Eaton Fuller Failure Analysis
Eaton Fuller Failure Analysis
Eaton Fuller Failure Analysis
Eaton® Clutches
CLTS1271
September 2011
Introduction
Clutch Diagrams
Introduction
Table of Contents
Introduction Glossary
Clutch Diagrams.......................................................... 1 Clutch Glossary ......................................................... 39
Factors that Effect Clutch Performance ....................... 1
Solo Clutch
Solo Clutch Failures .................................................. 25
Miscellaneous
Miscellaneous Failures .............................................. 27
Pilot Bearing
Pilot Bearing Recommendations ............................... 30
Troubleshooting
Clutch Troubleshooting ............................................. 31
Introduction
Heat or wear is practically nonexistent when a clutch is fully engaged. But, during the moment of engagement (when the clutch is
picking up the load), it generates considerable heat. An improperly adjusted or slipping clutch will generate sufficient heat to rap-
idly self-destruct.
Proper training of drivers and mechanics can go a long way toward extending clutch life. Anyone who drives the truck, whether
on or off highway, should learn how to operate the vehicle properly. The most critical points to cover in driver training programs
are: learning to start in the right gear, proper clutch engagement, recognizing clutch malfunctions, and recognizing the need for
readjustment.
Service Procedure
Maintenance personnel may want to attend driver training programs to see what driver misuse can do to clutch life. This training
will place them in a better position to spot and analyze failures during their clutch maintenance programs.
The most important areas to cover in the training programs that can affect clutch performance are:
STARTING THE VEHICLE IN THE PROPER GEAR
An empty truck can be started satisfactorily in a higher transmission gear ratio than when partially or fully loaded. If auxiliary trans-
missions or multi-speed axles are used, they must be in the lower ratios for satisfactory starts. Drivers should be shown what
ratios can be used for safe starts when the truck is empty or loaded. If the truck is diesel powered, a good rule of thumb for the
driver to follow is: empty or loaded, select the gear combination that lets you take up the slack and start moving out with an idling
engine or, if necessary, just enough throttle to prevent stalling the engine. After the clutch is fully engaged, the engine should be
accelerated for the upshift into the next higher gear.
GEAR SHIFTING TECHNIQUES
Many drivers upshift into the next gear-or even skip-shift into a higher gear-before the vehicle has reached the proper speed. This
type of shifting is almost as damaging as starting off in a gear that is too high, since the engine speed and vehicle speeds are too
far apart, requiring the clutch to absorb the speed difference as heat (excessive slippage).
EXCESSIVE VEHICLE OVERLOAD OR OVERLOADING THE CLUTCH
Clutches are designed and recommended for specific vehicle applications and loads. These limitations should not be exceeded.
Excessive or extreme overloading can not only damage the clutch, but the entire vehicle power train as well. If the total gear re-
duction in the power train is not sufficient to handle excessive overloads, the clutch will suffer, since it is forced to pick up the load
at a higher speed differential.
RIDING THE CLUTCH PEDAL
This practice is very destructive to the clutch since a partial clutch engagement permits slippage and excessive heat. Riding the
clutch pedal will also put a constant thrust load on the release bearing, which can thin out the lubricant and also cause excessive
wear on the pads. Release bearing failures can be attributed to this type of operation.
HOLDING THE VEHICLE ON AN INCLINE WITH A SLIPPING CLUTCH
This procedure uses the clutch to do the job normally expected of the wheel brakes. A slipping clutch accumulates heat faster than
it can be dissipated, resulting in early failures.
COASTING WITH THE CLUTCH RELEASED AND TRANSMISSION IN GEAR
This procedure can cause high driven disc R.P.M. through multiplication of ratios from the final drive and transmission. It can
result in “throwing” the facing off the clutch discs. Driven disc speeds of over 10,000 R.P.M. have been encountered in such sim-
ple procedures as coasting tractors down an unloading ramp. While an ample safety factor is provided for normal operation, the
burst strength of the facing is limited.
1
Introduction
When drivers and mechanics are properly trained, there are still certain problems that may occur. The following failure analysis
and troubleshooting guide lists some common problems, their causes, and suggested corrective action. Note that some of these
problems relate back to the previous discussion on poor driving and maintenance techniques.
2
Clutch Cover/Intermediate Plate
3
Clutch Cover/Intermediate Plate
4
Clutch Cover/Intermediate Plate
Additional damage occurred to both the clutch cover and the re-
lease yoke as a result of their interference with each other (refer
5
Clutch Cover/Intermediate Plate
Fig 12
6
Clutch Cover/Intermediate Plate
To view the resulting damage that can occur to the facing mate-
rial of the driven discs, please refer to Figures 53-56 and 58.
7
Clutch Cover/Intermediate Plate
8
Clutch Cover/Intermediate Plate
Fig 22
9
Clutch Cover/Intermediate Plate
Fig 24
An additional result from the above failure is that while the clutch
is engaged, it can begin to slip due to the unloading condition
created by the disc and retainer interference. This, in turn, will
create excessive heat and can cause the pressure plate to break
(see Figure 25, black arrow on pressure plate) and /or the ceram-
ic buttons to separate from the disc (see Figure 58). The above
failure may also be preceded by a noise complaint.
10
Clutch Cover/Intermediate Plate
The use of “guide studs” plus a “hydraulic clutch stand” will help
prevent this 150 lb. clutch from being dropped during installation
and removal.
11
Clutch Cover/Intermediate Plate
12
Clutch Cover/Intermediate Plate
13
Clutch Cover/Intermediate Plate
Both items 1 and 2 can cause the thinning and loss of bearing lu-
bricant. They can also cause rapid lever wear due to constant
contact with the bearing.
• A throw out bearing which fits too tightly on the front
bearing cap stem. As a result, the return spring(s) (at-
tached to the linkage or throw-out bearing) may not be
capable of retracting the throw-out bearing away from
the clutch levers. This will cause contact between these
parts.
• Worn and/or binding linkages are causing the throw-out
bearing to make “constant contact” with the clutch’s
three (3) release levers (Figure 38).
• Using a throw out bearing of inferior quality.
WARNING
Continually adjusting for clutch wear via the linkage can lead
to the failures shown in Figures 4, 5, 25, and 57-58.
14
Clutch Disc Assembly
Furthermore, oil on the disc buttons can cause the clutch to re-
lease poorly due to increased drag, and/or chatter/slip during en-
Failure - None
Normal Wear Patterns
When troubleshooting Eaton Fuller Clutches, do not be con-
cerned with the wear pattern (darkened areas) of the disc buttons
(see Figure 42). More specifically, it is normal for the darkened
areas to vary in color, size, and their relative position upon each
button.
15
Clutch Disc Assembly
Greasing the splined areas of either the input shaft or disc hub(s)
is not recommended because the grease can be spun onto the
facing material of the driven disc(s) (refer to both arrows in Fig-
ure 44) . The circled area in Figure 45 reveals the numerous paths
which the grease took as it moved toward the buttons (facing
material) of this ceramic driven disc. The photographs in Figures
44-45 are of the same driven disc.
Note: Eaton does not recommend the reinstallation of driven
discs which have become contaminated with grease or oil.
16
Clutch Disc Assembly
17
Clutch Disc Assembly
18
Clutch Disc Assembly
19
Clutch Disc Assembly
20
Clutch Disc Assembly
21
Clutch Disc Assembly
Note also the adjusting ring pictured in Figure 65. It was removed
from a non-Eaton rebuilt clutch. This ring was cut open on one
side, spread apart, and then welded (see arrow) at a larger diam-
eter to prevent the adjusting ring from becoming loose once it
was reinstalled. (Eaton Clutch does not weld adjusting rings, but
rather discards any rings that are too loose.)
22
Clutch Disc Assembly
23
Adjusting Mechanisms and Clutch Brakes
24
Solo Clutch
25
Solo Clutch
Eaton has created a tool that may help free up the clutch to allow
it to continue adjusting. #CLPISOLOTOOL can be obtained by
calling 800-826-HELP (4357).
26
Miscellaneous
Miscellaneous Failures
27
Miscellaneous
A galled or rough input shaft (in the non-splined area) will dam-
age the bushing(s) of not only the original clutch, but also that of
the newly installed clutch. As a result, make sure you replace the
input shaft and any worn linkage components to prevent the fail-
ure from being repeated.
28
Miscellaneous
29
Pilot Bearing
Below is a list of the recommended Pilot Bearings. All of these bearings have Viton seals and high temperature grease in addition
to a C3 fit. It is acceptable to use synthetic high temperature grease and a C5 fit if desired.
Bearing Series
Vendor Seal Type 6205 Bearing 6306 Bearing 6006 Bearing
NTN VITON 6205 LLUAV/C3 6306 LLUAV/C3 6006 LLUA1 C3/LX16
KOYO VITON 6205 2RKF-S2/C3 6306 2RKF-S2/C3
NSK VITON 6205 DDU7/C4 ENS 6306 DDU7/C4 ENS 6006 DDWA18A C4/ENSS
SKF VITON 6205 2RS2/C3 6306 2RS2/C3
FED-MOG VITON 6205 VV/C3 6306 VV/C3
30
Troubleshooting
Clutch Troubleshooting
This section will provide the service technician asistance to diagnose a malfunctioning clutch using the following 3-step process:
1. Identify the customer’s specific “complaint”.
2. Investigate the “possible causes” that can be contributing to the customer’s complaint.
3. Perform appropriate “corrective actions” to remedy the customer’s complaint.
Additionally, it is intended that a thorough reading/understanding of the previous section (Failure Analysis) and the following sec-
tion (Troubleshooting) will:
1. Allow the service technician to solve some complaint problems without removing the clutch.
2. If clutch removal is necessary, these sections will give the technician the appropriate information for determining why
the clutch may have failed, thus preventing a possible reoccurrence of the complaint.
Troubleshooting
It is important to note that the statements/photos of failed components represent quality Eaton Fuller Clutch parts which were
subjected to abuse and/or misapplication. Consequently, the failures pictured in no way represent defective Eaton Fuller Clutch
components.
3. Measurements/checks to make:
• Measure release bearing travel (take the free pedal out by pushing lightly on the pedal with your hand to load bearing).
• Measure clutch brake squeeze (hint: use a business card or a .010” feeler) Response: Minimum 1/2”.
• While pushing pedal down, check linkage for interference or premature bottoming.
4. Use a 1/4” diameter flat-nosed drift and lightly tap each of the four separator pins to ensure they are against the flywheel.
31
Troubleshooting
32
Troubleshooting
Troubleshooting
lation methods. Do not force transmission drive gear
into disc hubs. This will distort or bend driven disc
causing poor release. Also, do not allow transmission
to hang unsupported. Replace any distorted or
warped discs.
Disc(s) installed backwards (see Figures 49 & 50) or Install new discs. Also, investigate the clutch cover
front and rear discs were switched with each other for any damage. Replace if damaged.
Spline worn on main drive gear of transmission. Replace drive gear and check driven disc hubs for ex-
(see Figure 77) cessive wear. If worn, replace disc. Check flywheel
housing alignment of engine and transmission. Make
sure driven discs slide freely on drive gear splines.
Flywheel pilot bearing fits either too tight or too loose Check pilot bearing for proper fit.
in the flywheel and/or end of input shaft
Damaged or dry (rough) pilot bearing (see Figure 76) Replace with new bearing.
Failure to use the anti-rattle springs packaged with all Always use new anti-rattle springs.
14” AS and EP Super Duty clutches (see Figures 20 -
22)
(3) Anti-rattle springs were installed backwards (see Install them so the rounded sections are pointing to-
Figures 23 - 24) ward the flywheel/engine.
Failure to set the positive separator pins during clutch It is important to note that the procedure for setting
installation the positive separator pins (model 1552, Solo & SAS
1402 clutches) can be performed while the transmis-
sion is installed. The steps are as follows:
1. Remove the transmission inspection hole cover.
2. Rotate the clutch cover until one of the holes (for
setting the pins) is at the 6 o’clock position.
3. Using the appropriate tool, lightly tap the separator
pin to verify that it is seated against the flywheel.
4. Repeat steps 2 and 3 for the remaining three sepa-
rator pins.
5. Reinstall the transmission inspection hole cover
For additional information, refer to Eaton’s Installa-
tion Instructions.
33
Troubleshooting
34
Troubleshooting
Noisy/Rattling
Complaint Possible Cause Corrective Action
Noisy/Rattling Excessive flywheel runout Consult Eaton’s Installation Instructions.
Corrosion of disc hubs to transmission input shaft Clean the mating parts to ensure that the discs slide
freely over input shaft.
Engine idling too fast Readjust engine to proper idling speed.
Clutch release bearing is dry or damaged Lubricate the bearing. If the noise persists, install a
(see Figures 28 - 29) new clutch cover (the release bearing will be included
with the cover).
Flywheel pilot bearing is dry or damaged (see Figure Replace flywheel pilot bearing.
76)
Bridge of the yoke hitting clutch cover Refer to the section titled: “Failure - yoke bridge rub-
bing into clutch cover,” Figures 1 - 2.
Troubleshooting
Fingers of release yoke hitting clutch cover Refer to the section titled: “Failure - yoke fingers rub-
bing into clutch cover,” Figures 4 - 5.
Failure to use the transmission inspection hole cover Re-install the cover.
Failure to use anti-rattle springs (AS and EP 1402 Su- Always install the new anti-rattle springs packaged
per-Duty only) (see Figures 20 - 22) with each 14” Super-Duty clutch.
Worn sleeve bushing Investigate for any side loading conditions on the re-
lease bearing housing. Determine the cause, being
sure to correct before installing the new clutch.
Linkage system is frozen, improperly lubricated, worn Clean, lubricate and reassemble or replace missing/
excessively, has missing parts (washers, etc.), or the worn parts.
linkage itself is rattling excessively
Idle gear rattle coming from the transmission —Specify driven disc assemblies which feature Free-
Travel design.
—Check the engine for the correct idle speed. Consult
the OEM engine manual.
Dampener spring cover of the driven disc assembly Install correct clutch assembly.
interfering with the flywheel (Figures 48 - 52)
Rivets of the rear disc are interfering with the retainer Adjust the clutch internally (via the adjusting ring),
assembly (see Figures 25 and 57) not externally (via the linkage system).
Clutch is loose on flywheel (see Figures 8 - 10) Install a new clutch assembly and eight new mount-
ing bolts.
35
Troubleshooting
Vibrating Clutch
Complaint Possible Cause Corrective Action
Vibrating Clutch Loose flywheel Retighten flywheel mounting bolts to the proper spec-
ifications.
Worn universal joints Replace worn parts.
Improper phasing of driveshaft Investigate for correct yoke phasing.
Driveshaft is not balanced Balance and straighten driveshaft. Also, ensure that
no balance weights have come off the driveshaft.
Incorrect driveline angles Shim drivetrain components to equalize u-joint an-
gles.
Flywheel is not balanced Balance the flywheel.
Pilot area of the clutch is not completely seated into Ensure that no dirt, burrs, etc. are preventing the cov-
flywheel er from completely seating into the flywheel mounting
surface.
Failure to tighten the clutch cover mounting bolts, us- Consult Eaton Clutch Service Manual.
ing a criss cross sequence, can cause an out-of-bal-
ance condition. Loose mounting bolts can also induce
this condition (Figures 8 - 10)
Damaged, loose, or worn out engine mounts Replace any damaged/worn parts. Retighten all loose
bolts to proper specifications. Refer to the OEM en-
gine manufacturer’s service manual.
Misfiring of engine Refer to OEM engine manufacturer’s service manual.
Excessive flywheel runout Refer to Eaton’s Installation Instructions.
Rivets of the rear disc are interfering with the retainer Adjust the clutch internally instead of externally.
assembly (see Figures 25 and 57)
Clutch is loose on flywheel (see Figures 8 - 10) Install a new clutch assembly and eight new mount-
ing bolts.
Insufficient amount of free travel. When the clutch After first adjusting the clutch for l/2”-9/16”release
was initially installed, the linkage was not adjusted to bearing travel, adjust the linkage to obtain an 1/8” free
obtain a full 1/8” free travel travel (distance between the release yoke fingers and
the release bearing wear pads) travel.
Misapplication of clutch, causing premature wear If a service clutch, determine whether the clutch is
properly specified for the vehicle’s particular applica-
tion.
Starting out in too high a gear may lead to premature Start the vehicle in the proper gear. Refer to item 1 of
clutch wear “Factors That Effect Clutch Performance”.
Worn cross shafts and/or linkage system Investigate entire linkage system to determine if it is
binding or operating sporadically and/or worn exces-
sively.
Clutch discs wore down to rivets Install new clutch.
Riding of clutch pedal, causing premature wear Refrain from using the clutch pedal as a foot rest.
36
Troubleshooting
Vibrating Clutch
Complaint Possible Cause Corrective Action
Holding the vehicle on an incline by using the slipping Refrain from using the clutch pedal as a brake.
clutch as a brake. Doing this can cause premature
wear.
Sporadic changes in the amount of free play/free trav- Consult the engine OEM Service Manual.
el due to excessive crankshaft end play
Troubleshooting
move toward the half worn position.
Solo Clutch has over adjusted (release bearing is less Reset the wear tab to the new position. Readjust the
than .500” {standard stroke Solo} or .430” {short Solo using the normal adjusting procedures.
stroke} from the transmission)
Failure to properly set-up the clutch linkage Reset the linkage to obtain a free travel (at the yoke)
range of 1/16” -1/8”.
Nothing is wrong. It is normal for the free play to in- None is required, but if the additional free play is ob-
crease during the Solo’s “Breaking in” period. jectionable, you may readjust the linkage until you
have 1/16” -1/8” of free travel at the release yoke.
Clutch Slippage
Complaint Possible Cause Corrective Action
Clutch Slippage No free pedal Readjust clutch. Refer to adjustment instructions
found in Eaton’s Installation Instructions.
Release mechanism binding Free up mechanism and linkage, check clutch adjust-
ment. Refer to adjustment instructions found in
Eaton’s Installation Instructions.
Failure to remove shipping/resetting bolts (Solo HD & Remove shipping/resetting bolts.
MD)
Grease or oil on facings (see Figures 41, 43 - 44) Replace driven disc assembly.
Driver riding clutch pedal Refrain from riding clutch pedal.
Overloaded clutch Verify that the proper clutch has been specified for the
vehicle’s application.
37
Troubleshooting
Noisy/Rattling
Complaint Possible Cause Corrective Action
Noise/Rattling Throw out bearing is worn/seized Replace the throw out bearing. If reusing the clutch,
ensure that the release levers are not damaged (see
Figure 38).
Incorrect driven disc has been installed Install correct driven disc assembly.
38
Glossary
Clutch Glossary
1401
14” single plate clutch (pull-type).
1402
14” two plate clutch (pull-type).
Adjusting Ring
Threaded lever support ring inside clutch. Needs to be rotated toward FW to keep proper angle relationship between pressure
springs and levers. Turned by mechanic via Kwik-Adjust (SAS and EPP), or lock strap (AS).
Angle-Ring (A/R)
Medium-Duty, push to release, uses Belleville spring, no internal adjustment, 310mm, 330mm (Ford), 350mm.
Angle Spring (AS)
Predecessor to EP. No longer in production. Large population in Reman and rebuilt markets.
Bearing Load
Load applied to release bearing to move it .500” releasing the clutch. Bearing load relates to load at clutch pedal.
Glossary
Bearing Travel
With clutch engaged, gap between rear bearing cover and front of clutch brake (or transmission bearing cap if not using clutch
brake). This is how far the bearing moves when the pedal is depressed. Adequate bearing travel is required to release clutch com-
pletely, and for Solo to adjust Industry standard: .530 ± .030” (1/2” - 9/16”).
Clutch Brake (CB)
Brake device that rides on transmission input shaft of unsynchronized transmissions behind clutch release bearing. “Sandwiched”
between back cover of clutch bearing and front of transmission bearing cap. Should be used to stop excess disc rotation when
shifting into first or reverse. Single Piece - Torque limiting (OE standard), Two Piece - not torque limiting (service replacement).
Clutch Brake Squeeze
Distance of clutch pedal movement from floor of cab to point at which a 0.010” feeler gage is no longer clamped between back of
clutch bearing and front of transmission bearing cap. Target usually around 1”.
Coaxial (CO)
Spring inside of a spring. Many dampers use this design to achieve higher bottoming torque.
Cover Assembly
see Pressure Plate.
Damper
(Disc, Driven Disc, DDA, Clutch Plate) Portion of clutch affixed to transmission input shaft. Supports friction facings and torsional
damping springs.
Drive Pins
(Drive Dogs) Used with 14” pot style flywheel and 14” cast clutch. Used to carry torque of intermediate plate.
Easy-Pedal (EP)
Heavy duty 15.5” cast 2-plate clutch that uses 3 assist springs to reduce release loads. Launched in ’90 now superseded to EPP.
Easy-Pedal Plus (EPP)
Easy-Pedal with added features: 2-piece retainer, Super Seal on adjustment threads, improved Kwik-Adjust, positive pin separator
in intermediate plate.
Engaged
Release bearing is in its rest position - clutch discs clamped up.
39
Glossary
40
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Note: Features and specifications
listed in this document are subject to
change without notice and represent
the maximum capabilities of the
software and products with all options
installed. Although every attempt has
been made to ensure the accuracy of
information contained within, Eaton
makes no representation about the
completeness, correctness or accuracy
and assumes no responsibility for
any errors or omissions. Features and
functionality may vary depending on
selected options.
For spec’ing or service assistance,
call 1-800-826-HELP (4357) or visit
www.eaton.com/roadranger.
In Mexico, call 001-800-826-4357.
Eaton Corporation
Vehicle Group
P.O. Box 4013
Kalamazoo, MI 49003 USA
800-826-HELP (4357)
www.eaton.com/roadranger
Printed in USA