HD clutch adjust procedure with pics - Pirate4x4.Com : 4x4 and Off-Road Forum
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Old 03-04-2009, 09:16 PM   #1 (permalink)
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HD clutch adjust procedure with pics

The following is the basic procedure for adjusting the clutch on the vast majority of class 6-8 trucks. It not meant to be all inclusive and serves only as a general familiarization writeup and is not intended to be a sole reference. Always consult your mfg's data before performing a clutch adjustment for your specific rig.

Q: When I need to adjust my clutch?
A: - Any time clutch has been replaced
- Linkage has been replaced
- Not enough free play at pedal ( normal operating wear)

Q: What tools do I need to adjust my clutch?
A: Aside from common hand tools and a helper you will need the following:
-A "Spicer clutch tool" (far right in photo) costs approximately $25-35 and works much better than a long screwdriver/prybar ( see step 4 in adjustment procedure).
-An 1/8 gauge tool (middle in photo) it's a piece of 1/8"x3/4" bar stock.
-A 1/2" gauge tool (far left in photo) can be bought or fabbed from 1/2" dia. rod. If you decide to make your own, the fork legs are approx. 2 1/2" apart and 4" deep.
-An engine barring socket (not shown) or a trustworthy helper. Barring socket varies by engine mfg.


Inspecting clutch

1) Remove inspection cover from clutch bellhousing - it's the rectangular piece of sheet metal with four small bolts holding it on.
2) Insert 1/2" gauge tools between clutch brake and release bearing - see fig 1 below. Tool should fit snugly without force. If it fits sloppy or does not fit at all - you'll need to adjust the release bearing clearance

Adjusting release bearing clearance:

1) Rotate flywheel so locktab is visible on the pressure plate. The locktab is visible at the 6 o'clock in the pic below. The mfg approved way to do this is to use your engine barring socket. The unofficial way involves your helper in the cab, the ignition key, you under the truck, and some yelling back and forth.
2) have a helper or use a block of wood to hold the clutch pedal down far enough to where there is at least 1/8" of clearance between release bearing and clutch brake (pedal almost fully depressed, but not on clutch brake) this allows adjusting ring to rotate.
3) Remove the bolt holding the lock tab on (usually takes a 9/16" socket)
4) Turn adjusting ring to increase pedal free play. For Rockwell 1 notch = .020". 4-8 notches is a normal adjustment. Tool at far right in above photo works much better than a prybar/ big screwdriver. It screws into the same hole that the locktab bolt screws into. I usually turn it a few notches and ask helper how pedal feels. See fig 2 below.
5) Reinstall locktab. Torque to 25-30 lb/ft or "German torque" (Gudentight)
6) 1/2" tool should fit just right, give your helper a break/ remove wood block and use 1/8" gauge tool to check release bearing clearance
7) If 1/8" tool doesn't fit or is excessively sloppy, adjust pedal linkage.
8) Lube release bearing zerk if applicable
9) Lube clutch releases bearing cross shaft zerks (1 on each side of bellhousing)
10) reinstall inspection cover.
Fig 1

Fig 2

Fig 3

Hope that answers everything - good luck and drive safely

Last edited by BumpyDodge; 03-05-2009 at 09:43 AM. Reason: typo fixes - it's late
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