Ipe
06-12-2007, 07:55 AM
I've been wanting to improve the off-road ability of my H3 for some time. I wanted to improve the ground clearance and increase the flex available in the rear suspension. Bebe and I talked for a long time before the project was started, figuring out what parts were going to work and what we were going to need. So far the results have been pretty good!
The original article was written by Manny MacMillan and published in the Hummer section of Off-Road.com (http://hummer.off-road.com/hummer/article/articleDetail.jsp?id=431913). Here are some details that may help anyone interested in doing this sort of mod.
These are the parts that I used:
http://hummer.off-road.com/hummer/data/articlestandard/hummer/232007/431913/H3Flex-3_l.jpg
Shackles are from http://www.Rocky-Road.com and are the 2" Jeep lift shackle for the Jeep YJ. They measure 6" center to center and bolt right up. $50 shipped. They're not the fastest shippers though. Expect a week handling/transit time.
The disconnects are from Rough Country and are the TJ/XJ front disco. $60 shipped.
The rear shocks are Rancho RS5000's and are from Summit Racing (http://store.summitracing.com/partdetail.asp?part=RAN-RS5190), model number RS5190. $44 each.
The front shocks are Rancho RS5000's as well, but they're going back. I will be replacing them with the H3 Cognito shocks from Trail Duty. The problem is that the Rancho's are either too long when fully compressed, or too short when fully extended. Rancho does not seem to make a shock that really satisfies the issue. The closest is the RSX17512, but after much research on the issue still seems too short when extended. The Cognito seems to be the optimal front shocks.
Installation Notes:
Helpful hint #1, go to this page (http://home.comcast.net/~f5fstop/H3_UNDERCARRIAGE_TORQUES.htm) for proper torque specs. F5 was nice enough to get us this info, so lets put it to good use. :D
Shackle installation:
I was lucky enough to have Manny's hydraulic center lift (The man has a very cool garage!) to use. This made things a bit easier. Okay, a lot easier. :smokin: But, that said, if you have some jackstands, a jack (or even better, two jacks), tools, metric sockets and extensions (sizes 12mm, 18mm, 19mm, and 21mm seem to ring a bell) you should be all set. A creeper will make life a bit more comfortable too.
First things first. Lift the truck by the frame until the rear shocks are fully extended but are not lifting the weight of the axle. Once this is done disconnect the rear shocks top and bottom. The top mounts will need the 12mm socket (I think, don't quote me on socket sizes, I didn't take note of them at the time) and a very long extension. You can connect the new shocks at this time. The Ranchos do not push out when unloaded like the OE shocks do so this won't be a factor.
Now continue lifting the truck until the tires just barely leave the floor and then lower back down a little bit until the leaf spring are fully unloaded. You can now disconnect the shackle bolts. You need a 21mm socket both sides. If the springs are fully unloaded you should be able to pull the bolts out w/o any effort. I removed the bottom bolts first and then the uppers. When I did the work at Manny's we didn't know that the rear shock was the limiting factor so when we removed the lower bolt first, with a LOT of effort, the leaf spring eye snapped up HARD against the upper mount and stayed there until we removed the shocks. If the springs are neutral and unloaded the bolts come out with zero effort.
Once the OE shackle was removed we decided how to mount the YJ shackle. The YJ shackle came with a dog-leg bend in it. I think this is so that the shackle can clear the frame or bumper on the Jeep. We mounted them with the short leg towards the top with the "knee" facing forward. You can sort of see that in this picture:
http://ipedog.smugmug.com/photos/155519894-L.jpg
We reused the OE shackle bolts top and bottom and used one of the supplied bolts in the center hole to act as a stabilizing link. (Since then I've had a machine shop make a spacer that I slipped over the center bolt. This will keep the shackle from being the flexiest thing ever, but more stable in the highway. You can remove it at the trailhead with a 19mm socket if you want to maximize your flex.)
We mounted the top of the shackle plates first and then lifted the truck until we were able to slide the lower shackle bolts in. Now tighten them top and bottom to the proper torque. Until I got the spacer, I tightened the center bolt until I could no longer move the washers by hand. Here is a pic of the installed shackle with spacer:
1-1/4" diameter, 3" long
http://ipedog.smugmug.com/photos/161945067-L.jpg
Rough Country disconnects:
Believe it or not, I don't think that they are on the RC website. I found them here (http://www.rockymountainsusp.com/SwayBarLinks.htm) (look about 2/3 down the page) and called these people to ask questions. They didn't know the answers and had me call RC. They were the same price so I just ordered from RC when I was on the phone with them. Call the 888 number on the http://www.roughcountry.com site.
Washer spacing and Disco cutting:
The shackles came with more bolts and washers than was necessary, especially as I reused the OE top and bottom shackle bolts. I ended up using ALL the washers, about an inch worth per side. The picture above shows the washers. I cut the disco's down this weekend and other than drilling, it was no big deal.
I disconnected the bottom links from the disconnect so that the sway bar was free. I then held the sway bar basically level (with the truck sitting level) and made a mark on the center link roughly 1/2" below the bottom hole in the lower connector. I then removed both center links from the truck and making sure that I cut off the end with two holes only, cut at my mark. In total I ended up lopping about 3" off the center link.
The toughest part of the whole thing was drilling the holes. The pins are 1/4" in diameter and the holes are slightly larger than that. I ended up using a 17/64" bit as that was the closest I could find to the existing holes. Now comes the hard part, actually drilling the holes. If you have a drill press this makes life a lot easier. If you have a drill press vise its even easier still. I had the drill press but no vise, so I made do with a wood working clamp. That worked, but allowed the piece to wander enough that the holes were not properly centered and as a result, wouldn't allow the pin to pass through.
Soooo... another 1/2" got lopped off and ground down flat, parallel, and redrilled. This time it worked out fine, and the new length was actually better (I had been conservative before, just in case I screwed up. I ground the edges smooth and painted them up. All in all it wasn't all that hard, taking about maybe an hour, hour and a half total.
Center link overall length = 4-5/8"
http://ipedog.smugmug.com/photos/161951809-L.jpg
Center to center length = 3-3/4"
http://ipedog.smugmug.com/photos/161944532-L.jpg
Pic all on its own shot from the rear
http://ipedog.smugmug.com/photos/161951558-L.jpg
Shot from the side
http://ipedog.smugmug.com/photos/161945234-L.jpg
Finally, before you go and try out your new found flex there is one final thing that needs to be done, and its easy.
In the rear wheel well there is a plastic "anchor" holding the ABS cable. The cable has a rubber section grafted onto it that keeps it in the anchor. If you turn the anchor so that the cable is vertical you will see a thin gap on one side. Using a broad flat head screwdriver you can gently open the anchor so that the rubber section is free. Making sure that the rubber section is below the anchor, close the anchor so that the cable is now captive within it. Doing this will allow your rear axle to flex easily to its maximum potential and you won't have to worry about tearing the ABS cable from the truck.
http://ipedog.smugmug.com/photos/160712082-L.jpg
The original article was written by Manny MacMillan and published in the Hummer section of Off-Road.com (http://hummer.off-road.com/hummer/article/articleDetail.jsp?id=431913). Here are some details that may help anyone interested in doing this sort of mod.
These are the parts that I used:
http://hummer.off-road.com/hummer/data/articlestandard/hummer/232007/431913/H3Flex-3_l.jpg
Shackles are from http://www.Rocky-Road.com and are the 2" Jeep lift shackle for the Jeep YJ. They measure 6" center to center and bolt right up. $50 shipped. They're not the fastest shippers though. Expect a week handling/transit time.
The disconnects are from Rough Country and are the TJ/XJ front disco. $60 shipped.
The rear shocks are Rancho RS5000's and are from Summit Racing (http://store.summitracing.com/partdetail.asp?part=RAN-RS5190), model number RS5190. $44 each.
The front shocks are Rancho RS5000's as well, but they're going back. I will be replacing them with the H3 Cognito shocks from Trail Duty. The problem is that the Rancho's are either too long when fully compressed, or too short when fully extended. Rancho does not seem to make a shock that really satisfies the issue. The closest is the RSX17512, but after much research on the issue still seems too short when extended. The Cognito seems to be the optimal front shocks.
Installation Notes:
Helpful hint #1, go to this page (http://home.comcast.net/~f5fstop/H3_UNDERCARRIAGE_TORQUES.htm) for proper torque specs. F5 was nice enough to get us this info, so lets put it to good use. :D
Shackle installation:
I was lucky enough to have Manny's hydraulic center lift (The man has a very cool garage!) to use. This made things a bit easier. Okay, a lot easier. :smokin: But, that said, if you have some jackstands, a jack (or even better, two jacks), tools, metric sockets and extensions (sizes 12mm, 18mm, 19mm, and 21mm seem to ring a bell) you should be all set. A creeper will make life a bit more comfortable too.
First things first. Lift the truck by the frame until the rear shocks are fully extended but are not lifting the weight of the axle. Once this is done disconnect the rear shocks top and bottom. The top mounts will need the 12mm socket (I think, don't quote me on socket sizes, I didn't take note of them at the time) and a very long extension. You can connect the new shocks at this time. The Ranchos do not push out when unloaded like the OE shocks do so this won't be a factor.
Now continue lifting the truck until the tires just barely leave the floor and then lower back down a little bit until the leaf spring are fully unloaded. You can now disconnect the shackle bolts. You need a 21mm socket both sides. If the springs are fully unloaded you should be able to pull the bolts out w/o any effort. I removed the bottom bolts first and then the uppers. When I did the work at Manny's we didn't know that the rear shock was the limiting factor so when we removed the lower bolt first, with a LOT of effort, the leaf spring eye snapped up HARD against the upper mount and stayed there until we removed the shocks. If the springs are neutral and unloaded the bolts come out with zero effort.
Once the OE shackle was removed we decided how to mount the YJ shackle. The YJ shackle came with a dog-leg bend in it. I think this is so that the shackle can clear the frame or bumper on the Jeep. We mounted them with the short leg towards the top with the "knee" facing forward. You can sort of see that in this picture:
http://ipedog.smugmug.com/photos/155519894-L.jpg
We reused the OE shackle bolts top and bottom and used one of the supplied bolts in the center hole to act as a stabilizing link. (Since then I've had a machine shop make a spacer that I slipped over the center bolt. This will keep the shackle from being the flexiest thing ever, but more stable in the highway. You can remove it at the trailhead with a 19mm socket if you want to maximize your flex.)
We mounted the top of the shackle plates first and then lifted the truck until we were able to slide the lower shackle bolts in. Now tighten them top and bottom to the proper torque. Until I got the spacer, I tightened the center bolt until I could no longer move the washers by hand. Here is a pic of the installed shackle with spacer:
1-1/4" diameter, 3" long
http://ipedog.smugmug.com/photos/161945067-L.jpg
Rough Country disconnects:
Believe it or not, I don't think that they are on the RC website. I found them here (http://www.rockymountainsusp.com/SwayBarLinks.htm) (look about 2/3 down the page) and called these people to ask questions. They didn't know the answers and had me call RC. They were the same price so I just ordered from RC when I was on the phone with them. Call the 888 number on the http://www.roughcountry.com site.
Washer spacing and Disco cutting:
The shackles came with more bolts and washers than was necessary, especially as I reused the OE top and bottom shackle bolts. I ended up using ALL the washers, about an inch worth per side. The picture above shows the washers. I cut the disco's down this weekend and other than drilling, it was no big deal.
I disconnected the bottom links from the disconnect so that the sway bar was free. I then held the sway bar basically level (with the truck sitting level) and made a mark on the center link roughly 1/2" below the bottom hole in the lower connector. I then removed both center links from the truck and making sure that I cut off the end with two holes only, cut at my mark. In total I ended up lopping about 3" off the center link.
The toughest part of the whole thing was drilling the holes. The pins are 1/4" in diameter and the holes are slightly larger than that. I ended up using a 17/64" bit as that was the closest I could find to the existing holes. Now comes the hard part, actually drilling the holes. If you have a drill press this makes life a lot easier. If you have a drill press vise its even easier still. I had the drill press but no vise, so I made do with a wood working clamp. That worked, but allowed the piece to wander enough that the holes were not properly centered and as a result, wouldn't allow the pin to pass through.
Soooo... another 1/2" got lopped off and ground down flat, parallel, and redrilled. This time it worked out fine, and the new length was actually better (I had been conservative before, just in case I screwed up. I ground the edges smooth and painted them up. All in all it wasn't all that hard, taking about maybe an hour, hour and a half total.
Center link overall length = 4-5/8"
http://ipedog.smugmug.com/photos/161951809-L.jpg
Center to center length = 3-3/4"
http://ipedog.smugmug.com/photos/161944532-L.jpg
Pic all on its own shot from the rear
http://ipedog.smugmug.com/photos/161951558-L.jpg
Shot from the side
http://ipedog.smugmug.com/photos/161945234-L.jpg
Finally, before you go and try out your new found flex there is one final thing that needs to be done, and its easy.
In the rear wheel well there is a plastic "anchor" holding the ABS cable. The cable has a rubber section grafted onto it that keeps it in the anchor. If you turn the anchor so that the cable is vertical you will see a thin gap on one side. Using a broad flat head screwdriver you can gently open the anchor so that the rubber section is free. Making sure that the rubber section is below the anchor, close the anchor so that the cable is now captive within it. Doing this will allow your rear axle to flex easily to its maximum potential and you won't have to worry about tearing the ABS cable from the truck.
http://ipedog.smugmug.com/photos/160712082-L.jpg