Stock Clutch Pedal Forces

[MAYoung]

I recently installed a new clutch in my 1998.5 Dodge 2500 Quad Cab. No real problems with the old clutch with about 75,000 miles (261,000 total since new) but I was doing other things so I added the new clutch to my to do list. It is a strictly stock Luk model with no extra bells and whistles. I did not touch the hydraulic master/slave cylinder system.

My question is this: the clutch pedal forces are now incredibly light, almost feather light. I queried the shop that I worked with and the shop manager indicated that the new Luk clutches require significantly lighter forces to operate. Is this true? It seems contrary to Newtonian physics that a manufacturer could pull such a feat off. Everything else about the clutch, (engagement, release, etc.) seems normal.

Your comments will be welcome. I am trying to make sure that we are not overlooking something.

 

[petersonj]

I just replaced my original clutch (a LUK) at 297,000 miles, about 6,000 miles ago. I replaced it with a stock Luk clutch and yes, the clutch pedal is light, just like the clutch was when the truck was new. This clutch (just like the last one) is handling a Smarty tuner on SW5 with default settings towing three different kinds of trailers up to a combined weight of 19,000 lbs.

I think your clutch is just fine and you made a good choice going with Luk.

Personally, I really like the light pedal effort of the clutch.

- John

 

[GCroyle]

Your observation is normal and correct.

As a disc gets thinner the release load (pedal effort) increases in particular at the end of the service life of the clutch. Have you looked at your HS yearbook pic lately? We all age.

Now a new bearing is installed, slides freely on guide tube, fork pivot gets cleaned and lubed.

Pedal effort goes back to as designed.

Test for torque capacity, load truck normal, 55-60 MPH roll on the throttle. RPM and MPH should increase w/o any spike in RPM. Should be able to select 1st or REV from standing start, push pedal down, count to 2 and select gear.

Passes those tests, shop did a good job.

 

[MAYoung]

Truck shifts smoothly without any "hesitation" when selecting gears, 1st or Reverse. I travel I-80 over the Sierra Nevadas and the clutch shows no sign of slippage upon acceleration with a load. I just do not recall the clutch forces ever being this light but the last clutch was nearly 10 years ago, also a Luk.

Thanks for your feedback. As usual, I will continue to drive the truck until something else breaks.

 

[GCroyle]

The thick disc normal pedal effort vs thin disc heavier pedal effort is a characteristic of a traditional diaphragm clutch. In early 90's LuK introduced the Self Adjusting Clutch, SAC in a Ford Ranger. Dodge introduced it in the Ram in mid 2005 with the G56 trans and the SAC holds the same clamp load and release load thru its life cycle, the diaphragm spring angle and operation is maintained (Self Adjusting, right) so driver doesn't feel difference except for mechanical friction of aging release system mechanical components, fork to bearing and bearing to guide tube.