[Miguel Duncan (Cmduncan)]

I need to replace the rubber shackle bushings on my 72 Challenger rear leaf springs. Does anyone know where the spring equilibrium point is with the front of the spring still attached to the frame? That is, how far should the axle drop down to not put the shackle "U bolt" in compression or tension to make it easy to pull out of the rubber bushings. Is it above or below the shock full length extension stop? Do I really need to disconnect the shock from the lower stud to let the axle drop farther to reach equilibrium?

[Dave-R (Roppa440)]

Take off the lower shock bolt and pull the shock off it.

[Dave-R (Roppa440)]

I have more time for a fuller answer now.

If you want to do this with the springs still attached to the axle;

Disconnect the shocks from the axle and support the body so that the axle can drop down as far as it will go when unsupported. Watch out for the brake lines. Then with your trolley jack under the diff just take a bit of the weight. Lift it about an inch. Then remove the rear spring shackle bolts. It might be a good idea to put them back in before doing the front spring mounts if you are doing them as well. Replace the original rubber bushings with polygraphite and the axle will not flex side to side so much.

If you want to remove a spring completely to do the job support the axle just the same and remove the U-bolts first. You might need to replace the original U-bolts if you do this though.

[Miguel Duncan (Cmduncan)]

Thank you for the additional words..... I was waiting for the other "shoe to drop". You answered my question. You are saying the spring equilibium point is with the axle farther down than the connected shocks will allow. Putting it back together should be easier because you know exactly when the shackle holes line up with the spring loop and frame tube.

I have already bought the Mopar Performance rubber bushings as I had heard that the ride would be too jarring with the polyurethane/graphite. However, it is good to know you recommend them. I thought I would wait on the forward bushings as they look like they would be difficult to get off and remove the old bushings and insert the new bushings.... any tricks there to make it easier if you don't have the special tool shown in the shop manual? Again, I thank you Dave for the detailed instructions.

[Dave-R (Roppa440)]

Best to take the spring off completely to remove the front bushes. I cant remember how I did mine but I dont remember having any trouble. If you do have trouble just set fire to the rubber with a gas torch and they will push out easy like soft soap. The amount of heat needed will not effect the spring.

When I think about it I remember when I put them back in I attached the REAR of the spring first because it was easy to lift and then used a jack to lift the front of the spring into place. The axle you can leave sitting on stands but if you take both springs off at the same time support the nose of the diff with an axle stand or wood or something to stop it dropping.

The people that claim the poly bushes give a 'harsh' or 'jarring' ride are the same soft arsed people that think a car rides better with no sway bar and the shocks removed.

[Hans (72challenger)]

These people better sell the Challenger and buy an old 'duck' (citroen 2cv) Dave!

[Dave-R (Roppa440)]

Oh now there's a car with a 'nice ride' Hans!

[Alex (Alex)]

Ciroen DS fantastic ride!

[Dave-R (Roppa440)]

I was in an old Citroen SM once with a 3L maserati (how do you spell that?) V6 i think it was. Bloody good looking car at the time and pretty quick too.

But we digress..