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Rear Suspension rebuild.
So what is involved with doing a rear suspension?

[Image: 100_1305.jpg]

first i had never worked on a rear suspension or 3rd member in my life. This was my first experience.


my steps:

jacked up car and inserted jack stands under the rear frame just inside of the front bolts to the leaf spring mount. this let the rear axle hang down free.

1)pulled out drive shaft.

2) took apart the rear drum brakes totally(i had serviced these the year before so it was easy for me to take them apart since all the parts were new.

3) pulled the drum backing plates 4 bolts per side, disassembled the brake lines (brake lines were also replaced previously making the job easier. loosened the parking brake cable and pulled them out of the backing plates.

4) pulling the backing plates off the axle ends gains access to both axle shafts from the rear axle housing. inspected bearings both were good.
removing the shafts allows access to the diff itself.

5) pulled out 3rd member(pumpkin) made a huge mess and the smell of diff fluid is horrible. The pumpkin weighs about 100 pounds its extremely heavy and dangerous to remove when using jack stands due to the clearance. I had help and used a floor jack to support the front of it. after removing the nuts i pried it loose and slowly inched it onto the jack. dealing with the weight of the 3rd member was by far the hardest part.

6) with the rear axle now stripped i loosened and removed the U bolts.
this left the rear shocks dangling with the mounts attached. the now empty axle case was then easy to grab and remove from the leaf spring perch.

7) next i removed the rear shackles 2 nuts per-side droping the rear leaf springs on the ground. I had a lift kit that was installed in the past, it was removed and thrown out. i pulled all the rubber bushings.

8) next can be another difficult part removing the front bolts for the leaf springs, these are usually frozen up, worst case scenario you will need to use a hacksaw blade or a power tool to cut the bolt to get get the front of the leaf out. in my case i was lucky a little work with the mapp gas torch and a breaker bar and i managed to bust my bolt loose. getting the leafs out was then easy.

9) working inside the car i pulled out the rear seats, pulling up the rubber floor plugs allows access to the top of the shocks. check for major problems here as rust can destroy this area, my car was previously repaired with steel plates in this area. i was able to easily pop out both shocks.

10) the rear end is now stripped.

11) take stock of what you want to replace.

i ended up ordering all new hardware from AMK.
i bought all new Rubber Bushings, not Poly, i felt poly while stiffer was going to make my rear end squeak like crazy, so rubber it is.
bought new shocks, a rear sway bar, and new oem length shackles.

i then media blasted all the small parts, and wire wheeled all the large parts.

I bought a new set of rear leaf springs which hemikiller had recommended, however it turned out my original leaf springs were much beefer then the catalog replacement 351 boss springs. i opted to keep my original springs which were in good shape. i just repainted them.

i carefully masked off the 3rd member housing so the mating surfaces were clear of paint then from bare metal i primed and painted using SEM trim black, semi.

new cork seals all around from feltpro and used an OEM cork seal for the 3rd member and again used AMK for all the hardware.

the shock mounts were media blasted and painted using eastwoods bare metal gray.

the 3rd member was sent out to check for wear and lash and a new pinion seal, when returned i let a friend dress the 3rd member to new condition in the paint department.

the drive-line was then also wire wheeled to bare metal and i dressed it using eastwoods bare metal gray and some GM red engine paint that i liked the color of for the yoke and roller bearing mounts.

I had a huge mess trying to get the correct roller bearings for the yoke and drive line, the catalogs all list the incorrect part #s. i ended up buying almost every roller bearing on the market until i came across one with the correct dimensions. since there is a lot of variation and my C6 yoke and drive-line was not original to the car your luck might be better then mine.

after deciding on reusing my original leaf springs i checked the front eyes rubber mount for any deterioration, it was actually in near perfect shape so i reused it, otherwise i was ready to replace it with the correct tool to pop a new one in place.

i took the time to inspect the rear frame rails for structural issues, i then lightly cleaned the chassis up and repainted the areas i was working in.

since i had the opportunity, i also replaced the fuel tank, fuel sender, fuel tank vent line and main fuel line, and restored the original fuel tank top vent to be reused. in the pictures you can see the new tank installed.

having nothing in the way to work in that area lends itself to the perfect time to replace your tank with a new one. the fuel and vent lines i replaced the original ones with is stainless steal. the fuel and vent line went in easy and i didn't have any issues just re-bending them slightly here and there for a better fit.

ok so now lets put it together.

1) installed front leaf spring mount, install new bolt, torqued to spec and installed new rubber plug in access hole (original was missing)

2) installed new rubber bushings in the leaf spring rear mount. used a rubber mallet to install them. installed new rubber bushings in rear frame rails for shackles.

3) new shackles slid halfway into place i used a little graphite grease to easy things up, the leaf is lifted into place and the shackle is then pushed into the leaf and the rear frame rail through the bushings.
shackle plate then installed and 2 nuts torqued to spec. for both sides.

4) both leaf springs are now attached to car

5) axle case placed into springs perch. (center rivet for leafs fits into a little hole in the axle mounts to hold it in place)

6) shock plates, new u-bolts, new nuts installed and torqued to spec 8 nuts 4 u bolts. (in the pictures i began to install a adspec rear sway bar kit, i did not use it. i had interference issues with the fuel-line and was not impressed with its design, i later removed it)

7) the axle is now secured to the leaf springs.

8) next i slid the axle shafts back into the case with new feltpro gaskets, careful remember which one is right and which one is left.

9) next i setup for install of the 3rd member i preped the mating surface and used gasket maker all around, next the 3rd member was jacked in place, and after nearly killing 2 people we got it back on the axle studs and got it in place, all the nuts were then replaced from AMK and torqued to spec where they could be,, the top of the axle is very hard to access.

10) reassembled the drum backing plates on one side torqued to spec.

11) reassembled all axle bolt on parts, brake lines, vent and vent hose.

12) due to the fill hole on the axle being hard to access working as i did. I jacked the car up diagonally lifting up the one side with the shaft i left loose, and proceeded to fill the 3rd member with the correct amount of diff fluid and traction fluid (i have a posi rear)

13) with the car still angled i completed installing the drive shafts torquing everything to spec, Yippy no leaks.

14) drum brakes dressed again and re-assembled.

15) with the entire rear axle assembled i then jacked the axle up a little to make installing the new rear shocks easier to bolt to the leaf spring mounts and up into the chassis behind the rear seat.

16) checked my brake lines and adjusted my drums, then re-bleed the brakes system. remember to check for leaks.

17)rear seat reinstalled.

18) brakes, axle, 3rd member, shocks, springs all done, the re-dressed driveline was re-installed the rear tires re-installed and the engine started to take her for a spin.

total time, a few days spread over 3 months, had lots of trouble with backordered parts, and it took hours to strip all the metal down and repaint everything.

took about 4 hours to disassemble everything frozen bolts will hold you up.

once i had all the parts i was able to assemble the rear axle and suspension in one day.

if you want to rebuild your rear suspension quick and have all the parts it can be done within 8 hours. i recommend a helper to help with either the pumpkin itself or lifting a completed axle all at once into the leaf springs. your dealing with a lot of weight so be careful.

I'm sure i overlooked something or made a slight error this is not a bible just to give a general idea of what is involved.

have fun Smile
Instead of waiting another 17 years to retire, I've decided to collect all of 72HCode's posts and publish them as the "Layman's Guide to Working on Your Mustang While Avoiding Most of the Headaches". It'll come in both hardback and softback editions with a CD of early '70s songs (or whatever suits your fancy).

See you in Aruba next November.... Big Grin



[Image: 6y14ea.jpg]

Project started 8-7-10
Completed: All new suspension, rebuilt 351C H Code bored .030 over with mild cam and intake, new 3.50 TracLok, custom exhaust system
Current "mini-project": interior upgrade Undecided
LMAO!! No kidding.

BTW - Nice write-up, 72HCODE. It'll come in handy when I finally make it back there again.


[Image: mach1sig2.gif]
Wow this is a great write up. You're right about the stink of the diff fluid. I'm still in the "remove the rust on the underbody while all the stuff is off the car" part of the rear end work, but will use the reassembly instructions when it's time.

Thanks again for the steps....


1973 Mach 1 - Medium Bright Yellow - (in restoration mode)
X3 on gear lube smell.

One suggestion on the 3rd member... If you are removing the entire axle, wait to remove the 3rd until the axle is out and install the 3rd before you reinstall the axle. If you roll the axle in on a floor Jack with the front of the springs mounted then attach the u-bolts and spring plates. after the axle is on the springs jack the rear end up and attach the springs to the shackles.

It'll save busted knuckles and the gear lube bath.

BTW gear lube is the only auto smell my wife knows INSTANTLY!

Jeff T.

Low buck, touring style, '73 Convertible "rolling restoration", 351c, 2v heads with a shave and a haircut, Performer intake, Holley 650(ish), roller rockers, screw in studs, guideplates, stainless valves, Duraspark / Motorsports MSD, T-5 conversion. 1-1/8" front, 3/4" rear swaybars KYB shocks and some home brewed subframe connectors. Future plans; JGC steering box, Cobra brakes and... paint, interior, etc.

When I die I want to die like grandpa, peacefully in my sleep... not screaming, like his passenger.

[Image: 1_12_09_14_10_15_11.png]
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