Miata Mailing List: September 1993, Message #169
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   From: buck@petra.ma30.bull.com (Kenneth J. Buck)
Subject: roll bar bushing replacement report
   Date: Tue, 21 Sep 1993 13:12:32 -0400

okay gang, time to complete my report on changing my
anti-roll bar bushings...

my task:
replace the factory bushings around the anti-roll bars
and in the attached end-links.  handling was starting to
degrade, so i figured, why not try this.  i got a set of
urethane replacement bushings from Motorsport for i think
around $60 (i don't have the price list handy).  Motorsport
advertises in the Miata Magazine and has lots of useful
Miata stuff...

summary:
once you have the right tools, this is pretty easy and
can be done in an afternoon.  in my case, a long afternoon... :-)

qualifications:
none required, good thing because i don't have many.
anybody who knows one end of a wrench from another can do this
(what, you mean wrenches have 2 different ends!?).

required tools:
-wrenches: torque wrench, a small/medium socket wrench, various sockets
           in the 9-14mm range, 14mm box wrench.
-some WD-40 or equivalent for rusted nuts & bolts.
-small propane torch for removing the stock bushings from the end links.
-medium size or larger vise for squashing the new bushings into the
 end links.  i have a Sears 4.5" vise, costs about $40, works fine.
-maybe a small razor or hack saw
-hammer/mallet
-jack, jack stands, chocks, etc.
-patience.


doing the job:
front and back are similar, except the front has a few more bolts
to undo and some tighter clearances.

on the front, jack up the car, remove the wheels, and remove the
plastic engine compartment splash shield, lots of little bolts and
a few screws.  this is easy.

remove the bolts attaching the end links to the roll bar and to the
lower control arms.  remove the bolts attaching the roll bar to
the frame.  squeeze the original bushings off of the roll bar and
replace them with the new ones.  the replacement bushings have a
hard-to-see slit, so all you have to do is pry them apart and press
them over the bar.

remove the bushings from the end links requires the torch to break
the bond between the bushing material and the link.
i used the razor saw to remove the "ears" of one side of the bushing
to make it easier to pound through but i don't know if that's really
necessary or not.  you have to heat the link/bushing up pretty well
to break the bond - the thing may start flaming away, so bring some
marshmallows to toast.  if you're radical, it burns well enough to
drop out all by itself, otherwise you can pound it out with a hammer
pretty easily.  repeat until all links are done.  remember, they get hot!

insert the new bushings into the links(.  wait til they're cool!)
they come with some lubricant to help make this process easier.
without a vise or press of some kind, this is nearly impossible, though.
(as i reported previously, i managed to do one link without a vise
using wrenches, etc., but it was Not Easy).  a vise makes it _very_ easy.
i placed two flat boards inside the vise opening to give a larger
pressing surface, and that seemed to help.  then you just compress
the vise and the bushing squeezes gently into the link.
make sure you insert the metal center piece into the bushing before
it's completely squashed into the link, or else you'll NEVER get it
in there...

finishing the job just requires putting everything back into place
the way you found it, shouldn't be hard.

the whole job probably took me a total of 4 to 5 hours, but that's
including a lot of fumbling around and interruptions.  if you
pay attention and know what you're doing, it probably shouldn't take
that long.


evaluation:
the new bushings are indeed stiffer than the stock ones.
granted, the stock ones were also 3.5 years and 48K miles old
so maybe they had degraded somewhat over the time...
the whole thing was sort of like a cheap roll bar replacement;
cornering is flatter, and response is a bit firmer, but not
excessively so.  i'm quite happy with the results.


additional notes:
while this improved the car in general, this *didn't* solve
another handling mystery that i've been trying to track down.

it feels like the suspension has some slop in it somewhere,
you can feel it when just pulling away from a stop, or
occasionally when travelling on the road at moderate speeds.
it's noticeable even immediately following a 4-wheel realignment,
and is still present after the roll-bar bushing replacement.

my next possible guess is maybe the control arm bushings need
replacement?  (this doesn't look as much like a do-it-yourself
job as the roll bar bushings were)
otherwise, i'm at a loss.  i haven't yet asked a dealer re: this
because i wanted to have some self-diagnosis in place first.
(i don't need to hear them tell me "there's nothing wrong" or
"they all do that".  when the car was new, it *didn't* do that.)
any ideas/suggestions will be welcomed.


question:
i'm curious how folks who have replaced the front roll bar did so.
i couldn't see how you could remove it without disconnecting some
of the plumbing under the radiator - it didn't look like there was
room to fit the bend through the available openings.  anyone?

--                                             
Ken Buck                                          /|
Internet: k.buck@ma30.bull.com                \'o.O'    ACK!
Mail:     Bull, MA30-833A                     =(___)= THPTPHH!
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