How hard is it to replace a clutch in a 5-speed manual transmission?

On Fri, 22 Sep 2017 06:47:18 -0600, rbowman > wrote:

>> How do you measure that the engine is "level"?
>> I have levels, of course.
>
> I hesitated when I wrote that. The axis of the engine's crankshaft when
> it is supported has to be the same as that of the transmission's input
> shaft. The whole lashup could be at a 20 degree angle relative to the
> floor as long as both match.
>
> Another way to look at is the perpendicular mating surfaces need to have
> matching angles.

Thanks for clarifying that the engine needs to be in line with the
transmission shaft, where they look (to the naked eye) parallel to the
garage floor that the vehicle will be parked on.

On Wed, 20 Sep 2017 00:30:51 +0000 (UTC), Chaya Eve > wrote:

> How hard is it to replace a clutch in a 5-speed manual transmission?

I know this is long but there are zero DIYs that I can find on the net
for my particular vehicle but there are a few that are for "similar"
vehicles from Toyota (see the reference section for what DIYs I did use).

How does this "future DIY" look for putting a DIY together?

New Tools:
.. Buy/rent/borrow/steal a transmission jack or saddle
Jack: https://www.harborfreight.com/automo...ack-61232.html
Saddle: https://www.amazon.com/Gotobuy-Trans.../dp/B01MTXZE6J
.. Buy/rent/borrow/steal the proper centering tool & bearing pullers
.. Pilot bearing puller (or blind hole puller from HF or autozone)
.. <http://www.harborfreight.com/blind-h...ler-95987.html>
.. Note that some people pack behind the bearing with grease to punchhole it out
.. Clutch alignment tool (fits splines of clutch disc)

Parts for the Toyota W59 transmission (Toyota 4Runner, 2WD, base, 5-speed).
.. New clutch disk (apparently Aisin, Eddy, or MC but not LUK or XTD; 1200# weight?)
.. New pressure plate
.. New pilot bearing (is that the same as a throwout bearing?)
.. It is said to only use the factory NSK throwout bearing (orange inner seal)
.. New #136? flywheel (resurfacing=$60 Kevin @408-379-7290, All Standard)
.. New rear main seal (since you're pulling the flywheel anyway)
.. Locktite Red (flywheel bolts & clutch cover bolts)
.. Locktite Blue (starter and bellhousing bolts)
.. Maybe a new slave cylinder (they don't last forever)

Existing tools:
.. Lots of 1/2-inch sized u-joints
.. Literally 2-1/2 to 3 feet of 1/2-inch socket extension bars (16" bare minimum)
.. Snap-ring pliers (for the transmission case snap ring)
.. Gear pullers
.. Torque wrench & sockets (all 1/2 inch sized)
.. Note that the 4-cyl ten 14mm flywheel bolts are 12 point (not 6 point)

Existing fluids:
.. 2.7 quarts replacement 75W90 GL4 gear lube
.. Thick high-moly graphite grease to lube the spline input shaft & ID of throwout bearing
.. Toyota FIPG for the rear main seal (RTV is ok but not as good)
.. No grease on diaphragm springs, pressure plate or throwout bearing face.
.. Light grease on throwout bearing ID, input shaft splines
.. Light grease on clutch fork pivot points & outside the shaft collar

Torque specs:
.. Starter bolts 30ft#
.. Bellhousing bolts 54ft#
.. Flywheel (either 19 ft lbs+1/4 turn for 3RZ or 65ftlbs for the 2RZ and 5VZ engines)

Here is my tentative DIY (composite from a few non-correct-truck DIYs):
(It's detailed because I have never done it; so I might miss a critical step otherwise.)
.. The night before, PB blast (or oil and bang) all bolts if necessary (mine are clean)
.. Check before/after clutch pedal free play (1/4" to prevent throwout bearing wear)
.. While the 4Runner is on the ground, put the transmission in 1st gear
.. Remove the cabin gear shift mechanism
.. While above, snap pictures of the pitch-fork-shaped wiring harness from above
.. <http://www.showstop.org/images/misc/r150F-harness.jpg>
.. If possible, unbolt the "conning tower" for the shift mechanism
.. Disconnect the battery negative cable (since the starter bolts will be removed)
.. Then 4x-jackstand the car as high as you can get it (I have four 18", 6 ton stands).\
.. Attempt to level the vehicle as best you can so the engine is level with the trans
.. While below, snap pictures of the pitch-fork-shaped wiring harness
.. Loosen both the fill plug and drain plug (should be easy as I just drained it 3 days ago)
.. Drain the expensive Red Line MT-90 I just put in! (20 bucks a quart!)
.. (Lesson for next time: Use cheap gear oil for the first flush-fill & then the good stuff.)
.. Remove the rear-facing drive shaft 14mm bolts & pull out the drive shaft (do first if hard)
.. Remove 2x12mm bolts for the clutch slave cylinder & hang safely on hangar wire
.. It is said to not follow FSM procedure which says to remove exhaust pipe (leave the pipe)
.. Remove 17mm bolts holding exhaust pipe bracket to transmission housing
.. I don't know if the next step is needed because some say yes while others say no
.. Remove 12mm bolts holding exhaust pipe into the bracket (these may be corroded)
.. Do no separate the exhaust pipes!
.. Remove 2x10mm oxygen sensor bracket bolts holding the wiring & sensor to the housing
.. Remove the reverse light sensor
.. Remove the speed sensor
.. Remove the oxygen sensor
.. Remove the 7/8ths-inch speedometer cable hex cap
.. Remove the main harness which connects to a bell housing bolt
.. Remove two 14mm bolts around the starter housing
.. Remove the bottom set of forward facing long 14mm or 17mm bellhousing bolts
.. Remove the bottom series of rearward facing 14mm bolts around the bell housing
.. Remove anything else in the way
.. Zip tie any cables in place so that they don't get damaged later
.. Then support the transmission with a transmission jack or jack saddle
.. Strap the transmission in routing the straps under any wires
.. Remove the 12mm and 14mm bolts holding the rear transmission mount assembly
.. Remove the top series of three short 17mm bolts on the bell housing
.. These are said to need a 1/2-inch short socket, swivel, & at least 16" to 18" socket bars
.. The frame cross member is welded in so you need to twist the transmission
.. Tip the front down an twist the front of the transmission to the driver side
.. Lower the transmission (most seem to do it by hand even when they have a jack???)
.. In a star pattern, remove the series of 12mm bolts holding the clutch into the bell housing
.. You must snap pictures of the asymmetrical nature of the clutch disc before removing
.. V6 has the springs toward the flywheel; the 2.7L I4 has the springs toward the trans
.. Remove the clutch disc
.. Remove the pressure plate
.. Remove the ten (12-point) 14mm bolts ringing the flywheel to the engine
.. Have the flywheel replaced or resurfaced
.. Remove the pilot bearing in the back of the engine with a bearing puller
.. Most DIYs stop right there (reassembly supposedly being the reverse of removal)

On reassembly (which most DIYs ignore), these topics came up after the fact:
.. A screwdriver wedged into the flywheel teeth immobilizes it for bolt tightening
.. It is said that so does a punch through one of the flywheel holes
.. The wiring harness layout has to be considered while lifting the transmission back
.. It is said to put it in gear when aligning splines (allows output & input shaft to turn)
.. Input shaft alignment stage 1 is getting the splines to go into the clutch disc.
.. Input shaft alignment stage 2 is the last inch onto the input shaft bearing
.. Jack fine tuning matters in that last inch (use bellhousing bolts as alignment pins)
.. It is said the bellhousing has an alignment dowel near the slave-cylinder mount
.. It is said to grease the top & inside of the clutch fork ends
.. And grease the adjoining surfaces of the throwout bearing.
.. Grease the divot in the middle of the clutch fork
.. Just before you install the clutch slave cylinder, grease the divot at the end fork
.. Cover the clutch fork mushroom bolt with HD grease.

References this came out of (none of which are my vehicle and year)
<http://www.ttora.com/forum/2-early-tacoma-tech/149715-5vz-clutch-job.html>
<http://www.ttora.com/forum/2-early-tacoma-tech/146210-w59-shifting-problems.html>
<http://www.ttora.com/forum/6-performance-engine-exhaust/35936-clutch-install-tips.html>
<https://www.youtube.com/watch?v=k-sscHblanc>.

On 23/09/2017 7:26 AM, Chaya Eve wrote:
> On Fri, 22 Sep 2017 06:47:18 -0600, rbowman > wrote:
>
>>> How do you measure that the engine is "level"?
>>> I have levels, of course.
>>
>> I hesitated when I wrote that. The axis of the engine's crankshaft when
>> it is supported has to be the same as that of the transmission's input
>> shaft. The whole lashup could be at a 20 degree angle relative to the
>> floor as long as both match.
>>
>> Another way to look at is the perpendicular mating surfaces need to have
>> matching angles.
>
> Thanks for clarifying that the engine needs to be in line with the
> transmission shaft, where they look (to the naked eye) parallel to the
> garage floor that the vehicle will be parked on.
>
Most engines that I've come across are not "parallel to the garage
floor". In fact, most are inclined at a slight downward angle. There are
reasons for this and it has to do with driveshaft alignment. More likely
to be horizontal if the vehicle has a triple jointed driveshaft.

--

Xeno

On 23/09/2017 8:04 AM, Chaya Eve wrote:
> On Wed, 20 Sep 2017 00:30:51 +0000 (UTC), Chaya Eve > wrote:
>
>> How hard is it to replace a clutch in a 5-speed manual transmission?
>
> I know this is long but there are zero DIYs that I can find on the net
> for my particular vehicle but there are a few that are for "similar"
> vehicles from Toyota (see the reference section for what DIYs I did use).
>
> How does this "future DIY" look for putting a DIY together?

As always, observe the RTFM principle before doing anything.
>
> New Tools:
> . Buy/rent/borrow/steal a transmission jack or saddle
> Jack: https://www.harborfreight.com/automo...ack-61232.html
> Saddle: https://www.amazon.com/Gotobuy-Trans.../dp/B01MTXZE6J
> . Buy/rent/borrow/steal the proper centering tool & bearing pullers
> . Pilot bearing puller (or blind hole puller from HF or autozone)
> . <http://www.harborfreight.com/blind-h...ler-95987.html>
> . Note that some people pack behind the bearing with grease to punchhole it out
> . Clutch alignment tool (fits splines of clutch disc)

The clutch alignment tool does not need to have splines. That said, most
people of my acquaintance keep on hand a swag of transmission input
shafts from trans rebuild jobs. Ask about the possibility of securing
one of these at a trans place near you. Alternatively, I have had
success building a shaft that is too small up to size using humble old
plastic electrical insulation tape. Did that on the tractor I recently
changed a clutch on since we didn't have the exact dummy pilot shaft we
needed, and it worked perfectly. Necessity is the mother of invention,
not to mention cost savings.
>
> Parts for the Toyota W59 transmission (Toyota 4Runner, 2WD, base, 5-speed).
> . New clutch disk (apparently Aisin, Eddy, or MC but not LUK or XTD; 1200# weight?)
> . New pressure plate
> . New pilot bearing (is that the same as a throwout bearing?)

No. It is the bearing or bush that fits into the back end of the
crankshaft and supports the front end of the gearbox input shaft, hence
supporting the weight of the clutch plate.

> . It is said to only use the factory NSK throwout bearing (orange inner seal)
> . New #136? flywheel (resurfacing=$60 Kevin @408-379-7290, All Standard)
> . New rear main seal (since you're pulling the flywheel anyway)
> . Locktite Red (flywheel bolts & clutch cover bolts)
> . Locktite Blue (starter and bellhousing bolts)
> . Maybe a new slave cylinder (they don't last forever)
>
> Existing tools:
> . Lots of 1/2-inch sized u-joints
> . Literally 2-1/2 to 3 feet of 1/2-inch socket extension bars (16" bare minimum)
> . Snap-ring pliers (for the transmission case snap ring)
> . Gear pullers
> . Torque wrench & sockets (all 1/2 inch sized)
> . Note that the 4-cyl ten 14mm flywheel bolts are 12 point (not 6 point)
>
> Existing fluids:
> . 2.7 quarts replacement 75W90 GL4 gear lube
> . Thick high-moly graphite grease to lube the spline input shaft & ID of throwout bearing
> . Toyota FIPG for the rear main seal (RTV is ok but not as good)
> . No grease on diaphragm springs, pressure plate or throwout bearing face.
> . Light grease on throwout bearing ID, input shaft splines
> . Light grease on clutch fork pivot points & outside the shaft collar
>
> Torque specs:
> . Starter bolts 30ft#
> . Bellhousing bolts 54ft#
> . Flywheel (either 19 ft lbs+1/4 turn for 3RZ or 65ftlbs for the 2RZ and 5VZ engines)

Pressure plate bolt torques? As critical as flywheel bolt.
>
> Here is my tentative DIY (composite from a few non-correct-truck DIYs):
> (It's detailed because I have never done it; so I might miss a critical step otherwise.)
> . The night before, PB blast (or oil and bang) all bolts if necessary (mine are clean)
> . Check before/after clutch pedal free play (1/4" to prevent throwout bearing wear)

Learn to differentiate between pedal free play and release bearing free
play - you should be able to feel two (2) distinct steps - pedal play,
then release play. Some systems work on zero free play at the release
bearing (e.g. carbon thrust block types) but, in the case of hydraulic
systems, there is *always* a need for free play at the master cylinder
end. This is to ensure correct operation of the MC hydraulics.

> . While the 4Runner is on the ground, put the transmission in 1st gear
> . Remove the cabin gear shift mechanism
> . While above, snap pictures of the pitch-fork-shaped wiring harness from above
> . <http://www.showstop.org/images/misc/r150F-harness.jpg>
> . If possible, unbolt the "conning tower" for the shift mechanism
> . Disconnect the battery negative cable (since the starter bolts will be removed)
> . Then 4x-jackstand the car as high as you can get it (I have four 18", 6 ton stands).\
> . Attempt to level the vehicle as best you can so the engine is level with the trans
> . While below, snap pictures of the pitch-fork-shaped wiring harness
> . Loosen both the fill plug and drain plug (should be easy as I just drained it 3 days ago)
> . Drain the expensive Red Line MT-90 I just put in! (20 bucks a quart!)
> . (Lesson for next time: Use cheap gear oil for the first flush-fill & then the good stuff.)
> . Remove the rear-facing drive shaft 14mm bolts & pull out the drive shaft (do first if hard)
> . Remove 2x12mm bolts for the clutch slave cylinder & hang safely on hangar wire
> . It is said to not follow FSM procedure which says to remove exhaust pipe (leave the pipe)

This will impact on how far you can lower the transmission to possibly
gain the required clearance from the transmission hump or access to
upper bell housing bolts.

> . Remove 17mm bolts holding exhaust pipe bracket to transmission housing

This point can, if care isn't taken, result in damage to the exhaust
pipe if following the point immediately above.

The above two steps will always be a case of *it depends*.

> . I don't know if the next step is needed because some say yes while others say no
> . Remove 12mm bolts holding exhaust pipe into the bracket (these may be corroded)
> . Do no separate the exhaust pipes!
> . Remove 2x10mm oxygen sensor bracket bolts holding the wiring & sensor to the housing
> . Remove the reverse light sensor
> . Remove the speed sensor
> . Remove the oxygen sensor
> . Remove the 7/8ths-inch speedometer cable hex cap
> . Remove the main harness which connects to a bell housing bolt
> . Remove two 14mm bolts around the starter housing
> . Remove the bottom set of forward facing long 14mm or 17mm bellhousing bolts
> . Remove the bottom series of rearward facing 14mm bolts around the bell housing
> . Remove anything else in the way
> . Zip tie any cables in place so that they don't get damaged later
> . Then support the transmission with a transmission jack or jack saddle
> . Strap the transmission in routing the straps under any wires
> . Remove the 12mm and 14mm bolts holding the rear transmission mount assembly
> . Remove the top series of three short 17mm bolts on the bell housing
> . These are said to need a 1/2-inch short socket, swivel, & at least 16" to 18" socket bars
> . The frame cross member is welded in so you need to twist the transmission

That movement in other than the fore and aft direction that the trans
mount adapter needs to be capable of will be of great assistance here.

> . Tip the front down an twist the front of the transmission to the driver side
> . Lower the transmission (most seem to do it by hand even when they have a jack???)

Depends on how strong/old you are.

> . In a star pattern, remove the series of 12mm bolts holding the clutch into the bell housing
> . You must snap pictures of the asymmetrical nature of the clutch disc before removing
> . V6 has the springs toward the flywheel; the 2.7L I4 has the springs toward the trans
> . Remove the clutch disc
> . Remove the pressure plate
> . Remove the ten (12-point) 14mm bolts ringing the flywheel to the engine
> . Have the flywheel replaced or resurfaced
> . Remove the pilot bearing in the back of the engine with a bearing puller
> . Most DIYs stop right there (reassembly supposedly being the reverse of removal)

No mention of what you should be inspecting for, both on bits you intend
to replace and those you intend to refit. Flywheel face, for instance.

No mention of cleaning and safety precautions associated with same.

>
> On reassembly (which most DIYs ignore), these topics came up after the fact:

These are the sorts of things tradesmen learn, and do, almost as a
reflex action after many years of involvement with the trade.

> . A screwdriver wedged into the flywheel teeth immobilizes it for bolt tightening
> . It is said that so does a punch through one of the flywheel holes
> . The wiring harness layout has to be considered while lifting the transmission back
> . It is said to put it in gear when aligning splines (allows output & input shaft to turn)

Top gear always.

As a learning process, when you have the trans out, select low gear,
turn the output shaft and discover why top gear is the choice.

> . Input shaft alignment stage 1 is getting the splines to go into the clutch disc.
> . Input shaft alignment stage 2 is the last inch onto the input shaft bearing
> . Jack fine tuning matters in that last inch (use bellhousing bolts as alignment pins)
> . It is said the bellhousing has an alignment dowel near the slave-cylinder mount
> . It is said to grease the top & inside of the clutch fork ends
> . And grease the adjoining surfaces of the throwout bearing.
> . Grease the divot in the middle of the clutch fork

Use care on the type and placement of any grease. Excesses can be bad
news as can the wrong type of grease.

> . Just before you install the clutch slave cylinder, grease the divot at the end fork
> . Cover the clutch fork mushroom bolt with HD grease.
>
> References this came out of (none of which are my vehicle and year)
> <http://www.ttora.com/forum/2-early-tacoma-tech/149715-5vz-clutch-job.html>
> <http://www.ttora.com/forum/2-early-tacoma-tech/146210-w59-shifting-problems.html>
> <http://www.ttora.com/forum/6-performance-engine-exhaust/35936-clutch-install-tips.html>
> <https://www.youtube.com/watch?v=k-sscHblanc>.
>


--

Xeno

On 09/22/2017 08:21 PM, Xeno wrote:
> The clutch alignment tool does not need to have splines. That said, most
> people of my acquaintance keep on hand a swag of transmission input
> shafts from trans rebuild jobs. Ask about the possibility of securing
> one of these at a trans place near you. Alternatively, I have had
> success building a shaft that is too small up to size using humble old
> plastic electrical insulation tape. Did that on the tractor I recently
> changed a clutch on since we didn't have the exact dummy pilot shaft we
> needed, and it worked perfectly. Necessity is the mother of invention,
> not to mention cost savings.

At one time I had a generic alignment tool. It had a number of
interchangeable ends for the various pilot bearing sizes, and a tapered
guide to fit various sizes of clutch bores. However they now have very
inexpensive plastic tools for most popular vehicles. iirc the one I got
was $3 or $4.

On 23/09/2017 2:46 PM, rbowman wrote:
> On 09/22/2017 08:21 PM, Xeno wrote:
>> The clutch alignment tool does not need to have splines. That said, most
>> people of my acquaintance keep on hand a swag of transmission input
>> shafts from trans rebuild jobs. Ask about the possibility of securing
>> one of these at a trans place near you. Alternatively, I have had
>> success building a shaft that is too small up to size using humble old
>> plastic electrical insulation tape. Did that on the tractor I recently
>> changed a clutch on since we didn't have the exact dummy pilot shaft we
>> needed, and it worked perfectly. Necessity is the mother of invention,
>> not to mention cost savings.
>
> At one time I had a generic alignment tool. It had a number of
> interchangeable ends for the various pilot bearing sizes, and a tapered
> guide to fit various sizes of clutch bores. However they now have very
> inexpensive plastic tools for most popular vehicles. iirc the one I got
> was $3 or $4.

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.

--

Xeno

On Sat, 23 Sep 2017 11:44:43 +1000, Xeno > wrote:

> Most engines that I've come across are not "parallel to the garage
> floor". In fact, most are inclined at a slight downward angle. There are
> reasons for this and it has to do with driveshaft alignment. More likely
> to be horizontal if the vehicle has a triple jointed driveshaft.

I may very well have been wrong when I said that the transmission seems to
be parallel to the garage floor.

When I align the transmission jack, based on what you just said, I will
plan to be tilted a few degrees such that the rear is lower than the front
then.

On Sat, 23 Sep 2017 12:21:31 +1000, Xeno > wrote:

>> . Starter bolts 30ft#
>> . Bellhousing bolts 54ft#
>> . Flywheel (either 19 ft lbs+1/4 turn for 3RZ or 65ftlbs for the 2RZ and 5VZ engines)
>
> Pressure plate bolt torques? As critical as flywheel bolt.

Thanks. I appreciate your advice because most of the DIYs I read were just
words, where the words meant something only to someone who has already done
it.

For example, I didn't even know the pressure plate had bolts.
The DIYs I found just said "remove pressure plate" so I assumed there were
no bolts.

I added an empty spot for the pressure plate bolt torque, which I will fill
in when found!

> Learn to differentiate between pedal free play and release bearing free
> play - you should be able to feel two (2) distinct steps - pedal play,
> then release play.

I admit, the whole "clutch pedal adjustment" procedure is a fog to me at
the moment. I can only distinguish, when pressing a clutch pedal, the
distance that nothing happens, versus the distance that something happens.

> Some systems work on zero free play at the release
> bearing (e.g. carbon thrust block types) but, in the case of hydraulic
> systems, there is *always* a need for free play at the master cylinder
> end. This is to ensure correct operation of the MC hydraulics.

I need to study that further to understand it better.

> No mention of what you should be inspecting for, both on bits you intend
> to replace and those you intend to refit. Flywheel face, for instance.

That is a good point that I don't know what to look for.
In the case of the DIYs, everyone shows a picture of a chewed-up clutch,
but I'm expecting to replace the clutch, so that won't matter much.

Also most expect to resurface the flywheel.
And most expect to replace the two "bearings", the throwout & pilot.
And they expect to replace the "rear engine seal".

I'm not sure of what else that people routinely inspect to replace.
In my case, I'm not expecting any "damage" since the transmission is
essentially working fine (the clutch is merely "due" for a change based on
time and miles).

> No mention of cleaning and safety precautions associated with same.

I'm not sure what 'cleaning' is needed other than wiping off old grease.

>> . It is said to put it in gear when aligning splines (allows output & input shaft to turn)
> Top gear always.

The thing I didn't get is how I'm supposed to put it in gear when it's
already removed from the vehicle?

Is it easy to put a transmission in top gear when it's just sitting there
on the garage floor without a shifter mechanism?

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?

On Fri, 22 Sep 2017 22:46:09 -0600, rbowman > wrote:

> At one time I had a generic alignment tool. It had a number of
> interchangeable ends for the various pilot bearing sizes, and a tapered
> guide to fit various sizes of clutch bores. However they now have very
> inexpensive plastic tools for most popular vehicles. iirc the one I got
> was $3 or $4.

I have to openly admit I don't understand this step.
None of the DIYs referenced show HOW to do this step.
So it's just something I wrote - but it means as much to me as it would to
a fifth grader.

I can imagine that there is a shaft that has long "grooves" in it that has
to fit into "something" that has correspondingly long "opposite grooves" in
it.

But I don't have any feel for why a special "tool" is needed to get the two
sets of matching grooves to line up. I haven't seen any pictures of that
yet nor videos. So it's just words to me at the moment and not an image in
my mind.