Ken Cates' Hudson Stepdown Restoration Resources

RESTORATION AIDS

Clutch Service

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

The overall thickness measurements for a 10-inch Hudson Clutch are: .210" max thickness and .180" min thickness before replacement

Clutch performance is dependent on proper fluid service and adjustment. Keeping these two factors following maintenance recommendations will ensure a long life.

Thanks to Doug Wildrick who shows how to properly replace the clutch and throw out bearing on a Hudson Stepdown.  https://www.facebook.com/watch/?v=1724994320889626

Thanks, Greg de La Grange  YouTube Video showing how to service the HUDSON WET CLUTCH

Use section 7 of the Hudson Mechanical Procedures 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:

Changing Hudson Clutch fluid - Roger Tallent

How to replace the corks - Hudson Cork Clutch Discs 

 Successful installation of a clutch requires proper sealing of the fluid chamber. 

Sealing the Clutch Fluid chamber 

New 10-inch Hudson Clutch

How to ID what size clutch is in a car 

HUDSON CLUTCH ADJUSTMENT - Mechanical considerations

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)

Another:  from Brandon Wight

On clutch fluid, you have a few options. One use some from WRP, or mix your own 30wt non detergent oil and k1 kerosene. That's a 50/50 mix for 6oz.

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. 

DON'T FORGET THE FLUID IN THE CLUTCH

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" in diameter and use a 1/32" thick X 1/2" ID X 11/16" crush washer which is Dorman part number 725-015.

http://rbinc.com/p-11327-725-015.aspx

Since the hex head of the bolt is so thin, don't get ham-fisted with it. About 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'Reilly's Auto Parts for 19 cents each.

http://www.oreillyauto.com/site/c/detail/DAG0/725015.oap?ck=Search_725-015_-1_527&keyword=725-015

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This page was updated in January 2024

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