Strut Mods

PostPost by: type26owner » Sat May 18, 2002 3:41 pm

Has anyone devised a way to key the outer races of the hub axle bearings
to the strut housing so they can't spin under any operational
conditions?
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PostPost by: ardee_selby » Mon May 20, 2002 2:06 pm

Not directly related, but I recall a late '70's Club Lotus newsletter
with an owners +2 rebuild. The owner had drilled/tapped into rear hub
to fit a grease nipple.

I can't remember if a bleed hole/plug was mentioned, but imagine the
bearing seals would soon protest at any over-pressure.

Has this tweak been done successfully, or is it another one like HP
oil pumps?

Cheers - Richard

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PostPost by: garyeanderson » Mon May 20, 2002 2:23 pm

I bought a pair of struts that were modified like that, they held
about a half a pound of grease. I am not sure of the thinking behind
it. I will rebuild as stock and plug the holes tapped for the grease
nipples. I am not to sure what Keith is trying to achieve
by "pinning" the bearings in place, I have not yet had one spin in 8
years of "highway" driving.

Gary

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PostPost by: nigelrbfurness » Mon May 20, 2002 2:34 pm

Hi all,
An interesting one, this - the nipple mod was touted
for a while in the Club Lotus magazine years ago. I
won't comment on it other than to say in my experience
(25 years of Elan ownership) the diff bearings (which
are the same as the outboard ones except on S4s where
the inner race is larger) last for ever whilst the
outer hub races fail standing still. I put this down
to the fine mist of oil that penetrates the diff
output shaft oil seals. The outboard driveshaft
bearing seem to fail through corrosion due to water
ingress rather than actual wear through high mileage.
I inspected a failed bearing recently and found a
mixture of grease and rust - grease is certainly _not_
a rustproofer, so its not lack of grease that is the
problem.

Neither have I ever had an inboard hub bearing turn on
the shaft - for this to happen, surely the bearing
race would have to seize? And I have put a
respectable amount of horsepower through them on
occasions!

On several occasions I have found water
(condensation?) in the strut housing during bearing
changes.

Just my two-pennorth.
Nigel Furness

--- ardee_selby <***@***.***> wrote: > Not
directly related, but I recall a late '70's Club
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PostPost by: gobw2 » Mon May 20, 2002 4:15 pm

Nigel - My examinations of many failed outboard bearings agrees with your
conclusions - failure due to contamination. I noted that they failed
rather quickly when car exposed to road salt used in winter. To reduce
the road muck slung about, I made slinger rings for the inside shafts,
and plastic cone extension for the housing to reduce clearance between
housing and hub. This more than doubled bearing life. I also noted
moisture in the bearing housing, and wondered how it got in there. George
67 S3
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PostPost by: nigelrbfurness » Mon May 20, 2002 4:27 pm

George
This sounds like a good idea. When reassembling my
hub carriers I considered whether it would be worth
making up some sort of protection for the outer
bearings but couldn't see an easy way to do it so
reolved not to take the car out in the rain!

Water in the housings is another problem. My feeling
is it probably comes from the strut gland nut area,
getting in via the piston rod hole then running down
the outside of the strut insert. That would be
consistent with the rust trails on the strut insert.
Water vapour from this ingress might then find its way
into the inner bearing perhaps?

I wonder if drilling a small drain hole in the housing
is worthwhile with a split pin to keep it open?

Nigel Furness
64 S1, 66 S2, 69 S4, 70 S4SE mumble mumble...!


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many failed outboard

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PostPost by: ardee_selby » Mon May 20, 2002 5:06 pm

George,
Any chance of a pic of these? Did you do anything to
the diff output shafts? These failed on mine, not hub
bearings

Cheers - Richard - '67 S3

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PostPost by: type26owner » Mon May 20, 2002 5:18 pm

Kevin,
I'm beginning to suspect all these effects are actually from
fretting. Unless the axle is beefed up in diameter and the strut
housing somehow also strenghted these failures will continue
periodically. The modulus of elasticity of steel and therefore the
amount of flexing of the axles as it rolls along is coming into play
I suspect. The cantilevered moment is to much for this arrangement.

I wonder if removing the force contribution of the donuts would help
in any way?
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PostPost by: Elanman99 » Mon May 20, 2002 8:19 pm

I confess to being guilty of fitting a grease nipple to one of my rear hub housings! I cant really remember why I thought it was such a good idea, as Gary said it holds a lot of grease! and not much of it has any real chance of actually getting into the bearings.

I did it at the second bearing change only 18 months/15,000 hard road miles after buying my S4, incidentally although it was an S4 it had the older narrow bearings. When the dampers failed I bought new rear strut assemblies with the bigger outboard bearings and threw the originals away.

Ian Phillips
S4 DHC

----- Original Message -----
From: garyeanderson
To: ***@***.***
Sent: Monday, May 20, 2002 3:23 PM
Subject: [LotusElan.net] Re: Strut Mods


I bought a pair of struts that were modified like that, they held
about a half a pound of grease. I am not sure of the thinking behind
it. I will rebuild as stock and plug the holes tapped for the grease
nipples. I am not to sure what Keith is trying to achieve
by "pinning" the bearings in place, I have not yet had one spin in 8
years of "highway" driving.
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PostPost by: nigelrbfurness » Tue May 21, 2002 7:59 am

--- Eric Camiel <***@***.***> wrote: >

That is quite correct and exactly what I usually do -
it just slipped my mind.
Nigel Furness








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PostPost by: garyeanderson » Tue May 21, 2002 1:43 pm

This is not clear to me, the subject is about grease in the bearing
housing. I assume that you are talking of filling the strut tube that
the shock insert goes into with anti-freeze or oil. Not the bearing
housing. Am I correct?

Gary

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PostPost by: type26owner » Tue May 21, 2002 2:04 pm

Kevin,
Had the exact same failure of the bearing adjacient the hub inner race
wearing the axle away. This is almost impossible for one person to
detect if you have the sprint donuts installed. Takes one person
heaving on the wheel and the other looking around the back for any
movement. The bearing hadn't siezed. When taken apart and examined it
looked to be a little worn but certainly not the problem. A spacer to
capture the race isn't feasible I pretty certain. Got to ask why a
duplex bearings weren't used here. This seems like an obvious choice
since there are sizeable axial loads in it's operation.
<http://www-eng.lbl.gov/~franck/Car_stuff/1966_S2_Elan/%23other_failur
es/spun_bearing.JPG>
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PostPost by: nigelrbfurness » Tue May 21, 2002 2:05 pm

Yes, we seem to have got muddled here. It's my fault
as I was thinking out loud as to how water would get
into the bearing housing and mentioned the gland nut
on the strut. Of course the bearing housing and the
strut housing are separate chambers in the casting.
The only possible ingress of water into the bearing
housing chamber is through the bearings themselves or
by condensation.

The original thread was about filling the bearing
housing with grease which I think we all agreed would
be pointless as lack of lubrication is not the
problem.

Nigel Furness


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PostPost by: G4ILN » Tue May 21, 2002 9:50 pm

Greetings All.

My Elan +2 had grease nipples fitted to the rear stub axle bearing castings
when I bought it. I dutifully pumped in some high melting point grease
every 6 months or so. When I removed the bearings some years later I found
a great dollop of clean grease inside. Not enough grease had been pumped in
to completely fill the casting. Even if the casting had been completely
filled with grease it would have had great difficulty in reaching the
bearings even under pressure, as the neoprene? seals were still fitted to
the inside of the bearings. I think these would have acted as quite good
non-return valves, preventing grease entering the bearings. So if you
decide to fit nipples, it's probably worthwhile prising out the inner seals
before refitting the bearings. This does of course mean that grease under
pressure will force out the outer seals, assuming that a washer or shoulder
does not prevent this.

My bearings weren't actually worn much, so I prised out the seals, washed
out the old grease, repacked them with HMP grease and refitted the seals.

I have been trying to think of an application where an automotive ball or
roller bearing, as opposed to a plain bearing or ball joint or universal
joint is fitted with a grease nipple, but I can't think of one at the
moment. ISTR though that some very old cars had grease nipples fitted to
the ends of the dome shaped covers in the middle of the front brake drums.
This would have allowed grease to be pumped directly into the outer taper
bearing, along the hollow bearing carrier and through the inner taper
bearing. Old water pumps also had them and it was often possible to cure a
leaking seal for a short while by pumping in some grease. Grease
lubricated ball bearings all seem to be sealed for life these days. No
doubt someone on this list will know of a modern application where a grease
nipple is used to lubricate a ball bearing.

Regards

Graham.
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PostPost by: gobw2 » Tue May 21, 2002 10:39 pm

Keith - I looked for that too - with original wheels, on the street, most
of the problem seems to be caused by the use of a lip seal as the sole
means of protection. Examination of exposed lip seal surfaces always
showed penetration, whereas the inside lip was usually in good condition.
In 1972, I was working with Fafnir on an unrelated project, used their
bearings in axle, and asked them to examine. As I recall, I was told
this was an improper application for lip seal. Their other
recommendations - a higher temperature grease, trying forced lubrication
by removing inner lip seal and greasing.
Use on the track, wider wheels, stickier tires, etc will most likely
exceed original design parameters, which as we know, usually did not have
a substantial reserve. This could cause the conditions you mention,
which, after a time, should show up as fatigue failures. George
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