Do it yourself zero rate springs
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Technical Article Contributor
Joined: Jan 2011
Posts: 171
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From: NorCal
Do it yourself zero rate springs for rear end sag
Do it yourself zero rate project
Recommended Tools:
Engine hoist or lift
Receiver shackle adapter
Floor jack
Drill press
½ drill bit for hard metal
Bench grinder
Angle grinder
Jack stands
Torque wrench
Breaker bar, ratchet, and sockets including 7/8 and ¾
Vise-Grip pliers
C-clamps
Scribe or Sharpie pen
Materials:
3” wide by 6” long steel bar in ½, ¾, or 1” thickness
½ -20 x 3 ½ ” Grade 8 fine thread bolts (4)
½ -20 Grade 8 hex nuts (4)
Liquid wrench, Break Free, etc.
Spray paint
I have a 2007 super crew that I recently purchased. The truck has a 6” Fabtech lift with 325/65-18 tires. After having the bed Line-X’ed, I then proceeded to purchase a bed cap. I went with a SnugTop Rebel. This cap weighs about 250 lbs. After the cap was installed and with an empty bed, I found that the truck no longer sat perfectly level as it had originally. My truck now looked like this:
The sag is not dramatic, but I could tell the difference. You can see it a little comparing the running board to the curb. I decided to rectify the situation as I had done before with a 1976 Chevy Blazer that I previously built. On that build, I installed 4” Tough Country leaf springs in the rear along with an Offroad Design (ORD) shackle flip for a total of 8” of lift. In the front I had installed 6” Tough Country springs on a swapped in D60. Even with the additional lift in the rear I was still slightly sagging especially with a load of gear in the back. The solution was to go with an ORD 1” zero rate spring. For those of you unfamiliar with a zero rate, it is essentially a small short block that bolts to the bottom of the spring pack. It is not a helper spring and does not change the spring rate. And, because it bolts to the spring pack, it is not just adding another block to the rear. It looks like this:
I still had a set of the ORD zero rates but my rear springs utilize two center pins instead of the usual one pin that the ORD zero rates utilize. An Internet search yielded no results for a company that makes the ORD equivalent zero rate for a Ford. If I missed it, feel free to post up. I considered modifying the ORD set that I still had. However, the ORD set has three sets of holes to provide options in moving the axle forward and backward. Two of the holes appeared to be close but they were smaller in diameter and would put the spring block offset to the lift block. They were also 5” long and the lift block is 6” long.
I decided that I would fabricate my own zero rates. I went to my local steel supply outlet and purchased three different thicknesses of 3” wide steel bar in 6” lengths. I did not know exactly how much lift I would need and so I bought ½”, ¾”, and 1” thick bars. The store cut the bars to length and my total for all six was $46.00. Had I chosen just one set, I would have been out the door for less than $15.00 including tax and cut charge.
Prior to starting I had to decide how I was going to lift the rear end and separate it from the axle. I ended up using a method that I had used on my 1978 F150 that I am also building for a bit more hard core off roading. The ’78 was much lighter in the back but I had great success swapping axles using this method then. I used a receiver shackle adapter with two heavy duty shackles. I then used my engine hoist to lift up the rear end. The receiver is rated at 5,000 lbs. weight carrying and 9,900 lbs. weight distribution. Nevertheless, that is for pulling and not lifting. I decided to give it a try anyway carefully watching for any problems.
Prior to lifting the rear end, I wanted to make sure the shackle did not rub on the bumper and so I cut some scrap rubber bed mat and placed it in between the bumper and the shackle.
I used the floor jack to lift the rear end up to place the axle on the floor jacks and to remove the tires. I then lifted the rear end until the axle just began to come off the jack stands so that all the weight would be off the springs. Prior to loosening any bolts I sprayed Liquid Wrench on the spring pack bolts on the top of the springs.
I removed the U-bolts and placed C-clamps on the spring pack around the center pin area. If you have ever had a spring pack separate on you then you know why this is a must. Once the spring gets out of alignment, getting the center pins back in is a real pain. I only did one side at a time.
I then removed both center pin bolts, the top thin piece of metal used to locate the U-bolts, and the lift block. You may have to use a pair of Vise-Grip pliers to hold the bottom of the center pin in order to remove the center pin nut.
Once you have the center pins out, you will need to replace them with a longer bolt. Obviously the ideal scenario would be to source a stock center pin but in a longer length. I probably could have spent some time at the dealership and found a center pin the same dimensions but longer. I chose another route that I have used before on other vehicles. The stock center pin is 2 ½” long ½ fine thread Grade 8 bolt with a round head. I went to OSH and purchased the same bolt in a 3 ½“ length but with the standard hex head.
I used my bench grinder to slowly and incrementally round the points down until it fit snugly in the lift block like the stock center pin did. Although the stock center pin head is thicker, I have never had any issued fabricating a center pin this way before. Both bolts are Grade 8 and I would assume the sheer strength of the bolt would be the same. The head would not be as substantial but I don’t think it should be an issue. If there is an engineer that can post otherwise, feel free to comment. After modifying the bolt heads of all four bolts, I made sure each fit in the lift block.
Next I set about making the zero rate spring. I debated on which thickness I would start with and hoped that I would only have to do this once. I was also concerned that the existing U-bolts would not accommodate the 1” block so I opted to start with the ¾” block. I used the piece of metal used to locate the top of the U-bolts as a template to scribe my center pin holes.
I used my drill press with a good ½” drill bit to drill the center pin holes in the block. I would suppose that you could accomplish this with a hand drill but I would not want to attempt it. Even the slightest variation as you drill through the block is going to make your exit holes vary enough that the bolts will most likely not line up with the spring pack. After drilling the holes, I used an angle grinder and then my bench grinder to round off the top corners. I copied the design of the ORD blocks assuming that the rounded corners are better for the springs as they flex downwards against the top of the block. I did not round them quite as much as the ORD block but close. You can see that mine are slightly wider and 1“ longer with the proper holes.
I degreased both blocks well and threw a couple coasts of hi-temp black paint that I had laying around prior to installation. Once they were dry, I then bolts the spring pack back together using the zero rate, new bolts and hex nuts. I torqued the hex nuts to 60 ft. lbs.
After assembling the spring pack, I lowered the springs back down onto the lift block. It took some playing around to get the center pin heads to line up with the lift block. I ended up getting the bolt heads just touching the block with slight pressure and then tapped on the spring and block a few times until it popped in. Once the spring was back on the block I reinstalled the U-bolts. I have read various opinions on reusing U-bolts. Some say once you remove them you should not use them again. I’ve also read that if you only do it once or twice, you can get away with reusing them. I chose to reuse the stock U-bolts for now. However, if I decide to pull them off again in the future, I will probably get new U-bolts and nuts. I then torqued the U-bolts to 100 ft. lbs.
After completing the one side I went over and repeated the procedure on the other side. The second side went very fast and the spring pack and lift block lined up perfectly with no issues. I put the tires back on and checked the pinion angle. The angle essentially remained the same so I took it out and drove around the block a few times. I then re-torqued the U-bolts and checked the center pin nut torque, which was fine.
The change in stance was not huge and I was a little surprised that it was not that noticeable. I could see the difference but in the picture below, it is tough to tell. The truck now sits back level as it was before the installation of the bed cap. I had wished that I would have gained a slight raise to the rear to accommodate loading up the bed with camping and hunting gear. I now wish that perhaps I would have gone with the 1” block instead. The good part is that I can just swap in the 1” block without too much difficulty as it is already fabricated and ready to go. I would need new center pin bolts in a longer length as the current ones were just right for the ¾” block. Given that I am not in a rush, I might source a stock center pin if I can in a longer length before I change out the blocks, if I choose to do so. I may go with a Super Spring in the future to prevent significant sag under a full load so these zero rates may stay put for a while.
In the end I am very happy with the project. Had I simply bought only the ¾” steel to begin with my total project cost would have been about $25.00. As it was I still only spent $55.00 and I have two other sets of zero rates available to me. ORD charges $45.00 for a pair of zero rates and I would assume that if a company did make them for my truck they would be a similar price. In this case, I had the time to make my own and therefore the project was a success.
Recommended Tools:
Engine hoist or lift
Receiver shackle adapter
Floor jack
Drill press
½ drill bit for hard metal
Bench grinder
Angle grinder
Jack stands
Torque wrench
Breaker bar, ratchet, and sockets including 7/8 and ¾
Vise-Grip pliers
C-clamps
Scribe or Sharpie pen
Materials:
3” wide by 6” long steel bar in ½, ¾, or 1” thickness
½ -20 x 3 ½ ” Grade 8 fine thread bolts (4)
½ -20 Grade 8 hex nuts (4)
Liquid wrench, Break Free, etc.
Spray paint
I have a 2007 super crew that I recently purchased. The truck has a 6” Fabtech lift with 325/65-18 tires. After having the bed Line-X’ed, I then proceeded to purchase a bed cap. I went with a SnugTop Rebel. This cap weighs about 250 lbs. After the cap was installed and with an empty bed, I found that the truck no longer sat perfectly level as it had originally. My truck now looked like this:
The sag is not dramatic, but I could tell the difference. You can see it a little comparing the running board to the curb. I decided to rectify the situation as I had done before with a 1976 Chevy Blazer that I previously built. On that build, I installed 4” Tough Country leaf springs in the rear along with an Offroad Design (ORD) shackle flip for a total of 8” of lift. In the front I had installed 6” Tough Country springs on a swapped in D60. Even with the additional lift in the rear I was still slightly sagging especially with a load of gear in the back. The solution was to go with an ORD 1” zero rate spring. For those of you unfamiliar with a zero rate, it is essentially a small short block that bolts to the bottom of the spring pack. It is not a helper spring and does not change the spring rate. And, because it bolts to the spring pack, it is not just adding another block to the rear. It looks like this:
I still had a set of the ORD zero rates but my rear springs utilize two center pins instead of the usual one pin that the ORD zero rates utilize. An Internet search yielded no results for a company that makes the ORD equivalent zero rate for a Ford. If I missed it, feel free to post up. I considered modifying the ORD set that I still had. However, the ORD set has three sets of holes to provide options in moving the axle forward and backward. Two of the holes appeared to be close but they were smaller in diameter and would put the spring block offset to the lift block. They were also 5” long and the lift block is 6” long.
I decided that I would fabricate my own zero rates. I went to my local steel supply outlet and purchased three different thicknesses of 3” wide steel bar in 6” lengths. I did not know exactly how much lift I would need and so I bought ½”, ¾”, and 1” thick bars. The store cut the bars to length and my total for all six was $46.00. Had I chosen just one set, I would have been out the door for less than $15.00 including tax and cut charge.
Prior to starting I had to decide how I was going to lift the rear end and separate it from the axle. I ended up using a method that I had used on my 1978 F150 that I am also building for a bit more hard core off roading. The ’78 was much lighter in the back but I had great success swapping axles using this method then. I used a receiver shackle adapter with two heavy duty shackles. I then used my engine hoist to lift up the rear end. The receiver is rated at 5,000 lbs. weight carrying and 9,900 lbs. weight distribution. Nevertheless, that is for pulling and not lifting. I decided to give it a try anyway carefully watching for any problems.
Prior to lifting the rear end, I wanted to make sure the shackle did not rub on the bumper and so I cut some scrap rubber bed mat and placed it in between the bumper and the shackle.
I used the floor jack to lift the rear end up to place the axle on the floor jacks and to remove the tires. I then lifted the rear end until the axle just began to come off the jack stands so that all the weight would be off the springs. Prior to loosening any bolts I sprayed Liquid Wrench on the spring pack bolts on the top of the springs.
I removed the U-bolts and placed C-clamps on the spring pack around the center pin area. If you have ever had a spring pack separate on you then you know why this is a must. Once the spring gets out of alignment, getting the center pins back in is a real pain. I only did one side at a time.
I then removed both center pin bolts, the top thin piece of metal used to locate the U-bolts, and the lift block. You may have to use a pair of Vise-Grip pliers to hold the bottom of the center pin in order to remove the center pin nut.
Once you have the center pins out, you will need to replace them with a longer bolt. Obviously the ideal scenario would be to source a stock center pin but in a longer length. I probably could have spent some time at the dealership and found a center pin the same dimensions but longer. I chose another route that I have used before on other vehicles. The stock center pin is 2 ½” long ½ fine thread Grade 8 bolt with a round head. I went to OSH and purchased the same bolt in a 3 ½“ length but with the standard hex head.
I used my bench grinder to slowly and incrementally round the points down until it fit snugly in the lift block like the stock center pin did. Although the stock center pin head is thicker, I have never had any issued fabricating a center pin this way before. Both bolts are Grade 8 and I would assume the sheer strength of the bolt would be the same. The head would not be as substantial but I don’t think it should be an issue. If there is an engineer that can post otherwise, feel free to comment. After modifying the bolt heads of all four bolts, I made sure each fit in the lift block.
Next I set about making the zero rate spring. I debated on which thickness I would start with and hoped that I would only have to do this once. I was also concerned that the existing U-bolts would not accommodate the 1” block so I opted to start with the ¾” block. I used the piece of metal used to locate the top of the U-bolts as a template to scribe my center pin holes.
I used my drill press with a good ½” drill bit to drill the center pin holes in the block. I would suppose that you could accomplish this with a hand drill but I would not want to attempt it. Even the slightest variation as you drill through the block is going to make your exit holes vary enough that the bolts will most likely not line up with the spring pack. After drilling the holes, I used an angle grinder and then my bench grinder to round off the top corners. I copied the design of the ORD blocks assuming that the rounded corners are better for the springs as they flex downwards against the top of the block. I did not round them quite as much as the ORD block but close. You can see that mine are slightly wider and 1“ longer with the proper holes.
I degreased both blocks well and threw a couple coasts of hi-temp black paint that I had laying around prior to installation. Once they were dry, I then bolts the spring pack back together using the zero rate, new bolts and hex nuts. I torqued the hex nuts to 60 ft. lbs.
After assembling the spring pack, I lowered the springs back down onto the lift block. It took some playing around to get the center pin heads to line up with the lift block. I ended up getting the bolt heads just touching the block with slight pressure and then tapped on the spring and block a few times until it popped in. Once the spring was back on the block I reinstalled the U-bolts. I have read various opinions on reusing U-bolts. Some say once you remove them you should not use them again. I’ve also read that if you only do it once or twice, you can get away with reusing them. I chose to reuse the stock U-bolts for now. However, if I decide to pull them off again in the future, I will probably get new U-bolts and nuts. I then torqued the U-bolts to 100 ft. lbs.
After completing the one side I went over and repeated the procedure on the other side. The second side went very fast and the spring pack and lift block lined up perfectly with no issues. I put the tires back on and checked the pinion angle. The angle essentially remained the same so I took it out and drove around the block a few times. I then re-torqued the U-bolts and checked the center pin nut torque, which was fine.
The change in stance was not huge and I was a little surprised that it was not that noticeable. I could see the difference but in the picture below, it is tough to tell. The truck now sits back level as it was before the installation of the bed cap. I had wished that I would have gained a slight raise to the rear to accommodate loading up the bed with camping and hunting gear. I now wish that perhaps I would have gone with the 1” block instead. The good part is that I can just swap in the 1” block without too much difficulty as it is already fabricated and ready to go. I would need new center pin bolts in a longer length as the current ones were just right for the ¾” block. Given that I am not in a rush, I might source a stock center pin if I can in a longer length before I change out the blocks, if I choose to do so. I may go with a Super Spring in the future to prevent significant sag under a full load so these zero rates may stay put for a while.
In the end I am very happy with the project. Had I simply bought only the ¾” steel to begin with my total project cost would have been about $25.00. As it was I still only spent $55.00 and I have two other sets of zero rates available to me. ORD charges $45.00 for a pair of zero rates and I would assume that if a company did make them for my truck they would be a similar price. In this case, I had the time to make my own and therefore the project was a success.
Last edited by TheDesertRat; Mar 6, 2011 at 02:49 AM.
Thread Starter
|
Technical Article Contributor
Joined: Jan 2011
Posts: 171
Likes: 0
From: NorCal
I was a bit nervous but it worked out great. I've used that method to lift up my 78 repeatedly but it is much lighter in the back end. That cherry picker has been worth every penny I paid for it.
