astro-babys guide to stripping and rebuilding the HEQ5 mount
3 - Synta HEQ5 - Stripping & Cleaning the Right Ascension (RA) Axis

This procedure will guide you in stripping down and cleaning the HEQ5 Right Ascension axis. Re-assembly of the RA axis is covered HERE.

To carry out this procedure you will need a good assortment of tools including cross head and Phillips screwdrivers, a rubber or nylon mallet, a soft toothbrush,

degreasing agent, metric Allen keys, long nosed pliers, lots of lint free cloths and lithium grease.
I found commercial degreasing agents somewhat ineffective and resorted to using good old hot soapy water. Lithium grease is easily available from shops

selling bicycles. Its also advised to have a large soft towel or similar to lay the mount on while working on it to protect its external finish.

I would strongly advise you do not attempt this procedure without reading it through a few times in advance to understand the process. The procedure takes
around 2 hours from top to bottom unless you are very confident of what you are doing and have exactly the right tools. Its definitely best to have someone
around to help you with some elements of it - remember take your time and when in doubt STOP and think. Take a break when tired because you dont want
to bodge anything.

The DEC and RA worm gear adjustment process required after re-assembly can be quite lengthy as its very much trial and error so bear this in mind before
starting and allow plenty of time to carry out the procedure - it will pay dividends in terms of smooth and precise running and longevity of the mount.

Stage 1 - Stripping the RA Axis
Removing the polar scope cover Using grips to loosen the polarscope removing the polar scope
Remove the polar scope cover. Remove the polar scope. You may need to grip it
with a wrench - if so wrap a cloth around the
polar scope to protect it. Alternately use some
masking tape to protect the scope.
Once loosened simply unscrew the polar scope and
place it somewhere safe.
removing the RA lock lever screw removing the RA lock lever removing the locking bolt
Remove the silver Phillips screw in the RA
lock lever.
Remove the lock lever. You may need to prise this
up by using the tip of a flat bladed screwdriver and
gently twisting the tip - see the Declination strip

down procedure for a picture of this.
Remove the brass RA lock bolt. You may
need to use a small spanner or pliers. Also remove

the small brass button beneath the lock bolt.
If this is hard to do leave it -it can be removed easily
later in the procedure.
Removing the motor cover screws Removing the heq5 motor cover
Unscrew the 6 Phillips screws around the plastic
motor cover.
Remove the motor cover and lay it aside with its
Slacken the two lock screws on the polarscope
mounting plate.
Removing the dovetail carrier Loosening the Dec barrel set screws
Now remove the polarscope mounting plate by
unscrewing it. You can use either some snipe
nosed pliers to locate into the holes OR a pair of
small/medium Phillips screw drivers or similar OR
a pair of small Allen keys.
Loosen and remove the RA setting circles lock nut. Now remove the RA setting circle. It should just
slip off.
Removing the round nut on the Dec barrel Lossening the counterweight collar set screws Removing the counterweight collar
Loosen the three lock screws set around the large
circular aluminium nut.
Unscrew and remove the circular nut. You may
need a wrench to do this - if so be careful of the
polar-scope mounting plate threads.
Alternately use a pair of flat bladed screwdrivers or
similar to apply even pressure using the slots in
the nut - do this with care.
Once removed observe the tapered bearing. It may
come out at this point - if not it can be removed
easily after the following step.
Remove the main RA Unit (right) from the base (left).
The Alt-Az base contains a bearing which will most
likely not remove easily. Leave it in-situ but clean
the bearing and the Alt-Az internal area and grease
the bearing face with lithium grease.
Note: At this point the small brass button for the
RA locking lever will be easy to push out if you
were unable to extract it earlier.
Removing the tapered bearing Removing the declination scale from the counterweight collar Lossening the worm adjustment under the power panel
Remove the tapered bearing from the polarscope
end of the RA axis.
Here's the RA axis removed - naturally it also has
the DEC axis as part of it.
Note the red washer on top of the worm gear. Make
sure this is kept safe and is replaced during
Unscrew the power panel. Its attached using two
Phillips screws.
Lossening the worm adjustment opposite the power panel Removing the worm carrier cap head bolts Tapping out the declination shaft
Shift the power panel slightly. Be careful not to pull
too hard as it has wires which connect to the main
board inside the RA main housing.
Loosen the worm engagement set-screw located
behind the power panel.
Loosen the worm engagement set screw opposite
the power panel and above the Declination scale.
Removing the declination shaft Removing the declination gear The declination gears clear washer
Remove the 3 cap headed bolts (silve coloured)
from the worm carrier.
Remove the worm carrier.. Remove the brass worm gear making sure the small
red washer is kept aside.
Removing the worm carrier
Remove the roller bearings from the brass worm
gear. They should slip out easily.
Stage 2 - Stripping the Worm Carrier
Removing the worm carrier float screw extracting the worm from the carrier
Remove the brass drive gear from the end of the
worm. This has two set screws and may need to be
pulled off using some blunt nosed pliers.

Do not lever this off as it can be easily damaged.
The worm is held into the carrier by two 'float'
adjusters. These require a special tool BUT can
be removed by using a pair of small screwdrivers.
Insert the drivers into the small slot and rotate
using even pressure. Remove only ONE of the
float adjusters.
Remove the worm itself. You will notice it has two
small bearings, these can be removed. One of the
bearings is shown in the picture in the bottom
right hand corner.
Note the worm adjustment set screws. You will
need to adjust these at the end of re-assembly.
Stage 3 - Cleaning & Lubrication
Bearings and worm gears after cleaning
With a clean lint free cloth wipe all of the oil from the components. On my mount the roller bearings
were sealed and appeared to be well lubricated so were left alone. The tapered bearing had almost no
lubrication and so was cleaned and reblubricated with lithium grease.

To lubricate bearings put a blob of grease onto the palm of your hand and press the bearing into it and
then rotate the bearings around forcing the grease into the inside of the bearing.

The brass worm gears and steel worm should all be cleaned in a degreasing agent. I personally find
really hot water and a basic detergent works best. These were cleaned with a soft toothbrush and the rinsed and left to dry. All of the gears showed either little lubrication and/or engineering swarf present.

The picture to the left shows the brass worm gear and its roller bearings and the steel worm. The motor gear, brass RA lock nut and small roller bearings from the worm assembly aren't shown.
That completes strip down of the Right Ascension axis. If you wish to go to the re-assembly guide click HERE
or go back to the main page HERE