Thursday, June 26, 2014

Taking apart a Porsche 996

I wish I was as handy as some of you.

As you may remember, Edvin al-Helsinki-i bought a 911 last year. He has shared some pictures and background of some recent work.

Did a bit of preventive maintenance on the car. The car came with a one year warranty on the engine and drivetrain when I bought it. Since that was almost a year ago, I decided to tackle the infamous IMS (Intermediate shaft, if the bearing goes, then so does your engine) issue just for continued peace of mind. It made sense to also renew the clutch simultaneously. It also made sense to deal with the RMS (crankshaft Rear Main Seal) while I’m at it. Also, since I’ve already renewed my engine mounts and replacing the transmission mount requires dropping the transmission from the car, now was a good time to do that as well. I rented the required special tools from a fellow Porsche enthusiast and ordered the following parts:

- IMS bearing update kit
- Seals and plugs for IMS replacement
- Clutch kit
- Clutch fork update kit (to 997 style)
- Bolts for clutch and flywheel
- Transmission mounting bushing
- 9 litres of Mobil 10W40 & original filter 

While waiting for some parts to arrive I also removed the Aerokit side skirts that had been retrofitted to my car. I prefer the cleaner original look. Pics to come later as I get the proper OEM plastic bits to cover the holes left by the side skirts.

I didn’t have access to a garage with a lift, so I chose to jack the car up on stands and crawl under the car, which wasn’t too bad really. I had intended to document the job better, but once I started working I was too impatient to constantly be removing my gloves to take pics. Removing the transmission was fairly straightforward and now that I’ve done it once I could probably do it in a third of the time spent. Anyway, here are a few pics of the procedure.

New clutch kit and clutch fork.

Pelican Parts IMS upgrade kit. The new bearing has been assembled in the installation tool (the cylinder on the left).

The transmission has descended.

Old clutch in the car.

Old clutch fork mechanism.

New and improved clutch fork design.

Dual Mass Flywheel. Luckily this one was still in perfect shape. No scoring worth mentioning and it did not move more than the intended 15mm in both directions. I’m happy I didn’t have to replace it.

Removing the flywheel revealed a surprisingly tidy sight. All the pics I had seen so far had the RMS leaking very badly, whereas mine was still in perfect nick. According to a date on the old seal, it has been replaced after 2010. Because of that and the fact that they are notoriously difficult to install so that they don’t leak (may require 2-3 seals and tries), I decided not to touch it. At least I have the new seal bought if it starts to leak in the future. You can see the IMS cover has leaked a bit. 

Old clutch assembly. These were actually still had some life left in them and didn’t really need replacing, but I did it anyway seeing as I had the parts.

New IMS bearing installed.

Old transmission mount. Not completely destroyed, but has noticeable cracks in the rubber. I’ve heard that Porsche recommends all rubber bushings to be replaced every 6 years despite whether they look perished or not, because the dampening properties of the rubber has decreased noticeably at that point. Makes sense. 

Pressing out the old rubber mount. We had to fabricate a special tool for this job. Not the prettiest one, but it worked.

New bushing going in.

If you’re gonna do this job, don’t forget to run the shift cables between the body and rear transmission mounting. NOT like in this picture, because then you’re gonna have to lower the transmission again. Sigh…

The clutch slave cylinder had been assembled incorrectly by the previous mechanic, which caused it to disassemble when I removed it from the car. This gave me the opportunity to overhaul the cylinder and bleed the clutch. Correctly assembled and cleaned cylinder in the pic.

Was it worth it? Yes. The main point in this undertaking was to deal with the IMS issue. Peace of mind has been restored and the car will be easier to sell when the time comes (not any time soon, I think). To be honest the new clutch parts haven’t made much of a noticeable difference in clutch feel, but increased reliability is the keyword here too. The transmission mount had a noticeable positive effect, not huge, but clearly better. Now it’s just like the factory intended. So that’s a few big things ticked off the shrinking to-do-list. Next up, a set of new tyres, at least for the rear. And maybe a few refurbished control arms. 



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