My Rear End

	My Rear End! Update-Update 3-16-02: Misinformation is really out there, be it the Web, newspapers or Magazines! Take Hot Rod March 02, Pit Stop! (please!) Not only is the writer obviously Prejudice, referring to a Thunder Bird as a "Chicken Bird", but can he be also ignorant, or misinformed, or doesn't give a dam, or Prejudice, (sorry, I already mentioned that) or what? Not only didn't he provide information on really how to over come problems that were fixable, but he actually said that the T-Bird's axle width was a "whopping 3.375" wider" that a Mustangs! When it is only 1 1/2" wider! Readers, beware!!! Update 2-16-02: It's finally in! A couple surprises tho! I can't have been the first to do this combo, but I never heard of these problems, but they are fixable! The 1st is because of the 3/4" inset but not sure if this had anything to do with the 2nd one! The flex line to the Caliper was pinched between the Caliper & shock, taking the "float" out of the Floating Caliper! Fix was to drill a new 1/2" hole inward for the lower shock mount. But this area isn't flat & may not stay tight for the long run! The "fix-fix" is to get a lower shock mount adaptor which is "U" shaped, from a T-Bird or such, & weld in on. (This "pinch" may have been what happened to the T-Bird mentioned below) Another way (if it's not 11 PM & 30 miles from home when you discover this) is to use a brass adaptor block at the caliper & a non stock flex line with both ends flared tubing. Or, the 89 Taurus, 90 Continental, etc., FWD with rear DB's, have long Flex Lines that should be useful! Then the two adaptor to caliper bolts (15mm socket) stick through about 1/4" & can jam the Rotor! The rotors can vary in fit so some will clear & some will not. So be sure to trim them back! Will be checking out some production Mustangs with rear DB's to see how they got around this. Alltho some Lincoln Emergency brake cables can be used, it is hard to secure the outer sheath well. Looks like it's best to use the Turbo-Bird E-Cable by cutting it's long cable & reswaging the end. More on this later. And it really stops better! Also know it because the rears locked-up in the rain, never did that before! Good (a must!) to have the adjustable proportioning valve! Now to up-grade the fronts! ------------
	The 7.5" 3.27 was a bit noisy at 140k miles when I got my "new" LX, & now with 190k, it is definitely irritating at all speeds. Have to be careful when shifting into OD as it really "bangs" at light throttle & especially if it shifts as I am letting off the gas! This happens because of the extra slop in the gears which is ampfiled when the AOD goes into OD, as it is then directly, mechanically coupled. The other gears are coupled through the torque converter which is oil coupled & mushier.
	The 7.5 should run into the mid 90's, 1/4 mile, if used without slicks. But being weaker than the 8.8, it doesn't last as long even on the street or is as quite as a 8.8 .
	Hot up-date from Binnie: The 7.5 was improved about 87 (Explorer?) with a stronger "S" clip, Spider gears, & Track-Lock!
	They used to say it was cheaper (& more reliable) to buy a Ford Motorsport SVO 8.8" complete housing assembly, (less axels & brakes) than to rebuild one to get a different gear ratio.
	But finding one in the junk yard is defiantly cheaper & more rewarding. The easiest (relatively speaking) is from the 87-88 Turbo-Coupe T-Bird which most always will be a 3.55 (or 3.73, but rarer, with Automatic?) & many with disk brakes to boot!
	But Ford had to make the T-Bird look bigger (and/or was it to make room for the ABS sensor?) than the Mustang & one way was with a wider track. This was accomplished by adding 3/4" to each axle. This make for a tight fit on a Mustang or LTD running stock Mustang 7x15's & 225-60-15's. For this combo to work, about 3/4" must be removed from the inner wheel opening, or use inset wheels, or maybe install a "panhard bar" to keep the rear end from moving sideways during cornering!
	Another way around this without removing sheet metal & keeping the Disk Brakes, is to replace the DB mounting bracket with a Motorsport SVO Mustang bracket (M-2C100-B, RH & M-2C101-B, LH) which has an off-set which moves the caliper inward 3/4" which then allows you to use your original 7.5's (also Mustang 7.5 & 8.8's) shorter axels. The early version doesn't have provision (tabs) for mounting dust shields! The Fox 7.5 & 8.8 share the same axles (Mustang/LTD), axle bearings & axle seals which is convenient, but a weakness to be aware of is that they don't use a pressed on bearing race at the wheel end. The bearing rides directly on the axle so when wear occurs, the axle & bearing must be replaced together. The bearing is pressed into the rear end housing & takes a special puller to remove it as it's pressed in very tight. While I don't care for the "C" clip axle retainer, it's again convenient that the axels are the same length, where the 8 & 9" were a different length, left & right. This "C" clip isn't safe to use for serious Road Racing or High Speed Drag Racing. A kit is available, M-4220-A, that locks the bearing to the axle so if the axel breaks it won't come off the car along with the wheel. This is the way the 8 & 9" rear ends are made & one reason why they are so popular!
	The T-Bird rear end can also be used with your original Drum Brake assy & Axles. Even the T-Bird's rear drums are different, 3/4" deeper reach, (but still only 9" while the LX, station wagon or Police is 10" dia), in order to reach the shoes due to the longer axles. The Mustang/LTD/T-Bird rear end measures 54 1/4", housing flange to flange. Will be checking the Lincolns soon.

	The Residual pressure valve spring in the brass Metering/Distribution block, needs to be changed from the 10 lb pressure one in the car now, that keeps the slack out of the mechanical brake shoe mechanism, to a 2 lb one found in the Turbo-Bird with rear DB's. The spring is behind the front plug with the rubber nipple. Make sure the piston shaft fits into the plugs rubber nipple port to seal it or the nipple will blow out & you will lose half your brakes. This would not take much pressure to blow out & will almost certainly happen during the bleeding process if it's not assembled properly. Since the LTD is lighter than the T-Bird, you will also need to add a Proportioning Valve M-2328-A or M-2328-C, so you can reduce the rear braking pressure to prevent lock-up. An easy (relative again) place to put this is next to the right (passenger) side hood hinge. There is already a brake line coupling there. I'm going to try mounting mine under the car with the Knob sticking through the floor so I can easily make adjustments while driving.
	The 86-95 5.0 HO Mustang also had a 8.8 but with 2.73 was the standard ratio with 3.08 (& maybe 3.27?) optional. About the early 90's(?), Rear Disk Brakes were available as an option on regular Mustangs.

	The code for a Track-Lock 7.5 & 8.8 with 2.73 is "M"; 3.08 is "Z"; 3.27 is "E"; 3.55 is "K". 3.73 & 4.11's weren't available from the factory. None TL's, 2.73 is "8"; 3.08 is "Y"; 3.27 is "5". No 3.55 non TL's.
	Want more choices? The 8" & 9" with the 3th member "pumpkin" can be modified for the "Foxes". The 62-65 Fairlane & 75-79 Granada 8" is 58" axle flange to flange, while the Fox Mustang/LTD is 59" & T-Bird 60 1/2" So with this 8" you can gain wheel clearance using stock axles. Also the 57-58 Ford & Lincoln Versailles (with DB's) have a 9" that's 58". But while the 9" is stronger, it's heaver & it isn't as efficient & will cause a small drop in MPG & speed in the 1/4 mile.
	DISK BRAKE DRAG? Yes there is a bit of drag compared to really no drag for drum brakes. But if it were really bad, wouldn't the factories have done something if it were affecting the MPG ratings? But then one notices when changing wheels or working on the brakes, that one can hardly rotate the wheel due to the DB drag! What has happened is that the brakes were used to fully stop the car & there isn't a return spring to pull the pads away from the rotors. The seals have a little pull-back effect on the piston, but not enough. But upon driving the car again, the Rotors (due to the heat) have a "wobble" which pushes the pads back just a bit & eliminates most of the drag. A way to check this out is when the tires/wheels are balanced on the car & compare the before & after drag. The Turbo-Coupe with Disk Brakes has a added brace which goes from the caliper to the axel housing where it is welded on. At first I though is was because the DB's produced more force in braking but that's not true because more force than the Drum Brakes would cause the rear wheels to lock up! Disk brakes do produce more uniform braking & are much less affected by water! So apparently what happens is the rotor develops a "wobble" from heat, & the vibration can weaken/break the 4 bolt flange. I once found a mid 80's, 5.0 T-Bird with a SVO aftermarket 8.8" 3.55 with Disk Brakes upgrade, without the added bracket, which had broken the 4 bolt flange & the "nut" kept driving it till the brake line was severed, between the Shock & Caliper, causing a crash! So if you add DB's to a 7.5 or 8.8, be sure to add a brace too. Now, if you want to experiment, get a M-2450-A, "Plug, Fixed Proportioning Valve". With this you can do without the inner spring & piston. You most likely will have a bit softer peddle as there is no residual pressure, but you will most likely also have no pad drag on the rotor. Just what you want for Racing? Found one of these solid plugs at the junk yard, but don't remember on what car!