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Rear U-bolts loose?

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Old 07-09-2015, 12:45 PM
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Rear U-bolts loose?

I've noticed for a little while that when I let off the throttle at highway speed it felt like my truck would jump a little to the left. I looked around at the suspension, especially in the front, and never could see anything unusual. I thought maybe something loose in the drive train. my reasoning was that it would be under stress from the torque at that speed and when it was released, something was shifting.

This morning on my way to work I was going pretty fast, about 80 or so. When I let off the gas I actually felt the rear end kick over to the right. So, I guess that's why I had felt before instead of the front of the truck shifting to the left. When I got to work I looked at the leaf springs and u-bolts in the rear and I could see shiny spots where the u-bolts have been moving against the axle. On the passenger side rear there is a good 1/4" shiny spot on the u-bolt where the lift block has been moving up and down and it looks like the lift block might be angled a little bit forward at the top. I'm wearing my purdy work clothes so I can't get up under there to see if the pin is centered in the perch. (Hope all my terminology is right.)

Here's a picture of the front of the right rear u-bolt.

<a href="http://s90.photobucket.com/user/Norton72/media/Mobile%20Uploads/2015-07/IMG_20150709_123103709_HDR_zpskyzrvdqb.jpg.html" target="_blank"><img src="http://i90.photobucket.com/albums/k279/Norton72/Mobile%20Uploads/2015-07/IMG_20150709_123103709_HDR_zpskyzrvdqb.jpg" border="0" alt=" photo IMG_20150709_123103709_HDR_zpskyzrvdqb.jpg"/></a>

I tried to get my phone up under the perch to see if the pin was coming through, but this is the best shot I could get without crawling on the ground. Sorry for being such a pansy.

<a href="http://s90.photobucket.com/user/Norton72/media/Mobile%20Uploads/2015-07/IMG_20150709_123112060_zpszcgnj9lg.jpg.html" target="_blank"><img src="http://i90.photobucket.com/albums/k279/Norton72/Mobile%20Uploads/2015-07/IMG_20150709_123112060_zpszcgnj9lg.jpg" border="0" alt=" photo IMG_20150709_123112060_zpszcgnj9lg.jpg"/></a>

I'll drive home easy tonight, 20 miles, get the manual out and find the torque specs. One side of one u-bolt is bent below the nut and has a smaller depth nut on it. There is one of these on each side of the axle. I'm suspicious of the quality of these nuts. I guess I should think about replacing the u-bolts.
 
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Old 07-09-2015, 02:02 PM
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But, if the leaf springs have shifted...
 
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Old 07-09-2015, 05:44 PM
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i would not even attempt to tighten them, they will most likely break. i would just park it if you can until you get new u-bolts.
 
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Old 07-09-2015, 05:56 PM
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Thanks, and right on time. I was just about to go out there and do it. Did that wear mark look as scary to you as it did to me? I'm still going to go out and see if I can see the pin through the hole in the bottom of the perch.
 
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Old 07-09-2015, 05:58 PM
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not as scary as thinking of doing 80 mph with a "floating" rear.
 
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Old 07-09-2015, 06:42 PM
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Originally Posted by tjc transport
not as scary as thinking of doing 80 mph with a "floating" rear.
Yeah, that's what thought of when I saw it, and that's why I was scared. I don't even want to show you what I found when I got home -- you might need to change your pants. It wasn't like that this morning after I got to work. If it was and I didn't see it, I'm too stupid to live.
 
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Old 07-09-2015, 07:47 PM
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not to worry, i drove my 88 for 4 days with a broken main leaf, sheared center pin, and 1 broken ubolt.
i felt it loose, but did not pay much attention to it because i did not have time to look at it. when i finally crawled under it saturday morning, the block fell out when i jacked the truck up.
 
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Old 07-09-2015, 09:56 PM
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Yep change both sides too. Don't forget to retighten after awhile also. That's some scary chit. At least you caught it before really bad things happened.
 
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Old 07-09-2015, 10:37 PM
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The leaf spring pack has a pin that holds the leaf springs all together, and it goes in the top of the block and yes there is a pin on the bottom of the block that goes in the leaf spring axle pad.

With all that play, when you replace the u bolts with new...I would insp both pins for being worn.

Don't forget since you have overloads you will need one's a little longer than stock. Yes torque IAW specs, then retorque in 25/50/100 miles, and again in 500 miles.
 
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Old 07-10-2015, 06:44 AM
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Thanks, I don't feel so stupid now. I'll show you one picture:

<a href="http://s90.photobucket.com/user/Norton72/media/Mobile%20Uploads/2015-07/IMG_20150709_180619951_HDR_zpseomn4ihd.jpg.html" target="_blank"><img src="http://i90.photobucket.com/albums/k279/Norton72/Mobile%20Uploads/2015-07/IMG_20150709_180619951_HDR_zpseomn4ihd.jpg" border="0" alt=" photo IMG_20150709_180619951_HDR_zpseomn4ihd.jpg"/></a>

OK, twol

<a href="http://s90.photobucket.com/user/Norton72/media/Mobile%20Uploads/2015-07/IMG_20150709_180630945_zpsudyxlkqc.jpg.html" target="_blank"><img src="http://i90.photobucket.com/albums/k279/Norton72/Mobile%20Uploads/2015-07/IMG_20150709_180630945_zpsudyxlkqc.jpg" border="0" alt=" photo IMG_20150709_180630945_zpsudyxlkqc.jpg"/></a>
 
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Old 07-10-2015, 02:18 PM
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So I've decided to try rebuilding my rear leaf springs. I can get grade 8 u-bolts and center pins from ATS. I replaced my front leaf springs about a year ago, but I just bought the spring packs from LMC. The rear springs cost way more than the front ones though.

Anything I need to know about this process? I have a feeling that reinstalling the rebuilt packs will not be easy. I assume they will still be arced, but won't they be a bit unsprung making them harder to install?

Thanks. it seems the older I get, the more stupid stuff I do. Isn't it supposed to be the other way around?
 
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Old 07-10-2015, 02:33 PM
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nope, because as we get old we forget the useful things and only remember the useless things.
 
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Old 07-10-2015, 11:30 PM
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Biggest thing, SAFETY! I used a over head HD chain lift to hold ol red in place to do that lift install. Try to do it on cement and use GOOD jack stands right behind the front spring shackle attachment point.

And a back up at the trans cross member. That was my set up for ol blue's 4" lift install. Front frame section needs to be very secure because you will be pulling, tugging, pushing, wrestling on it, to get them front springs in.

Leave the rear tires on and chalk both rear wheels. With the frame and the suspension un loaded and the front tires maybe 1" off the gnd, remove tires and then use smaller jack stands and a good floor jack to lower the axle from the springs.

Pull the calipers off and hang for now with a piece of wire from the frame and disconnect and remove the shocks all together. Tie rod fork (hammering force on your steering box output shaft ) or better to use a actual pitman arm gear puller (rent-able tool). I left the d/s connected helped keep the axle from rotating around.

Leave the front springs rear shackles in place where they connect to the frame. Insp the bushings very well, might be a great time to replace? I did red's lift by myself, sure helps to have a friend or 2.

HERE YOU GO: For the rear springs, support the frame just in front of the rear springs front hanger. and a back up at the bumper. Have the rear suspension totally unloaded. Front connection point is easy, but the rear with the spring shackle can be a PITA. If your lower bolt is froze, and you have to remove the upper, the frame can be in the way because of how the leaf springs and shackle were assembled at the factory. Then installed on the truck, they installed the bolts at the factory (from the frame out), so the nut is on outside....also great time to replace the shackle bushing. No bed made it easy to rotate the complete spring and shackle to get the other bolt out.

Pick a end and do it start to finish spring wise, then do the front steering stuff, then the brake lines, then the shocks. Have fun, take pics. And after an initial and test drive your u bolts will settle in and then loosen up. So torque ck at 25, 50, 75 100 miles, they will loosen up like crazy. Even at 250.

You do know that Atlas has rear springs that will let you eliminate the need to reuse the rear block all together? http://www.atlassuspension.com/ford-performance.html

I copied and pasted this out of my save folder, so yea it has some extra info.
 
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