Unsticking a Stuck Clutch

As I learned with our 1929 Town Sedan, the Hudson clutch is unusual, in that it uses an oil bath rather than dry clutch plates. Hudson referred to this special oil as Hudsonite. Owners were instructed to make their own Hudsonite by mixing equal parts of light motor oil and kerosene. However, dealers also sold 6-ounce cans of Hudsonite that presumably had a somewhat more sophisticated formulation. The clutch plate itself is an aluminum disk pierced with 144 1/2-inch holes, with a piece of cork inserted in each hole. When properly maintained, the oil bath clutch functions very smoothly. However, if a Hudson is left to sit for long periods (4 decades, in the case of our car) the oil dries and literally glues the clutch plate to the flywheel. Some Hudson owners have reported success in unsticking their clutch by replacing the clutch oil with kerosene and soaking the clutch for several days, then stressing the "glued" surface by towing the car or other means. A Hudson Service Bulletin recommends a mixture of three parts kerosene and one part acetone, which might be more effective than just kerosene. Having tried the kerosene soak without success, my advice is this: if your clutch is frozen, take it apart and fix it properly, and replace the pilot bearing while you're at it.

Some Hudson owners also have successfully experimented with the use of modern Type F Automatic Transmission Fluid, which is better able to stand up to heat generated by frequent starts and stops than the original "Hudsonite" fluid.

Hudson provides detailed instructions for servicing the clutch, which I repeat here (with comments in italics) for anyone who doesn't have access to a Hudson Repair Manual. These instructions are for Super Six cars with serial number 750,001 and higher.

1. Remove front compartment rubber and felt mats and take out front toe and floor boards. This requires disconnecting the accelerator connecting rod, which runs along the underside of the floorboard, on both sides. The left-side connector goes to the hand throttle mechanism, and the right side to the carburetor.
2. Remove clevis pin from brake pedal and disconnect brake pedal to equalizer bar pull rod.
3. Remove clevis pin from lower end of starter pedal shaft lever. Disconnect starter operating shaft and spring.
4. Remove clevis pin from clutch adjustable link and disconnect throwout yoke.
5. Unscrew sleeve at rear end of speedometer shaft and disconnect shaft from transmission.
6. Remove bolts from universal joint flange and disconnect propeller shaft. In today's parlance, this is the drive shaft. I had to disconnect it at the rear end as well to obtain enough clearance to remove the transmission.
7. Remove bolts holding pedal control bracket to transmission case and take off pedal control assembly.
8. Remove cap screws holding hand control lever asssembly and transmission cover to transmission and disconnect control assembly. It isn't in the maintenance instructions, but it is a very good idea to drain the oil out of the transmission at this point, either using the transmission drain plug or by siphoning or pumping from the top of the now-open transmission.
9. Remove clutch drain plug from flywheel and drain oil out of clutch. The clutch drain plug requires a 7/16-inch square drive wrench. I made one by grinding down an extra shaft from a half-inch socket drive.
10. Remove cotter pins and nuts from 3 bolts, take out bolts and 2 cap screws holding transmission case to crankcase, taking out upper bolt last. This will permit the the transmission to be withdrawn from the clutch asssembly and lowered to the floor. This is heavy! Use a floor jack to support it, and/or heavy straps with two strong people holding the ends.

All this is necessary to gain access to the clutch. Now all you have to do is remove the cap screws holding the clutch cover in place, exposing the glued-on clutch plate. Gently pry the clutch plate loose. If you're lucky you won't lose any or many of the corks. Thoroughly clean the clutch plate, flywheel and presure plate surfaces with steel wool and WD-40 or Liquid Wrench.

Reassembly is simply the above steps in reverse order, with the following notable details:

1. While you have the clutch disassembled, replace the clutch pilot bearing. NAPA Auto Parts dealers carry an exact replacement part, listed as NAPA part number 6204-J. If the clutch is frozen, the bearing probably is, too. (Ours was.)
2. Getting the alignment right as you reassemble the clutch is tricky; exact alignment of parts is necessary. Paul O'Neil loaned me a nice alignment tool he had fabricated. If you email him, I expect he'd do the same for you.
3. I had trouble getting the transmission back in place. It turned out that the starter control shaft had rotated 180 degrees, and a grease fitting had gotten in the way. Rotating the shaft fixed the problem. Again, two people will make the job a lot easier getting the heavy transmission back in place.
4. If you slightly damaged the clutch gasket during disassembly, one of the gasket dressing compounds (or "instant gasket") on the market will keep a tight seal.
5. Ditto for the gasket that seals the joint between the transmission and transmission cover.
6. When you replace the transmission hand control lever assembly, it's not easy to properly mate the two "forks" on the shift assembly with the gear mechanism. To get it right, the "forks" must be positioned to line up with two pulley-like sections on the gear shafts. This sounds confusing, but it will be obvious when you inspect the transmission mechanism carefully.
7. Be sure to replace the transmission oil and clutch oil before you start the car. The clutch is bathed in 1-1/2 cups of "Hudsonite Oil," which is a mixture of 3/4 cup of kerosene and 3/4 cup of motor oil. Or, as discussed above, use modern Automatic Transmission Fluid Type F. (If you put in too much Hudsonite or ATF, the clutch can slip. This should be renewed every 2,500 miles.) The transmission requires 1-1/2 quarts of light transmission oil.

Removing the transmission and renewing the clutch has been the most difficult job I've undertaken on the Hudson, mostly because you're dealing with heavy parts in a position that's somewhat awkward. But having a smooth-functioning clutch makes it worthwhile.

If your clutch needs help beyond your own resources, professional assistance is available. One company that advertises a specialization in Hudson clutch repair is Wildrick Restoration of Indianapolis, IN. The company offers general old-car restoration, plus a wide range of specific Hudson clutch restoration services. They also offer a clutch aligning tool for $5.