Help Needed With Diy Tutorial's For R33 Clutch & Gearbox.

[Sweep]

Hi guys I have a 95 S1 R33 and have been searching the tutorials and the forum in general but I am not having much luck and was wondering if someone might be able to point me in the right direction to where they are if any.

I am looking to swap out my clutch in the next couple of weeks and after doing some research it looks like while I have the box out I should replace the gearbox seals & rear engine seal?

I am a bit of a noob to car mechanics but I have plenty of tools and have rebuilt a couple of motorbikes, so I thought that I would try and save my self some cash and do this myself.

I think I have a idea on removing the box after research but cannot find much on the seals side of things.

I have a friend who has changed clutches on other cars who will be helping me out to, so looking for a how to on the following.

clutch replacement, rear engine & gearbox seal's replacement.

Thanks in advance for any help given.

[breaker1845]

If you follow the service manual for your car it is pretty straight forward and probably a decent tutorial. If your mate can change a clutch on another car then you shouldn't have any major problems.

If you are doing it at your home make sure you have the time, space and equipment (trolly jack and stands) available as not having a hoist or proper equipment will require patience.

Gearbox removal is straight forward and there are plenty of guides on that, doesn't have to be very specific because the general process is the same.

Once you have the clutch out, get flywheel off and inspect condition and if okay to reuse make sure the surface is machined before going back on. Don't ever reuse the flywheel bolts either, buy new ones.

Tackle the rear main seal next and make sure you do it properly or it will just leak down the track and you'll have to replace it again.

[GeeDog]

This is a doc I wrote some time after we replaced our clutch - there might be a few errors & omissions - be interested in your feedback. As always, make your own decision on stuff and don't blame me if you injure or kill anyone while following this procedure. We've since discovered that if you have 3 people available it is easier to remove the gearbox without the trolley jack & straps - get the car as high as you can (we did it on the trailer last time - bloody brilliant) - and 3 people can simply man-handle the gearbox off the engine & lower to the ground.

R33 GTST Gearbox removal / installation & clutch replacement

Tools:

Metric socket set – including extra ½” drive extensions

Metric ratchet spanners

Internal circlip pliers

Axlestands / ramps

Cambuckle type tie-down strap or length of rope (for supporting the back end of the gearbox, through the shifter hole)

Degreaser & clean rags

Rattle gun & air ratchet, compressor to drive them (optional)

2 Trolley jacks (could do it with one & the standard car jack)

At least 2 people, but a third makes life much easier

Plenty of patience

Overview:

To remove the gearbox, the front of the motor has to be tilted up, and obviously the rear of the motor & the gearbox tilted down. Before doing this we removed the fan blade, so it couldn’t hit the radiator as the motor tilts. The exhaust has to be disconnected somewhere, and removing the cat makes sure that it won’t catch on itself as the motor tilts. There is a heater hose between the back of the motor & the firewall – be careful not to crush this to the point of breaking it. The exhaust bracket from the cat to the gearbox cross member needs to be removed so it doesn’t catch.

In Detail:

Raise car, support well on axlestands and/or ramps. Get it as high as you can now, particularly if you want to get the gearbox out from under the car. Make sure it isn’t going to fall of the stands – we used ramps under the back wheels, and 4 axlestands under the front. Be aware that the placement of axlestands behind the front wheels will make your access to the gearbox harder, but there isn’t much choice. You will probably have to “jiggle” the gearbox a bit (or a lot) to get the spline to mate with the clutch plate, so make sure it’s safe.

Disconnect battery – we will be removing a high-current capacity unfused positive cable from the starter motor, and don’t want things shorting.

Drain a bit of coolant using the drain plug under the radiator. Remove the top radiator hose at the radiator end, and loosen the clamp at the engine end. Turn the hose so it points up in the air, so no more coolant come out. Unbolt the fan & the shroud, lift both together until the fan blade can be removed.

Remove shifter –Put gearbox in first gear (makes it easier to re-install gearbox later), unscrew knob, remove ashtray, remove screw behind ashtray, remove shifter cover & boot, remove rubber boot (4 bolts), remove circlip, remove shifter.

Consider removing front passenger seat. Ours was already out for another job, and this allowed us to put 2 axlestands – one in the driver’s footwell, the other where the passenger’s seat was, and a length of 4x2 timber across them. We used this to support the back of the gearbox using the cambuckle strap.

Drain gearbox – remove drain bung (using ½” drive extension & ratchet) and drain all oil into drain pan (or onto floor if you prefer). Refit bung once oil stops flowing. If you don’t drain the oil, it will run out through the tailshaft drive later.

Disconnect loom to gearbox (3 connectors near rear on driver’s side), remove from cable hooks & tuck out of the way in engine bay.

Unbolt clutch slave cylinder and tuck out of the way. Support it in the engine bay so that it falls while trying to juggle the gearbox back in & hits you in the faceJ

Remove the tailshaft – 4 bolts at the back end & it just pulls out of the gearbox (you did drain the oil already...). Before removing the bolts mark the tailshaft flanges, so it goes back in the same way. This is to avoid possible vibrations, but is probably being a bit OCD.

Remove cat converter, and exhaust mounting bracket from the gearbox crossmember. Remove front exhaust pipe if it’s easy to get to, to create a bit more room under the passenger’s side. We left it on, as it is a pain to get off.

Remove cables from starter motor – there is 1 spade connector & one bolted connector – tuck out of the way somewhere.

Remove starter motor. There are 2 bolts, the bottom one is easy to remove from under the car, the top one is the hardest bolt to remove & refit in this whole job. We used a ratchet ring spanner (14mm) – one person put it on the bolt from the top, and another person loosened the bolt from under the car. We then used a medium length extension & socket to undo the bolt the rest of the way, once the ring spanner stopped ratcheting. Remove the starter motor through the bottom – takes a bit of juggling but it does fit.

Just a note on bolts – there are several different length bolts used to hold the gearbox & engine together. Some thread into the motor, some into the gearbox, one has a nut on it. Try and record where each bolt came from, including the clutch slave cylinder bolts & the starter motor bolts. A piece of paper with each bolt’s location written on it, or a drawing of the bell-housing with each bolt sitting in its position will work.

Put a troller jack under the gearbox – we put it under the front, near where the gearbox meets the motor, with a bit of wood between the jack & gearbox – and take up the slack. Remove the gearbox crossmember from the chassis – 2 bolts each side, then from the gearbox – 2 nuts, and set aside. The trolley jack is now supporting the gearbox & stopping the motor from tilting.

Put a pair of axlestands in the car (assuming you removed the passenger seat) – 1 in the driver footwell & the other where the passenger seat was – use something to stabilise the second one. Get a 1 metre or so long piece of 3x2” (thats 70 x 45 for you younger readers)and put it across the top of the axlestands. Make sure it will stay there – tape or cable tie if needed. Our axlestands had a long flat top surface so we just sat it there. Run your cambuckle strap around the piece of wood, through the shifter hole, around the back of the gearbox, and through the buckle. Leave loose for the moment. Put it a bit forward of vertical on the gearbox, so when the gearbox moves back it isn’t trying to pull it forward again. This strap provides a bit of security (that the gearbox isn’t going to drop), and a bit more control when lowering the gearbox.

Now we need to tilt the motor. Lower the trolley jack until the heater hose behind the motor (you can see it from under the car) is just starting to be squashed. If you left the fan on make sure it doesn’t hit the radiator while doing this. Support the front of the motor so that when the gearbox is removed, the motor doesn’t tilt back the other way. We used a second trolley jack & a bit of wood under the belt tensioning bracket.

Remove all bolts holding the gearbox to the motor, all 14mm heads. There are 4 across the bottom (one with a nut on the other side), 2 at the top, and a couple of others (from memory) on the sides. The top ones are the hardest to undo – use several ½” socket extensions to reach them over the top of the gearbox, with a ratchet near the back of the gearbox. It is easier to guide this long extension set onto the bolt if you use the least number of individual bits – each joint adds more flex. Try and use a couple of the longer (300mm?) extensions plus whatever else you need to reach. The top bolt on the driver’s side also secures a metal bracket with the gearbox breather on it – take note how it sits. We removed the top bolts first, because they were the hardest to get to, then the rest. Be careful removing the last bolt – our gearbox didn’t separate by itself but some may. We used a wheel brace (the bent one with a large flat “screwdriver” on one end) to lever the gearbox & motor apart. Support the gearbox as you do this, as it separates from the motor it will tend to fall sideways – it can’t go far as the bell-housing will hit the sides of the tunnel, but you don’t want it to fall off the trolley jack.

This is where it gets interesting – some Japanese engineer has calculated precisely how big the tunnel needs to be to remove & install the gearbox with the motor in the car, and has allowed a couple of mm clearance beyond this. As the gearbox moves back the front of the bellhousing will catch on the tunnel, and it won’t be able to move any further back. At this stage the gearbox input shaft will (should) be out of the clutch plate spline, but still inside the clutch cover. You need to lower & move the gearbox back a bit at a time, until the spline is clear of the clutch cover & the gearbox can be lowered completely. Remember to lower the rear (with the strap) as you lower the jack. And support the gearbox from rolling sideways – you don’t want it to fall off the jack.

Once the jack has been fully lowered you can move the gearbox further back out of the way – how far it will move depends on how high you have the car off the ground, as it will catch on the floorpan. We used a flat metal plate on casters (that I built for moving a motorbike on it’s centrestand) under the back of the gearbox, and a bit of wood under the front, and left it under the car. If you are going to replace the gearbox input shaft seal it would be easier to get the gearbox out completely – we didn’t do this as it was done 6 months ago. The gearbox is heavy (my guess is around 70 -90 kg), so be careful.

You can now remove the clutch fork from the gearbox – pull the grommet out and the fork pops off the ball – it’s held on by 2 bits of spring wire on the back. The clutch release bearing will now slide off. If replacing the bearing you need to pop the old one out of the carrier & fit the new one. Clean & lube (sparingly) the gearbox shaft outer before refitting the new bearing, and put some lube on the fork ball before fitting the fork. If replacing the gearbox input seal remove the bolts holding the front housing on, remove & refit the seal, then bolt the housing back on.

You can now remove the clutch from the back of the motor – a heap of 12mm head bolts around the outside of the cover. Be careful as you remove the last one – the clutch plate is sandwiched between the cover & flywheel and will fall out. The cover also sits on 3 dowel pins to locate it correctly – you may need a screwdriver to lever it off these pins.

The flywheel is now exposed, and can be removed by undoing the 6(?)19mm head bolts. A rattle gun is best to loosen these, as the motor won’t be trying so hard to turn over (in the wrong direction). If it is trying to turn use the same wheel brace as earlier to wedge between the motor & the ring-gear to hold it. Once again be careful as you remove the last bolt – the flywheel is very heavy and has sharp teeth – it will bite if it falls on you, or be damaged if it falls on the ground. It sits on a flange (a bit like a wheel) so needs to be moved away from the engine slightly to get it off. Note the single dowel pin to locate the flywheel – you will need to line this up when you re-fit it.

The black sheet-steel dust cover can now be removed – it sits on 2 locating dowels. Don’t forget to re-fit this before putting the flywheel back on.

There is a brass spigot bush inside the flange on the end of the flywheel – this should be replaced when fitting a new clutch. Xtreme generally supply a new one with their clutch kits, but I don’t think Exedy do. If you don’t get one, they are available from Nissan or Ebay quite cheaply. Removing the old one can be tricky – I spent a bit of time with a seal pick, and then tried the wet paper & compress trick – neither method worked. I then tapped the square end of a ½” socket extension into the bush – it’s slightly too big and the 4 corners cut into the brass. Then gently turn the extension with a ratchet, while pulling gently outwards and slight to one side (so it doesn’t separate from the bush). This worked, and took a few seconds once I worked out what to do. The new bush can now be tapped in with a socket the same size.

You can now see the motor’s rear main seal – it is recommended that this be replaced at this point, even if it isn’t leaking. You won’t want to be in this far anytime soonJ Remove the old seal with a pick or a self-tapping screw, and use the old seal to tap the new one into position.

There is also a welsh plug above the flywheel – check the condition of this & replace if needed.

If fitting a new clutch, get the flywheel face machined. This will cost $50 - $100 depending on who does it, and provides a good mating surface for the new clutch disk. Xtreme won’t warranty a clutch without proof that the flywheel was machined when fitting. Not sure if Exedy is the same or not.

Reinstallation is a reverse of the removal process. Be careful of the following:

Use a clutch alignment tool when re-installing the clutch to ensure that the clutch plate is centred in the cover. Once the cover is bolted on there is no way to move the clutch plate until the gearbox is back on & the slave cylinder refitted. If it isn’t centred now you will have all sorts of trouble getting the gearbox spline to mate properly. Xtreme include an alignment tool with clutch kits, but I don’t think Exedy do. If you don’t have one, beg, borrow or steal.

Make sure the surfaces of the flywheel & clutch cover are clean, and free of greasy fingermarks. I cleaned these with wax & grease remover just before fitting the new clutch.

Re-installing the gearbox makes removing it seem easy. You need to get it in exactly the right position vertically & horizontally, and be at the same angle as the motor in both planes as well, for the spline to have any chance of going in. Use the trolley jack to lift the bulk of the gearbox & the strap to lift the rear & adjust the angle. Similar to when removing the gearbox, you will need to lift it and move it forward a bit at a time – the bell-housing will again catch on the tunnel & it will look like it will never go back in. It will, but it isn’t easy. Once the input shaft tip is in the clutch plate spline, push the gearbox forward & jiggle it around. If you are lucky it will just go in. Usually you will need to turn the gearbox output spline (this is why we left it in first) and/or the crankshaft (using a socket on the harmonic balancer bolt) to get the splines to mate up. This is where a third person is good (along with passing tools & bolts while the other 2 are under the car). We used 2 of the longer bolts, with several washers on each, in the bottom holes to pull the gearbox onto the motor, making sure the top is pulling in with the bottom. If you’ve got this far without petrol & matches being used, have a celebratory beer or 2 – the hard part is (almost) finished.

Once they are together, re-fit all the bolts in their correct location & tighten. Refit the 2 top bolts as you removed them, with the long extension setup. Don’t forget the breather bracket. At about this point refit the clutch slave cylinder, and check that the clutch works – that you have pedal pressure, the fork moves, and that the clutch disengages when pressed (in gear, try turning output shaft with clutch pressed / not pressed).

Re-install starter motor – once again the top bolt is very hard. We put the bolt in the 14mm socket on a medium extension. Then from the top, feed it into its hole. It helps if someone is under the car helping to locate the bolt. Do it up as far as you can by hand with the socket, then use a ratchet ring spanner to tighten. Reconnect spade & eyelet cables to starter motor. Time for another beer – it’s an easy cruise from here.

Remove the front jack (holding the front of the motor up). Jack the gearbox back into position, refit the crossmember, re-attach the cat & mounting bracket, re-install the tailshaft (using your markings if you were that anal), reconnect the gearbox loom, refit the fan & shroud (if you removed them), refit upper radiator hose & tighten clamps, & top up coolant (open bleed bolt to let air out).

Refill gearbox with your choice of oil – we used Redline Lightweight Shockproof, hoping to get rid of a small amount of crunch. It will take around 3.5 -4 litres, depending on who you believe. We had 4 quarts (about 3.8 litres), and used the lot. Easiest way to fill is though the shifter hole (don’t so this on a GTR). If you remove the side fill plug, then fill through the shifter until oil comes out of the side hole, it will have the correct amount in (assuming the car is level). If you aren’t that anal,l decide how much it should take and just put it in, leaving the side fill plug in place.

Re-install the shifter, which will seem easy after re-fitting the gearbox. Refit trim pieces.

Check that everything is reconnected & all bolts are tight. Check that the clutch pedal feels good, and that the fork moves correctly. Put the car on the ground & go and start bedding in (& wearing out) the new clutch (wait a while if you had too many beers).

[Humbla]

Fantastic ,but at the end of the day is easier and works better if you get a mech,to do it.

Got mine replaced 11 years ago with an exedy sports tuff ,still works perfect,only

way to go IMO.. :-)

[MrStabby]

Geoff - thats awesome - you should put that up in the DIY section: http://www.sau.com.au/forums/forum/57-tutorials-diy-faq/

My DIY for 32 GTR is in my sig.