Replacing a rotoflex

["Jang, Raymond (JANG]

Hi Geo:

Place a jack-stand to support the a-arm. Squeeze down the rotoflex with a
circular clamp. Undo the 6 bolts attaching the donut to the driveline.
Replacement is the reverse process. Easier said than done. This task can
be one of the most frustrating chores on an Elan. But, there is one key
tip.

In my experience it is VASTLY simplified by really cinching down the
rotoflex with two large diameter hose clamps run end-to-end to make a long
enough ring to fit around. If you crank the clamp down to where the bolt
holes on the rotoflex line up closely with those on the axle and diff output
shaft you can remove and insert the bolts almost by hand with very slight
pressure. If you do not get the holes lined up it will be one of those tug
and tussle fights on every bolt. When that happens I often find a few more
turns on the hose clamp screw will ease the struggle. Also, after you get
the intermediate shaft bolts installed, it helps to get one bolt in the
diff output ears and then walk the donut around to line up with the
remaining holes by rotating the wheel hub.

Hope that helps and good luck!

Ray.

[jcocking]

Should you replace?

a) one at a time
b) all four
c) one complete side
d) by pairs (inboard or outboard)



jeff

[geojo <geojo at xxxxxx]

Jeff, A one inboard is badly ripped, the rest seem in good shape. geo


Jeff Cocking wrote:

[rodney]

At 08:00 AM 10/19/99 -0500, you wrote:

I have had no problems with replacing one at a time. But then I haven't
done an indepth study to see if there is any difference in not doing this.

Rodney Stevens

Email: [email protected]

Work Phone: 61 2 97106701
Work Fax: 61 2 97106789
Email: [email protected]

Elan SS s/e 45/7616
http://sites.netscape.net/rodjohnstevens/homepage

[jcocking]

I was just wondering. They are a wear item and ussually you replace wear
items in pairs. Normally you would replace tires, brakes, shocks, bushings,
etc. in pairs. With rotoflexes, an older one would flex more than a newer
one. I would think the difference would be limited to somewhere between a
live axle car and a car with limited slip. Just some outloud thinking.
What does the group think?

Should rotoflexes be replaced in pairs?
or
It does not matter?

jeff

-----Original Message-----
From: Rodney Stevens [mailto:[email protected]]
Sent: Tuesday, October 19, 1999 6:03 PM
To: [email protected]
Subject: RE: [lotuselan] Replacing a rotoflex


From: Rodney Stevens <[email protected]>

At 08:00 AM 10/19/99 -0500, you wrote:

I have had no problems with replacing one at a time. But then I haven't
done an indepth study to see if there is any difference in not doing this.

Rodney Stevens

Email: [email protected]

Work Phone: 61 2 97106701
Work Fax: 61 2 97106789
Email: [email protected]

Elan SS s/e 45/7616
http://sites.netscape.net/rodjohnstevens/homepage

[types26/36]

It seems to me that it would be wise to replace all four, if all four
rotoflexes are of the same age and one fails.

However, since the parts are not cheap and not easy to change, look for
rubber pulling away from the steel anywhere on the other donuts. Any signs
of this and the donuts should be changed. Slight checking of the rubber
doesn't seem to be an indication of iminent failure.

Also, an Elan in standard tune with standard wheels and tires will allow
the rotoflexes to live much longer than those that have to transfer a lot
more power through sticky tires.

-Randall

[Foxie]

-----Original Message-----
From: Jeff Cocking <>
To: [email protected] <[email protected]>
Date: 19 October 1999 14:05
Subject: RE: [lotuselan] Replacing a rotoflex



Jeff,

My thoughts on this. Some components such as shocks, tyres, should always
be replaced in pairs at least, to balance effectiveness which decreases
with time/wear. In the case of Rotoflexes, which work continuously with
unchanged effectiveness until they break, (although deterioration normally
becomes visibly obvious beforehand), the foregoing requirement does not
apply.

However, groups of components which eventually fail through a combination of
stress and time, such as valve springs, bearings, and Rotoflexes normally
have a similar lifetime, and should ideally be all replaced at the same
time. If your Rotoflexes normally last 15,000 -20,000 miles, you can
rely on 15,000 miles with no problem in this area if they all start life
together. If you change them one at a time as they fail, you can
statistically expect the next one to go _anytime_ in the next 5,000 miles.
Russian Roulette.

Of course, if you don't change them until they fail (If it works, don't
fix it !) , you save on parts costs, but at the cost of reliability.
Murphy's Law that it will go wrong at the worst possible time can make this
a high cost. You also have the cost of downtime/disassembly, which is
often not much longer if you do the lot rather than just the one.

I use the policy of changing all similar parts at the same time, such as
valve springs, brake seals, valve seats, suspension bushes, wheel
bearings. I've had to be towed home _once_ in the last fourteen years.

BTW I've also fitted Spyder CV jointed drive shafts. The 2 heavy duty
Rotoflexes I fitted at the same time are still perfect after 25,000 miles.

Hope this helps,

Sean Murray
1970 +2S
Wexford

[rodney]

At 06:45 PM 10/19/99 -0500, you wrote:

I would assume that the newer more flexible one would do more of the work
and this may actually enhance the life of the older work hardend coupling.
I have not noticed any diference in the drivetrain characteristics when I
have done this.

I have also replaced single brake pads on rare occasions and under normal
driving have not found this to be a problem. If I was racing the car then
this might be different.

I would agree that tyres are something that should be replaced in pairs if
they are of a different brand/model but, rotating tyres with a spare at
regular intervals is equivalent to just replacing one tyre at a time so
even tyres don't always have to be replaced in pairs.

The same with wheel bearings. Inner and outer bearings on one wheel should
be replaced (just so that you don't have to disassemble it all again) but,
there is no reason to do the other side if it is running ok.

My thoughts.

Rodney Stevens

Email: [email protected]

Work Phone: 61 2 97106701
Work Fax: 61 2 97106789
Email: [email protected]

Elan SS s/e 45/7616
http://sites.netscape.net/rodjohnstevens/homepage

[rodbean]

Jeff Cocking wrote:


I don't think it makes any difference that way. The reason people generally
replace one side's worth at the same time is just because they're there anyway,
once the half shaft is removed.

On my yellow S1, I discovered a ripped donut when I first got it (the only one
that wasn't a Sprint type). The others looked fine so I only replaced the one
(with a Sprint type, of course). Never had any more (visible) problems, even
with a few slaloms, etc. added to regular street use. When I'm driving the car
regularly, I inspect them fairly frequently (had one go in a big way years
ago).

Rod

["Jang, Raymond (JANG]

An observation. 2-3 years ago, an outboard donut broke on my Elan. It was
one of a set of Sprint donuts that were all new on my total restoration some
4 years previously. I replaced only the broken donut and put that car into
street use. It gets pretty good use in the summer. I haven't noticed
anything unusual in driveline action and I'm running a stroker TC.
Depending on the condition and age of the remaining donuts, I'd say for
street use replacing in pairs or sets is not a critical concern.

Nevertheless, next time I'm under the car I will take a closer look at the
donuts.

Cheers, all. Ray.

[Brian Walton]

One of the more unusual vehicles I have owned was a BMW Isetta (Yes I
had the keyring!). They enjoyed rubber donuts just like the Elan. I
managed to travel some 30,000 miles in the thing. It was RHD even
though the LHD version would have only made a seat difference of a
foot! Twice the donuts gave up. Both in the most awkward places.
Ref: Donuts. It all comes down to "sods law". Leave em for a moment
and they let you down.........check them all the time and they last
for decades!

["Ken Woodburn"]

What an interesting subject, we have just completed the replacement of two
couplings and a driveshaft on a +2. The lady driver had inadvertently
dropped the clutch as the car rolled backwards - result one shredded
coupling, one broken driveshaft and one dented chassis. All fixed now, but
at a price! I always go for replacement in pairs, besides being safer ( I
think ) its usually easier to fit two new ones with the bands on than to
refit one without a band.

Regards
Ken W.