Rear Leaf Spring Block Removal

WS6FirebirdTA00 · August 21, 2018

I figured I would share dropping the rear of my truck. Searching I couldn’t find all the answers easily so hopefully this will help others.

While replacing my center caps to the black logo, I removed the rear leaf spring spacers to level out the truck more. I did not want to raise the front without bigger tires. Since mine are brand new that option will have to wait.

I ordered some 2WD ubolts and reused the original nuts and washers. The part number is 15002781 and a set of 4 is around $50.

I had to have the rear end off the ground and use a jack under the rear to remove tension from the lower shock bolts to remove them. The rear would not drop enough without doing this. When reinstalling, the torque spec is 85 ft-lbs.

I actually had to knock the driver side block out by prying, but the passenger side came fine. It was simply stuck on there from being clamped. I pushed up on the leaf spring enough to pop it out. Put it all back together after lining up the alignment pins by first going to 59 ft-lbs, backing off 180 deg, torque back to 59 ft-lbs and then tightening another 120-140 deg (GM spec).

One concern I had was pinion angle, but from what I read 2WD does nothing different for the lower height/pinion angle (could be wrong, maybe the blocks are tapered?) plus a loaded up truck would be in a similar situation with a lot more driveline stresses. I measured a 0.5-1.0 deg change in driveshaft angle but don’t have a good flat rear reference (that I know of) to check the rear/calculate the total angle. Stupid me never checked a general reference point to see how that angle changed.

The rear fender height is 38.5” or so and front is 36.25”. Still has a nice rake to it and looks more “normal”. I don’t plan to haul heavy loads so this works for me. Total drop was around 1”. I am trying to find exact measurements from pics I from last week but my network is acting up. If anyone can measure their drivershaft angle vs. the lower driver rear end rib that would help. I would be interestsd to know the total pinion angle change.

I will try to get better after pics (and a few before).

Another unaddressed concern was the shock travel with the lowering which may not be of any concern, but if so I see as low risk.

Curious if anyone knows the 2WD bump stop part number and if it is different from the Z71 package.

Thanks.

Sierra706 · August 21, 2018

I figured I would share dropping the rear of my truck. Searching I couldn’t find all the answers easily so hopefully this will help others.

While replacing my center caps to the black logo, I removed the rear leaf spring spacers to level out the truck more. I did not want to raise the front without bigger tires. Since mine are brand new that option will have to wait.

I ordered some 2WD ubolts and reused the original nuts and washers. The part number is 15002781 and a set of 4 is around $50.

I had to have the rear end off the ground and use a jack under the rear to remove tension from the lower shock bolts to remove them. The rear would not drop enough without doing this. When reinstalling, the torque spec is 85 ft-lbs.

I actually had to knock the driver side block out by prying, but the passenger side came fine. It was simply stuck on there from being clamped. I pushed up on the leaf spring enough to pop it out. Put it all back together after lining up the alignment pins by first going to 59 ft-lbs, backing off 180 deg, torque back to 59 ft-lbs and then tightening another 120-140 deg (GM spec).

One concern I had was pinion angle, but from what I read 2WD does nothing different for the lower height/pinion angle (could be wrong, maybe the blocks are tapered?) plus a loaded up truck would be in a similar situation with a lot more driveline stresses. I measured a 0.5-1.0 deg change in driveshaft angle but don’t have a good flat rear reference (that I know of) to check the rear/calculate the total angle. Stupid me never checked a general reference point to see how that angle changed.

The rear fender height is 38.5” or so and front is 36.25”. Still has a nice rake to it and looks more “normal”. I don’t plan to haul heavy loads so this works for me. Total drop was around 1”. I am trying to find exact measurements from pics I from last week but my network is acting up. If anyone can measure their drivershaft angle vs. the lower driver rear end rib that would help. I would be interestsd to know the total pinion angle change.

I will try to get better after pics (and a few before).

Another unaddressed concern was the shock travel with the lowering which may not be of any concern, but if so I see as low risk.

Curious if anyone knows the 2WD bump stop part number and if it is different from the Z71 package.

Thanks.

Your in the clear as far as pinion angle and shock travel.

Sent from my iPhone using Tapatalk

Druder · August 21, 2018

I've been debating doing this, glad to see someone else have success before being the guinea pig. Beats a leveling kit in my opinion.

WS6FirebirdTA00 · August 21, 2018

My thoughts exactly. Doesn’t seem like the most popular option from searching so I wanted to share. My main concern was pinion angle and total drop.

Another note is the ubolt nuts were quite loose. It took next to no effort to remove them, which seems consistent with other posts I have read.

WS6FirebirdTA00 · August 21, 2018

Of course I deleted my old numbers, but pretty sure rear height reference was 39.75” vs front at 36.25” which made this a 1.25” drop of the rear. Should have just measured the blocks before I stuck them in the attic

Sierra706 · August 22, 2018

Of course I deleted my old numbers, but pretty sure rear height reference was 39.75” vs front at 36.25” which made this a 1.25” drop of the rear. Should have just measured the blocks before I stuck them in the attic [emoji4]

Correct

Sent from my iPhone using Tapatalk

WS6FirebirdTA00 · August 26, 2018

FYI - put the quad fold bed cover on and it took it down about another 1/2". With the cover and what I put in the back it is around 150 lbs. I am about the same weight, sank another 1/2" with me in the bed. I figured around 300 lbs in the back it would sit completely level. Just a caution for those looking to level, after about 400-500 lbs of weight it levels.