12 bolt axle position

[bbcmudtruck]

I need to weld new trailing arm saddles to my 12 bolt rear end. It is the correct rear end, however the previous owner had cut the original trailing arm saddles off and welded leaf spring saddles in their place. Well I'm switching back over to a coil spring frame and have come across a potential problem. If I locate the axle saddles in the stock position, the pinion is located towards the passenger side of the vehicle by about an inch or so. I understand that the pan hard bar is supposed to pull the axle back over to the driver side in order to center the axle to the frame. My question is this: Can I slide both of the saddles over a little before I weld them on? My thought is that welding them in the stock location and then pulling the axle over with the pan hard bar will create tension on the coil springs as well as the trailing arm bushings. I don't understand why you would want to put stress on them? I've dug through the archives and managed to find this thread asking about this issue. There was never a solid solution or answer given though. Here is his picture of exactly what I'm talking about. Thoughts?

http://67-72chevytrucks.com/vboard/a...1&d=1412717695

[SCOTI]

I would install the mounts w/the rear centered in the frame. Where does that put the drive shaft? How much difference would there be @ the mounting positions if you compared each side.

Then, I would utilize an aftermarket long Panhard bar that's is installed parallel to the ground @ ride height vs how it was installed from GM.

[bbcmudtruck]

Thanks for your help Scotti! If I centered the axle in the frame, the drive shaft will be offset to the passenger side around an inch or so. I don't have any weight on the frame, so I don't know exactly what will shift, if anything? I have 6" rear lowering coils on the rear with ECE trailing arms, trailing arm cross member and CCP tubular shock tower. I also have the ECE super track bar along with their shock relocation brackets. I think what I'm going to do is set the bed on the frame and see where the axle ends up with the saddles in the stock location. At least I'll be able to find out if the tires end up in the same location in relation to the wheel tubs. Any other ideas?

[crazy longhorn]

Originally Posted by bbcmudtruck

Thanks for your help Scotti! If I centered the axle in the frame, the drive shaft will be offset to the passenger side around an inch or so. I don't have any weight on the frame, so I don't know exactly what will shift, if anything? I have 6" rear lowering coils on the rear with ECE trailing arms, trailing arm cross member and CCP tubular shock tower. I also have the ECE super track bar along with their shock relocation brackets. I think what I'm going to do is set the bed on the frame and see where the axle ends up with the saddles in the stock location. At least I'll be able to find out if the tires end up in the same location in relation to the wheel tubs. Any other ideas?

With the rear centered, the pinion will be slightly to the pass side (3/4 " or so).....that is with the wheels centered. As far as the track bar, check that @ ride height, with all the weight on the wheels? Longhorn

[SCOTI]

Originally Posted by bbcmudtruck

Thanks for your help Scotti! If I centered the axle in the frame, the drive shaft will be offset to the passenger side around an inch or so. I don't have any weight on the frame, so I don't know exactly what will shift, if anything? I have 6" rear lowering coils on the rear with ECE trailing arms, trailing arm cross member and CCP tubular shock tower. I also have the ECE super track bar along with their shock relocation brackets. I think what I'm going to do is set the bed on the frame and see where the axle ends up with the saddles in the stock location. At least I'll be able to find out if the tires end up in the same location in relation to the wheel tubs. Any other ideas?

If it were me.... I would use OE dimensions for the saddles. Bunch of these T/A set-ups that have 6-8" rear drops still running around utilizing those dimensions w/o issue. If I recall, my 68 & now the 64 weren't centered in the T/A x-members loop (the 68 was the OE x-member, the 64 uses a modified ECE unit). The 68 was 7-8" rear drop. My 64 is modified a little more extensively (more drop) but the d-shaft was @ about the same placement because of how I did the mods.

I never had an issue w/my 68 touching in 6yrs of daily use.

[bbcmudtruck]

Sounds good fellas. I'll mock the saddles up in the stock location and set the bed on. I guess I could go ahead and mount the transmission up and see how the driveshaft will pass through the cross member as well. So far I've put my frame together and taken it apart at least 50 times hahaha. A simple frame swap turned into a complete frame off resto-mod.

[SCOTI]

Originally Posted by bbcmudtruck

Sounds good fellas. I'll mock the saddles up in the stock location and set the bed on. I guess I could go ahead and mount the transmission up and see how the driveshaft will pass through the cross member as well. So far I've put my frame together and taken it apart at least 50 times hahaha. A simple frame swap turned into a complete frame off resto-mod.

Wait..... There's other ways to do it??

[bbcmudtruck]

Well, not that I'm aware of! I had to buy a complete $500 68 short bed in order to get a frame. Once I got the donor truck striped down, the frame was less than desirable... Lots of rust that I simply couldn't ignore. A year and a half later and I now have a frame almost ready for sand blasting and paint. A $500 dollar frame has cost me nearly $2000 and its still not done. I lack the ability to do anything half assed, at the same time I lack the ability of knowing when to stop and call it good. I really do appreciate the help you guys have given. I'll post updates as I make progress.

[SCOTI]

Originally Posted by bbcmudtruck

Well, not that I'm aware of! I had to buy a complete $500 68 short bed in order to get a frame. Once I got the donor truck striped down, the frame was less than desirable... Lots of rust that I simply couldn't ignore. A year and a half later and I now have a frame almost ready for sand blasting and paint. A $500 dollar frame has cost me nearly $2000 and its still not done. I lack the ability to do anything half assed, at the same time I lack the ability of knowing when to stop and call it good. I really do appreciate the help you guys have given. I'll post updates as I make progress.