The rear end rebush is finally done, the TR6 off the stands and on the
road again! For novices, like me, some thoughts on my experiences below
FWIW. For the experienced, just delete and move on if you want.
First thank you thank you thank you to all who gave me tips on this job,
especially Roger Bollick who was particularly helpful as well as patient
and with my ramblings! I would have been tough and I probably would have
lacked the courage to proceed if all I had was Haynes and beer and no
list to turn to. Also, the folks at BPNW and Goodparts were really
helpful.
Poly diff mount bushings:
What I did:
Replaced all diff mount bushings with Poly's from BPNW
What I learned:
You can do this alone but a floor jack is your best friend.
It is really obvious why the Poly diff mount bushings are preferable
over the rubber stock mounts after you see the originals when they come
out of there. The Poly's just pop right in place, in fact you have to
put a little adhesive or tape on the uppers to keep them there when you
remount the diff. Also, though you can do this without removing the diff
altogether, you have to pull the diff as far aft as possible to slip the
hard poly bushes into place since the diff will hang up and rest (
conveniently) on the frame.
I thought leaving the trailing arms, axles and hub/brake assemblies
attached would create a nice counterbalance to the weight of the diff.
This was true, but later,after finishing the diff mounts, when I
removed those assemblies to do the trailing arm mounts, there was so
much more room to work that, if I were to do these two jobs together
again, I think I would opt for removing the trailing arm and axle
assemblies to get more working room. BTW I think these are good jobs to
do together as one project. Also, getting to the brake hoses back
connections was was a bear with all that stuff in place.
Also, luckily the PO had done the welding repair of the front right diff
mount. This is the one everyone says to watch out for and it broke on
mine somewhere in the past proving the point. The welding job was rough,
and the sharp edges left by the welder had torn up the rubber mount. I
filed off all the sharps before mounting up the polys. Judging from
where this mount is, I heartily agree with everyone who says install the
Poly's _before_you have to deal with a broken mount.
I found in my car the mount spindles were a little longer than the poly
mount bushings depth and had to add an extra very wide washer at the
base so the stock washer did not get stopped by the lip on the spindle
above the threads and I could get good compression on the polys. This is
not a problem on the stock rubber system because (gasp) it relies on a
metal sleeve.
Road test results:
I detect no added noise at the rear end with the Poly's as some are
concerned with. Of course its difficult to hear anything over the smell
of my Monzas ;-P ( which by the way I was able to work around by
releasing all the mounting hardware and spreading them down and apart,
holding in place with bailing wire)
Trailing arm bushings:
What I did:
Replaced trailing arm bushings with Nylatron from GoodParts (TRF was out
of stock). These have a stock of various washers to act as precise
spacers in fitting in imprecisely cast aluminum trailing arms.
What I learned:
You can do this alone but a floor jack sure helps.
The Nylatron system with the fitted washers popped right in. They are
rock hard. They are more precisely designed than the Polys and the
polys are noticeably softer, which I also had ordered for comparison but
will return. This precision actually worked against me as I have a so-so
job rewelded frame and the trailing arm brackets are a little out of
proper spacing, so I have had a lot of fiddling to do and had to go
without washers spacers on one side of one mount on each side. The polys
would have had a better naturally adjustable fit, but I beleived the
Nylatrons would perform better. I would guess that a good frame and
brackets should not have any problems at all. Another advantage is the
stainless sleeve ( the polys are regular steel I beleive) is internally
bevelled out from the center, that is , the outer ends are wider than
the center so you can toggle the mounting bolt back through the
bracket-sleeve-bracket with ease when remounting the trailing arms.
3/8" Threaded rod with washers is the best removal method for the old
rubber bushings. I found it much easier after drilling a few holes
throught the old bushings than my first attempt without drilling the
holes. I ran the arm through both sides of the trailing arm and pulled
inward. All great advice of the list of course.
I found that remounting the trailing arms while "aiming" and fitting
the mounting hardware was eased by resting the trailing arm on a cinder
block which I could move in and out under the curvature of the trailing
arm to change and then hold the height I wanted to work with. This would
of course require the car to be up about 16" on stands as mine was.YMMV
on this.
I also replaced the rubber spring packings with Poly's.
Road test results:
The tendancy of the rear end to feel like it wants to come around to the
front on curves, especially long sweepers, is gone. Just like everyone
said it would be. This scary feeling was first really noticeable after I
rebuilt the front suspension last fall ( BPNW poly's throughout, mild
comp (blue) springs from Moss, Spax shocks, other stuff stock ). Now
there is a much more secure controlled feeling. Very straight and
stable feel at highway speeds and a sense that if pushed in the curves
it would four wheel drift before losing the rear end. No detected
additional harshness. Autocross is looking more interesting now!
I did not notice much difference in ride height. I always had near zero
but slightly negative camber in rear before, though unequal on both
sides. However now one side is ever so slightly positive and the other
closer to neutral which I think is more likely the rise from the poly
spring packings than the trialing arm mounts. I will wait a couple of
thousand miles for settling before looking into new trailing arm
brackets to fix this if still needed.
I also replaced the brake hoses with stainless braided to match the
fronts as long as I was in there along with replacing the half shaft and
spline rubber covers. POR-15'd or painted everything I could reach while
I was in there.
Shocks:
I am currently in the process of testing the BPNW ( also VB at higher
price) tube shock system against rebuilt and uprated lever arms from
Worldwide Autoparts ( Madison WI). I will (amateur) report on this in a
separate email FWIW.
I hope something here might be helpful to other first-timers. Again,
thanks to the list for all the advice and courage.
BTW, if I were only doing the diff mounts, it would be a day maximum
assuming nothing was frozen, but I like to linger. Same with the
trailing arm bushings. For a pro, maybe a quarter of that time max. For
a good pit crew, 5 minutes each!
I anyone has questions, feel free to ask. I am in digest mode so it
might be next day service.
Keith Ehrlich
74 TR6 smoother and straighter than ever.
I bought both tubes from BPNW and rebuilt and firmed up lever arms from
Worldwide Autoparts in Madison WI. Comparison in progress to be reported
in another longwinded message for those interested in this aspect.
Road test:
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