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11-01-2000, 03:19 AM
| #1 (permalink) |
| Guest |  The hard way to lower a Lightning "If it ain't broke, fix it." I've never liked the idea of throwing on taller shackles to lower the truck. It greatly increases the lateral forces on the hangers and makes it worse if they have polyurethane bushings. So, having nothing better to do last weekend, I decided to simply relocate all the rear suspension 1.75" up. 20 hours later...  removing the bed Those are Corvette body lift straps with adapters I made to fit the bed tie downs. Worked like a charm. This would have been a nightmare with the bed on. Notice the masking tape X on the floor so I could reposition the truck exactly back under the bed when I lowered it back down. I usually don't think of those things until it's too late, I was feeling especially clever that night.  half naked lightning It only took about an hour to get the bed off. Just 6 bolts, two hose clamps, three hoses, one electrical connector and two lights.  front spring hanger I used the existing frame holes where ever possible and added a few extra. I used only grade 8 bolts for obvious reasons. The brace should help keep the hanger from flexing, assuming there is any flex to begin with. Everything got a thick gooey layer of Hammerite for rust protection, which is only slightly less obnoxious than the factory frame wax.  rear spring hanger I beefed up the rear shackles by welding some steel onto back of them. Seemed like a good idea until I noticed I had made them so they would hold about a 1/2 cup of water. I ended up drilling a couple of small holes to let the water out and gave the inside a double coat of Hammerite.  anti-sway bar linkage I'm not sure if it was strictly necessary, but I moved the anti-sway bar links up too. I added a 3/16" thick plate to the back of the frame for strength.  before and after The results were exactly as I'd hoped for. The truck still has a slight rake front to back, and the gap at the top of the wheel is exactly the same in the front and rear. I didn't expect to see much of a difference, but after I saw it from a distance in a parking lot, I could see a huge improvement. That 1-3/4" difference took all the "utility" look out of it. I didn't change the bump stops, there was no evidence that they had ever contacted the axle with the stock ride height, despite hauling lumber, pianos, 50gal drums of diesel, etc. I'll check the dirt pattern in a week and see if they need to be trimmed a bit. Conclusion: I can't say for certain that the handling is improved, but did I manage 58mph this morning on the short twisty road leading to my office, 2mph higher than ever before. ------------------ Mark '00 Lightning '79 Corvette |
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11-01-2000, 12:49 PM
| #4 (permalink) |
| Guest |  One of the main reasons I did it this way was so it would not change the pinion angle. Those kits that replace the shackles only will change the angle and increase wear on the u-joints and cause driveshaft vibrations, among other things. What is a "Supercab LIGHTNING"? ------------------ Mark '00 Lightning '79 Corvette |
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11-01-2000, 02:42 PM
| #6 (permalink) |
| Guest |  Mark, You are scaring me! Seriously, very impressive. Regards, ------------------ -Steve :} N.L.O.C. #84 '00 Black #???? (My wife's new toy!) '95 Black #1556 (Now it's mine!) '98 Black Cobra Coupe #2745 (Autocrosser) '00 Ducati MH900e (coming soon??) '99 Ducati ST4 (a 916 you can live with) '91 Bimota Dieci (120 rear wheel HP; 480 lbs wet weight) '83 Honda CB1100F (Wiseco 1127cc, Manley valves, Supertrapp) San Diego, CA  |
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11-01-2000, 02:53 PM
| #7 (permalink) | |
| Guest | Quote:
------------------ #1481 of 5276 Supercab LIGHTNING Vortech S-trim Borla catback Kenne Bell Boost-a-spark Lowered 2 and 4 Centerlines Chrome yellow paint | |
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11-01-2000, 04:26 PM
| #9 (permalink) |
| Guest | Hey Mark, How did you make sure it wouldnt dog leg down the road when you got finished. Even if you got a measurement 1/16" out it would appear crooked going down the road? I re-drilled my front lowering hangers so I wouldnt get the full drop on my Gen 1 Lightning and screwed it up royal. All I can say is you have a huge set of b--ls to take that one on. Good job! ------------------ 94 Crimson. NLOC member #343 Team Powerdyne, 8psi,bypass 13.633@ 100mph |
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11-01-2000, 05:06 PM
| #10 (permalink) |
| Guest | Why yes, they are quite large. Thanks for noticing.  I took my time and measured everything down to 0.001” about three times. A good quality steel dial caliper and square makes all the difference in the world. This isn’t a job for tape measures and levels. All the frame holes were center-punched, pre-drilled with a 1/8” bit, then drilled to their final size to avoid walking and chattering from the larger bit. And the holes on the brackets were all made clamped into a big drill press. I think the key is to ignore everything but the factory holes. If you start measuring from the edge of the frame or even worse, the floor, everything gets out of whack. Now that I think of it, I was working under the assumption that an imaginary horizontal line drawn between the holes on either side of the front bracket would run parallel to the same line drawn from the rear bracket (if that makes any sense). If they don’t, it could move the hangers closer or further apart by a tiny amount. As long as I was consistent on both sides it won’t matter, any difference would be absorbed by the shackles. ------------------ Mark '00 Lightning '79 Corvette |
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11-02-2000, 08:15 AM
| #12 (permalink) |
| Guest | Guys and Gals, if you want to find true centers, all you have to do is level the frame on jack stands using the bed mounts on the frame as reference for the level, then take to jack stands one on each side of the front hangars and hang four plumb bobs off of a piece of steel and lay it across the two jack stands. Line two up on the center bolt of the front leaf spring eyes and the other two on the frame. Where the two touch the frame is the center of the eye for the front springs. You can do the same for the back. If you want to pull measurments for checking accuracy, always measure diagonal across the reference points. You can also hang the plumb bob off the center bolt and make a mark on the floor. When you think you have it right check it again with the plumb bob and the mark on the floor. Just dont move the truck while working on it. Okay fire away. ------------------ Red 2000 L 22 July 2000 Best stock ET: 14.19 Best stock MPH: 96.41 4.10 Gears Superchips Flip chip (New 2000 Burn) Downs Ford Intake Best Ever ET 13.76 Best Ever MPH Spinning 99.85 Recent Buys... MTX Thunderform Sub enclosure I Feel The Need..... The Need For Speed. |
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11-03-2000, 02:12 AM
| #13 (permalink) |
| Guest |  Hmmm... Pretty clever, actually. The bed does mount parallel to the frame, so that method would move the axle directly up in relation to the wheel well. I would have had to buy three more plum bobs. And I probably would have wasted the whole weekend just building a set of screw type jackstands. By measuring diagonally, do you mean from the new hole centers at each hanger to make sure they are square? Not that it matters now, it's a bit late. But I'm always interested in this kind of thing. I wish I'd taken some engineering classes in collage. ------------------ Mark '00 Lightning '79 Corvette [This message has been edited by Mark_2kL (edited 11-03-2000).] |
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11-03-2000, 12:16 PM
| #14 (permalink) |
| Guest | Mark, You dont need screw type jackstands, just level the bar you hang the plumb's from. Whenever you measure distance as in building cars, you always want to measure diagonaly (Commonly called Xing) It gives a much more accurate measurement then measuring in a straight line. As an example Measure the distance from the Left rear spring eye to the right front spring eye and then vise-versa to see if your back where you started from once the new hangar positions are made. The same is true with stringing a centerline down the vehicle for reference. The farther you run the string past each end of the vehicle the more accurate the center line will be. Then you can use a framing sqare on the floor referencing off the centerline. Tony ------------------ Red 2000 L 22 July 2000 Best stock ET: 14.19 Best stock MPH: 96.41 4.10 Gears Superchips Flip chip (New 2000 Burn) Downs Ford Intake Best Ever ET 13.76 Best Ever MPH Spinning 99.85 Recent Buys... MTX Thunderform Sub enclosure I Feel The Need..... The Need For Speed. |
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