65 Rear End Question

65-Fstbk · Jan 2, 2013

A couple of years ago I was looking for a new (to me) drivers seat frame for my project since mine was broken. I found one and the guy also had a 65 rear end for sale too. I knew I would need one of those eventually for my I6-V8 swap so I made a deal for that too.

It's getting time to get the rear ready for install so I un-tarped it and brought it into the shed for a better look. It's a plain Jane rear with an open 2:80 (I assume). The thing is, when I measure from the outside of brake drum to outside of brake drum I get 57 1/2", not 57 1/4". Inside the drums has been stripped of all parts so a whole new spring kit, wheel cylinders, shoes etc will be needed. The width of the machined surface inside the drums is approx 2 1/2". The guy told me the rear would need going through to get everything in order so I'm just wondering if the drums sitting on this axle are from the front drums not the rear.

The axle has the tapered tube where the u-bolts go so I'm thinking it's likely the correct rear with some old drums (front) thrown on it. The drums are old and damaged and need replacing anyway but before I order the rebuild kit I want to see if you think my suspicion is correct. The stamping on both of the the drums reads C3DA 1125B. The dates codes are different (one 63 and one 65). These drums look like they would take a 2 1/4" shoe and not the 1 3/4" shoe that a V8 rear should have.

Am I right????

Realmongo · Jan 2, 2013

Do these drums have a 9" or 10" inside diameter?

65-Fstbk · Jan 2, 2013

Inside dim = 10"

horse sence · Jan 2, 2013

the v8 rear end is a little different in width from the 4 lugger ,will not be a problem
the wider shoes would also be better if the drums are a match for the backing plates.the two different year numbers may just mean one is a replacement. do you have any pics?

horse sence · Jan 2, 2013

9 inch brake drums will bolt on an 8 inch rear end if you use the matching
drums and backing plates for wider shoes.

65-Fstbk · Jan 2, 2013

horse sence said:
the v8 rear end is a little different in width from the 4 lugger ,will not be a problem
the wider shoes would also be better if the drums are a match for the backing plates.the two different year numbers may just mean one is a replacement. do you have any pics?

Yep. Just went out to the shed and snapped a few pics.

horse sence · Jan 2, 2013

looks like the right drum for the backing plate go with the wider shoes

65-Fstbk · Jan 2, 2013

horse sence said:
looks like the right drum for the backing plate go with the wider shoes

The drums have to be replaced anyway so I'm thinking of just ordering a rebuild kit. Regardless of the kit it should be complete for this rear end right? I guess what I mean is that the drums and shoes it comes with (even though not the same as these) should fit the rear axle properly right??

woodsnake · Jan 3, 2013

Isn't there something special about the tapered axle tubes?

horse sence · Jan 3, 2013

they just use smaller leaf u bolts and they are narrower than the later rears

Realmongo · Jan 3, 2013

I believe the 1125 casting drums are for the front and the 1126 casting drums are for the rear.

65-Fstbk · Jan 3, 2013

The more I try to read into this the more confusing it gets. It seems that some 1965/66 cars came with 1 3/4" rear shoes and some came with 2 1/4" shoes. I'm not sure but I think the drum backing plate that's bolted to the axle is different for each type of drum (can anyone confirm). If my rear axle did in fact come with 2 1/4" shoes then I'm not sure if I can use a drum for 1 3/4" shoes as that drum may not mate properly with the drum backing plate. Weird. Hellllp.

Realmongo · Jan 3, 2013

All V8 cars with drum brakes had 10" x 2-1/4" shoes up front and 10" x 1-3/4" shoes in the back.
6-Cylinder cars had 9" x 2-1/4" up front and 9" x 1-1/2" in the rear except for convertibles which had 9" x 2-1/4" in the rear.

65-Fstbk · Jan 3, 2013

Realmongo said:
All V8 cars with drum brakes had 10" x 2-1/4" shoes up front and 10" x 1-3/4" shoes in the back.
6-Cylinder cars had 9" x 2-1/4" up front and 9" x 1-1/2" in the rear except for convertibles which had 9" x 2-1/4" in the rear.

Yeah I saw that in the Shop Manual. I had read that some cars (some K codes and GT 350's) came with 2 1/4" rear shoes but it's very difficult to find info online to confirm that. If all cars all came with 1 3/4" rear shoes then that would mean all of the drum 'backing plates' were the same I would think. So if I were to order a standard rebuild kit for my rear brakes (kit includes: drums, shoes, springs + hardware, wheel cylinders etc) the standard drums should mate up correctly with the backing plates right?

My concern is that the friction surface of the old drums that are on there now measure almost 2 1/2" across which makes me wonder if these were for 2" or even 2 1/4" shoes. If I turn the drum dish side up and put a tape measure into it the depth from the bottom to the top edge is 2 5/8". Does that sound like a drum for 1 3/4" shoe?

horse sence · Jan 3, 2013

the shelbys's had 2 1/2 inch brakes in the rear .the backing plate is different for the
2 1/2 inch. if the drums are the proper ones for the backing plates the lip on the drum will over haing the the lip on the backing plate when bolted tight about 1/8 -1/4 inch and will not rub when the axle is rotated. the difference between the 1 3/4 and the 2 1/4 brakes is in the step down on the drum at the wheel mounting surface . the wider drum is flater on the wheel mounting side than the 1 3/4 drum that is more bell shaped. it apears you have the correct matching drum and backing plate set up for the wider shoes. i will see if i still have the drums for the narrow shoes and take some pics tomarrow for comparison. the drum width is slightly wider than the actual shoe so it doesnt rub inside.

65-Fstbk · Jan 4, 2013

horse sence said:
the shelbys's had 2 1/2 inch brakes in the rear .the backing plate is different for the
2 1/2 inch. if the drums are the proper ones for the backing plates the lip on the drum will over haing the the lip on the backing plate when bolted tight about 1/8 -1/4 inch and will not rub when the axle is rotated. the difference between the 1 3/4 and the 2 1/4 brakes is in the step down on the drum at the wheel mounting surface . the wider drum is flater on the wheel mounting side than the 1 3/4 drum that is more bell shaped. it apears you have the correct matching drum and backing plate set up for the wider shoes. i will see if i still have the drums for the narrow shoes and take some pics tomarrow for comparison. the drum width is slightly wider than the actual shoe so it doesnt rub inside.

Thanks, much appreciated.

I called a local parts shop today and asked about new rear drums for a 65 Mustang. They told me there were either 2" or 1 3/4" drums for the car but when they checked into it the 2" came up as discontinued which would leave only the 1 3/4" drums. Very confusing considering how many of these cars were made.

Realmongo · Jan 4, 2013

I believe the Shelby's used the 10" x 2-1/2" rear drums from the 1965 Fairlane Ranch Wagon.

Ford P/N C3OZ-1126-A

Try NAPA 4401130

UPDATE: I confirmed these are the drums used on '65-'67 Shelbys.

horse sence · Jan 4, 2013

Realmongo is correct try a Nappa parts store they still carry parts for older cars.
auto zone and some others only carry parts for newer cars. Nappa usualy has what i am looking for.

65-Fstbk · Jan 4, 2013

There is so much conflicting info that I decided to take the backing plate off and look for a part number. Here is a pic of the backing plate. There is a FoMoCo stamped into it on one side and KH 70866 across from it, the KH I'm assuming is Kelsey Hayes.

I searched that KH number and found a Cougar site that had a couple. They state that they were for 1 3/4" brakes which I'm thinking is good news as I could just order the rebuild kit that comes with new drums for the 1 3/4" shoes. I can't seem to confirm anywhere that that's the backing plate for the rear on a 65 V8 Mustang though. Does anyone have a wheel & drum off at the moment (or one laying around) they can compare to.

In the pic you will see a red arrow pointing to the stamping on the backing plate. I think the depth of this stamping might be deeper than what is on a standard V8 car. Anyone know?

Realmongo · Jan 5, 2013

horse sence said:
Realmongo is correct try a Nappa parts store they still carry parts for older cars.
auto zone and some others only carry parts for newer cars. Nappa usualy has what i am looking for.

I found if I go with NAPA's higher line, I get the best items available (Federal-Mogul, Moog, etc.). With AutoZone, you never know what's in the box.

65 Rear End Question

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