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9 inch brake offset - very confused

 
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Old 03-03-2009, 02:46 AM
patience
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9 inch brake offset - very confused

I'll admit to being a little new to the whole 9 inch discussion, but simply, here's the problem: The brake offset (or do you call it the axle flange offset?) on my 9 inch is 2.00". And I don't understand why.

The details - I recently bought a 1956 F100. The rear end has been replaced with a 9 inch. The axle tag indicates that this is a 9 inch taken from a '69-'71 Mustang, built in November of 1968. It is supposed to have a 28 spline, and I have confirmed that by removing the axle and counting the splines. I expected it to have a small bearing, but it does not. I made all the measurements and it definitively has the larger bearing (not the later Torino bearing). Because of this I expected an axle offset of 2.36". It is not. I measured from the outboard surface of axle flange to the outboard surface of the wheel stud flange (the surface that the wheel gets mounted up to), and it is exactly 2.00" (on both sides).

So what gives? I pushed the axle all the way in unti it bottomed out, and the wheel bearing is sitting flush with the axle flange. I have removed drum brake backing plates, etc. and used a caliper to make the measurement. The only thing I can figure is that this is a non-standard housing? I noticed that the axle flange has been welded on on both sides. Is it possible someone replaced the original small bearing axle flange with a large bearing axle flange, and why would they do that?

The reason I discovered all of this is I was replacing the wheel cylinders (which blew out), and then realized that all the parking brake hardware was missing. I still haven't found the parking brake hardware (someone said to check with Rocks Ford Goodies or Napa) so I was thinking about upgrading to rear discs, but in order to get all the right hardware, I ended up having to figure out my brake offset, hence this thread.

Thanks for reading all of that (if you're still with me). Any enlightenment greatly appreciated.
 
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Old 03-03-2009, 07:35 AM
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You may want to try a google for Kevinstang 9" for 9" rear info.
 
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Old 03-03-2009, 09:28 AM
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Patience,
(good name for this hobby!) Are you refering to the fact that the rear end pumpkin is offset to one side, making the axles two different lengths?
If so, no worries, the passenger car rear axles were built that way to give a little more space to the driver's side of the driveshaft tunnel. Pickup truck 9"ers are symetrical side to side since they do not have a driveshaft hump. Both work equally as well as a replacement in our trucks.
 
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Old 03-03-2009, 05:34 PM
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First let me say welcome to the board! Secondly, what bolt pattern are the lugs? 5x4.5" would be car, and 5x5.5" would be truck typically.
bare housings for mustangs widths:
65-66 Mustang 52.25 inches
67-70 Mustang 54.25 inches
71-73 Mustang 56.25 inches

they all had small bearings. The four bolt holes are 3.312" x 2.00". Is it possible this rear end was from a Galaxie or some other full size? Most big bearing axles had 31 splines. Since someone put it under a '56 f100, any mods could have been done.
 
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Old 03-03-2009, 05:52 PM
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OOPs! sorry, I misread your question NEVERMIND!
 
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Old 03-03-2009, 05:55 PM
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Originally Posted by patience View Post
but in order to get all the right hardware, I ended up having to figure out my brake offset, hence this thread..
Are you sure?

From the net (on eBay);

9 Ford Rear Disc Brake Conversion Kit
It will fit any of the 9 rear ends that have the LARGE BEARING, 3.5 x 2.375 or 3.5 x 2 flanges with either .375 or .500 t bolts. Another plus to the kit, you can run either the Ford or Chevy bolt pattern as our rotors are drilled for both 5 x 4.5 and 5 x 4.75
Im sure that you can get all the hardware from NAPA or from a parts car, but a curious mind wonders why the PO left it out?

More misinformed and misguided information available upon your request!
 
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Old 03-03-2009, 05:55 PM
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Originally Posted by havi View Post
First let me say welcome to the board! Secondly, what bolt pattern are the lugs? 5x4.5" would be car, and 5x5.5" would be truck typically.
bare housings for mustangs widths:
65-66 Mustang 52.25 inches
67-70 Mustang 54.25 inches
71-73 Mustang 56.25 inches

they all had small bearings. The four bolt holes are 3.312" x 2.00". Is it possible this rear end was from a Galaxie or some other full size? Most big bearing axles had 31 splines. Since someone put it under a '56 f100, any mods could have been done.
Thanks for the welcome, the posts I've been reading have been extremely helpful already. The bolt pattern is 5x 5.5", which is what makes me think someone has swapped axle flanges on it. The four bolt holes on the flanges are 3.5" x 2.375" which is definitely the big bearing. But it's a 28 spline and the axle tag says it's a 69-71 mustang. I'm not at home right now, so I'll have to measure it later, but definitely there are welds just inboard of the flanges, suggseting that this is a hack job.
 
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Old 03-03-2009, 06:15 PM
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What exactly does the tag say? Indications to me make me think it might be a truck 9" from 57-72. Is there a drain plug located anywhere?
 
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Old 03-03-2009, 06:24 PM
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Old 03-03-2009, 06:31 PM
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Originally Posted by havi View Post
What exactly does the tag say? Indications to me make me think it might be a truck 9" from 57-72. Is there a drain plug located anywhere?
Looking at the rear of the pumpkin, you can see two dimples and the drain plug. No traditional hump in the middle, which suggests this is an earlier 9 inch. The axle tag says WES-AA 8KB on the top line and 3 00 952A on the bottom line.
 
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Old 03-03-2009, 06:32 PM
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Originally Posted by Old F1 View Post
Are you sure?

From the net (on eBay);



Im sure that you can get all the hardware from NAPA or from a parts car, but a curious mind wonders why the PO left it out?

More misinformed and misguided information available upon your request!
Actually, it's mostly about getting the right spacers. The disc brakes aren't so much the challenge anymore. I'm just trying to figure out what weird Frankenstein rear end I have.
 
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Old 03-03-2009, 06:46 PM
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Sounds like an early Galaxie or similar pre-66. Large bearing, 28 spline, and 2 dimples with flat face and drain plug (not oil level hole) Are the shafts tapered?

Of course if you can find any Ford part numbers, that might help. IE C9AE- on the pinion snubber or something. The tag doesn't jibe with the rest of the 9" parts.
 
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Old 03-03-2009, 07:17 PM
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One more thing is that the likelihood of the 9" drain hole on the back is actually an oil level hole. This would be more in tune with the rest of the info provided. It would include most full size cars 64-71, galaxies 61-67, and pickups from similar years. The cars had a 61" width and the pickups had a 61.25" width. So an accurate measurement would help. The mustang axles had an oval hole for the 28 splines, and the 31 splines had 2 opposite holes with a countersink in the center. All of the google searched sites provide the same info only rehashed in different ways. So who do you trust? That's the biggest question thus far. Either way, there are some things that can be figured out. First would be measuring the thickness of the axle tubes, bearing sizes, housing width, overall width, and a picture of the back of the center section showing the dimples and plug. Loaded with all of this, we can figure out your rear end. (I've been measuring a few myself)
 
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Old 03-03-2009, 07:34 PM
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Originally Posted by havi View Post
One more thing is that the likelihood of the 9" drain hole on the back is actually an oil level hole. This would be more in tune with the rest of the info provided. It would include most full size cars 64-71, galaxies 61-67, and pickups from similar years. The cars had a 61" width and the pickups had a 61.25" width. So an accurate measurement would help. The mustang axles had an oval hole for the 28 splines, and the 31 splines had 2 opposite holes with a countersink in the center. All of the google searched sites provide the same info only rehashed in different ways. So who do you trust? That's the biggest question thus far. Either way, there are some things that can be figured out. First would be measuring the thickness of the axle tubes, bearing sizes, housing width, overall width, and a picture of the back of the center section showing the dimples and plug. Loaded with all of this, we can figure out your rear end. (I've been measuring a few myself)
Havi, you are a star. You're right, I mistyped. The hole in the back is the oil level hole. Here's the crazy thing. The axle end has the 2 opposite holes with the countersink in the middle, but it's definitely 28 spline (I went blind staring at them). My google searching seemed to indicate that they had the 2 opposite holes w/countersink was occasionally used on 28 spline, although more commonly it was for the 31 spline.
 
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Old 03-03-2009, 07:35 PM
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I'll measure up the rest tonight. Any online resource you know of with all these measurements indicated? (P.S. I don't think mine was tapered either, but I'll have to double-check).
 

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