Info on lowering, DJM beams, Hanger flip, axle shims

[Randle]

Thanks for the info.

[guhfluh]

I'm wondering if you ever looked into raising the hanger bearing? On my truck, it looks like I'll be able to raise it 1-2" just by replacing the stock drop bracket on the cross member, to a flat plate. I can't calculate the angle changes, but I think it should keep my front joint and shaft angle within tolerance and help reduce the angle on the rear shaft and joints angle.

[toddspeed]

Are you referring to an aftermarket spring hanger?

[guhfluh]

The center driveshaft support bearing.

[guhfluh]

For those with a two piece driveshaft who are flipping the front hangers and having pinion issues, raising the hanger/carrier bearing helps greatly. It took about 3-4° out of my rear joint angle and kept the front two within spec. Mine being a crew cab, and having longer shafts, should make less angle change than a regular cab long bed, but only slightly. I now have a 3.5* angle on my rear joint and the local OReilly Auto and Advance Auto both had 2* shims I can use on the axle to get the final setting.

[guhfluh]

Also, I have 2" drop rear shackles and didn't even do a complete half hanger flip, just moved the front hanger up the frame about 3". Those doing a full flip or even a half flip with a 2 piece driveshaft and no rear lowering shackles, I don't see how you can get the angles back to stock without raising the carrier bearing and still using very large axle shims or re welding the spring perches back on at the correct angles.

[jthulan]

Okay. I have a 71 long bed with a two piece driveshaft and the helper springs (flex-o-matic.) I have restored many vehicles, but have never lowered one. I am interested in lowering my truck, but only maybe 3-4 inches. It will become my tow vehicle to pull a trailer with a Gran Torino on it, so the helper springs will still come in handy.

I will be honest here and admit that I have read this thread a couple of times now and have some questions.
Front hanger, full flip, half flip, pinion angle under 3 is good, lowering shakel, moving the spring saddles....?
I have a basic understanding of pinion angles as the angle of the driveshaft compared to the twist of the differential, specifically at the u-joints. What I dont understand is the front hanger half flip vs full flip? If you flip the front hanger only halfway, would it even work???

From what I figure, if I want to keep my flex-o-matic springs without c notching my frame and still lower my truck a little, I should use lowering shakles, do a hlf flip on my front hanger and raise my hanger bearing.... Sounds all greek to me.

Please advise and educate.

[jthulan]

Saturday morning I will put the rear on jack stands and remove the rear wheels. I figure this will make it easier to slide off the bed. I will need to clean off the pumpkin and look for a tag. I would like to figure out if I have a 9" rear end or what I do have. Removing the bed will also allow me to get to the suspension, and probably install a 70 mustang gas tank.

[guhfluh]

There's a few other threads that explain the half hanger flip and full hanger flip with pictures. When the hanger is flipped, it raises the front spring attachment point and turns the pinion angle the wrong way for a lowered truck.

If you have a flexomatic spring setup, you have a unique rear spring shackle and can't use a rear lowering shackle. You have to change springs to use a lowering shackle.

If you only flip the front hanger, your pinion angle will be horrible. Raising the carrier bearing will help the rear driveshaft angles, but you will still need large degree shims under the springs to fix the pinion angle.

[jthulan]

Thank you for that information. I have never done this and am trying to figure it all out.

[BobbyFord]

Measure the pinion angle before performing any mods.