Ford Muscle Cars Tech Forum banner

1 - 20 of 64 Posts

·
Premium Member
Joined
·
1,950 Posts
Discussion Starter #1 (Edited by Moderator)
Now that I have your attention, yes they are cheap brakes, and they are big brakes, but they are not brakes with 13" rotors. Still interested, read on. What we have here is a simple, easy disc brake upgrade for you Mustang, Falcon, Fairlane, Ranchero, etc. It will work on any intermediate Ford V-8 drum brake spindle from about '63-'73. It uses two fabricated caliper brackets, two 11" Granada rotors, and here is the big part- two big GM calipers that have the 2 15/16" piston.

-Why the big GM calipers?

Unlike most disk brake swaps tha use the small GM metric calipers, this swap uses the same calipers that would have stopped a big Impala or even some 1/2 ton pickups. The "metric" calipers that alot of swaps use have a 2 1/2" piston, but the big GM calipers have a 2 15/16" piston that offers 12% more clamping force. The big calipers also use a brake pad with a bigger friction surface. The big GM calipers are also more rigid and will flex far less that the metric calipers.

There are three ways to increase braking force:

1. Increase rotor swept area via a larger diameter rotor.
2. Increase piston diameter or number of pistons for more clamping force.
3. Increase brake pad surface area.

We have two of the three covered, and I can tell you that this same system was in use on the front of my IMCA dirt modified for several seasons and and it will out stop a metric caliper system.

The rotors are common '75-'80 Ford Granada or Mercury Monarch. There were bought new at O'Reillys for $49.99 each:


The calipers are '75 Impala items that were $14.99 each at O'Reilly's. The brake pads cost $14.99 and were bought at AutoZone:


Here is a comparison between the metric and big GM brake pads, the metrics are on top:


We also used six 2" long x 3/8"-24 fine thread grade 8 bolts with steel locknuts to hold the caliper brackets to the spindles. The brake caliper bolts come with the new calipers. Cost $3.24:


Here are the 3/16" inverted flare to #4 adapter fittings that will allow the use of two 18" long stainless steel braided hoses. The adapter fitting connects to the stock brake line and fits in the stock bracket. Cost $9.99 a pair for the fittings and $9.99 a piece for the hoses:


We also used two 7/16"-20 to #4 banjo fittings that will allow the hose to connect to the caliper. Cost $6.99 each:


The brackets started out as common circle track weld on brackets that allow the big GM calipers on the rear ends of race cars. Cost $8.00 a piece:


The bottom of the brackets are cut off, and two holes are drilled to allow it to bolt to the spindle:



Six 3/4" O.D. x 7/8" long spacers are needed to space the brackets out. The spacers fit between the brackets and the spindle. A small "dog leg" brace is also needed to allow it to bolt to a third spindle hole:


Everything is bolted to the spindle and the dog leg brace is welded to the main caliper bracket between the arrows. Sharp viewers will notice that the brackets are in front of the rotors. The calipers are flipped backwards and swapped side for side on this system. Meaning the left caliper is on the right side and the right caliper is on the left side:


Here are the finished brackets:



The drum, hub and backing plate will need to be removed:


Clean any burrs off the spindle around the holes:


The brackets are bolted on using the grade 8 bolts:


The rotors are bolted on using new bearings and seals. I re-used the original '66 Falcon bearings as they were new and had zero miles on them:


Here is a shot of the brackets bolted on from behind:


The calipers are bolted on and the hoses are hooked up:






Here is a break down for the cost:

-Granada rotors-$49.99 x 2 = $99.98
-Big GM calipers-$14.99 x 2 = $29.98
-Brake pads- $14.99
-Brake adapter fittings - $9.99
-Caliper banjo fittings- $6.99 x 2 = $13.98
-#4 stainless steel braided lines- $9.99 x 2 =$19.98
-Brake caliper brackets- $8.00 x 2 = $16.00

-Total cost = $208.14.

I did machine my own spacers, and make the small dog leg brace, and that would add slightly to the cost to have someone do it for you, but it would still come in at far less than $300.00, and you end up with awesome stopping power. I also need to add that these calipers will clear 14" disc brake steel or aluminum wheels. I omitted the master cylinder installation as there are plenty of articles covering that sort of information, but I will tell you that I used a non power '75 Maverick M/C with a 15/16" bore and no proportioning valve of any kind. It stops awesome.


.
 

Attachments

·
Premium Member
Joined
·
333 Posts
Thiis is awsome. I wanted to do a swap but cant afford the $500 + just for parts 3 days out. Couple of question thou. What year were the impala brakes pads for, motor? Same with the calipers. I want to go into the auto parts store. The brackets were can I get thoes? at the auto parts store? . Do I NEED to replace my proportion valve or m/c? Last thing What brake line do I need to get? off of what car will fit? Sorry if the question are stupid, I have never done this and dont want it to be a pain in the ass. lol thanks
 

·
Premium Member
Joined
·
1,950 Posts
Discussion Starter #3 (Edited)
Thiis is awsome. I wanted to do a swap but cant afford the $500 + just for parts 3 days out. Couple of question thou. What year were the impala brakes pads for, motor? Same with the calipers. I want to go into the auto parts store. The brackets were can I get thoes? at the auto parts store? . Do I NEED to replace my proportion valve or m/c? Last thing What brake line do I need to get? off of what car will fit? Sorry if the question are stupid, I have never done this and dont want it to be a pain in the ass. lol thanks
I used '75 Impala calipers and brake pads, they are all the same with any engine. I bought the brackets, stainless lines, banjo fittings and adapter fittings from Speedway Motors. I used a disc/drum non power Maverick M/C with no prop valve at all.
 

·
Premium Member
Joined
·
333 Posts
Thanks, I dont have a phd in brakes:), but would like to someday. You said you didnt use a prop valve. is there any harm in not using them vs my stock 67 mustang manual drum one? Same with the m/c? was it a power m/c. My understanding is that the prop valve splits the pressure 70-30 so the rears dont lock up. I have no idea why some people use disk m/c and others use drum m/c with a disk conversion.
 

·
Premium Member
Joined
·
1,950 Posts
Discussion Starter #5 (Edited)
Thanks, I dont have a phd in brakes:), but would like to someday. You said you didnt use a prop valve. is there any harm in not using them vs my stock 67 mustang manual drum one? Same with the m/c? was it a power m/c. My understanding is that the prop valve splits the pressure 70-30 so the rears dont lock up. I have no idea why some people use disk m/c and others use drum m/c with a disk conversion.
The drum/drum M/C will have built in residual pressure valves that are designed to keep a slight amount of drag on the drum brake shoes, while it will work, you don't really want drag on the calipers all the time. It is best to use a non power disc/drum M/C for this application. You don't want a power brake M/C because it will have a bigger piston that will cause a rock hard pedal that will require altering the pedal ratio. I don't use any kind of prop valve because in all of the disc converions that I have done over the years, I have never had a situation where I needed one amd I simply chose to leave them off when I do disc conversions now. You may chose to add a proportioning valve if you like, and I am in no way condemning their use.
 

·
Registered
Joined
·
924 Posts
How did you determine where to cut and drill the holes in the adapter plate? Do you have a template for that? I notice the spacers you made have a shoulder on them, how large is the sholder.
Thanks Mike
 

·
Premium Member
Joined
·
1,950 Posts
Discussion Starter #8
How did you determine where to cut and drill the holes in the adapter plate? Do you have a template for that? I notice the spacers you made have a shoulder on them, how large is the sholder.
Thanks Mike
I installed a rotor on the spindle, and placed the caliper on the rotor with the brake pads in place, making sure there was clearance between the caliper and the rotor. I applied a small amount of air pressure through the brake fitting opening so the piston would clamp down on the rotor, and I used a transfer punch to mark the holes in the plate. The shoulder is 1 1/8" in diameter and 1/4" high.
 

·
Registered
Joined
·
110 Posts
The shoulder is 1 1/8" in diameter and 1/4" high.
What was the reason for the shoulder? Did you use the shoulder as a point to weld the spacers to the bracket or did you leave the spacers loose? (Could not tell from the pictures).



Also, I was just curious, why was the dog leg not even with the bracket. I have not torn my car that far apart yet, is the one side of the spindle not even with the other? It does appear the the dog leg is ALMOST touching the upright on the spindle, how much clearance is actually there (I know it does not really matter as it is a solid mounted piece, but just curious).

Definitely looks like a good possibility for me when I get to the brake section of my "restoration" or upgrading.
 

·
Premium Member
Joined
·
1,950 Posts
Discussion Starter #10
What was the reason for the shoulder? Did you use the shoulder as a point to weld the spacers to the bracket or did you leave the spacers loose? (Could not tell from the pictures).



Also, I was just curious, why was the dog leg not even with the bracket. I have not torn my car that far apart yet, is the one side of the spindle not even with the other? It does appear the the dog leg is ALMOST touching the upright on the spindle, how much clearance is actually there (I know it does not really matter as it is a solid mounted piece, but just curious).

Definitely looks like a good possibility for me when I get to the brake section of my "restoration" or upgrading.
The "dog leg" has to clear the upright portion of the spindle, so it overlaps the main bracket. There is about 1/8" clearance between the dog leg and the spindle. I left a shoulder on the spacers because I welded the spacers to the bracket at the shoulder. You do not need the shoulder, and the spacers do not have to be welded to the brackets as the bolts hold everything together.
 

·
Registered
Joined
·
1,233 Posts
How critical is the dogleg? Is it only there for added support or would the caliper bracket by itself possibly fail w/o it?
 

·
Registered
Joined
·
120 Posts
Inspired by your posting, I decided to do the master cylinder upgrade from stock single reservoir.

At the local parts store, the part number for Maverick disc/drum or drum/drum non-power brake master cylinders is the same.

I got confused and put it on hold until I find out if I'll end up with the wrong part or not.

Should I ask for a specific year?

Shawn
64 Fairlaine-390/C6 mod
 

·
Premium Member
Joined
·
1,950 Posts
Discussion Starter #15 (Edited)
How critical is the dogleg? Is it only there for added support or would the caliper bracket by itself possibly fail w/o it?
Most aftermarket disc brake kits like Wilwood use only two bolts to retain the caliper bracket. I added the third hole for bullet-proofness after a buddy of mine who is an engineer calculated that the two bolts were more than adequate.
 

·
Registered
Joined
·
110 Posts
I added the third hole for bullet-proofness as a buddy of mine who is an engineer calculated that the two bolts were more than adequate.
Did you mean to say you added the third as the buddy calculated they were NOT more than accurate?

Sentence just seems weird because you say you added more because he said 2 were enough... Why would you add the third then?

Or did you add a third and then the buddy calculated and said that two were more than accurate?

Sorry if I am missing something, it just seemed to be the opposite of what I was expecting to read.
 

·
Premium Member
Joined
·
1,950 Posts
Discussion Starter #17
Did you mean to say you added the third as the buddy calculated they were NOT more than accurate?

Sentence just seems weird because you say you added more because he said 2 were enough... Why would you add the third then?

Or did you add a third and then the buddy calculated and said that two were more than accurate?

Sorry if I am missing something, it just seemed to be the opposite of what I was expecting to read.
Two bolts were deemed more than adequate, but I like piece of mind, so I added a third. I tend to over build everything.
 

·
Registered
Joined
·
222 Posts
I have a few questions as well. By the way great write up! Would there be a way you can post the part #'s for the bracket & #4 brake line? Also what are you using for bearings? are they the year of the orginal car? or the year of the rotor?
 

·
Premium Member
Joined
·
1,950 Posts
Discussion Starter #19
Here are the fittings:

Part number 6174029 Speedway Motors


Part number 916-41008 Speedway Motors


Part number-617-2062 Speedway motors


Part number-910-31844
 
1 - 20 of 64 Posts
Top