[DML] Re: Trailing arm bolt procedure w/ jack stands?

[tobyp@xxxxxxxxxxxx]

List - I thought that I'd touch on the questions - why have weight on 
the rear suspension when torqueing up the TAB's, and why have the 
joint unloaded to remove them?  In terms of removing them, when there 
is weight on the suspension, the joint (TAB, rubber bushing, and 
trailing arm) have loads on them from the camber of the rear wheels, 
and loads created by the alignment of the wheels and basic geometry 
of the rear suspension.  In order to manipulate the joint to remove 
the preloads, and allow the bolt to gracefully exit the joint, the 
car should be jacked up with the wheel off the ground (you can do one 
side at at time).  If the joint is preloaded, the bolt will be harder 
to drive out, and things can suddenly shift around when the bolt 
finally comes free.  It's best to have everything relaxed for easier 
removal.  For installation, the joint goes back together best with 
the wheel off the ground (for the same reasons as removing the TAB), 
but here's the reason for setting the car back down for the final 
torque.  The trailing arm joint is supposed to be a clamped joint.  
In other words, there should be no relative motion of the bolt, 
trailing arm, and sleeve through the bushing.  All motion is supposed 
to be in the rubber of the bushing only.  Realistically, the sleeve 
that is bonded into the bushing can tear loose fairly quickly, so the 
sleeve starts to rotate in the rubber.  However, if the rubber 
bushing is still intact (sleeve to rubber still bonded), you want to 
install everything so that the bushing is in a relaxed state with the 
car in its normal stance.  Then, the rubber has equal available 
deflection in both directions.  If the car is in the air when the 
bolts are torqued up, the rubber is twisted all the way in one 
direction to start with, which will cause premature failure of the 
rubber to sleeve bond.  If this is not clear, or you have any 
questions that arise from this, feel free to ask off-list.

Toby Peterson  VIN 2248 "Winged1"
DeLorean Parts Northwest, LLC
www.delorean-parts.com  

--- In dmcnews@xxxxxxxxxxxxxxx, "therealdmcvegas" <dmcvegas@xxxx> 
wrote:
> When torquing everything back up, it's important to have the weight 
of the suspension on the car, so you don't stress the bolts. David T 
reccomends to unbolt the TABS with the weight off of the suspension. 
Why, I honestly don't know, and it's the first time that I've ever 
heard this reccomendation before, so I'm a bit curious as to what 
advantage he's seen with it.





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