Ken Cates' Hudson Stepdown Restoration Resources


Clutch Service

All Hudson cars with the exception of those equipped with an automatic transmission utilize a steel clutch which is populated with corks which make up the driven surface of the clutch. For reasons that Hudson engineers failed to share, this cluch came in a 9 inch diameter and 10 inch diameter version. The smaller cluch is usually found in the lower horsepower varients while the larger clutch was installed in all models equipped with an overdriver transmission. The clutch operates in a sealed chamber that captures one-forth pint of a fluid called HUDSONITE. This fluid soaks into each of the clutch corks and when properly adjusted provides quite and smooth performance thoughout the full range of the Hudson motor's power.

Clutch performance is dependant on proper fluid service and adjustment. Keeping these two factors inaccordance with maintenance recommendations witll assure a long life.

Use section 7 of the Hudson Mechanical Proceedures manual for service and maintenance information.

Repair parts and seals needed to repair the Clutch system can be found with dealers listed on the front page of this website under the listing:

New 10 inch Hudson Clutch

Clutch fluid formula :

12 ounces Ford type F automatic transmission fluid, 12 ounces power steering fluid, 12 ounces Hudsonite, 4 ounces kerosene.  Mix all components and use 6 ounces per refill in clutch.  (this is a way to extend the Hudsonite, you have on hand, and  a less expensive way of refilling, when several refills are required)

Flushing cork clutches:

make solution 4 parts tri-chloral-ethane and one part acetone, available at drug stores.  To flush-drain clutch, refill with flushing solution, start engine, with transmission in neutral, depress and release clutch about 100 times at various engine speeds, drain and refill with clutch fluid mixture.

Clutch chatter solution suggestions   by Doug Wildrick 317-862-4171 

The fingers on pressure plate must be correct height, from top of the cover, with the new disc  installed.  This measurement should be no more than 1.450, and the fingers should be set at .010-MAX ., variations between them.  If this isn't done  correct, the clutch will probably chatter. 


Following items to check for clutch chatter (other than pressure plate and clutch Disc)

*   Check for cracked bell housing (usually passenger side of bell housing starting at cross shaft)

*   Input shaft excessively worn at pilot bearing end.

*    Input shaft (twisted and/or excessively loose-front transmission bearing excessively loose)

*   Clutch cross over shaft bushings (usually worn excessively)

*   Alignment of transmission with engine (bell housing bolt up surface free of dirt)

*   Back  of block cleaned and dowels secured in place.

*   Engine and transmission mounts are good and solid. (not soft-very important for proper clutch operation.

*   Flywheel resurfaced  correctly and torqued at correct specs with clean flange on crank and flywheel. Use soft setting Permatex and seal flywheel to crank flange (thin coat)

*    Throw out bearing fork not worn (what did old throw ought bearing look like-worn spots in bearing housing)

*    Engine tune (is it running properly)

Above items are not necessarily in order-each vehicle is different!

Clutch drain crush washer - March 2017

The clutch fluid drain/ fill bolts with the 11/16 Hex  heads are 1/2" diameter, and use a 1/32" thick X 1/2" ID X 11/16" crush washer which is Dorman part number 725-015.

Since the hex head of the bolt is so thin, don't get ham-fisted with it. About is 15-20 foot lbs is plenty with a new crush washer. Trying any harder is liable to either round the corners off or the wrench will try to slip off.

You can get these washers from O'reillys Auto parts for 19 cents each.

About Us | Ownership and data use | Contact Us |

Providing this web site is an ongoing cost to it's owner. You can defray some of those costs by moving your mouse cursor over the word DONATE above and clicking. . It will provide you with an immediate easy and safe method to donate, THANK YOU!

This page was updated January 2018

© Klassic Concepts Consulting 1998 - 2018 all rights reserved