Information

General Guidelines For Installing A McLeod Clutch

• Before replacing your old clutch determine the cause of its failure. If anything but normal wear caused your current clutch to fail then you can bet it will cause your new clutch to fail.
• If oil is present on your old clutch, do the repairs necessary to ensure oil will not get on your new clutch. Oil will ruin your new clutch.
• The best reference guide for replacing your clutch is the factory service manual for the specific year, make and model of your car.
• Both the pressure plate and disc should be replaced together at the same time. They work and wear together. Never put a new disc with an old pressure plate.
• Resurfacing the flywheel is a must. Be sure it is machined to the original factory specifications. Failure to do so will result in a new clutch that doesn’t function correctly and or premature wear.
• Clean the friction surface of both the flywheel and pressure plate with brake cleaner. Be sure there are no traces of oil or grease on either surface.
• Inspect the input shaft on the transmission. Be sure the new disc slides smoothly on the splines. Be sure to inspect the shaft for any abnormal wear such as twisting, burring, broken splines and any other abnormalities.
• If applicable, be sure to replace the pilot bushing and throwout bearing.
• Use the proper clutch alignment tool.
• Ensure that only the proper bolts, washers, dowels and other application specific fasteners are used.
• Using a star pattern, torque all flywheel and pressure plate bolts to manufacturer’s specs.
• Properly adjust pedal freeplay if applicable to your vehicle. Failure to do so will result in premature clutch wear and or faulty operation and performance of your new clutch.

I. Melted Or Heavily Worn Clutch Levers (fingers) – T.O. Bearing May Or May Not Be Burnt Up.

A. T.O. Bearing adjusted too close.

B. Pressure in pressure plate too much for clutch linkage.

C. Driver constantly riding clutch pedal.

D. If one or two fingers how excessive wear while the other doesn’t, this indicates probability of factory maladjustment.

E. Bent or cracked fork.

II. Levers Bent Sideways Or Top Of Pressure Plate Badly Scarred.

A. Engine started before transmission was installed, causing T.O. Bearing and fork to be sucked into pressure plate, resulting in untold amount of damage.

B. If levers are bent down, pressure plate has been bottomed and gone beyond the stopping point.

III. New Units Burned Up.

A. Unit may be soaked with engine or transmission fluids.

B. T.O. Bearing misadjusted.

C. Unit miss-installed disc in backwards, improper bolts-lock washers used on some units that don’t require them.

D. Misapplication due to wrong rear end gears for height of tire or height of tire to weight of car or combination of all three.

E. Improper T.O. Bearing.

IV. Disc Problems

A. Facing Missing On Outside Portion Of Disc.

1. Usually just worn out or burnt facings.

2. Sometimes pilot bearing or main drive bad, allowing for banging of disc against side of clutch.

B. Loose Hub Springs.

1. These springs are designed to take torque; after use they will become looser than when new. This presents no problem unless the spring starts to wear the drive plate or back plate at the windows of the disc.

2. Some designs of plates on the market have springs too weak for most high performance cars. In these cases the springs will fly out of the disc, though the disc will still look good.

C. Center of disc breaks out.

1. If the hub and the two plates are still riveted together, but the plate, which the facings are riveted to, is broken out, then you have a misalignment in the transmission. This can be due to a pilot bushing gone bad or just “gone”.

2. If the hub comes out and the two plates are not riveted together, then the factory did not crush the rivets quite enough.

3. Clutch chatter (See General Information).

V. Bellhousings

A. Out Of Parallel.

1. In order for a clutch, transmission and related parts to function property the bellhousing must have two surfaces parallel to each other. One is where the bellhousing bolts to the motor. Where the transmission bolts to the bellhousing is the other. To check this, use a dial indicator with a magnetic base. Attach the base to crankshaft and indicator to (top) or transmission mating surface. Turn flywheel and mark the surface with something you can read (chalk, magic marker, etc.). Maximum run-out is +.005 to -.005.

2. To correct out of parallel; take bellhousing to someone that does Blanchard grinding (most steel flame cutter shops have one). Place the engine surface down on the table and have them grind the transmission-mating surface to bring it into parallel.

B. Center Hole Or Bore Out Of Alignment.

1. If center bore doesn’t run true to the center of the crank or pilot bushing, the clutch disc will suffer and possibly affect the transmission front bearing too. Erratic clutch engagement and disengagement can occur. Sometimes the center of the disc will break completely out if this problem is not corrected.

2. To check alignment in the car use a dial indicator tool that attaches to the crank with a magnet or use a regular magnet base indicator holder. Once the base is secure, set indicator dial at “O”. Slowly move the flywheel and observe the indicator. The maximum we recommend for the housing to be out of alignment is +.008 to -.008. When watching indicator it is best to mark the center bore in four places then read and record the indicator reading at those four positions. (We recommend the four positions be like a plus sign in math: “+”).

3. Correction of bellhousing alignment is usually done with offset dowel pins. Check with your local seed shop for appropriate part # and offset. If your bellhousing is not ours and it runs out of alignment more than .040 out on the black, then we recommend you purchase one of our new housings.