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Nov 13, 2015

Push vs Pull Clutch : Nissan Skyline GT-R Clutches

What style of clutch is this? 
Here is a question we get fairly often.  Push vs Pull clutch. What is the difference? What type of clutch is on my car? Why did Nissan switch from push to pull clutch? Why are most aftermarket clutches push?

If you are like us, at one point in your Skyline GT-R life, you needed a clutch. A couple too many 8,000 rpm off the limiter launches, and whatever is in there is done.  So you look up clutches, and pick one out, but the question comes up, is it a push or pull?

Push or pull refers to the action to release the clutch.  A push clutch, does just that, pushes on the disk cover or diaphragm, to release pressure on the disks, so the center is disengaged from the engine. A pull clutch pulls on the diaphragm to release pressure on the disks.

The early Nissan Skyline GT-R's are all push clutches.  You can identify the clutch itself by the clutch cover.  If it has open fingers, then its a push. If it has a ring, then its a pull.

Push style clutch. This is a Tilton carbon/carbon triple plate for a Nissan Skyline GT-R
Pull style clutch. This Nismo is made by Exedy, a twin plate, and in this case for a Getrag transmission

So which is better?  This is what Daikin/ Exedy has to say about push vs pull

Buy USA Legal R32 Skylines at! for Nissan Skyline GT-R and GT-R parts.

So why isn't every clutch pull? Some of it is complexity. Costs. What we have also heard, is it is because of patents. Daikin/ Exedy has the patents on the technology, so not everyone uses it.  I have seen people drill holes in their bell housing to release a pull style clutch. If the transmission comes off the engine, and stops hard at about an inch, then you probably need to release the throw out bearing. Its really not that hard. Watch the video below for instructions.

How to remove a pull style throwout bearing in a late R32,R33, or R34 Nissan Skyline GT-R transmission. Watch the video. Its easy when you know how. 

How do you identify what clutch actuation your car has in it? If your car is a 1989-1992, then it should be a push style clutch.   Later than February 3rd, 1993, it should be a pull clutch. Key words always being "SHOULD".While it is possible to change push to pull and vice versa, its not something you want to figure out when the car is on a lift.

02/03/'93 Minor change Late model. V-spec added
Rear diff cover fin removed
Clutch modified (push -> pull)
Synchronizers modified
Brembo caliper added(V-spec)
ETS program modified(V-spec)
Tires changed (V-spec: 225/50-17)
BBS mesh special wheel (V-spec)
# N1 model gets to based on V-spec

As with anything on a car that is over 20 years old, it has probably had a clutch change at some point. So its always best to check.  Follow the pictures below for some help identifying what you have.
Late R32 bellhousing. This has bosses for push and pull clutch. It is currently a push clutch, or early. 

Getrag with a conversion kit for an ATS carbon clutch
In the above picture, the slave cylinder is on the backside of the shift fork.  As originally placed this is a pull clutch. Now with the slave flipped to the new position, this becomes a push clutch actuation. .

Some of the R32/R33 bellhousings have bosses/are drilled for both style slave cylinders.
Pull clutch slave cylinder. Also clutch dampening loop is partially visible. 

The parts required for a pull to push conversion.

Clutch Pull to push conversion-
Late Model R32, R33
Front cover assembly :32110-05U11 (japan part only)
Gasket :32112-05U12
Clutch fork :30531-01S00 (same part for a 1991-1993 240SX)
Spring :30514-14600
Spring :30534-E9000
T/O bearing :30502-14601
Bearing sleeve:30501-S0160 / 30501-N1601 (14mm for twin / trip disc)
Bearing sleeve: 30501-K0404 (24mm for single disc)
Dust cover :30542-31610
Slave cylinder :30620-21U01
Flywheel bolt: 12315-04U00

 In addition to push and pull clutch actuation via slave cylinder and fork, there are also converters sold that go inside the trans, and hydraulic release (slave) bearings.

OS Giken clutch actuation conversion kit

Getrag converted to push clutch actuation

Getrag converted to push clutch actuation

Another push style triple plate clutch. 

Front cover. Notice the fork pivot. Its a ball on early R32.

Factory Clutch cover, disc, and throw out bearing part numbers

R32 GT-R
  • Early or Push style clutch
Throw Out Bearing Push- 30502-21000 

Koyo RCT4075-1S (Replacement for 30502-21000)

NSK 40TRK1 (Replacement for 30502-21000)

Early Push Slave Cylinder assembly- 30620-21U01
Early Push Slave Cylinder Piston kit - 30621-05U25

  • Late or Pull style clutch

Disc- 30100-0V708
Cover- 30210-24U00
Bearing- 30502-12U00
Late Pull Slave Cylinder assembly -30620-12U0A

Disc- 30100-21U01
Cover- 30210-21U00
Throw out bearing- Pull- 30502-12U00
 (300ZX part)
 or 30502-45P00 (300ZX part)
Bearing Sleeve- 30501-S0200 (18mm)

R33 GTR (OEM all pull)
Disc- 30100-0V708
Cover- 30210-24U00
Bearing- 30502-12U00
Late Pull Slave Cylinder assembly -30620-12U0A

R34 GTR (OEM all pull)
Disc- 30100-0V708
Cover-30210 - AA300
Bearing- 30502-12U00
Late Pull Slave Cylinder assembly -30620-12U0A

Crank dowel: 13032-18000
Rear Main seal - 12279-5L310
Pilot Bearing - 32202-B950A 
Supersession(s): 13021-B9500; 13022-B9500; 13023-B9500; 15041-B9500; 15043-B9500; 32202-30000; 32202-B9500; 32202B950A

Nissan Skyline Flywheel

I never looked an OEM flywheel up. I suppose I never had to replace one in the 25 or so years I have been doing this. Normally if the clutch is coming out, something aftermarket with an included flywheel goes in.  However as a reference I just did.  The way Nissans part numbers generally work, are if the last digit is changed, its just some supersession that is 99% backwards compatible with the earlier number. 

12310-05U11. This fits RB20DET, and RB26DETT models. This would have started as 05U10

12310-05U13 which fits pull/late R32 and early R33 according to part number. Then superseded to 05U14 and then 05U16.

Throw Out Bearing Sleeves

Depending on what clutch, and flywheel you are running, you may need a new throw out bearing sleeve for the early, push style clutches. The height listed is from the front side of the fork to the seat position of the bearing.

30501-22102 8mm
30501-B5000 10mm (Superseded to 30501-B0004)
30501-A3800 12mm
30501-N1601 14mm
30501-U0200 16mm
30501-S0200 18mm

Exedy push clutch throw out bearing for twin disk clutch

30502-14601  - OEM throw out bearing
RCT4067L1 -  Koyo release bearing

OS Giken Single and Multi Plate Clutch bearing information

NISMO R32 GT-R Clutch Change Time Lapse Video.

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