EZS_steering_dampener
ezs_steering_dampener.htm
The problem: The dampener (damper) rubber sleeve is/was leaking.
EZS steering dampener rubber bellows...that lower rubber sleeve, ...tends to crack from age and sun exposure. It will then leak oil. The rubber part is available from EZS (in Holland, only), but is pricey. You also need Oetiker clamp pliers and the two Oetiker clamps to install it, although sturdy nylon zips will work OK.
After contacting Pete Larsen (Liberty Motors, EZS sidecars USA) about this item, he referred me to EZS in Holland. The factory at first wanted me to return the entire shock dampener (damper) unit to them in Holland, for overhaul or exchange! The cost was 152 Euros and 35 Euros for shipping. A new dampener, no exchange, was 195 Euros, and the same 35 Euros for shipping!
After several
communications, not altogether satisfactory due to the language and
interpretation problem with the
EZS factory, I determined that the rubber part (at least I THINK it was ONLY the
rubber part??) was priced, in October 2008, at 16.75
Euros, plus 9.00 Euros for shipping. They cannot accept any form of
payment but Wire Transfers. The cheapest Wire Transfer I found at any
commercial bank was $30.00. This brings the total price to a ridiculous
amount, not to mention the cost of the part which was high, in MY
estimation.
I decided to search for a substitute.
The rubber sleeve covers two small ports (holes) and the rubber expands and contracts only slightly during operation of the dampener over large strokes. The rubber is used as a mild bellows, although there are no folds, curves, etc. Very little fluid/air is ever in the stock bellows.
A garden hose section won't likely work....and you'd need one with the proper inside diameter (possibly could stretch a 1" I.D. type to fit, but they would not have much bellows action, so that idea was rejected.
The shock tube outside diameter is 28 mm (1.10").
Note: The two shock holes that allow that bleed of air/fluid into the
bellows can not be plugged...I did experiment....and performance was not good
enough.
Below are photos of the stock shock with the stock rubber bellows:
Note that just inside the end is a ridge of rubber, that fits into the groove on the shock absorber body, and provides a solid oil seal. The substitute I found does not have that ridge, and time will tell if the substitute is OK.....but there are NO leaks, in the slightest, after a considerable number of miles.
During my search for an acceptable part, suggestions that have been made to me included the possibility that
some existing motorcycle dampener may have a similar rubber part. I
visited several such motorcycle stores, and the parts men did not recognize the
part.
A messy looking substitute that I did not try was a hub coupling as used with
piping. There is also a plumbing shop item called a Dressler fitting, but the
size was wrong, and the look was horrible.
In the McMaster-Carr (www.mcmaster.com) catalog, I found
a rubber bellows used for 'small U-joints', as item 94205K67 on page
3673.
That item was very promising. The size is 1.79" long and 2.03"
O.D., and the inside diameter is 1.12"....very close to the shock diameter.
There is no internal ridge, but I thought it was worth a try.
This rubber bellows is actually a product of the Lovejoy company, 2655 Wisconsin
Avenue, Downers Grove, IL 60515. It is sold to McMaster Carr
as "D8 upper boot w/ties".
I ordered one of these. In October, 2008, the cost was
$13.66 plus shipping.
Here is a photo of the new bellows as installed:
To install it I first removed the original Oetiker clamps and old sleeve. I held the stock shock with the ports downward, and manipulated the shock rod in and out until the shock was totally emptied of fluid.
I then carefully clamped the shock in soft vice jaws
(LIGHTLY!), with the ports end upwards.
Note: this bellows can hold lots more oil than the stock sleeve.
This bellows functions VERY nicely!
I did some research on the needed oil. A VERY
light oil is needed. I am comfortable in recommending the following oils. I
very much doubt that any
installation, even with motorcycle tires and not car tires (mine are car tires,
requiring less dampener action), would require heavier oil. I rode my rig
withOUT the dampener, and the dampener is hardly needed, if at all on MY rig, so
I wanted a very very light oil, even thinner than stock. I was unable to
find a good shock or suspension fluid with a viscosity of around 4 or 5 at
40°C. I used what the factory used, I THINK...about a 2.5 weight. I
could not find any oils lighter than the ones below, and the ones below ARE OK,
and similar to the stock oil, maybe a small amount lighter. NOTE that the
viscosity index of the Belray is
lower than the others, this is OK for
this application, as the dampener does not get hot.
Spectro SX400 (order number O.SXSF) Shock & Fork oil, 2.5W. 16
ounce size (1 pint) was lots more than needed. Specification: 10.9
Cst @ 40°C, 1.9 Cst @100°C, VI 400. I
preferred this oil, primarily because I felt that a lower VI would likely be
helpful....exactly the opposite of what one typically wants for most lubricating
oils for such as engines, gearboxes, etc.
Golden Spectro ULTRAlight shock fluid (order number L.SFUL).
specification: 10.4 Cst @ 40°C, 4.4 Cst @ 100°C, VI 385. This
oil would be OK and probably would be choice #2 or #3.
BelRay Fork oil 2.5W. specification: 9.2 Cst @40°C, 1.9 Cst @
100°C. This would be choice #2 or
#3
You will need about 100 cc of fluid, very approximately, to fill the shock internally. You will need an additional amount to add to the bladder (rubber bellows). A total of roughly 132 cc will be needed (very approximately). You do NOT have to fully fill the bellows, not at all. To fill the shock I used a hypodermic of 20 cc, with a long non-sharp needle.
Start with the plunger all the way upward, or nearly so (it is below, the body above, in the
soft jawed vice). Start SLOWLY injecting fluid while you lower the rod a
little bit at a time. You can tape over one of the holes if this is
helpful for you to avoid spillage...I used my finger.
When the rod is fully down, wait a minute, then VERY SLOWLY raise the rod again.
When oil just barely starts to come out the hole(s), then repeat the
process. Repeat until you cannot add any more. NOTE that the process
of installing fluid will cause aeration and microscopic bubbles, and you may
have to set the rod in some position and let it sit overnight. I did the
filling over several days and nights. I preferred to do it this way rather
than the 'bucket of fluid, and suck the stuff in' method...which aerates the
fluid badly.
Once the shock is filled, you can hold your fingers over the two ports (use some
fingers pressure) and see if the shock works well, over the ENTIRE range of rod travel,
WITHOUT any dead spots. At that point the shock, only, is filled, and the
rod fully out. Try to put more fluid in if you can.
NEXT:
Keep the shock vertical, ports upwards. Clean the shock body VERY carefully. Get every bit
of oily fluid off of it. Use a good solvent that evaporates to very dry.
Wipe the inside of the new bellows with solvent. Let that solvent
evaporate. Install the bellows over the shock eye,
and position the bellows. The bellows comes with two kind of narrow zip nylon ties, I
used stronger slightly wider ones. Fasten the LOWER, ONLY zip tie as tight as you can
without busting it. Be sure the top of the bellows is even with the top of
the shock body.
Using the hypo again, add about 10 or 15 cc more oil, sliding it down between the bellows top and the shock body. Try not to get the top of the bellows oily, nor the body, where the final zip tie will be put.
Note, in case you have not read the above carefully, that the bellows is only
zip-tied at one end to the shock body at this point...so don't try to overfill
or oil-pressurize the bellows...a totally unnecessary thing to do.
NOW add the zip tie at the end. Tighten quite securely. Wipe the area with a rag.
Operate the shock, with the bellows both UPWARDS and DOWNWARDS this time. The shock should not leak oil and provide good action over any portion of rod travel.
Re-clean the bellows at both ends...I used a strong spray solvent. This is to allow the next step: I used black RTV to seal the bellows ends to the body. This was strictly an idea to add some additional oil sealing.
I installed the shock the evening of 10-13-2008, and adjusted the mounts slightly so the steering could be moved through its entire range without binding the shock ends (no Heim joint is needed on this installation).
Time will tell....but no leaks after a 1500 mile trip
Revisions:
10-13-2008: final revision and released fully.
10-24-2008: minor update