Disc Swap to Ford Small Bearing 9" or 8" Rear Ends

Disc Brakes on a Ford 8" on Small Bearing 9" Rear End

I won't even start with a discussion of why I decided to change to discs, I'll just assume that if you're reading this you are already on board with that.

The reasons this is a good way to do discs:
1. Parts are readily available and as a result are
2. Reasonably priced.
3. 11.4" rotors are reasonably big, but still fit almost any 15" or bigger
rim, and some 14" rims as well.
4. You can have a working E-brake for minimal extra work and cost.

When I decided to do this I looked all over the internet for info and could not find everything in one place with photos, so this is my attempt to make the world a better place and synthesize what I found online and what I learned as I did my own setup. I don't claim any particular expertise, so if you know a better way of doing any of this, or have any info to add please chime in.

I'm going to show you how I did the disc brake swap on my 8" rear, but this should work on any 8" or small bearing 9". If your axle tube flanges look like this: or this: it should work for you.


What you'll need:

DONOR PARTS-

I won't even try to list all the donors for a suitable rear end, but mine came from a Granada.

You'll also need donor parts from a '92 to '02 Crown Vic or Mercury Marquis: you want everything associated with the rear brakes:

1. Calipers (Core charge is very high without old ones)
2. Rotors (who knows- maybe they'll be usable)
3. Backing plates / dust shields
4. Caliper mounting brackets
5. E-Brake cables, hardware, & brackets from the mid-car junction back. (These also are very expensive to buy at the parts store, so be sure and get them)

Brackets & dust shields:


Donor Notes: 1.The Crown Vic rear is a c-clip type, so you'll have to open up the pumpkin to take the c-clip off so you can get the axles out , so you can (finally) get the parts you really came for off.
2. Get every nut, bolt, spacer, & bracket.
3. My donor was a '95, so that's what you'll see here. The '96-'02 is basically the same, but will require a slightly different bearing spacer. I'll explain later. Also mine was a Police interceptor. AFAIK the differencs between cop car and standard C.V. brakes are: Cop cars have metal caliper pistons vs. standard cars have phenolic pistons. This means that the metal clips that hold the pads to the pistons are different. You cannot mix and match calipers and pads between cop and civilian.

AT THE PARTS STORE-

1. Center Brake Hose (in my case I used the Granada hose (Bendix #77009) that mounts to the OE distribution block on the breather bolt on top of the rear end housing. You could also put a screw-in breather there and do your hoses a different way if you like.

2. Caliper brake hoses.- one way- These will be the Crown Vic hoses per your donor. The left and right hoses are different. Obviously you'll need 2. They have mounting tabs built into them, and it will be easier to use 2 right-side hoses (Bendix 377961) because of the shape of the mounting tabs.

-Another way- Alternatively, you can get a pair of Wagner #BH98912 hoses (same as Raybestos #BH36845) They are originally for the front calipers of '79-'81 Camaros. They have different breckets on 'em than the Crown Vic hoses, but they work and don't need a bubble flare adapter to attach them to the hard lines on your 8" rear housing

3. Bubble Flare Adapters. You need these if you are using the OE Crown Vic hoses. The Crown Vic hoses are made for 10x1mm bubble threads, The hardlines on the 8"/9"rear ends are meant for standard 3/8" (for 3/16" line) inverted flares. You'll need 2 adapters. They are Edelman #271300. I believe they are also Weatherhead #1442, or Everco #3024B.

4. Invert Flare adapters. You'll need 2 of these to adapt the 3/16" hard lines you'll be making to the 1/4" flare on the junction (at the breather) where the brake line splits for the two sides. This is Edelman #258340

5. New Wheel Studs. The old ones wont be long enough for the thicker rotor hat. Depending what wheels you will be using you may be able to use Dorman #610-034, which are 1/2" studs 1 17/32" long with a .622 knurl. Measure carefully or else- like me- you'll buy 10 of them, install them, and then find that they are still just slightly too short. Then you'll need to buy ARP studs #100-7703 which are 1/2" studs 3" long with a .625 knurl. I ended up with these, and cut them to the length I really needed.

6. Hard lines. I used an 8" and a 30" piece of the pre-flared 3/16" stuff

7. Rotors & Calipers. If you will be replacing the stuff you got from the donor.

8. Brake Fluid. 'Cause you were going to forget this and have to make another trip out to get it.

9. Disc/Disc Master Cylinder. I'm making some assumptions here, but you probably need one. I can tell you for sure that an '80's S-10 disc-drum master won't do the job. I ended up using the very popular Corvette master and the (very large & powerful) booster off an early 90's Caddilac.

10. Adjustable Proportioning Valve. Who knows, maybe you'll get lucky and not need one, but I don't think that is likely, and it'll save you a lot of time to install it at the now. FWIW I got the Speedway-branded valve, and under the Speedway sticker it is marked Wilwood, so save a few bucks there if you can stand purple.

THE SWAP

Do you know the condition of your 8"/9"? I didn't since mine was salvaged long before I ever got it, and I had never run it. Since I know little about rear ends I took it to a specialist shop where they ended up pressing on new bearings, replacing a bent axle with one from their extensive bone yard, and straightening the tubes. All this on a rear end that seemed fine. The moral is to start with a good one, however you have to do it. You don't want to find out after you do the swap that your axle is junk.

You probably don't have to take the rear end out of your car if it is already in place, but mine wasn't so it was very convenient to work on it on one of those Black & Decker "Workmate" portable work benches. It'll support it by the center, whilst the ends of the housing & axles hang off the sides where you can get at them easily.

1. With the axle solidly supported and the wheels off take off the drums, disconnect the brake lines and the E-brake cables, and remove the drum backing plates. You can leave the shoes and hardware attached to the backing plates while you do this.

2. Gently slide the axles out of the housing whilst being careful not to F-up the seals. It should require- at most- a couple of gentle taps with a hammer and drift to get the axle bearings unseated from the housing. If it is harder than that, you have a problem somewhere that needs to be addressed before continuing.

Stuff some nice clean rags in the end on the axle tubes so you don't get grinding debris down there. Do a good job- you really don't want grit getting in there.

3. Now stand back and look at flange on the end of the axle tube. See how it is round on the bottom and flatish across the top? You want to cut it so the bottom is flat and parallel to the top.


I made a little cardboard template for how I wanted the finished product, matched the template against the recess in the Crown Vic caliper brackets to be sure it fit in there, and then used it to mark the cut on the axle flanges. I did the actual cutting with a cutoff wheel in a 4.5" angle grinder. The flanges cut pretty easily, and if your rear is out of the car you can rotate it upside down on your work stand so the cut line is easier to get to.


4. Now fit the caliper brackets to the axle flanges and bolt 'em on finger tight. You did remember to mark which bracket is right and which is left, didn't you??!! Just kidding....they're the same. On the passenger side the caliper mounts in front of the axle, on the driver's side caliper goes to the rear.


5. Stud time. Remove the wheel studs from the axle flanges. To do this with minimal tools I supported the axle flange in my big-ol bench vise with the studs pointing up and the head of the stud between the jaws of the vise (open the vise just barely wider than the head so the flange is well supported and doesn't get bent). Then I screw an old lug nut down just flush with the top of the stud and whack it a few times with the BFH.




My new studs were just slightly bigger diameter at the knurl than the old ones, so I took a 39/64" drill bit (I don't know why I had that oddball size handy...) and ran it through each hole with a hand drill. This bit was just big enough to take out the witness marks from the old studs.

5.5 With the axle in the vise, now is a good time to cut the bearing retainer plate. Just like you did with the axle tube flange, we need to cut off the bottom to match the flat top. Same procedure: straight and parallel
to the top.



To install the new studs I pushed them through the flange, then put on a couple of really thick washers , then an old lugnut. Get a little oil inside the hole in the flange and on the knurl, then use an impact wrench (turned up to 11) on the lug nut to pull the stud through. Quick & easy.

6. If you need to replace any bearings or seals now would be the time.

7. Now (carefully so as nut to damage the seals) slide the axle back into the axle tube. It should take very little convincing to get the bearing seated in the tube, and once it is seated if you position the bearing retainer plate where it goes you'll find some bad gap-osis between the outer face of the bearing and the inner face of the retainer plate. (PIC)

This is because the backing plate for the drums was thinner than the disc bracketry we replaced it with, and if we don't make a spacer to fill the gap, your axles would just go slamming in and out as you turn. I've seen different numbers for how much end play must be taken out, and I'm not capable of extremely accurate measuring anyway. Best I could measure I needed to take up just over .13".

After some looking around with a caliper at the hardware store I found some 1.25" Galvanized washers that were the right thickness and (this was a super-bonus) the right O.D.. In order to be able to install the spacers without having to take off my bearings, I cut a slot through each washer just a teeny bit bigger than the diameter of the axle, opened up the center of the washer to that same size, and chamfered the inner face of the hole just a little to make sure it wouldn't bind the bearing.

This all allows you to slide the spacer onto the axle just outboard of the bearing, then work the bearing retainer plate up against it to hold everything in place. Sliding the spacer in:


Again, bolt it up finger tight.

8. Now it is time to lay out your hoses and hardlines. Your setup will vary according to exactly what parts you are using, but I wasn't careful at this stage and made extra work for myself. In my case I ended up bending hardlines from the OE distribution block to a point about 9" in from each end of the axle. At that point I welded a 5/16" bolt to the housing(PIC), and attached my 2 right-side hoses to those bolts. Again, do a thorough mock up before welding anything. There are numerous ways of doing the brake lines.





Once you are happy with that- and before welding anything- pull out the Crown Vic E-brake cables. The passenger side cable will have to come across the car along the rear axle before it makes a 90 degree turn to head forward along the leaf spring or frame rail to where it joins the driver's side cable up just in front of the forward spring mount. If you need to add anchor points for the E-brake cable now is the tome to get those worked out as well. Also, pre-load the "Balance adjuster spring" This is the mechanism where the right and left side cables connect. You want the spring all the way compressed so that after everything is hooked up it will be able to self-adjust so the Ebrake on each side pulls evenly. (LINK)

It is also a good time to think about how you are going to hook it all up to your E-brake lever. I don't think how I did it on my '38 Chrysler will help very many folks here, so you're on your own, but to pull the cable requires a lot of force, so it'll need a strong anchor someplace.

9. Weld on whatever brackets/anchor points you've created. The rear end housing looks big and bulky, but it is possible to warp the axle tubes, so don't heat 'em up any more than necessary.

Paint everything if you are so inclined.


10. Now you have the axles in, put the caliper brackets, dust shields and brake lines & cables on if they aren't already, and get everything finger tight.

11. Pull the rotors out of their boxes and set them over the end of the axles. The hole on the rotor is bigger than the "Hub" (The circle that sticks out of the axle flange to locate the rotor or drum) on the axle flange. There are at least 2 different hub diameters. Some folks say thet you need a precisely made spacer to locate the rotor properly since it was intended to be hub-centric, and there is a guy on Ebay who sells these spacers. I also heard from folks who said it wasn't necessary- that the wheel studs would locate everything adequately. I had a machinist buddy make me some spacers

so my rotors are definitely centered, but I ended up needing 1/2" wheel spacers so my tires wouldn't scrape the edge of my inner fender well. To make a long story short, even though the rotors are centered, there is no guarantee the wheels themselves are, and everything seems OK. YMMV, but I think the hub spacers are probably unnecessary.

With the rotors in place, put your brake pads in your calipers and bolt 'em to the brackets.

12. You are pretty much done with the rear end. Tighten all nuts & bolts.Spin the rotors by hand and adjust the e-brake pads. They are just little drum brakes, but I found it easiest to set them up with no wheels on, and even more so with the rear end out of the car and up at workbench height.


If the rear end is out of the car, now is the time to put it back in. Make sure the brake hoses and ebrake cables won't rub on anything as the suspension moves through its travel and tighten the brake line fittings.

13. I won't go through the install of the new master as there are plenty of threads already if you need help on that. I will suggest strongly that you plumb in an adjustable proportioning valve when you install the new master. Since we are making things work together that weren't necessarily meant to go together the adjustability is a good thing to have. And having to put one in after you just had everything apart will make you feel really stupid.

14. Hook up the E-brake cable to the handle- however you have to do that.

15. Test drive time.

 

Excellent tech. Thanks for taking the time to show us how you did it.

 

Your bearing spacer was only .13"? I got the "actual" spacers for the explorer disc swap from strange sitting right here and they're almost a 1/4"... I know mine are the LBF ends, and yours is small, but I wonder if there are some other differences in the setups? I thought they were pretty much the same...

 

I think it took me about as long to write it up as it did to do the actual work...

To 35 Pontiac: I think the Exploder stuff is similar, but quite a bit different, as are the big bearing axle ends. It doesn't surprise me that your spacers would be completely different too.

 

Great Tech article.

Thanks for taking the time to write it.

Canuck

 

Good job!

 

Great tech article. Have an 8 inch in a 32 sedan and were working up to
doing the discs.lots of great info. Deucemanab

 

Awesome reply. I have all the parts ready for the swap for my 69 mustang. Can you please post a few pics of the ebrake cables connections, and mounting brackets ? Also a pic of the rear installed with the ebrake cable doing a 90 degree turn ?

Really appreciate your time.

thanks !

 

great tech ! thanks for sharing

 

How did I miss this? Very cool.

 

For e-brakes, you can try to figure out the stock setup, which looks like that's what 4woody did. You can also get a set of cables from lokar, which is what I did for my explorer setup. They're 120 bucks and meant for the explorer but they can be made to fit just about any car with explorer/crown vic brakes and you can route your cables how you want. FWIW

 

I don't have any better pics of the e-brake routing than that last photo with the complete setup behind the car. It is not too hard to figure something out once you get to that point, and what works on a '38 Chrysler with regards to brackets and such is probably not that helpful anyway.

Someday if I have access to a lift I'll do something cleaner with the brackets & routing, but for now it is just angle iron with holes and bolted to the frame as necessary.

I've never used the Lokar cables, and I'm sure they're nice. But I got the Crown Vic cables when I pulled the rest of C.V. parts (Remember I said to get EVERYTHING when you harvest the parts) so the cost was effectively $0.

Since Explorer parts have been mentioned a couple of times I want to be clear that while the Explorer and the C.V. both may use the 8.8 rear, I'm not so sure that the other brake parts interchange. Someone else can probably answer that...

 

Nice work and documentation - thanks for posting

 

This is SWEET...4woody.thanks for putting this together.

tok

 

Sorry, I wasn't trying to imply that everything would match up- I realize that they're different systems, but there are some things that would work. I've seen the e-brake setups on crown vics and used the explorer stuff myself, and I am pretty sure that the cables will interchange. I don't know that anything else will, either.

They're really not even very much of the same rear- the housing ends are different and the explorers used 31 spline axles. The e-brake cables are really all that I was trying to say would work... Sorry for any confusion!

 

Excellent info. Thanks for taking the time and effort to post it. I also wondered about the hub spacers but finally decided that there must be a reason that brake drum center holes are made by the OEM to fit the axle nub. I would think that over time the brake drum would wear or cut into the wheel studs from the impact of the force created when the shoes hit the drum.

 

This is the best tech on the internet on how to do this swap. I never would have made it through it without your help, 4woody!

 

Glad to hear you finally got 'er done.
Feel free to post anything you found that I left out, or whatever was different on yours.

 

Thanks a "Ton" you just help me make my mind up on doing this conversion.

 

I have the works from an 01 crown vic. There is a sensor on each caliper bracket that either 1: has to be removed and not used. or 2: the axle flange and bearing retainer plate has to be notched in order to use it. I see in picture 4, you don't have the sensor in. What is it and is it necessary?

 

Great tech. What is the dia. of that Caddy booster ? Is it a dual diaphram? I'm dealing with a very tight space twixt the frame rail and the C4 with an under floor MC.

 

old thread but some good info

 

First: I'm glad someone is using this tech again!

My caliper brackets never had any sensors that I can recall, so I can't answer your question.

Great tech. What is the dia. of that Caddy booster ? Is it a dual diaphram? I'm dealing with a very tight space twixt the frame rail and the C4 with an under floor MC.

It is a giant 11" dual diaphragm booster. I'll bet I could find you a part # or app if you need it.

 

missed this the first time - great job there and thanks for posting your work....

 

Great tech and nice to see it brought back up for others to see and use.

The sensor that is on the 2001 Crown Vic is most likely the ABS sensor. Not needed unless you are using ABS which is very unlikely on a hot rod swap. Especially for HAMB type vehicles.

 

My backing plate off an '01 was 1/4" as well. I couldn't find any washers big enough at any hardware store but I did find some steel rings 1/4" thick and a hair big on the OD. I cut a section out and hammered them down so they fit snuggly inside the backing plate opening.

The pencil in one of the photos is pointing to the mark on the retainer plate that touches the outer part of the bearing (next picture). The ring will contact the plate at that point. This should work very good.

 

save

 

Tagging along for the ride - nice article!

 

Besides the crown vic brakes set up, has anyone found another ford vehicle that will work (small bearing)?
Im having a hell of a time finding backing/anchor plates that are not rotted and item is no longer available at the dealer