Clutch, Flywheel, and Quaife Overview

[k-huevo]

With the amount of time required to remove and install the transmission I didn’t have enough extra for a complete Quaife, clutch & flywheel how-to, but I still wanted to share some of the experience so here is a general overview for the procedure.

Refer to the front swaybar install http://www.lonestarminiclub.com/forums/showthread.php?t=449 for the first stage of this task. I didn’t want to forget the small stuff so I started with something that is sure to be overlooked, the gear case sensor.
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I was prepared to remove the starter with the heat shield intact but discovered improper routing for the power steering cable which had caused some damage to the sheath.
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It was stuck in this crack between the heat shield and the coolant pipes mount.
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Either during manufacture or when the engine harness was replaced locally, the installer had become impatient with the heat shield and banged it in, bending the shield, missing the grommet mounts, and abrading a starter wire & powersteering cables.
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[k-huevo]

So out came the heat shield, followed by the starter, the passenger’s side drive & mid shafts, the driver’s side drive shaft and steering knuckle.
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I labeled the wiring least they be misplaced during reassembly and took photos of the routing both from below and above for a reference.

The shift cables had to be disconnected; shown is the nifty BMW/MINI tool for the job.
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[k-huevo]

The radiator support was put in service mode and every thing attached to the transmission or in the way had to be removed.
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In addition to an automotive jack I used the OEM engine support bracket suspended by an upper engine support. This provided more control during removal and the difficult realigning of the transmission input shaft with the clutch disc after the install.
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Out came the transmission.
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[k-huevo]

The pressure plate bolts require a Torx E8 socket.
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Here is the ill fated aluminum flywheel that I couldn't use. This had to be removed and because of time constraints I installed the latest OEM flywheel and pressure plate kit.
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Some of the lower bolts on the gear case were badly rusted and required cleaning up with thread restoration taps and dies.
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Before separating the two case halves, wrap the input shaft splines with tape and apply a thin coat of transmission fluid to avoid damage to the output shaft seal. The R53 shaft is a larger diameter than the R56 shown in the photo below.
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The split gear box and stock open differential.
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[k-huevo]

Here are metal shavings captured by the transmission magnet. The magnet is about the size of a half-dollar coin; this is not very bad and does not mean damage has been done. An analysis of the OEM fluid (the second change interval) showed very little wear residues.
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Here are the early and late model Quaife ATB differentials. The one on the left is the newest version which had 2lb-6oz trimmed away. The early version has very close tolerances and the Quaife on a diet rattles like a maraca when shaken.
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Press new bearings on the new differential.
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The differential ring gear has to be removed from the OE differential and fastened to the Quaife. Tightening torque for the differential ring gear bolts is 65 ft-lbs; with ten bolts to tighten on this critical component, quality control measures become very important. Clean and degrease the ring gear bolt and differential threads, tighten in a cross pattern to 30 ft-lb, place a mark on each completed bolt.
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Remove each bolt one at a time in a cross pattern, apply red threadlocker, and torque to the final 65 ft-lb. Apply a second mark as each are completed.
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All exposed bearings, races, and gear teeth are lubricated with fresh transmission fluid. Both gear case edges are thoroughly cleaned, anaerobic surface prep is applied to one side and a thin bead of anaerobic sealant is applied to the other mating surface and the two halves carefully put together. Once again it’s important to monitor the torque applied (30 ft-lb) to all the gear case bolts because it is easy to forget your place and miss one of them.

Here are some of the extras needed when splitting the gear case and replacing the flywheel; threadlocker, anaerobic sealant, special grease for the clutch shaft splines & release bearing, and two new bearings.
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The rear main seal had been weeping and I had ignored it when the aluminum flywheel was installed. When I pulled the lightweight flywheel I could see the areas I’d cleaned were moist again. I chose to replace the seal, however, more experience with the rear main seal on many other MINIs has altered my opinion of how much weepage is allowable. If it's only wet and not dripping, it's not necessary to replace, most likely a little weeping won't progress to a worse full-on leak.

[k-huevo]

The only OEM MINI installation tool available was a seal protector sleeve which I was glad to have during the install. I used some PVC fittings to drive the seal and this was not easy either.
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It was a successful seal install in the end.
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Here’s a tip I learned from Paul at the MINI Center to hold the crankshaft while tightening any bolts. That’s the most resent version of the stock dual mass flywheel and it is much quieter than the original on my vehicle.
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The entire kit installed. Clutch engagement is now right in the middle of travel instead of an inch off the floor like the old one and pedal pressure is very light and effortless. The difference is so pronounced there must have been a problem with the old flywheel.
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Here is where I don’t have any time left for photos. I was pressed for time to complete the job before the weather turned bad again and I had few difficulties (new strut install) that put me way behind. The transmission housing required some wiggling to fit again, this is where the transmission dolly and two engine supports came in handy for a solo install. I corrected the improper routing of the engine harness and fixed the heat shield along the way. Bleeding the clutch slave after this job is a must; plenty of bubbles could be seen in the catch bottle hose.

All of the torque values except for those involving the gear case can be found in the Bentley Service Manual along with any specialty tools.

Although this job can be performed “by-the-numbers” it does require a little more than average mechanical skills. I recommend contracting a professional for this install, but the money savings can be substantial for the do-it-yourselfer.

[k-huevo]

Not long after the install, fluid appeared at the transmission weep hole. My first thought was a failure of the rear main seal again; as fate would have it the OEM seal driver I ordered over two months ago finally arrived and I had a new approach for removing the old seal, so it felt like I was prepared this time. Well, the leak was coming from the transmission input shaft seal instead and it was a big mess. Enough had pooled to be picked up by the starter ring gear and slung around the clutch housing contaminating the clutch disc as well.
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[k-huevo]

The rub with this seal is a bearing located behind it so extra care is required during removal to avoid damaging the bearing retainer. After a couple of pros gave me a cavalier suggestion to “just use a screw driver” I gave it a try. I used a nut driver for a fulcrum and a screw driver as the lever to pry open a space, then an angled needle nose to pull it out; there is a shoulder on the input shaft that provided perfect leverage for the pliers’ elbow. That’s plastic from a water bottle protecting the shaft.
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This is the prophylactic method I used when sliding the seal over the shaft splines.
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[k-huevo]

The seal was driven flush using a PVC sink fitting, first using the flange side to drive it flush, then the smaller diameter side to take it a little further like the way the stock seal fit.
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While I was in there, it was a good opportunity to freshen up the clutch release mechanisms. The latest guide tube has a polished surface to reduce friction with the clutch release bearing; the older model has a course Parkerized finish.
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[k-huevo]

The new version of the clutch release bearing has a self-lubricating nylon sleeve for the sliding surface.
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The older bearing is all metal in the interior diameter.
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[k-huevo]

Since the clutch release parts had to be removed to degrease the clutch housing, the clutch release shaft’s nylon bushings were also replaced along with new threadlocker equipped OEM bolts. Before replacing the bushings, the shaft had play in all directions, after the new bushings the shaft would no longer wiggle. BTW, there was no wear on the clutch release fork’s contact pads so need for that part to be replaced.
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The Bentley Service Manual calls for a light film of ESSO Unirex S2 grease on the guide tube and the directions with the pressure plate kit extend that recommendation to the transmission input shaft splines. It requires only a very small amount of this special tenacious grease.
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A final inspection to make sure the clutch release bearing is in its place before bolting up the gear box.
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In all the clutch & flywheel install threads I’ve read it’s only mentioned to replace the clutch release bearing, but I think it makes sense to replace the other wearing parts in the mechanism also; the clutch release bearing and guide tube as a pair would seem a must.

[justintime]

keith you need to write a book, like haynes for minis. Only it will have better pictures