On 23/09/2017 6:39 PM, Chaya Eve wrote:
On Sat, 23 Sep 2017 15:08:54 +1000, Xeno wrote:

We had such a generic alignment tool available. The issue was that it
didn't handle the dual clutch system on the tractor at all well. The
local dealer didn't have a *factory one* for the tractor but he lent us
one he'd made up on a lathe. It wasn't a firm fit however, hence the
need to pack it up with tape. Coupled with 4 alignment dowels, made out
of bolts with heads removed, fitted into the block, the mating up
process was the smoothest I'd ever encountered.

What I don't understand, since I don't even know why this "alignment tool"
is needed, is what happens if I don't have this special alignment tool?

You either need a very good eye - or be very good with god.
Most people, in my experience anyhow, seem good with neither.

I have aligned clutch plates by eye in the past, and been successful,
but I have a good eye for such things. Most people do not. Hence the
need for a clutch aligning tool.

http://lh4.ggpht.com/_Ii1ukGkfijY/Sq...jpg?imgmax=800

In the picture link above, observe the right hand diagram. It shows the
gearbox mounted up and the input shaft passing through the clutch plate
and entering the spigot bush. The plate faces are clamped to the
flywheel by the pressure plate. When you release that clutch, the plate
comes free of the faces but is still on the input shaft. So it stays
there but spinning freely.
Now refer to the left hand diagram. When you are installing the clutch
and pressure plate, that is what you will have - no gearbox hence no
input shaft. The input shaft will be sitting on the floor still attached
to the gearbox. Not a lot of use there when you need it to align that
plate into the correct central location during installation. That's why
you need a *dummy shaft*. A clutch aligning tool is nothing more than a
dummy shaft that you can use temporarily as a substitute for that input
shaft while fitting up the clutch and pressure plate to the flywheel.
In short, the exact centre of the clutch plate needs to be aligned
exactly with the centre of the spigot bush. The dummy shaft ensures that
alignment exists as you tighten the pressure plate bolts.
If you fail to align the two, and it only needs to be a poofteenth of a
millifart out, when you insert the input shaft (still attached to the
gearbox, remember), you will get it up to and onto the spline - possibly
- but the nose of the shaft may not be able to go the next step - enter
the spigot shaft bush. This is simply because of misalignment. If, for
any reason, you drop the rear end of the gearbox down whilst the input
shaft is partially on the clutch plate splines but not in the spigot
bush, you run the real risk of distorting the clutch plate after which
it will be stuffed. A distorted clutch plate will fail to release
cleanly - or at all.

You can get the exact tool for your vehicle that looks like this;
https://frsport.com/images/detailed_...00_FG02-01.jpg

Note how it looks just like a gearbox input shaft.

Or a universal tool like this one;
http://www.toolsinstock.com/admin/images/0314.jpg

I prefer this type if I am going for a universal type.
https://i.frg.im/Srp6lau/121048656058-0_600.jpg
The top row of adapters is meant to fit the different internal diameters
of the clutch plate spline. The bottom row of adapters is meant to fit
the spigot bearing.

Alignment is everything. It's also why your jack needs a lot more *tilt
angle* than you think.




--

Xeno