poky_L16 Posted March 29, 2015 Report Share Posted March 29, 2015 Hey guys, I'm Will and I live in SE Idaho about 3 hours from salt lake. I've had my 72 620 for a few years now and finally decided to lower it. After throwing in 3" blocks and some longer torsion bar bolts, I've got to say, it looks sick! Anyway, I noticed that the overall drive ability of my pickup has gone to complete crap. It tracks all over he road and won't drive straight over 30 mph. A good friend of mine says that it appears my rear axle is "crab walking" and toe'd out to one side when driving under load. I don't really understand how this could happen with a solid rear axle? Is there anyway that this could have happened after lowering it? Any advice/ input would be mucho appreciated. Thanks again. Quote Link to comment
ggzilla Posted March 29, 2015 Report Share Posted March 29, 2015 Did you use blocks that keep the stock locating pin? Crabbing is caused by uneven mounting, that is the axle is further back on one side than the other. Usually due to bent chassis after a wreck. Quote Link to comment
.sunlover Posted March 29, 2015 Report Share Posted March 29, 2015 I would assume you missed the hole for your spring bolt on 1 side, so its either moving out of place, or held in the wrong place. Quote Link to comment
datzenmike Posted March 29, 2015 Report Share Posted March 29, 2015 Also lowering the front increases negative camber and toe in. Top of wheels closer to the body than the bottoms and wheels pointing inward instead of straight ahead. Needs alignment. When you are done and you notice a low HUMM or vibration, this is because your drive line angles are now way off from the lowering. Usually this can be fixed by placing a 2" spacer under the center bearing bolt down. 1 Quote Link to comment
poky_L16 Posted March 29, 2015 Author Report Share Posted March 29, 2015 Wow thanks for the fast responses. I used some blocks from the local parts house, oreilly etc. I'm pretty sure I didn't miss the locating pin though. @datzenmike, the front wheels are looking okay, it's the rear that's he problem. I'll try and check my driveshaft angles tomorrow if I can get to a shop. Quote Link to comment
datzenmike Posted March 29, 2015 Report Share Posted March 29, 2015 It may be a subtle amount but if you lowered the front it WILL be out of whack. As to the rears just measure from the rear shackle forward to the axle. Both sides should be equal. 1 Quote Link to comment
ggzilla Posted March 29, 2015 Report Share Posted March 29, 2015 If u used straight blocks, the angles will still match. With large blocks, the angle will be too great, causing vibration. Blocking the center support will help. Quote Link to comment
poky_L16 Posted March 29, 2015 Author Report Share Posted March 29, 2015 @mike how would I adjust the rear axle toe? I'm not too worried about vibrations, and don't really feel any. I measured the rear tires to the front, and the drivers side is definitely toe'd out Quote Link to comment
ggzilla Posted March 30, 2015 Report Share Posted March 30, 2015 Toe is non-adjustable on a live axle. IF the axle housing is bent then a shop can bend it back. Measure toe from side-to-side. Measure from the front to rear is not the toe. Quote Link to comment
datzenmike Posted March 30, 2015 Report Share Posted March 30, 2015 But if the distance is different then the axle has to be slightly sideways. Measure from the shackle to the axle. If the change was after mounting lowering blocks then one side is not on the leaf spring 'nub'. Just loosen the U bolts and set it straight again. Quote Link to comment
poky_L16 Posted March 30, 2015 Author Report Share Posted March 30, 2015 Ok thanks, I will check to see if one side came out of the "nub." Quote Link to comment
.sunlover Posted April 1, 2015 Report Share Posted April 1, 2015 Well, what was it? Quote Link to comment
datzenmike Posted April 1, 2015 Report Share Posted April 1, 2015 Well it is April 1st.... Quote Link to comment
poky_L16 Posted April 1, 2015 Author Report Share Posted April 1, 2015 Believe it was the misalignment of the driveshaft u joint to the rear diff. Couldn't find anything out of whack with pins inside the lowering blocks. Does anybody know if the front hangers are adjustable to compensate for dog walking? Quote Link to comment
5t341tH Posted April 1, 2015 Report Share Posted April 1, 2015 i had this issue. Accelerating would pull one way while decelerating would pull the other. I readjusted the lowering blocks/axle and it went away 1 Quote Link to comment
ggzilla Posted April 1, 2015 Report Share Posted April 1, 2015 They are not adjustable. Crabbing is not a normal condition, and is not a maintenance issue (is not caused by wear). The thing to do now is unbolt the spacer and lift the axle up to inspect how the spacer fits right the nub in the spring packs and how it fits into the axle pad. Quote Link to comment
.sunlover Posted April 1, 2015 Report Share Posted April 1, 2015 Well it is April 1st.... I respectfully disagree. 31 days this month. 1 Quote Link to comment
Stoffregen Motorsports Posted April 1, 2015 Report Share Posted April 1, 2015 Loose u-bolts? Bad shackle bushings? Loose shackles? Loose hanger bolts? Did you install a different set of wheels and tires at the same time? If so, try the original set and see if it goes away or gets better. Quote Link to comment
datzenmike Posted April 1, 2015 Report Share Posted April 1, 2015 I respectfully disagree. 31 days this month. I was post dating. If the axle turns when accelerating then one side or the other is moving or shifting forward. It must be a huge amount to be noticable. If the wheels turn to the right, check the left side. There should be a 'nub' on the spring pack and another on the top of the block to fit into the axle spring perch. Quote Link to comment
poky_L16 Posted April 1, 2015 Author Report Share Posted April 1, 2015 So many diagnostics! I havey work cut out for me to inspect. This is a great forum. Thanks again everyone. Quote Link to comment
poky_L16 Posted April 6, 2015 Author Report Share Posted April 6, 2015 Just so everyone knows, turns out one of the rear lowering blocks jumped past the top side of the spring bolt, causing the drivers side of the axle to be forward over 1.5" Got it back in the correct spot and cured everything. Even measurements on both sides now. 1 Quote Link to comment
Stoffregen Motorsports Posted April 7, 2015 Report Share Posted April 7, 2015 Thanks for the update. It's good to know that you found it and fixed it. That could have been really dangerous if it eventually fell out. Quote Link to comment
.sunlover Posted April 7, 2015 Report Share Posted April 7, 2015 Just so everyone knows, turns out one of the rear lowering blocks jumped past the top side of the spring bolt, causing the drivers side of the axle to be forward over 1.5" Got it back in the correct spot and cured everything. Even measurements on both sides now. Hah, called it :). Waited a week to say that :) 1 Quote Link to comment
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