ZHP Clutch Replacement DIY (Long & Detailed)

[lkstaack]

Part I: Introduction

I’m going to explain how I went about replacing the clutch on my 2004 ZHP Sedan in five parts. Part I is the introduction and explains how I prepared for the replacement. Part II explains how I removed the transmission. Part III details the clutch parts I replaced. Part IV details transmission installation. Part V details lessons learned, clutch review, a shifter replacement DIY, and ancillary information.

While there are a few E46 DIY clutch sites, I didn’t find any that were complete; they all left out critical information. I researched the Bentley manual, the BMW ETK, and online resources prior to starting. Our ZHPs with 6-speed are unique to E46s; they use a different flywheel, pilot bearing, clutch and driveshaft. These instructions are not detailed: they assume that 1) you have some mechanical background, 2) you can figure some stuff out for yourself or can look it up in the service manual or internet, and 3) you have a healthy respect for safety. Please follow these instructions at your own risk; failure to take appropriate and reasonable safety precautions can lead to injury or death.

I had a lot of help planning and executing this project from the enthusiasts at these sites:
http://www.pelicanparts.com/bmw/tech...ch_Replace.htm
http://www.my330i.com/mod42.php#F
http://forum.e46fanatics.com/showthr...clutch+install

I needed to replace the clutch on my ZHP because it was slipping under load (particularly at hard launches), even though it had less than 90k miles on it. Although my ZHP puts out between 325-350 HP because of the installation of an ESS TS2 supercharger, I treat it pretty civilly. It never had a clutch delay valve and I don’t ride the clutch, so I’m not certain of the cause of its premature wear. Perhaps the self adjusting clutch (SAC) feature has something to do with it.

I had a number of decisions to make prior to ordering parts. I made these decisions using the following criteria:
1. Keep expenses to a minimum (I’m semi-retired and on a fixed income)
2. Increase clutch clamping force if possible
3. Replace all parts removed in the process that are likely to fail within the next 50k miles
4. Replace all parts as indicated in the service manual
5. Ease of installation
6. Keep it as OEM as possible
7. Get backup hardware for unique items

My most important decision was what clutch, pressure plate and flywheel to purchase. There are not as many clutch assemblies available for our ZHPs as there are for 5-speeds. I considered three different types: 1) stock SAC clutch, pressure plate, and flywheel, 2) Sachs heavy duty (HD) clutch and pressure plate with stock flywheel, and 3) UUC high performance clutch, pressure plate, and lightweight flywheel.

I quickly eliminated the Sachs clutch option. While it is probably the best clutch assembly of the three, it also cost $300 more than stock. I initially discounted the UUC product because of its lightweight flywheel. Although every Ricky Racer wants to install a lightweight flywheel into their ride, they often don’t know the draw backs. First is the infamous lightweight flywheel rattle; even though it is benign, it sounds like you have some loose bolts rattling around inside your transmission when in neutral. Then, you sometimes have to adjust how you drive; additional throttle is required when you start from first gear because you no longer have flywheel inertia to propel the car. And for what? To save a few pounds and get slightly better throttle response? Meh.

I initially selected the stock clutch, pressure plate and flywheel because I believed it would be the lowest price, easiest to install, and provide adequate clamping force. However, research showed me that 1) the UUC product was cheaper when including shipping (OE dual mass flywheels are expensive and heavy), 2) installation was more involved because of the SAC mechanism, and 3) I may end up with the same problem if my slipping was caused by the SAC mechanism.

During my selection process, UUC advertised a particularly good sale: 15% off and free shipping (flywheels are heavy and expensive to ship). I went for it, but soon found that there was some unexpected expenses with UUC. Their sales person indicated that the UUC kit would include flywheel bolts and a clutch alignment tool for additional savings. However, that is incorrect. After receiving the kit and calling them, I found that they provide those items with the 5-speed kit, but not the 6-speed. They also advise to re-use the original flywheel bolts and align the clutch using the OE shift lever. That is wrong too. Flywheel bolts are single use only and the OE shift lever does not have a snug fit into the flywheel bearing.

Next, I had to decide which clutch parts to reuse and which to replace. I ended up replacing all parts that could wear with OE parts. I didn’t get all new transmission mounting bolts, but I got one of each size just in case one broke.

Then, I decided which ancillary parts to replace and what to keep. I decided to replace all of the shifter wear parts and get an OE performance short shifter. I had a UUC short shift kit in my old E36 M3 and didn’t really like it. I also decided to replace the Guibo and transmission mount. I decided not to replace the rear main bearing seal and the transmission input and output seals. Those seals should last 200k miles or so, but can start leaking once you start messing with them. Of course, I replaced all hardware specified in the service manual (Guibo nuts, reinforcement plate bolts, exhaust nuts and gaskets, etc).

So, I got parts numbers from RealOEM, checked around for the best prices, captured all the information in the attached spreadsheet, and ordered the parts. The whole project will cost me about $1,200. Now it’s time to get to work.

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