[Vwdiesel] All about starters

[Sandy Cameron]

Here are two files about starters, archived some time ago.

One relates to cleaning and lubrication, the other, to the jumper from the
solenoid (heavy copper) to the starter motor, which tends to disolve in to
dust in a salty environment. 

Also inspect the steel jumper from the motor terminal of the solenoid, to
the conection to the suck-in coil on the bakelite end. It is usually in bad
shape on salties, and will prevent solenoid operation if it is open..


STARTER R&R
Take a 2' length of 2x6, a tranny jack, and jack the oil pan.
A piece of 2" thick styrofoam against the pan (same size as the 2x6) will
help distribute the load and save the oil pump bulge in the pan.

Jack until the front of the car rises an inch or so.

Loosen the starter bolts a bit (show a thread or two)

Adjust jack height until you can turn the bolts with your fingers.

Change the starter.

You might want to consider changing the bushing in the tranny bell housing,
see Bentley or others  will explain how. I've never done one. Requires a
simple special tool
But be sure to lube the end of the shaft of the replacement starter with a
bit of grease before inserting..

Below, my starter o-haul story.


WARNING! As stated elswhere, use no hammers on starter, don't drop it on
concrete floor.
The shock can demagnetize the magnets.
Also be carefull with tools when the starter is open, the magnets will suck
them in.
You will have to degauss some of your tools when finished, as they will pick
up some of the magnetism.

Short form rear bearing lube: 

The info below details my 94TD (Hecho en Mexico) That started to make a low
frequency screech noise, dry shaft in dry sleeve bearing chatter, upon
release when starting.
This specific problem can be dealt with (and swiftly, before the bearing is
destroyed) without removing the starter from the car, by removing the little
shaft cover protrusion from the motor, (2 self-tap screws) hosing of the end
of the shaft and inside of the cover with brake cleaner, and re-lubing.
I use motor oil first, then fill the cap with grease, squish it on and
replace the screws. This bearing is the weakest/dryest one in the starter
However, once or twice in the life of the car, it is useful not only for the
starter, but for our education, to dismantle it and check out everything,
including the brushes.

On brushes, and starters in general, having an engine that starts instantly
every time is essential to the longevity of the starter. (my instant start
87-A2 starts first stroke after 100's of thousands of miles.)

namely:

Good glow plugs always!

Replace wimpy VW battery cables with heavy duty #2 types (both of them)

Run the ground cable direct to one of the starter mounting bolts, not the
rusty, wimpy bolt on the tranny bracket.(body to engine connection still
required or harness may smoke and instruments vaporize)

Synth oil of your choice

Good battery and alternator

Long cranking is self defeating, killing the starter and battery, and does
the engine no good.


THERE IS NO EXCUSE FOR AN ENGINE THAT DOES NOT START ON THE FIRST STROKE--FIX IT
***************************************************************
Details: Starter R&R
1994 A3 TD Jetta

Funny noise when starting. Sounds like dry bushing/bearing chatter when engine
starts and bendix releases. Lasts for 1-2 seconds after engine starts until
motor stops spinning.
Confirmed with stethescope on rear end of starter.

This car is 7 years old, but has only 150,000Km (Less than 100,000 miles)
My 87 has 400,000km on it and it's starter, which has never been opened, or
given any trouble. Same type. (Lubbed the rear bearing this year on spec)

Remove battery, battery pan, get wiring out of the way, get Pwr steering
reservoir out of way.
Disconnect cables from starter.
Using tranny jack and short length of 2x4 against oil pan (avoid oil pump bump
on bottom of pan) jack engine to just remove weight from front mount. (part
of starter bracket bolts. Nasty surprise if you don't jack it) Loosen 3
bolts holding starter and engine mount, and fine tune jack level so bolts
are free of binding.
Remove 3 bolts holding starter. Lots of room to work from above with battery
out and PS reserv. tied out of way.
Gently remove starter fron bell housing to bench.

Remove rear bearing cap, find gooey mess. Remove C washer, spacer washer.
Remove through bolts and back plate with bearing. Brushes and plate stay in
starter. :-)
Decide to go all the way. H---l of a time getting solenoid screws out,
finally heat with propane torch, loosen with impact screwdriver. Red stuff
on them must be locktite! (around heads). Disconnect motor cable from solenoid.
Get solenoid off, (catch that spring as it flies across the shop!) unhook
plunger from throwout arm 
Pull bendix/reduction gear asembly out of motor. Do not pull out armature
unless replacing brushes. (mine were barely worn)

Beautifull little planetary reduction gear, 3.5/1 ratio, grease in planetary
is all dry and chalky! Looks like bird dirt. Tortilla dough? Are the bosch
components assembled in Mexico too?

Rinse out goop and crud, bearings look ok, just dry. 
Inside of motor is dirty, dry crud. Clean it all out.
Put a little oil on bronze rear bush and replace back plate.replace washer
and C washer. Fill clean end cap with green grease and replace, squishing
some of the grease into the bearing.

Wash out inside of solenoid with WD40, wipe plunger/core with clean paper
towel (fits tight) oil it by wiping with oily paper towel. Dont use too much.
Wash old cruddy grease out of planetary, and inside front end of motor.
Clean bendix assembly. Wipe some grease on the bendix screw behind the
over-running clutch, and on the shaft at the front.

Pack a small amount of grease into planetary, DON'T fill it! Just enought to
get all gear surfaces greasy. put a dab in the pilot hole in the middle of
the planetary that the motor shaft goes into.


Stuff the planetary carrier (white plastic) into the motor, be sure it's
locating tabs are aligned properly . Leave the aluminum front end loose
until you hook the plunger loop over the end of the arm. You CAN'T do it
after assembly.

Once the plunger is hooked on, assemble carefully, the blue plastic arm
fulcrum widget fits against the square rubber block that fills the hole
between the motor and the front bendix housing. When all this stuff is
properly positioned, it all goes together easily. Replace motor through bolts.

wipe the solenoid core, insert the flying spring you caught earlier, fit the
core into the solenoid and push together, insert a screw to hold things in
place.

Replace and tighten the 3 screws. snug up the motor through bolts.
Re-connect the motor cable to the solenoid. Wipe some grease on the front
shaft bearing, put a dab right on the end of the shaft so it will get pushed
into the bearing/hole in the bell housing.

Ready to replace it. Slip it into the bell housing as straight and centered
as possible.
My jack had sagged a bit while I was doing all this, so I fine tuned the
height so the bolts would slip right through to the mount and catch the
threaded holes without binding.

The bolts were cruddy with white aluminum crud when they came out, so I
buffed them clean and wiped them with a thin coat of grease before replacing
them.

Went together slick as snot on a doorknob.

Dressed all wiring, replaced the battery, tried it out, How sweet it is.
Will probably last the life of the car with real grease instead of guanno in it.

Would have ground up the bushing quickly if I had left it, and $300-$400 to
replace the starter.

Now where did I put the radio code?


Sandy 


SALT EATEN MOTOR CABLE

Driving the A3, stopped at the local coffee shop for a cuppa yesterday, and
when I came out it would not start. No solenoid click, no interior light
dim, very strange. Tried a hotwire from the battery to the solenoid control
terminal, no click, small spark.

Got a husky friend to push it down the parking lot and bump-started it
(always bump-start in 4th gear, 5th is not strong enough and may strip
teeth, and anything lower than 4th just results in a sudden stop) and went home.

Remembered that most, if not all solenoids have 2 coils in them, one very
strong to suck it in to mesh the pinion with the ring gear, and another
higher resistance to hold it there while starting. The solenoid core also
pushes a copper washer against the back of the 2 large terminals (trust me,
you can't get at them, it's swaged together) completing the circuit from the
battery to the motor.

The less obvious thing is that the "suck-in" coil is not grounded at one
end. Here's why.
It draws a lot of juice and is best switched off as soon as the core is far
enough in to mesh, and close the heavy switch.
So....... One end of both coils are connected to the actuator terminal
(comming from the ignition switch).

The other end of the "hold" coil is grounded.

BUT,  the other end of the "suck" coil is connected to the big terminal that
goes to the motor.

How it works:
When the key is turned to START, +12 volts is applied to the start terminal
of the solenoid.
current flows through the hold coil to ground as long as the key is held to
start.
Current also flows  through the "suck" coil, and this is a trick,  THROUGH
THE MOTOR  to ground.(a very low resistance path)

When the suck coil does it's job, and the solenoid core bottoms and the
copper disc applies +12 volts to the motor lead,  both ends of the suck coil
are at +12 volts so no more current passes through it, and only the hold
coil keeps the starter engaged untill the key is released.

Of course, as this is happening, +12 is applied to the motor and it is cranking.

How come +12v from the main battery cable does not go back through the suck
coil from the motor terminal, to power the hold coil when the starter switch
is released? 
It does, for an instant.
When the key is turned to start, both coils are powered, together, in the
same polarity, aiding each other, to pull the solenoid core in.
When the key is released, the current comming back in the opposite direction
from the motor terminal through the suck coil is now reversed, and the suck
coil magnetic polarity is reversed,  canceling the polarity of the hold
coil, neutralizing the magnetisim and releasing the solenoid, breaking the
circuit (this happens almost instantly). Very clever. That was a trick used
in the old electro-mechanical generator cut-outs before alternators and
solid state, that disconnected the generator from the battery when the
engine stopped.

Until yesterday.............

Now, the rest of the story.

When I got in to it today, I pulled the starter, thinking I had solenoid
trouble. (see starter R&R, archives)

However, it's a 94, Hecho en Mexico, Mexican wire, not used to the great
white north, cold, polar bears, snow and ice, and road salt.

The formerly thick piece of cable from the solenoid to the motor disolved in
my hand when I touched it. No current through the suck coil, (could not
reach ground through the motor) no click, no action, tiny spark at the start
terminal caused by the small current through the hold coil

Replace the wimpy wire with a chunk of a booster cable hanging on the  shop
wall, soldered connections made by propane torch. Gave it a quick test on
the bench (quick, because there is no front bearing when it is out of the
car) and it worked. 
Re-installed, and all is well.

Note that worn out brushes, an open armature segment, or other motor fault
that opens the circuit, can result in similar symptoms.

Don't I just love to stiff the dealer parts man the cost of a new starter,
for a simple stupid piece of too-small, NAKED AND UNPROTECTED wire!
It's in my genes.

Sandy