rotors, calipers and bracket for $749...just think you can get a COMPLETE reputable system for possibly less if not the same amount or slightly more with everything you need. With his "kit", you would then have to buy all of the other stuff...you might as well go with Wilwood or Baer at that point.

[DarkBuddha]

About the spindle thing... I believe there are some differences between early spindles and later ones, but damned if I can remember the specific reason why. I did email Mustang Steve about his kit and he indicated it would not work for '69-'73 cars yet, but he is working on a kit for those cars as well. I also agree his brackets are a bit pricey for what they are... it's a shame that they are more in the $150-$200 range, which seems completely reasonable for such things.

With regard to rear disc options, with the right bracket, it shouldn't take much to adapt late model brakes from an 8.8" rear to 8" or 9" rears, except you'll also need a hub centering ring for the rotor. This is basically what the Ultrastang Mark VII rear disc conversion is, except that it uses the older/plentiful/cheaper/easier to find Lincoln Mark VII 11" rear brakes from the 8.8" rears. Ultrastang's brackets are like $100, which seems more in line with what this kind of thing should cost. And considering the Mark VII brakes are basically the same kit that SVO marketed as their "performance" 5 lug rear disc conversion for Fox bodies and also the exact same brake setup as SSBC's basic rear disc conversion for 8" and 9" rear ends (according to the 2 SSBC reps I spoke with at Hot August Nights a couple years ago), I'd say it's actually a good deal. I was able to able to secure everything for the swap for under $300 including the brackets, rebuilt calipers, turned rotors, hoses, adjustable proportioning valve and a rebuilt master cylinder. Cheap for rear discs.

Ultimately, I'd love to go to larger brakes, but for my budget and driving intents I expect the stock 11.25" fronts and the 11" rears will serve well for the time being. The only way I'd probably upgrade is if I could do the 13" conversion for under $500 including brackets and requisite parts. And the late model 12" rear disc conversion would have to be under $400.

[vintageracer]

1970 Mustang drum brake spindles have a larger axle stub diameter and therefore use bigger bearings than the earlier Mustang drum brake spindles. This is the reason that they are more desirable.

[sg69]

1970 Mustang drum brake spindles have a larger axle stub diameter and therefore use bigger bearings than the earlier Mustang drum brake spindles. This is the reason that they are more desirable.

It’s actually '70-73 that are larger. and 69 trans-am/boss spindles(but these have a different thread on the shaft then the '70-73. 70-73 mustang are almost identical as Granada’s except for the taper on the tie-rod which is slightly larger on a Granada, but not to the point it cant be used on a mustang tie-rod. Granada’s also weigh more indicating a beefier cast.

[64Comet]

wantahertz: Any update on the bracket progress?

[wantahertzdonut]

No none yet. My friend with the mill has been extremely busy with a new job and his wife is finishing school. I've barely been able to do anything with my car because nobody is around. Plus I'm busy at work so I don't have much free time to get on the mill and make parts myself.

I'm heading to the Columbus all Ford Super Swap this weekend to look for some parts (mostly manual conversion pieces) but will also be looking for brake parts. This was a winter project from the beginning anyway and I've just been doing my homework so far. If I can cover any ground in the next couple weeks I will put it up here.