Ford Muscle Cars Tech Forum banner

1 - 13 of 13 Posts

·
Registered
Joined
·
55 Posts
One of the main goals for my car when I started was to build a reliable performer that was upgraded in almost every regard from what you would have gotten from the factory.
Braking is often one of those overlooked aspects that many seem to ignore, but it is essential for an all around performer. My mustang came with power brakes and discs upfront and for some this would have been sufficient.

For me choosing to stick with drums in the rear was however, not acceptable so I began looking into rear disc conversions. Like many of you out there I am on a budget and after seeing how much rear disc kits can cost; upwards of $600 in many cases, I decided that it may not be worth the cash outlay.

That's when I stumbled across a small write up on using the rear disc set up from the Ford 8.8 and more specifically the one found in the numerous Crown Victoria and Grand Marquis. Utilizing crown vic parts and using some adapting hardware (available on ebay, link will be supplied) one is able to put rear discs on an 8" or small bearing 9" axle for less than $350 in most cases!

The first thing you must do is determine which axle you have. Any 8" will do but if you have a 9" like me then you need to make sure that it is a small bearing 2.835" diameter with a flange bolt pattern of 3.3125" x 2.0". If you have the big bearing 9" then you should pursue an Explorer based set up.


The next step is obtaining the necessary parts and from this will determine what spacers you will need. There are two sets of years that are applicable for this swap. The first set are cars from 1991 to 1995 and the second are cars from 1996 to 2002. The 96-02 set up is preferable as the caliper backing plates come with large dust shields, but the hardware for this kit is usually somewhat more expensive.

Be sure to obtain all the parts from the set up: caliper backing plates, backing plate retaining bolts and nuts, calipers, flex lines, rotors, e-brake hardware & cables, axle wheel studs. Not all the parts need to come from the salvage yard, the e-brake shoes and hardware can be purchased new from your local parts store for example. The parts from the two year sets are not interchangeable so stick with one set when collecting your parts.
Pictured here is the 91-95 backing plate from a 92 crown vic, I chose this set of years because my local salvage yards had many more of these cars readily available.


After you obtain the necessary parts you will now need to either purchase or fabricate the necessary spacers that allow the set up to adapt to early mustang rear axles. For ease of install I opted to purchase these spacers online, and included with them are detailed instructions on the modification of the axle and install so I would highly recommend this.

Included are a set of bearing spacers that compensate for the difference in the caliper backing plates and the old drum backing plates, and hub spacers that allow for the centering of the rotor on your current axle hubs. For the 91-95 years included are some washers that need to be installed on the backing plates prior to install on the axle, they allow for proper tightening of the axle retaining flanges. The entire kit is $50 which may seem steep for some small pieces of metal, however the entire job is laid out nicely in the provided instructions.


1965-1973 Mustang+ Rear disc brake adapting parts 9" 8":eBay Motors (item 320388531426 end time Jul-23-09 23:29:53 PDT)

After obtaining the spacers you will need to have the bearing spacers installed on your axle along with the crown vic wheel studs. The studs ARE necessary as their longer length is required and they have a small shoulder which is needed for the rotor's proper install. When doing this you should replace the bearings on your axle as well as the locking sleeve. The order for install is essential and should follow this:


Next you will need to modify your axle flanges to accept the new backing plates. From the factory they are D-shaped and will need to cut into a more rectangular shape.




Finally after all the prep work you may now go ahead and start the actual installation of the new set up. Installing the e-brake hardware on the backing plates is much easier with them off the axles and the bearing should fit through the center fairly easily.


Here is a diagram of the e-brake assembly that should help in adjusting them to proper spec.


IMPORTANT! When installing the backing plates and axles into the housing you must make sure the bearing spacer is seated properly against the bearing before tightening down the retaining flange! I used a light coating of grease to get the spacer to stick to the bearing and a coat hanger to maneuver it into position. This is very important and when done correctly all the retaining bolts should tighten evenly. This is probably the most hassle ridden part of the install and may take a few attempts.

Since both sides are the same I opted to mount the backing plates upside down so the parking brake cables would mount a little easier, but you may choose otherwise. After this the assembly should look like this:




Now you can add some threadlocker to the hubs and install the hub spacers. The ones in the kit are not meant to fit flush against the hub flange and are meant only to center the rotors.






Now you can install the calipers




Finally the vehicle specific adapting will have to take place, mounting the flex lines, bending new brake lines, mounting the e-brake cables, bleeding the brakes, installing a proportioning valve if needed etc. These are all formalities that are specific to the car that you have and will require a little bit of thinking on your part, but the lion's share of the work is now done and you should be well on your way to four wheel discs!



.
 

Attachments

·
Registered
Joined
·
368 Posts
Nice Write up! Thank you!

Do you need to also change the master cylinder? I would guess you should, right? Since the orginal one is set up for disk/drums, I wouldn't think it would move the right amount of fluid when you set on the brakes.

-chunger

'68 Ranchero 500
'70 Cougar XR7 Convertible
 

·
Registered
Joined
·
55 Posts
Discussion Starter #4
Nice Write up! Thank you!

Do you need to also change the master cylinder? I would guess you should, right? Since the orginal one is set up for disk/drums, I wouldn't think it would move the right amount of fluid when you set on the brakes.

-chunger

'68 Ranchero 500
'70 Cougar XR7 Convertible
Yeah it is a good idea to change the master, that is why I also opted for the one out of the crown victoria of the same year when I took the brakes. It mounts up nicely and is already proportioned for 4 wheel discs so there is no need for a secondary proportioning valve.
 

·
Registered
Joined
·
12 Posts
Yeah it is a good idea to change the master, that is why I also opted for the one out of the crown victoria of the same year when I took the brakes. It mounts up nicely and is already proportioned for 4 wheel discs so there is no need for a secondary proportioning valve.
GREAT Article!!! Is the master cylinder from the crown vic a direct bolt up to the power booster or is there modifications that must be done also?
 

·
Registered
Joined
·
10,299 Posts
Nice write-up! To save a few bucks (and there was nothing available back then), I used two stacked piston rings from an old lawn mower for the wheel bearing spacers. I could have used anything of that type about .125-.130 thick. I heard one guy say he used welded steel rings from the hardware store.

Another item was the wheel studs, which must pilot and center the disc as originally designed (lug-centric, not hub centric). My old notes say I used Dorman 610-148 studs instead of the CV studs. They may be easier or cheaper to get than the CV studs. No hub adapter was required. Just an option I chose.

Finally, the original master cylinder works fine for me and some others who have done this, after removing the residual valve from the front (rear brake) port. As an old brake master informed me, disks don't use a bunch of fluid as I assumed. He said they have big pistons, but they hardly move compared to the smaller double pistons in a drum brake setup that must travel relatively far to engage, amking the difference in volume surprisingly small.

Anyway, not swapping master cylinders saved a bunch of time and some cash, although I did splice a proportioning valve in. That was fine with me as I wanted to fine-tune my braking with the fat rear tires anyway. BTW - to remove the residual valve, I just threaded a screw into the brass brake line seat and pulled it out with a pair of pliers (not much force required), removed the little ball and spring, and put the seat back in. I was careful to avoid damaging the seat sealing area. Couldn't be simpler.

Hope that helps.

David
 

·
Registered
Joined
·
55 Posts
Discussion Starter #8 (Edited)
Hey guys here is a crappy pic of the CV master cylinder. I got a junkyard unit but its seals were gone so I replaced it with one for $37US from Murray's Auto, after searching for a seal kit and having everyone and their mother say they don't sell them anymore. It bolted right up to my existing booster but since I haven't run the lines yet I cannot say how well it works. After some testing I can post how well it works and whether or not I'll get a prop valve.
 

·
Premium Member
Joined
·
2 Posts
vented rotor?

I really like this type of parking/emergency brake setup with a small drum inside the rotor hat. I’m not as fond of the solid rotor, however. Does anyone know of an application with the same type of drum brake inside the rotor hat and a vented rotor?

Thanks,
steveg
 

·
Subscriber
Joined
·
888 Posts
Nice article! This is the setup I have on my '67 with the Granada conversion on the front. The nice thing is that both conversions are affordable, the replacement parts are available in-stock at just about any parts store, and they are very inexpensive as well!
As I recall, the guy that put my setup together opted to cut-out the backing plates rather than cut down the axle flanges.

And for those who would argue that this is a hodge-podge of parts, how is this really much different from an aftermarket set up except that all these components are factory Ford parts, a fraction of the cost, and you don't have to worry about an aftermarket company closing up or changing their design making replacement parts difficult or impossible to find???
 

·
Registered
Joined
·
2 Posts
OK, I am hoping to revive an old thread and maybe add some new information. I am currently doing this upgrade and have found some new information.

First I wanted the new style brakes for two reasons first the larger dust shields and to see how new I could go before the parts did not work. The car I sourced was a 2005 CV that served as a taxi. Upon giving it a junkyard examination it looked as though the 90's CV and the 2000 CV's shared the same rear brakes. I had them pulled and brought them home for inspection. I know people are concerned about price. I also know price will vary. I am going to include prices so people can have a number but your negotiating skills and region will be the biggest factor. I got the rubber lines, calipers, rotors, e-brake hardware in the drum, and the baking plates for $95 pulled.

I quickly and I mean quickly had the the whole assembly on the axle (sans the axle bearing spacers) just to mock everything up and find any possible issues. First off I found that the 2005 CV's calipers where in the same relation as the earlier models I looked at but found that the backing plate mounting holes have been rotated 90 degrees.

I felt this would not effect the brakes or hardware performance as the calipers don't care about the position they are mounted in. I did notice that the earlier models have a brace that attaches to the caliper and the axle tube. The 2005 CV did not seem to have this bracket. I also grabbed the MC off the same car and it bolted right up but the reservoir hit my hood when closed so I am going to have to try a different car for the reservoir like a Mustang.

As for the rest I am going to hopefully get to adding the spacers and plumbing it up this next week.
 

Attachments

1 - 13 of 13 Posts
Top