U-Bolt Tightening - After TSB

In January the dealer installed new leaf springs and the steering whee damper as part of the downshift vibrations. Now, the truck has the infamous "Taco Lean". It's approx 1/2" or more when the tank is full.

Today I crawled underneath to see if there was anything I could notice missing, different, etc.

On the top of each new leaf, there is a "+" towards the engine and a "RM" towards the rear.

The biggest difference I noticed was in the level of bolt exposed on the u-bolts. On the drivers side the front U-bolt appears to be tightened more than the rear, and the opposite is the case for the passenger side. The passenger side leaf rear u-bolt appears to be tightened further than the front.

My question, is that normal, could it be the cause of the lean? I assume the u-bolts could be different lengths, but also could assume a lazy tech just hit them with the impact and care less.

 

That kind of uneven tightening might lead to the brackets under the axles being clocked a bit off from even, but since the axle has pins which align into pockets on the springs, there shouldn't be a huge issue coming from that. It might be better to get the brackets evened out (or even get a ubolt flip kit) if you're going to go off road much; those brackets being clocked shouldn't hurt you any for regular street driving though.

Not sure about 3rd gens, but from what I understand of it, the "taco lean" is caused by the CG of the truck being a bit over to the driver's side, which compresses the springs on that side a little more due to them just carrying a little more weight. If you carry any gear with significant weight most/all of the time (hi-lift, tools, etc) just putting all that on the passenger side of the truck can balance things somewhat. Otherwise, there are kits which come with a 1/4" spacer to put on the driver-side front strut which compensates for the imbalance.

 

Thank you for your reply. I'll even them out a bit just to be safe. The only reason I kinda pointed the finger at the springs for the lean was I didn't see it before the new leafs were installed.

This may be a dumb question but, should I lift the truck when evening out the u-bolts?

I appreciate the information.

 

It's possible the TSB/Recall leaf springs are evenly stiff on both sides (or that the dealer made a slight mistake and put two of the same "side" leaf springs on your truck) and that the factory springs might have been tailored slightly. I ended up replacing my leaf springs with after-market springs for a 2" lift during the 2 years between the recall announcement and the rollout of the "remedy" springs, so I never got that replacement done and couldn't say what the replacement springs are or should be like.

There's no need to lift the truck up to even out the axle brackets and re-torque the u-bolts unless you need more space to reach something under there. If you do lift it for this, jack it up at the diff housing, and put jack stands under the axle and chock the front wheels, having the weight of the back end on the springs will keep everything in place while the brackets are loose; the last thing in the world you'd want to try to do would be to tighten those with the suspension drooped at all. Unless you're using an impact gun to break the nuts loose (I wouldn't personally use an impact to re-tighten them unless you've got the right torque control links), or you're running a custom low-rider on 13" wheels and low-profile tires there shouldn't be any need to lift it, though.

Check the brackets by eye to see if they're very far off from even with the ground, anything under 15 degrees clocking might not be worth bothering with, although it would give you a chance to also check the torque on the nuts since there have been a couple stories around here of dealers under-torquing them and the brackets shaking loose after a while. If you do shift things around, make sure to re-torque all four of the nuts on each side to somewhere around 80-85 ft-lbf to make sure they stay put for you, and re-check them after 100-200 miles of driving.

 

That happened on my 08 and I think the bottom plates were on backwards.

 

I just installed sumo springs on my truck the other day and noticed this same thing with the u bolts. My truck has had nothing done to it so I'm assuming it's just the way it is.

 

https://www.tacomaworld.com/threads/drivers-side-lean-fix.427443/

This is what I used. I also had to use the rear 1/2 block to level out even with dakar springs.

 

If I were to just change out ubolts will I need to jack the rear differential up or can I do it with truck on the ground.

 

All I'm doing is replacing the ubolts and I would have clearance with a wrench on the ground. My question is if I remove one ubolt at a time and add a new one will I have to lift the truck? It seems like it would have no tension and would be fine to replace with tires on and truck on ground..? All the ubolt do is mount the springs to axle

 

with the spring sitting on the axle, you can remove all of the u-bolts on the rear end without any real danger as long as the parking brake is on. There's an alignment pin on the axle housing that's in a hole in the leaf springs which will stop anything from slipping around while you're parked. As long as you can reach everything you need to with the wheels/tires mounted and sitting on the ground, there's no need to jack anything up. Probably the most important thing is to remember to re-check the torque on the nuts, and tighten them down as needed after a couple hundred miles of driving (if you do the swap with a full tank, sometime around the next time you need gas would be a good interval, and is simple to remember). If you have any little containers of touch-up paint with a small brush, you can "stripe" the nuts to make it easy to spot any loosening - paint a spot or vertical line down the side of each nut and make a matching mark on the bracket, as long as the marks stay aligned, the nuts aren't coming loose.

If the springs were run under the axle the way older jeeps were (I think my 1997 5-lug tacoma might have been built that way also, but I'm not sure since I sold that truck almost 14 years ago), then you'd be in a more complicated situation and would need to do the swap with the axle drooping on the springs.

 

Awesome thanks! What's the torque you recommend 73 ft lbs? Also I bought some cross check, it's like a yellow paste. Haven't used it yet but plan on it when changing ubolts. Just waiting for them to come in the mail

 

If you have to ask this question, then you should not touch the truck. Sorry that's my opinion.

But if you plan on fixing it yourself anyway then yes you can take the ubolt off without lifting the truck since the leaf spring sit on top of the axle housing. Just make sure you chock the wheels to be safe.

 

That's what I thought but wanted to make sure before I did this thanks and I don't mind your opinion. It's my first truck so still learning