Lotus Elan

Rear Strut - Axle Shaft & Bearing Removal.

PostPost by: ceejay » Mon Nov 14, 2011 11:23 am

Over three decades of elan ownership, you become
a little wiser about the various lotus quirks, and develop
a better understanding of these great little British sports cars.

But there are some parts that can be a pain to dismantle
and reassemble, and there can be a bit of frustration with
the elan, and the component I refer to is the rear struts which
hold the wheel stub axle and bearings.

I've tried two methods of disassembly, and I will discuss
them here to share with other elan owners.

The first attempt (About 2.5 decades ago) at pulling the
strut axles and bearings were a pain in the butt. But after
unclipping the circlips, or snap rings (Whatever you prefer
to call them) you are then faced with the removal of the
axle. Due to the design of the struts they are not easy
hold or to carry out work on.

If the alloy strut housings have been replaced during the
cars life, then the bearings are going to be a tight
interference fit.

But if the housings are old, the bearings are generally
not as tight as when new, and bearings are held in worn
housings with loctite, this stuff works and can still hold
bearing pretty tight..

The first method I tried was to make a large metal impact
tool, which has a threaded internal bore which is simply
screwed onto the existing thread on the outer end of the
axle, care must be taken when machining and cutting the
thread that the face of the tool is parallel with the shoulder
of the stub axle, and it will be if it is machined correctly, the
threaded hole in the impact tool must also be deeper then
the thread on the axle, the pictures further explain what this
tool is about.

The extraction method is to place the rear strut onto
(Across) a solid truck tyre placed on the ground, then
screw the impact tool on, and proceed to use a heavy
lead or copper hammer to impact and drift the axle shaft
out of the housing. (After unclipping the circlips of course)

Yes, I can feel and hear some you wincing at what sounds
like a heavy handed action, but if you work very carefully, the
method does work, the axle and one bearing will eventually
drift out.

But I now prefer to always use a garage press, the following
pictures will help to explain an easy to make press holding
jig which will make the job of removing the axle much easier
than you could imagine.

The jig in question was made from scrap metal found
in the workshop junk pile (Couldn't live without this)

The items required are:
Short length of 2 x 1 x 2mm RHS.
Square 6x6? X 6mm mild steel plate.
short length of 40 x 40 x 3mmRHS.
75 X 50 X 10mm flat mild steel .
Length of 7/16" Dia 4140 bar.
2 x 1.5" X 3/8" UNC bolts.
Study the pictures for more construction detail.

The jig is attached to the strut using the 4140 bar
passing through the strut housing bolt holes, and also through
the 40 x 40RHS support, which is welded to the 8mm mild
steel plate bolted to the upright.
The strut tube end is supported with hardwood blocks on the press
bed, the axle is required to be at 90Deg to the press bed.

All that is required after set up is to carefully apply pressure,
watch that the 4140 bar does not bend, the axle and bearings
in the picture let go with quite a loud crack and after a small
amount of movement, it dropped gently onto the press bed...The
main part of the job was done; all that remained was to
remove the inner bearing retaining circlip from the axle and
press the bearing off.

The jig made the job much, much easier than previous attempts
with the first tool we mentioned above. But some improvements
could be made; make a bracket that spreads the load across the full
width of the housing with the high tensile bar.
The hardwood support at the strut end is probably OK as
packing pieces can be placed underneath to help set the axle
vertical.

The remaining bearing is removed from the axle with a normal
bearing-press extraction tool.

A garage floor press allows careful set-up and the pressing
procedure can be monitored to make sure no undue force is
being applied which could bend the strut tube.

Here's a handy trick when pressing, when you know that quite
a bit of force has been applied (Check the pressure gauge
if the press is fitted with one) give the press bed a really hard crack
with a heavy ball peen hammer, the shock wave sent through the press
is generally enough to break the metal to metal bond which happens
over time with bearings contained in alloy housings.

The jig can also be used to support and hold the strut assembly
on the bench to drift out the bearing left in the housing.

So there you have it, experience straight from the coalface,
some elan owners may think this job a bit to much too tackle,
while others may be wondering "How To Do It", hopefully this
will be of help to someone.

Maybe it's time to give those welding and fabricating
skills a workout.

Ceejay.
http://www.elantrikbits.com
Attachments
stub-axle-14.jpg and
stub-axle-15.jpg and
rear-strut-jig-09.jpg and
rear-strut-jig-10.jpg and
rear-strut-jig-12.jpg and
rear-strut-jig-13.jpg and
Give tools to those who can use them.
Provide land to people who want to grow
things.
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PostPost by: miked » Mon Nov 14, 2011 1:31 pm

Interesting jig.

I have an old cut off hub shaft that has been converted to a slide hammer. I.E use the 3 bolt end piece. It is about 18 inches long and about 1/2 inch solid bar. Quite a hefty weight on it. About 4" long by about 2.5 inch bar. I bolt it up to the inside of the strut fitted shaft. Apply some heat to the ally case and then launch the slide weght. As my friend said who made this, it will pull your b&ll end off. :oops: He was right. Not failed yet. It is also very useful for diff out put shafts. Same trick.

I did see a small one of these somewhere, so not my idea. However the bigger version works a treat. I can't see it doing any harm with the central pull and the impact. I suppose leaving a disc on would help stiffen things.

Mike :D :oops:
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PostPost by: ardee_selby » Mon Nov 14, 2011 3:27 pm

miked wrote:Interesting jig.

I have an old cut off hub shaft that has been converted to a slide hammer. I.E use the 3 bolt end piece. It is about 18 inches long and about 1/2 inch solid bar. Quite a hefty weight on it. About 4" long by about 2.5 inch bar. I bolt it up to the inside of the strut fitted shaft. Apply some heat to the ally case and then launch the slide weght. As my friend said who made this, it will pull your b&ll end off. :oops: He was right. Not failed yet. It is also very useful for diff out put shafts. Same trick.

I did see a small one of these somewhere, so not my idea. However the bigger version works a treat. I can't see it doing any harm with the central pull and the impact. I suppose leaving a disc on would help stiffen things.

Mike :D :oops:


Mike,

I'm in favour of anything that keeps well away from the threaded stub. (Such a slide hammer has been described for removing diff output shafts, but can't recall it being used on hub shafts). I think keeping a disk in place would be good. In my experience the ears are also a bit of a soft spot! I assume disk run-out wasn't a prob after you used it.

BTW, how did you support the strut assy during removal, or was it still on the car?

Cheers - Richard (Q. Did Captain Beefheart have an Elan? :wink: :) )
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PostPost by: miked » Mon Nov 14, 2011 4:39 pm

Richard,
I had them in the lathe after and checked. No problems.
I have just had them sat on the floor on my rubber mat holding the strut tube upright and giving the slide a whizz. The heat softens the loctite and they usually start to move out after the second try. In about 4 slides they are out. I do clean up well around the circlip groove etc, then you are not trying to pull throught muck and dirt.

I have also drifted them out from the thread side with a couple of old nuts fitted. Dont like it as you say because of potential thread damaged.

Dont know about Captain Beefheart, but maybe old Mr Heath Robinson. :lol:

Mike
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PostPost by: AHM » Mon Nov 14, 2011 8:56 pm

Applying heat to the alloy housing (not the bearing) makes the difference between drifting it out, and belting it hard but getting nowhere! also heat destroys the loctite.
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PostPost by: alexblack13 » Mon Nov 14, 2011 10:19 pm

I too use a slide hammer for this but again after applying a little heat. Via a boiled kettle. The ally expansion is such that it should completely release the grip on the bearing. I don't use loctite as my housings are still nice and tight. Pressing bearings into ally housings will see the bearing 'taking a cut' and eventually the housing WILL become over-sized resulting in the need for the loctite. (glue)..
When we raced karts the engines were rebuilt approx every six hours. I Placed the engine halves in the oven and took the temp' up to about 120 deg, then just a tap of the casting on the wooden bench resulted in the bearing falling out. And if you were all ready to go the new bearing could be dropped into place. When cool the bearing was secure. The engine crank case did not get anywhere near boiling point temp when running by the way. We kept the fuel in the caravan fridge.. :wink:

IMHO... One should not press bearings into an ally casing and pressing them out can also be hazardous. You see many wrecked cases with circlip grooves destroyed by trying to knock out (or press out) bearings. I fit bearings just about every week and heat is the secret. Not hammers!! Even pressing them onto a shaft is not a great idea as they do take a cut each time. I use an induction heater supplied by most bearing supply companies. Also, the vast majority of premature bearing failures are due to bad fitting usually by using a hammer. I do not press them onto my drive shafts either. A little heat and the bearing will drop into place with NO hammering or pressing.

To each their own though.. This is just my humble opinion and my tip on how too. Read the bearing fit manuals available from various manufacturers.

Al' .....
Alex Black.
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PostPost by: mark030358 » Tue Nov 15, 2011 11:33 am

Alex,
I've seen induction heating used on "huge" bearings etc but these were not pre-packed with grease. How do you avoid the grease from running out?

cheers

Mark

ps thanks for the window bolts :)
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PostPost by: alexblack13 » Tue Nov 15, 2011 3:43 pm

2rs (rubber seals) or sheilded (Z) brngs the lube stays put normally. On open bearings one is supposed to wash out the oils therein as it a preservative. So I wash them out, fit them, then pack with the recommd amount and type of lube..

Not an issue at all...

My pleasure re bolts..

Alex..
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