Lotus Elan

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

--- In [email protected], "kstrutt1" <[email protected]> wrote:
On a similar vein has anyone modified the inner race to be a
positive fit on the driveshaft, I have already had one spin and
damage the shaft even though the bearing was only slightly worn I
believe this is quite a common problem.
I considered using a spacer tube between the bearings and a shim to
the hub but then you run the risk of reducing the clamp load on the
hub taper.

Kevin
+2S130

--- In [email protected], keith franck <[email protected]> wrote:
> 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?
> --
> Keith Franck
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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

--- In [email protected], "ardee_selby" <[email protected]> wrote:
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

--- In [email protected], "kstrutt1" <[email protected]> wrote:
> On a similar vein has anyone modified the inner race to be a
> positive fit on the driveshaft, I have already had one spin and
> damage the shaft even though the bearing was only slightly worn I
> believe this is quite a common problem.
> I considered using a spacer tube between the bearings and a shim
to

> the hub but then you run the risk of reducing the clamp load on
the

> hub taper.
>
> Kevin
> +2S130
>
> --- In [email protected], keith franck <[email protected]> wrote:
> > 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?
> > --
> > Keith Franck
"garyeanderson"
 

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: 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: 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
On Mon, 20 May 2002 17:18:24 -0000 "type26owner" <***@***.***>
writes:
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?
--
Keith Franck
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PostPost by: gobw2 » Tue May 21, 2002 10:45 pm

Cars of yesteryear had them all over - u joints,Steering and suspension
points (kingpins), rear leaf spring attachments, water pump. We are
talking about over 20 fittings - used to take over 1/2 hour to get them
all lubed. Some Luxury cars even had a bijur lube system that
automatically greased all
points as one drove! Of course, grease was of lower quality, and seals
were not as good. George 67 S3
On Tue, 21 May 2002 22:50:45 +0100 "Graham" <***@***.***>
writes:
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.
gobw2
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PostPost by: lotustony » Tue May 21, 2002 11:53 pm

Graham wrote of sealed/unsealed bearings:


<<<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.
<snip>
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.>>>

I can think of some NON-automotive applications but in practice, they were prone
to abuse from high pressure air powered grease guns which tended to destroy the
seal. An extremely handy devise is a grease fitting with a hypodermic
needle-style
probe which can be inserted through the seal lip to lube a suspect bearing.
It will NOT, of course, "repair" a failing bearing but it will prolong the life
of a serviceable unit. I found mine at a tractor dealership many years ago.

Tony
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PostPost by: john.p.clegg » Wed May 22, 2002 6:35 am

Daer All
Mr chapman would not of been impressed with the increase in unsprung weight
caused by large dollops of grease
john
68plus2

-----Original Message-----
From: Graham [mailto:***@***.***
Sent: 21 May 2002 22:51
To: lotuselan
Subject: [LotusElan.net] Re: Strut Mods


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: c.beijersbergen » Wed May 22, 2002 7:48 am

Hello to all of you,

Several times I attended the Technical Seminars given by the folks of Club Lotus in the Netherlands some 15-16 years ago. They also stated that in order to prolonge wheel bearing life one should pack them with as much grease as possible. I had an argument with them about this because its opposed to what I learned during my education in mechanical engineering.

The grease in roller bearings is there only to lubricate the balls in their cage and to give the balls and the races some protection against corrosion. For the bearing function itself it is not needed because the balls are supposed to be rolling perfectly, not slipping or sliding. Every ball in a roller bearing constantly has to push away any oil or grease that lies on its path when the bearing is in action. This causes heat build-up in the bearing. With a large amount of grease in the bearing, bearing life can and will be reduced considerably. This is the reason one does not see any grease nipples on roller bearings. The grease packed within the seals will last for the complete life of the bearing.

So my advise from general mechanical engineering practise: use the bearings from a well respected brand and use the type with the completely closed seals as opposed to the partly closed type. This will prevent any moisture or dust particles from entering the bearing.


Greetings,

Cor Beijersbergen van Henegouwen

'70 S4 SE FHC
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PostPost by: "garyeanderson" » Wed May 22, 2002 11:31 am

To All that joined the discussion late.

I don't beleave that any person on this group has recomended
packing the bearing housing with grease, it was once recomended by
one of the various lotus clubs many years ago. This has been a
discussion of what not to do to make the bearings live in the rear
strut housing.

Gary
"garyeanderson"
 

PostPost by: "Martin Stuart" » Wed May 22, 2002 9:26 pm

I agree with everything you have said, Cor, but I find it slightly suprising
that Club Lotus was advising packing the bearings with grease.

As far as I am aware, they now caution *against* fitting grease nipples to
the hub carriers for the very reason you have stated - packiing the bearing
with grease will tend to make it run hotter and *reduce* bearing life.

Maybe Club Lotus' current advice is based upon the feedback they have
received following their recommendations 15-16 years ago?!

Martin Stuart

----- Original Message -----
From: "c. beijersbergen" <***@***.***>
To: <***@***.***>
Sent: Wednesday, May 22, 2002 8:30 AM
Subject: Re: [LotusElan.net] Re: Strut Mods


Hello to all of you,

Several times I attended the Technical Seminars given by the folks of Club
Lotus in the Netherlands some 15-16 years ago. They also stated that in
order to prolonge wheel bearing life one should pack them with as much
grease as possible. I had an argument with them about this because its
opposed to what I learned during my education in mechanical engineering.

The grease in roller bearings is there only to lubricate the balls in their
cage and to give the balls and the races some protection against corrosion.
For the bearing function itself it is not needed because the balls are
supposed to be rolling perfectly, not slipping or sliding. Every ball in a
roller bearing constantly has to push away any oil or grease that lies on
its path when the bearing is in action. This causes heat build-up in the
bearing. With a large amount of grease in the bearing, bearing life can and
will be reduced considerably. This is the reason one does not see any grease
nipples on roller bearings. The grease packed within the seals will last for
the complete life of the bearing.

So my advise from general mechanical engineering practise: use the bearings
from a well respected brand and use the type with the completely closed
seals as opposed to the partly closed type. This will prevent any moisture
or dust particles from entering the bearing.


Greetings,

Cor Beijersbergen van Henegouwen

'70 S4 SE FHC
"Martin Stuart"
 

PostPost by: type26owner » Wed May 22, 2002 10:50 pm

The 6206_2RS1 radial bearings are rated for only 1200 lbs axial
loading. That seems to be a bit too close to overloading the capacity
IMHO. Seems the main criteria for selecting this type of bearing was
the fact they had intregal seals. My choice to fix this situation
would be the 3206_2RS1 double row angular contact bearings with
intregal seals at least on one bearing preferably the hub side.
However, the inner bearing actually is the one which is suppose to
take the axial loads because it's inner race is the only one held by
a retaining ring to the axle. The real challenge is how to clamp the
bearing races to the housing and the axle to stop the fretting. I
know using only retaining rings and interference fits on bits with
3:1 differences in the modulus and expansion coefficients and high
loading isn't very good practice. One needs to axially clamp onto the
races to do this correctly.
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