21 BMW 1983 R100RS Install Clutch

After installing the flywheel, I’m ready to install the clutch. You can see how I install the flywheel here.

Installing the clutch is a straight forward procedure.

Tools

I use a special tool that centers the clutch plate on the center of the flywheel. It aligns the the clutch plate so it will be centered with the transmission input shaft. I only have to rotate the transmission input shaft to align the splines on the transmission input shaft so they line up with the clutch plate splines.

Clutch Centering Tool for 1981+ Clutches

Clutch Centering Tool for 1981+ Clutches

Parts

I am installing new clutch parts as shown in the list below.

Part #                 Description                                      Qty
21 21 1 338 680 (Bolt)
21 21 1 242 377 (Washer)
Clutch Bolts & Washers 6
21 21 1 338 508 DIAPHRAGM SPRING (from 09/80) 1
21 21 2 302 200 PLATE (from 09/80)-Pressure Plate 1
21 21 1 451 512 CLUTCH PLATE (from 09/80) 1
21 21 1 457 280 HOUSING COVER (from 09/80) 1

Video

I made a short video showing highlights of this procedure.

VIDEO: 1983 BMW R100RS Install New Clutch

Clutch Parts and Markings

Here are the new clutch parts I am installing.

Clutch Assembly Parts

Clutch Assembly Parts: Clockwise From Top Left-Diaphragm Spring, Clutch Plate, Pressure Plate, Housing Cover

Clockwise from the top left,

  • Diaphragm Spring
  • Clutch Plate (aka, Clutch Disk)
  • Pressure Plate
  • Housing Cover, (aka, Front Cover)

The clutch parts are attached to the face of the flywheel with six M7 bolts and washers. I am installing new bolts and washers.

New Clutch Bolts with Washers

New Clutch Bolts with Washers

I took some pictures of the clutch parts and the part# markings on them.

Clutch Housing Cover

Clutch Pressure Cover-Outside

Clutch Housing Cover-Outside

Clutch Housing Cover-Inside Contact Surface

Clutch Housing Cover-Inside Contact Surface

Clutch Housing Cover Markings: 3072 092 230 02 | 18 3

Sachs Clutch Housing Cover Markings: 3072 092 230    02 | 18 3

Clutch Plate

Clutch Plate-Inside Surface Goes Toward Flywheel

Clutch Plate-Inside Surface Goes Toward Flywheel

Clutch Plate-Outside Surface with Sleeve For Transmission Input Shaft Faces You When Installed

Clutch Plate-Outside Surface with Sleeve For Transmission Input Shaft Faces You When Installed

Clutch Plate Markings: 1.451.512.2

Sachs Clutch Plate Markings: 1.451.512.2

Clutch Pressure Plate

Clutch Pressure Plate-Outside with Six Ridges

Clutch Pressure Plate-Outside with Six Ridges

Clutch Pressure Plate-Inside Contact Surface

Clutch Pressure Plate-Inside Contact Surface

Clutch Pressure Plate Marking: 3003 091 099

Sachs Clutch Pressure Plate Marking: 3003 091 099

Clutch Pressure Plate Rear Markings: 02 | 18 3071 072 030

Sachs Clutch Pressure Plate Rear Markings: 02 | 18   3071 072 030

Clutch Diaphragm Spring

Clutch Diaphragm Spring-Inside Goes Against Face Of Flywheel

Clutch Diaphragm Spring-Inside Goes Against Face Of Flywheel

Clutch Diaphragm Spring-Outside Goes Against Pressure Plate

Clutch Diaphragm Spring-Outside Goes Against Pressure Plate

Clutch Diaphragm Spring Markings: 108 101 11 17

Sachs Clutch Diaphragm Spring Markings: 108 101 11 17

Clutch Diaphragm Spring Markings: 12L17 3054 001 031

Sachs Clutch Diaphragm Spring Markings: 12L17 3054 001 031

Balance Marks

The flywheel, pressure plate and clutch housing cover have white paint balance marks. These indicate the heavy area of each part. To balance the engine, each part is mounted 120 degrees from the others so the clutch is balanced. It is important for a smooth running engine to evenly distribute the balance marks when mounting the clutch.

Flywheel Balance Mark

Flywheel Balance Mark

Clutch Pressure Plate Balance Mark

Clutch Pressure Plate Balance Mark

Clutch Housing Cover Balance Mark

Clutch Housing Cover Balance Mark

Preparing Clutch Parts

Even though these are brand new parts, the metal contact surfaces need to be cleaned to remove oil and debris. I use brake cleaner and blue shop towels and clean the contact surface of the pressure plate and the clutch housing cover. I do not clean the clutch plate’s friction surfaces.

Clean Clutch Pressure Plate and Housing Cover Contact Surfaces

Clean The Pressure Plate and Clutch Housing Cover Contact Surfaces

Cleaning Clutch Housing Cover Contact Surface with Brake Cleaner

Cleaning Clutch Housing Cover Contact Surface with Brake Cleaner

What Was On A New Clutch Housing Cover Contact Surface

What Was On A New Clutch Housing Cover Contact Surface

I apply a very thin smear of Moly 60 grease on the contact surfaces of the diaphragm spring and the pressure plate. The six bosses on back of the pressure plate contact the front of the diaphragm spring. The rear edge of the diaphragm spring contacts the face of the flywheel so each gets some Moly 60.

Put A Light Smear of Moly 60 On Inside Edge of Diaphragm Spring

Put A Light Smear of Moly 60 On Inside Edge of Diaphragm Spring

Very Light Coat of Moly 60 Applied To Inside Edge of Diaphragm Spring

Very Light Coat of Moly 60 Applied To Inside Edge of Diaphragm Spring

Put A Light Smear of Moly 60 on Top Of Six Ridges On Back Of Clutch Pressure Plate

Put A Light Smear of Moly 60 on Top Of Six Ridges On Back Of Clutch Pressure Plate

Install Clutch Parts

I turn the clutch housing cover over so the contact surface faces up. There are three locating pins, each 120 degrees from the others.

Clutch Front Cover Locating Pins

Clutch Housing Cover Locating Pins

I put the clutch plate on the contact surface of the pressure plate. The side of the clutch plate without the sleeve faces me. The transmission input shaft fits into the sleeve, but goes in from the other side of the clutch plate.

Orientation of Clutch Plate On Front Cover - Sleeve Faces Down

Orientation of Clutch Plate On Clutch Housing  Cover – Sleeve Faces Down

I attach the pressure plate on the three pins of the pressure plate. Each of the three straps on the pressure plate has three holes. The center holes in the three straps fit over the pins on the clutch housing cover. I make sure that the white paint balance mark on the clutch housing cover and the balance mark on the pressure plate are are not next to each other.

Pressure Plate Strap Center Holes Fit Over Front Cover Pins

Pressure Plate Strap Center Holes Fit Over Clutch Housing Cover Pins

Clutch Front Cover Paint Mark 120 Degrees From Pressure Plate Mark

Clutch Housing Cover Paint Mark 120 Degrees From Pressure Plate Mark

Clutch Pressure Plate Paint Mark 120 Degrees From Front Cover Mark

Pressure Plate Paint Mark 120 Degrees From Clutch Housing Cover Mark

I flip the assembly over so the outside of the clutch housing cover faces me to verify I have the clutch plate installed correctly. The sleeve the transmission input shaft slides into should face me.

Verifying Clutch Plate Sleeve Is On Front Side of Clutch Front Cover

Verifying The Sleeve Side Of The Clutch Plate Is On The Transmission Side of The Clutch Housing Cover

Then I put a light coat of Moly 60 the peak of the six ridges on the back of the pressure plate. The peak of the ridge rubs against the front of the diaphragm spring and the Moly 60 will reduce wear of the ridge.

Very Light Coat of Moly 60 On Ridge of Pressure Plate Rib

Very Light Coat of Moly 60 On Ridge of Pressure Plate Rib

Very Light Coat of Moly 60 On Ridge of Pressure Plate Rib

Very Light Coat of Moly 60 On Ridge of Pressure Plate Rib

Rear View of Clutch Pack with Clutch Plate Sandwiched Between Pressure Plate and Front Cover 

Rear View of Clutch Pack with Clutch Plate Sandwiched Between Pressure Plate and Clutch Housing Cover

I orient the white balance mark on the flywheel so it is at the bottom of the flywheel.

Flywheel White Balance Mark Oriented At The Bottom Of The Flywheel

Flywheel White Balance Mark Oriented At The Bottom Of The Flywheel

I put the diaphragm spring on the face of the flywheel with the bow in the spring facing me so the perimeter of the spring is against the face of the flywheel.

Install Diaphragm Spring On Face of Flywheel with Bulge Facing Me

Install Diaphragm Spring On Face of Flywheel with Bulge Facing Me

The three pins on the clutch housing cover fit into three holes in the face of the flywheel. I orient the clutch pack so the paint mark on the clutch housing cover is near the top (next to my thumb in the picture below), and the paint mark on pressure plate is at about the 4:00 position. Since the flywheel paint mark is at the bottom, this positions all three paint marks next to each other.

Install Clutch Pack So Pins Fit Into Holes On Flywheel Face with Front Cover Paint Mark At Top

Install Clutch Pack So Pins Fit Into Holes On Flywheel Face with Clutch Housing Cover Paint Mark At Top

I attach the clutch pack to the face of the flywheel with two new clutch bolts and washers. I  thread the bolts into the holes so the clutch plate is loose between the clutch housing cover and the pressure plate.

Two Clutch Bolts Just Threaded Into Holes Attach Clutch Pack To Face Of Flywheel

Two Clutch Bolts Just Threaded Into Holes Attach Clutch Pack To Face Of Flywheel

I insert the clutch centering tool into the center of the clutch plate so the pin on the tool goes into the small hole in the center of the flywheel. This centers the clutch plate on the flywheel so it will align with the transmission input shaft when I install the transmission. Then I install the other bolts and finger tighten them all.

Clutch Centering Tool Installed

Clutch Centering Tool Installed

Once more, I verify the location of the paint marks. I verify the flywheel mark is at the bottom and the clutch housing cover paint mark is at the top.

Flywheel Balance Mark Opposite The Other Two Balance Marks

Flywheel Balance Mark Opposite The Other Two Balance Marks

Clutch Housing Cover Balance Mark

Clutch Housing Cover Balance Mark

I rotate the flywheel counter-clockwise to position the pressure plate paint mark to the top so I can see it through the top of the starter motor opening. It’s hare to see since it’s on the edge of the pressure plate. All three marks are opposite each other and none of them are aligned with each other, so all the parts are installed correctly so the engine will run as smoothly as possible.

Clutch Pressure Plate Balance Mark Visible Through Starter Motor Housing

Clutch Pressure Plate Balance Mark Visible Through Starter Motor Housing

I use a socket wrench to tighten the six bolts until they are snug. To prevent the flywheel from turning while I torque the bolts, I put a large flat blade screw driver between two teeth of the flywheel with the screw driver shaft against the left side of the oil pump cut out. Then I torque the bolts to 15 Ft-Lbs in a cross-wise pattern.

Use Large Flat Blade Screw Driver In Flywheel Teeth To Immobilize Flywheel

Large Flat Blade Screw Driver In Flywheel Teeth Will Immobilize The Flywheel

Torque Clutch Bolts to 15 Ft-Lbs

Torque Clutch Bolts to 15 Ft-Lbs In Cross-Wise Pattern

I remove the clutch centering tool. The clutch is installed.

Clutch Center Tool Removed - Clutch Is Installed

Clutch Centering Tool Removed – Clutch Is Installed

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