[CM] Re: 1966 Mustang GT350 rear drum brake upgrade

[Michael J. Kupec]

Great writeup!

I guess now I have NO eacuse to get the Granada brakes installed on the
front and start looking for a early 90's Crown Vic to snag those rear discs
from!

Too bad this setup won't work well with big bearing 9" rears like what I
have on my Bronco.

Michael J. Kupec
mkupec at comcast.net
mkupec at blueovalcorral.com
http://www.blueovalcorral.com
WebMaster: www.earlybroncos.com
Pres. Core 4x4's http://www.core4x4.org
2000 Expedition XLT - Daycare kiddie hauler & tow vehicle 
1970 Bronco - Big Green (generally broke all the time!)
1996 Geo Tracker - Lil'Red Go Kart #1! (5spd)
1996 Geo Tracker - Lil'Green Go Kart #2! (auto)
1965 289 HiPo "K" Mustang Coupe w/PS, PB, & Pony Int. (Early '65, not a GT)
1964 1/2 260 Mustang Convertible  w/PS, PB, & Power Top (Loaded!)  

> -----Original Message-----
> From: classic-mustangs-bounces at lists.twistedpair.ca 
> [mailto:classic-mustangs-bounces at lists.twistedpair.ca] On 
> Behalf Of Keven Coates
> Sent: Tuesday, October 19, 2004 5:27 PM
> To: 'A list for owners of Classic Mustangs'
> Subject: RE: Re: [CM] Re: 1966 Mustang GT350 rear drum brake upgrade
> 
> If you have questions on this, email me directly, I don't 
> read the list much anymore, but here's some info that might help you.
> 
> This is the write up for the late model Crown Victoria or 
> Mercury Marquis rear disk brake setup swap into the early 
> Mustangs.  It fits the small bearing 9" rear end, or 8" rear 
> end in the early Mustangs.  
> 
> This details a heck of a lot of steps, and it's really not as 
> complicated as it sounds, but is difficult to describe in 
> text.  I'll have to take some photos when I have a website available.
> 
> Pros for this swap include;
> 1. Cheap! (<$300).
> 2. Solid and light, much lighter than any other disk setup I've seen.
> 3. Cheap, easy to find replacement parts.
> 4. Incredible difference in braking feel and confidence.
> 5. Good looking (as compared to drums!) through the wheels.
> 
> Cons include:
> 1. Solid rotor (11.4").
> 2. Phenolic pistons (unless you can find police or station 
> wagon calipers).
> 3. Difficult to install and use e-brakes.
> 
> Here's the meat:
> Every Crown Vic and Merc Marquis from '92-'95 used rear disk brakes.
> Later models use a similar, but slightly different setup.  
> This swap message only covers '92-'95 brakes, as this was 
> something I had more information on than the later years of 
> Crown Vics.
> 
> The resulting setup from this swap is some nice shiny disks 
> on the rear of your early Mustang (or other car with suitable 
> rear end) measuring 11.4"
> in
> diameter, non-vented, with parking brakes located inside the 
> drum part of the rotors, just like the Explorer setup, only 
> fitting the small bearing 9"
> and regular 8" instead of the big bearing 9".  This write up details a
> '68
> Mustang swap, but others should be similar.  Police use this 
> brake setup, with one change (steel piston calipers), 
> routinely for fast stops from over 100 mph.  Explorers use 
> the same setup as well for towing, so it's got to be decent.  
> I've never noticed any brake fade from it, although my car 
> doesn't see too much high speed track time.
> 
> With this swap I feel very confident in very hard stops, 
> contrary to my previous drum setup that occasionally wanted 
> to switch lanes by itself at the worst times.  Now I can stab 
> the brakes and all the tires bite pretty hard.  It's a much 
> more controlled stop.  In fact, I'd venture to say that it's 
> one of the best braking setups I've felt.  Much better than 
> any production car I've ever driven.
> 
> What you need:
> ===========
> About 14 hours of time, including a few parts store runs (a 
> friend is handy
> too!)
> Calipers (about $35 each with $50 core)
> Old caliper hose ends to see the new flare and get the flare 
> nuts(to match, since you'll have to flare your existing brake lines)
> Rotors    ($25-$50 each)
> Brake pads ($25 set)
> Caliper hoses ($20 each)
> Rear axle mounting brackets from a salvage yard (price 
> varies, got mine with cables and calipers for $55 pair!) 
> Emergency brake cables from salvage yard(up to the middle of 
> the car) All from a '92-'95 Crown Vic or Merc Marquis
> 
> Also:
> wheel studs that are 1 3/4"-2" long, 1/2"x 20 threads with 
> stock knurl of .625" (these are difficult to find sometimes, 
> stock length is 1 5/8").
> 1/8" steel cable end that you can bolt on a steel cable 
> (hardware store) Some scrap steel An old wheel bearing is 
> handy, and don't forget brake fluid
> 
> What you will need to fab (as explained below):
> axle bearing spacers
> brake hose mounting tabs
> e-brake mounting
> e-brake cables
> 
> 
> Tools:
> Something to cut 1/4" steel like sawzall, etc.
> pneumatic cut off tool (with 3" wheel)
> Welder or torch with brazing rod (not necessary if you clamp 
> the end hose brackets on)
> 
> Glossary
> ========
> Hard lines - Ridged brake lines that aren't supposed to flex
> 
> Brake hoses - Rubber hoses that fit between calipers and hard lines.
> 
> Disk brake mounting brackets- Brackets made of aluminum off 
> of the Crown Victoria that go between the axle flanges and 
> the disk brake calipers.
> axle retaining plates- Plates used to hold the axle bearing 
> to the disk brake mounting brackets, or originally to the 
> drum brake mounting brackets.
> 
> Axle retaining plate- plate that holds the axle on the car by 
> holding the pressed on rear axle bearing solidly inside the 
> place where they are supposed to go (bearing ends on each 
> side of the axle).
> 
> Hose brackets- Things to mount the ends of the rubber hoses 
> to so they fit to the hard lines.
> 
> e-brake- Emergency brake.
> 
> How to do it:
> =============
> Go to your local salvage yard and get the calipers, mounting 
> brackets, and e-brake cables, don't worry about rotors unless 
> you get a really good deal.
> You'll probably pay more to buy and turn a set of used rotors 
> than you would to buy them new.  You'll want to watch them 
> take off the mounting brackets so you can see how the 
> e-brakes go, and how the mounting brackets mount on the axle. 
>  Get every little part you can, you never know what you'll 
> need in these type swaps.  Pay attention to the orientation 
> of the brakes on the Crown Vic.  The caliper mounts on the 
> rear of the disk on the driver's side, but opposite (on the 
> front of the disk) on the passenger side.  This is so that 
> Ford can use one casting for both brackets.
> 
> I personally wouldn't use used calipers when replacing them 
> is so cheap.
> I
> only want to do this once.  But, you still need to get the 
> used calipers as the core prices are very high (about 
> $40-$50!), so you'll need them to get this money back when 
> you buy the new or rebuilt ones.
> 
> If possible, get the steel piston calipers when you buy new.  
> The regular pistons in these calipers is phenolic.  They 
> don't stand up to heat quite as well as the steel ones that 
> the police and station wagons use.  Not sure if Explorer 
> calipers use them or not, or if they interchange.  (added note:
> I've used phenolic pistons now for many years and so far, they work
> fine.)
> 
> If you want to clean and paint the outside of the hub of the 
> rotors, or calipers, now is the time.  Use 1200 degree temp 
> paint or higher.
> 
> Replacing the brakes:
> ==================
> 1. Disconnect the negative terminal of the battery (ha ha!  
> Not really, I just like saying that because it's so 
> completely irrelevant and if I were a Chiltons book, that's 
> what I'd say.  I'll get serious again... Ahem.) 2. Jack up 
> the car, preferably by the rear axle spring perch plate, and 
> take off the rear wheels and drums.  If you don't know how to 
> do this, you shouldn't attempt to do this swap!
> 3. Take off the drum backing plates and unscrew the brake 
> line connection.
> Then hurl the junky drums and backing plates as far as you 
> can towards the trash (O.K. really, I said I'd be serious...).
> 4. Slide out the axles temporarily, making sure to be careful 
> with the axle seals (if you're not replacing them) and stuff 
> a clean rag in the housing end to seal the inside of the 
> housing from the hacking you'll do on the axle ends.
> 5.  Cut off the lower part of the housing end so that it fits 
> into the new disk brake mounting brackets.  The Crown Vic 
> rear end has rectangular ends, 8" and 9" housings have a 
> circular end with the top side cut off.  Cut the bottom part 
> off flat to match the top.  This is heavy steel, so a sawzall 
> or other suitable cutter will be necessary.  A right angle 
> grinder will work, but you'll be there for a _long_ time.
> 6.  Test fit the disk brake mounting bracket on the axle.  
> The bolt holes line up!!!
> 7.  Bolt on this mounting bracket temporarily and turn your 
> attention to working on the axles (that are already out of 
> the car, right?!).
> 8.  Pound or press the old studs out of the axles.  They are 
> probably too short, since the rotors are about 1/8"-3/16" 
> thicker than the drums.
> 9.  Press in the new studs with a press or a lot of washers 
> piled up with a nut to draw it through with an impact wrench 
> (use oil on the threads and everywhere).  This is a pain staking task!
> 10.  Now is the time to replace your wheel bearings and/or seals!
> 11.  Slide in your axle temporarily and see how your axle 
> retaining plate (on your original Mustang axle, used to hold 
> the axle onto the
> flange)
> doesn't fit inside the new disk brake mounting bracket 
> indention.  Cut off the lower part of the plate to make it 
> rectangular too (just like the axle flange) to fit.
> 12.  Now we have a problem.  Once you slide in the axle you 
> might notice that the wheel bearing is held between the rear 
> end axle housing inset and the retaining plate, but the 
> retaining plate is not up against the bearing on the outside, 
> since the disk mounting bracket is thicker than the drum 
> backing plate.  On my car, and probably most others, the new 
> disk brake mounting bracket is .130" thicker.  That means we 
> have to have some spacer to put between the axle bearing and 
> retaining plate or the wheels will slide in and out .130" 
> every time we take a corner.
> 
> Let me rephrase to make sure we're clear.  The stock Mustang 
> drums are held on the axle by a piece of sheet metal that 
> forms the back of the drum brakes.  The Crown Vic disks are 
> held on to the axle by the disk mounting bracket, and it's 
> made of cast aluminum.  The cast aluminum is thicker than the 
> sheet metal used for the drum brakes, so we'll have to make 
> up that .130" thickness difference by putting a spacer in 
> there to keep the bearing solidly wedged in between the axle 
> retaining plate and the bearing end (where the bearing is 
> supposed to fit inside the axle). 
> 
> I made one the hard way by slicing the outer race of an old 
> axle bearing into .130" segments (one for each axle).  This 
> makes the spacer the correct size and shape.  Dimensions 
> aren't that critical, but you don't want the bearing to slide 
> sideways, so some spacer must be made, and it's best if the 
> hole in the spacer doesn't interfere with the seal on the 
> axle bearing, so it must be thin, but relatively strong.  To 
> slice an old bearing, I mounted the axle it was on (from 
> another car) into my vise and used the pneumatic cut off tool 
> to cut around the bearing as it slowly rotated.  This way the 
> thickness was relatively constant.  I used calipers to double 
> check after finish grinding it on my wheel grinder.  This 
> takes a while (about 30 minutes of continuous cutting), 
> because you are cutting a 3/16" thick slice of incredibly 
> hard, high grade steel (the bearing).  The second slice takes 
> less time since the bearing isn't as thick in the middle of 
> the race as it was near the end.  I slowed the bearing as I 
> cut it with an old shop rag.  Beware, this usually results in 
> the shop rag catching fire, since the sparks hit the rag 
> continuously.  Be careful.
> 
> 13.  After the spacer is ground to .13" or very close, which 
> is the difference in thickness from the old backing plate to 
> the new mounting plate (and therefore, the measure of side 
> bearing play), cut a slot in the spacer so that it just 
> barely slides over the axle between the bearing and retaining 
> plate.  Or, if you got new axle bearings you could just 
> install the spacers in between the bearing and axle retaining 
> plate before you get the bearings pressed on.  The notch is 
> just so you can put it there without taking the bearing off 
> (which would destroy them).
> 
> If you used my method and cut the spacer from an old bearing, 
> the spacer will be easy to place as you slide the axle in the 
> rear end housing before you put the retaining plate on.  Do 
> not bolt the axle in yet.  In fact, take everything off after 
> you have made a mental note of where the calipers go on each 
> side (they mount on the back side of the disk towards the 
> trunk on the drivers side, and towards the front of the car 
> on the passengers side.  This was how it was on the Crown 
> Vic, and makes e-brake cable routing easier).
> 
> 14.   You'll need to fabricate some things here again.  I used the
> existing stock early Mustang brake lines to each side past 
> the spring perches, then tacked on a caliper hose bracket 
> made from scrap steel (with my MIG welder) to adapt to the 
> late model caliper hoses.  Yes, you need rubber hoses so you 
> adapt to the Crown Vic caliper hoses.  Why do you need rubber 
> hoses between the brake calipers and the rear axle you ask?  
> Because there is some movement there in normal operation as 
> the single sided calipers slide to adjust for wear, and so 
> you can take off the calipers and replace the pads.  You 
> could clamp on brackets for the hoses instead of welding if 
> you use good clamping techniques.  
> 
> The hose holder that connects to the brackets you just made 
> is included as part of the brake hose.  You'll see when you get them.
> 
> After you have secured the fabbed brackets to the axle 
> housing, visually check the hose routing and location for 
> clearance and lack of sharp bends.  Remember that the axle 
> may be higher normally in relation to the car if you didn't 
> jack the car up by the axle.  Make sure not to block the 
> upper e-brake adjuster slot on the disk brake mounting bracket!
> 
> 15.  Cut the existing hard brake lines and double flare with 
> the new flares to fit the rubber brake lines.  Bolt in the 
> caliper hoses.  If you didn't have enough hard brake line to 
> work with (the stock rear end housing brake lines are a 
> little short on the passenger side), consider buying new hard 
> brake line and bending it with a tubing bender to fit.
> 
> 16.  Now stick on the disk brake mounting brackets and check 
> out the e-brake lines.  They route like this:  Drivers side 
> e-brake goes straight off the disk mounting bracket forward 
> along the leaf springs to the middle of the car.  Passengers 
> side e-brake line goes 90 degrees, across the axle to the 
> drivers side where it will make a gentle bend and go to meet 
> the other cable where they attach together just ahead of the 
> driver's side leaf spring perch.  
> 
> You'll need to fabricate two more things for the e-brakes.
> 
> First, a mount to hold up the passenger's side cable as it 
> goes across the axle.  I tacked a bolt to the rear of the 
> differential housing, right in the center, and bolted a 
> little hose holder to it.  
> 
> Second, a bracket to mount the passenger's side cable about 
> 2" behind the fuel line crossover (on my '68, this is about 
> 6" in front of the leaf spring mount).  This has to hold up 
> to the force of the e-brake, which is several hundred pounds. 
>  It holds the outer part of the cable so that the actual 
> steel cable inside slides in and out.  I used a piece of 3/4"
> square
> steel tubing about 2" long welded at 90 degrees to the fuel 
> line steel crossover cover (that three bolt thingy in front 
> of the spring perch).
> I
> notched the tubing to fit across the bump in the cover, and 
> welded an end cap on the tubing with a hole to fit the end of 
> the rubber part of the cable.  The cable end goes into this 
> hole and the outer part is held there while the inner part 
> goes to the connection between the two e-brake cables (the 
> connection comes with the cable).
> 
> This is more easily shown in a picture which I will send or 
> place on a website when I have one available (volunteers?).
> 
> 17.  O.K. this is the last fabrication, I promise.  Now take 
> your stock old Mustang e-brake cables off, from the bracket 
> under the driver's side footwell all way to the previous 
> drums.  That bracket, where the Mustang e-brakes adjusted, 
> needs to have a steel holder for the end of the cable because 
> we are converting to one cable for both rears instead of the 
> two cables, one for each side, of the stock configuration.  
> 
> I used a strong steel collar about 1/2" OD and 3/16" ID.  
> Something like a few nuts put together would work as well.  
> Then I welded it to the bottom of the bracket.  The e-brake 
> end goes through there (after cutting off the swaged end), 
> and then you'll add a bolt on or crimped cable end.  This 
> allows the stock Mustang adjuster to adjust this new setup.  
> BTW, cutting e-brake cable is not as easy as it might seem.  
> You can clamp it in some vise grips, and hack saw it, or cut 
> it with the cut off tool, these are hardened steel cables.  
> Wire cutters will not cut them!
> 
> 18.  Once you've gotten these parts fabricated and painted, 
> stick them on, and this is how it goes:  The passenger side 
> cable should wrap around behind the axle, mounted there 
> somehow, and make a sweeping bend and the end of the outer 
> part (cable cover) should be clicked into the bracket that is 
> welded to the fuel line cover (in front of the driver's side 
> axle leaf spring mount).  The steel cable comes out of that 
> and joins the driver's side cable and goes to the front 
> adjuster.  The steel cable goes through the adjuster and 
> after you pull it as tight as humanly possible, put on the 
> cable end (I used two bolt on types, just to be sure).  The 
> adjuster should be all the way out when you do this so you 
> can tighten it.
> 
> 19.  Now it's show time!  Put the disk mounting brackets on, 
> put the axles with the new studs in (making sure to get some 
> grease on those new seals if you put them on!), and put the 
> machined spacer carefully over the axle between the retaining 
> plate and the axle bearing.  This is a little tricky, but if 
> you made the spacer from the bearing, it will fit perfectly 
> and hold itself into place while you get the retaining plate 
> bolted up.
> 
> 20.  Put the rotor hat over the axles.  Note that the center 
> hole of the disk doesn't quite fit the stock axle hub.  It's 
> a little too large to be properly centered by the stock 8" 28 
> spline axle hubs, but I don't feel much, if any vibration 
> from this problem.  Later I may get the axles turned and have 
> them machine a spacer to properly center the rotor.  This is 
> what should be done.
> 
> 21.  Put the calipers, loaded with the brake pads in, and 
> bolt them up to the disk brake mounting bracket.  Now attach 
> the hoses.
> 
> 22.  Tighten up the e-brake until the steel cable between the 
> adjuster and mount isn't saggy.  Then turn the rotors with 
> and without the e-brake on and check for e-brake operation.  
> Make sure the e-brakes don't drag!  There are adjusters in 
> the e-brakes (mentioned earlier), so you can adjust them for 
> side to side brake balancing, but I'd adjust the cable as the 
> main adjustment.
> 
> 22.  Now we must rid the car of any residual pressure valve.  
> Loosen the rear brake line at the master cylinder and pull it 
> out, making sure not to
> drop brake fluid on your paint.   Use a screw to screw into the brass
> flange
> in the master cylinder and pull the flange out.  Remove the 
> check valve if one exists.  If you are using the granada 
> swap, with the front disk brakes for the granada, you'll need 
> to get rid of the stock proportioning valve and plumb in an 
> adjustable wilwood or similar unit in the rear brake line.
> I
> haven't done this yet, but it's necessary because the brakes 
> will drag if there is any residual pressure valve in the 
> system (disk brakes should not have any residual pressure 
> valve).  I know, I'm glossing over some things here, but this 
> part has a lot of variables.  I plan on using the stock 
> disk/drum master cylinder from the '68 with the residual 
> pressure valve pulled out of the rear brake side of the 
> master cylinder with an adjustable proportioning valve 
> mounted just under the dash inside the car.  This will allow 
> easier adjustment for brake proportioning.
> 
> 23.  Bleed the brake system, making sure to keep the shuttle 
> valve centered (if you still have one in the car).  There are 
> tools for this purpose.
> If
> you don't care about your brake light being on, don't worry 
> about the shuttle valve.
> 
> 24.  Test the brake operation with the car up and a friend 
> pressing on the brakes.  When satisfied, put the wheels on 
> and test the system for leaks and e-brake operation. Then 
> take a test drive and feel the benefits!
> 
> Added note: After doing this, I noticed some drag from the 
> rear brakes.
> I thought it was some residual pressure valve but it turned 
> out to be the emergency brakes.  After a while, it went away 
> (as the shoes were worn I suppose).  The e-brakes still don't 
> work well, but I think if someone were to convert to a foot 
> type e-brake, like from the later model (>'71?) Mustangs, it 
> would work much better.  A pull out e-brake lever, as the 
> stock early Mustangs had, is a poor activator!
> 
> As always, I offer this advice for the benefit of those who 
> are like me, and love to work on things like this yourselves. 
>  This information is as complete as I know, however this is 
> only a guide, and therefore the user bears all responsibility 
> for the use of this information.  I do not claim it to be 
> complete or completely reliable.  Use at your own risk, and 
> be careful!  Brakes are safety devices and as such, should be 
> built as well as possible.  Good luck!
> 
> Best Regards,
> Keven Coates
> '68 five speed, four wheel disk Mustang
> 
> -----Original Message-----
> From: classic-mustangs-bounces at lists.twistedpair.ca
> [mailto:classic-mustangs-bounces at lists.twistedpair.ca] On 
> Behalf Of Chris Stephens
> Sent: Thursday, October 14, 2004 11:00 PM
> To: A list for owners of Classic Mustangs
> Subject: Re: Re: [CM] Re: 1966 Mustang GT350 rear drum brake upgrade
> 
> 
> 
> > Thanks. Does this conversion work for small bearing 8" and 9" rear 
> > housings?
> >
> 
> Yea, thats what I have. A small bearing 9 inch.
> Chris 
> 
> 
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