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C2 Manual Bellhousing top bolt


17 May 2020
So the time has come to take my 98 C2 off the road and get the gearbox whine sorted out plus a few other jobs I've been saving up whilst the box is out.

It's up on ramps at the front and 4 axle stands at the back, w on the jacking points and 2 under each corner of the cross member.

All was going well until I got to the top bellhousing bolt on the gearbox. Access is awful, so I've removed the front gearbox mount and lowered the engine and gearbox down at the front on a transmission floor jack, until the box is resting on the aluminium chassis cross member between engine and gearbox.

I can now get a 16mm socket on the bolt from the front passenger side of the gearbox, with a universal joint, 2 x 250mm 1/2" extension bars and 2 x 125mm 1/2" bars. The problem here is that by the time my wrench with 2ft pipe slid over it plus the extensions and universal joint take up the slack, I'm almost touching the floor and the bolt won't shift.

I've broken the firs universal joint although it was old and am trying with a second one now, but it still won't give me enough solid leverage to budge.

Has anyone got any tips for this bolt? My only hope so far is waiting for a 500mm wobble head Draper 500m extension bar to arrive. This will allow me to bin the universal joint, as it allows 15 degrees of wobble, plus I can bin at least 3 of the current extension bars. I'm hoping this will take out enough slack to get a purchase quicker, as at present I must be turning it a good 45 degrees without it cracking, just slack being taken up in all the joints.

I have the drivers side rear wheel off, but access from there is just as bad.

I must be missing something simple, but can't think of a better way of getting access.

Your not doing anything wrong .. it's going to be a seized bolt basically ..

Gearbox as low as you can get it and that's full access .

I use a universal joint similar to this ..


The ones that go 90 degrees are no good for this job .

It must be 1/2 inch drive .. 3/8 and you have no chance .

I have a ramp .. i use long extensions to the back of the gearbox and a rather powerful air gun .. sometime even then they can be stubborn ..

On your back by hand ? it's going to be a struggle so all i can offer is the universal joint above .

Might be worth investing in an electric gun if you are going to be doing this sort of thing .. they aint cheap .. unlike my colleagues that all have these i prefer an airgun .. but they are good .
Thanks. At least I know there's not some silly way of getting to it, which I've missed.

I've got a 500mm wobble 1/2" extension coming today and one of those impact joints coming tomorrow now. I think a lot of the problem, other than lying on my back with limited access, is that there's too much slack between all the joints and extensions. Hopefully this will reduce it.

I have a decent DeWalt Impact gun which might stand a chance with a decent impact joint, instead of my sloppy 90 degree universal joint.

I'd removed the one to the drivers side of this, thinking it was the hard to get to one. My heart sunk when I spotted one even higher up and harder to get to! :sad:
No top tips I'm afraid but I did a gearbox change on my back and it is indeed a pain the arse. But it easily the toughest bit, once you got that cracked you're on the home stretch.
Just to point out something i missed on my last post ..

Never .. Ever ... use a 90 degree universal joint with an air or electric gun ..

The one i linked is fine .. to a degree ( you still need to be carefull ) but a 90 degree one .. it will shoot off and cause damage .. often to the person using it ..

A slingshot job which normally hits you in the face .. joint and socket .... lets just say .. it's a lesson i learnt many years before working on Porsche .. and i've been on these for 18 years !
Phew, got there in the end!

My Dewalt Ratchet gun couldn't touch it, but the impact universal joint, as suggested and a 50cm + 25cm extension, with a 1/2" drive ratchet with a pipe over the handle got it to crack eventually. It looks like someone thread locked it.

I found it better to get to the passenger side and pull the wrench towards me than trying to fight it towards the ground from the drivers side.

I can tackle the rest of it now.

Thanks for the tips!
Well the gearbox is finally out and waiting to be driven up to the rebuilder in SE London. I looked at pallet delivery and the cheapest for a standard 1.2M x 1M pallet up to 60cm high and 150KG (the smallest pallet option), was almost £100, even though all claim on Google to be "from £25".

As work drops quiet, I try and get an hour or so in every so often and the next job is clutch and flywheel, so I can see where the leak is coming from.

I've found a download of the workshop manual, so will have a look at this, as I need to apparently lock the crank and release chain tensioners before popping the IMS cover off to inspect it and reseal it.
YPVS said:
Well the gearbox is finally out and waiting to be driven up to the rebuilder in SE London. I looked at pallet delivery and the cheapest for a standard 1.2M x 1M pallet up to 60cm high and 150KG (the smallest pallet option), was almost £100, even though all claim on Google to be "from £25".

As work drops quiet, I try and get an hour or so in every so often and the next job is clutch and flywheel, so I can see where the leak is coming from.

I've found a download of the workshop manual, so will have a look at this, as I need to apparently lock the crank and release chain tensioners before popping the IMS cover off to inspect it and reseal it.

That sounds about right, just need to undo the two chain tensioners on the ims side of the engine don't need to remove the one under the a/c compressor.

Pallets are very expensive, better to load the transmission into the back of a car and drive yourself if you're not too far away/have the time in my experience.

Good luck!
Cheers, some of your tips from your thread are proving very useful!

As I'm not removing the IMS bearing, just the flange, for a visual inspection and reseal with new o-ring, I'm wondering why I need to release the chain tensioners. Is this because the IMS shaft sits on a spindle which is part of the IMS flange, so as I remove the plate, it could move if under tension, even though the bearing isn't being removed?

Maybe I'm being a bit overly worried about loosening the tension on the chains! :lol:
Hello - the reason to release the tension before undoing the cover is that the cover locates the bearing for the Intermediate shaft. So the chains could pull the shaft off-centre, if you undo the cover without having released the tension.

The bearing is running on the shaft that appears out of the middle of the cover...(the nut you can see in the middle secures the shaft to the cover).

Have done the same check that you are about to undertake. I also removed the outer cover off the IMS bearing, so any trapped oil can escape and it will also allow fresh oil to be splashed into the bearing and provide some lubcrication.
^^^^ that's my understanding too, make sure you lock the crank before you remove the tensioners and you'll be fine. And obviously don't move the crank with the tensioners removed!

Glad to hear my thread is of some use. It's a great feeling getting the car buttoned up again afterwards, some great peace of mind.
Well, the oil leak dribbling down to the sump plate doesn't look like it's from the RMS or IMS plate as it's dry as a bone at the bottom of the case. I'll probably still remove the IMS plate, inspect and reseal with a new O-Ring and whatever sealant I'm meant to use, whilst I'm there. I suspect it will be the same Porsche recommended Black Loctite in the small plastic tube, which I used to reseal the sump plate.

The flywheel feels OK, with just a few mm movement to either side and no obvious lip.

The clutch friction plate is, as the previous owner said, pretty new at 1.16 to 1.25mm from the flanged side of the rivet to the friction surface, as here. Lower limit is 0.3mm and new is 1.7mm.


But the pressure plate shows signs of overheating, so I suspect only the friction plate only was replaced. I might as well do the whole kit whilst I'm here for £210 or so. I presume the Sachs kits of pressure plate, friction plate and release bearing are OK? It's what was in there before, but this seemed to slip a bit too easy on a fast start for me. Maybe this was due to the pressure plate?

Whilst I'm there, I have a small leak to sort on the joint between the brake lines at the inner back offside arch (to the one over the gearbox), but on a plus note, this over the gearbox line has already been replaced with copper and is in good nick.

At least some of the leak is the OSV. I have a new set of bellows for this, so will take off the old ones and look for a leak. If it's a split bellows, I'll clean up the OSV and put the new bellows on.

Then I've just got to find a quiet work day without rail strikes, next week, to drive the gearbox the 50 miles each way to the repairer in SE London and back.


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A bit more progress on this today, as work dropped quiet.

The gearbox has been taken to Helical Gearboxes in SE London, to get the whine sorted out. These are the folks who fixed Shalmeneiser's gearbox successfully and remembered him taking his in as a passenger in a Boxster! :D

A new Sachs clutch kit with friction, pressure plate, release bearing a little sachet of grease has arrived. The flywheel looks OK, but I'll check this when I get it off finally. This was put on hold as my T55 bits are not a great fit and one slipped, so a new impact one with a flatter bottom has been ordered for tomorrow. The old release bearing feels rough and has play in in when compared to the new one. I'm guessing only the friction plate got replaced last time.

I also ordered a modified clutch release arm kit from Design 911, as my old clutch release arm is showing serious signs of wear where the slave piston rod touches and where it pivots at the other end. The modified arm and kit, appear to be 997 parts and no longer have the plastic pivot on the gearbox end. It's a longer pin, with different seal and clip.

Finally, I've been umming and arring over whether to replace the clutch slave cylinder. It's a Sachs one, so has been done before and it not leaking, but the rod end is worn and the plastic tip is just bare metal now and has been eating into my old clutch arm. The Sachs ones are not much, but I'm wondering if I can bleed it whilst not connected to the clutch, as this would be much easier. I wondered about holding the piston rod somehow to the slave mounting bolts, as I apply pedal pressure and unlock the bled nipple to remove air, before doing up again and repeating. All I have to do really is stop the piston rod from shooting out with no resistance on it.


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A change of plan now.

As the IMS/RMS is not leaking, I checked the paperwork which came with the car, again. The IMS was replaced less than 8,000 miles ago with an EPS roller type bearing, which I'm led to believe is a lifetime fix and much stronger than the normal ball bearing types. I have original purchase receipt from Design911 and a fitting invoice from a specialist, with photo's over the engine out (lots of other work done at the same time) and old and new bearings.

If it's not broken, don't fix it springs to mind.

I've replaced the OSV bellows are they were caked in oil as is that side of the engine OSV downwards. No obvious split, but clearly leaking past the Jubilee clips as someone had put silicone sealant on the pipes the bellows attach to. The new bellows comes with a spring clip which has a plastic release clip to aid installing. Still a pain to get on properly though, even with gearbox out.

The apparently leaking brake pipe connector, flagged at the last MOT, doesn't seem to be leaking at all. It's the one over the gearbox on the inner right ORS wheel arch, where it connects to the final section for that wheel. Someone has already recently replaced these with copper, so I've tightened the connector up (one side did turn a bit) and have left a lump of wood pushing the brake pedal down overnight to check.

Other than that, I've degreased the engine to see if the oil leak is just the OSV bellows and have sprayed some penetrating fluid on the clutch pipe release bolt at the salve cylinder, as even though not leaking, I'm going to replace the slave as the rod is just bare metal now and was eating into my old clutch release arm.

It's good to get a proper look underneath the car.

Gearbox rebuild progress

I picked the rebuilt gearbox up today. It was mainly the pinion bearing which was starting to fail.

Lucky it was caught early really, as other than new seals, it only needed the pinion bearing and a smaller bearing at the front end of the gearbox, which was starting to feel a little rough.

There was no grease in either bearing and even though they had oil inside, the pinion bearing had started pitting the outer and centre race, as below.

I've not got a few small jobs to do before refitting, as it was such as pain, I don't want to be doing many jobs in that area again. The coolant pipes over the gearbox are metal and in good condition, the rubber ones look good too. The over box brake line is copper and has been done already, but I decided to do the hoses and pipes to each rear wheel as the fixings were corroded and I had a slight leak at a joint. The OSV bellows have been replaced, as will the clutch slave cylinder and the rubber/metal hose and pipe to the clutch slave (£140 ouch).

I've got a lot of festivals coming up, but should have it back on the road in a few weeks now. :thumb:


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