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The Steering clutch design for the ALLIS CHALMERS is based on a solid engineering design that was used on several different clutches in the AC crawler line. You can even see the Allis Chalmers influence and their steering clutch design showing up as elements in the later Komatsu, Mitsubishi, Furukaw, Hitachi, and other crawler dozers and crawler loaders.   Even Caterpillar used this design when they engineered the D8 14A and 15A's.

We get a lot of calls and emails from customers all over the world, some of whom are working on their clutches for the first time, and their questions and concerns involve the basics of clutch disassembly and assembly.  Sending them copies of service manuals is sometimes helpful but often there is a language barrier so what may seem simple to some is still a puzzle to others. 

In an effort to take some of the mystery out of the process we've put together a picture album progression of taking the basic steering clutch apart and putting it back together. 

After you look through the process and mentally digest it a bit, if you need parts for the steering clutch or its components you can click on the following links to go web pages for your specific machine.  We also have these machines in the yard that we are parting out for additional parts availability.






GRIMY_Man_SM.jpg (55040 bytes)  So that you can continue on your journey to becoming a Grimy Man (See essay Here) the following primer is dedicated to you, the Allis Chalmers owner who is doing his best to keep his equipment going on his own.  I hope this helps.


While hydraulic presses, special jigs, and special tools are nice all you really need is a work surface and some all-thread and you'll be ready to take your steering clutch apart.   For the HD5, HD6, HD9, and HD11's you will also need a 3/4" wrench (or impact or ratchet equipped with a 3/4" socket) and a pair of wire cutters for the locking wires.   Pay attention to how the lock wires are strung between the adjoining bolt heads.  They are in a figure 8 pattern so that the wires are pulling the heads in a clockwise manner.   There will be additional items needed so read about the whole process and get all your items scrounged and rounded up.  The center post should be at least 5/8" or 3/4" all-thread.  You will also want some 1/2" coarse all-thread or bolts (8 inches long).  (To be used as guides later on)


AC_STRRG_CL_THRUST_RELEASE_PLATE_2.JPG (424189 bytes) This is the basic clutch we will be taking apart,  This happens to be a clutch removed from either an HD5 or an early HD6 (Who can tell since they are the same clutch!)  The center "donut" is the compession release plate.  When it is pushed in by the throw-out collar AC_050223_STRRG_CLUTCH_SLEEVE_HD6.JPG (219809 bytes) the pressure plate on the other side of the clutch is shoved out and pushed away from the clutch pack so the clutch discs lose their contact with each other and friction is lost. 

AC_STRRG_CL_PRESSURE_PLATE_3.JPG (435676 bytes)    The other side of the steering clutch shows the pressure plate with the retaining bolts, lock-wires and glimpses of the splined inner driving drum.

AC_STRRG_CL_SPACER_PLATE_4.JPG (428469 bytes)    The first thing you will need to scrounge up will be some kind of spacer to place under the clutch release plate.  It needs to be smaller in diameter than the release plate.  You can make a spacer out of some 2 x 4 scraps.  Just be sure that what you make stays within the diameter size of the clutch release plate.

AC_STRRG_CL_ASSY_5.JPG (437119 bytes)   You are now ready to line things up and start taking the steering clutch apart.  Keep everything centered around the all-thread post.

AC_STRRG_CL_6.JPG (426976 bytes)  Being centered is important.

AC_STRRG_CL_7.JPG (417731 bytes)   The second item you will need to scrounge up will be some kind of cross-piece  (T-Bar) to hold the pressure plate in place.  We were lucky to find an old exhaust manifold retainer with tapered ends and the tapered ends gave us clearance so that our 3/4" socket had clearance to remove all 8 retaining bolts.  These 8 bolts screw into the steering clutch release plate on the other side of the steering clutch.  They are 1/2" bolts 3 1/2" long. (Coarse thread)

Tighten the T-Bar snug to the pressure plate.   It only has to be snug so do not over tighten. You can break the pressure plate because everything is solid at this point between the pressure plate clutch release plate.

AC_STRRG_CL_8.JPG (420293 bytes)   Lock wires can now be removed.

AC_STRRG_CL_9.JPG (401016 bytes)   The qty (8)  1/2" bolts can be loosened and pulled.

AC_STRRG_CL_10.JPG (414803 bytes)   Loosen the T-bolt retaining nut until all pressure from the compression springs is relieved.   You will notice that the clutch is being raised away from the table by the freeing up of the springs.

AC_STRRG_CL_11.JPG (337981 bytes)   Compression spring expansion has raised the clutch and you can now see the exposed clutch release plate.  Previously this plate was recessed inside the clutch by about 1/8".

AC_STRRG_CL_12.JPG (419160 bytes)   AC_STRRG_CL_13.JPG (418810 bytes)   It is now time where you can begin to see why you will be using the 1/2" all-thread.   I have shown a couple of bolts in the pictures to show how they will be used as guides.  You can also use bolts if you cut the heads off of them.  You can pick up 1/2" x 8" bolts from your local Lowe's or Home depot for about 2 bucks/bolt.   All-thread can also be used if you don't mind cutting and dressing threads. You can now totally disassemble the clutch by removing the pressure plate and all of the discs.   You then can lift the inner driving drum off of the spring groups.  

AC_STRRG_CL_14.JPG (434906 bytes)   Springs are now exposed and can be removed and checked.  The springs, when new, are 3.93 to 3.94 in height.  We get to cheat a little by just putting a new spring next to the springs and look for any that are as much as 1/8" lower in height.  You can do basically the same thing by measuring your tallest spring and if it meets spec, line the others up next to it for comparison.

AC_STRRG_CL_15.JPG (437680 bytes)     AC_STRRG_CL_16.JPG (407252 bytes)  These springs all measured up so they could be re-used.  If your springs suffer from excessive rust and scaling you may want to consider replacing them anyway or going further and testing their strength.  Behind the springs, in the picture shown, you can see the bolt spacers.  It is these spacers and bolts that create the rigid connection between the pressure plate and the release plate.

AC_STRRG_CL_17.JPG (400539 bytes)   This picture may be a little misleading as bolts are shown that do not have their heads removed.    They act as guides to keep the spacers and springs lined up.   Without these guides the spacers can shift during assembly and keep you from installing the retaining bolts.  I've done this so many times that I can get away with some short cuts but for first timers, I highly recommend using the guide studs.   So now it is time to install your T-Bar and begin compressing the springs.

AC_STRRG_CL_18.JPG (390508 bytes)   As the springs are being compressed you can remove a couple of the guide studs and insert retaining bolts.  They will be floating until they make contact with the thread bosses on the clutch release plate.   As you continue to compress the springs with the T-Bar you will see a gap being created between the heads of the bolts and the pressure plate.   You can now begin to screw by hand the bolts into the clutch release plate.  Begin replacing the remaining studs with retaining bolts and tighten them until you bottom them out against the bolt spacers.  Now you can remove the T-bar and your clutch is assembled.  (Yes, the pictures shown do not include the clutch discs.  For this tutorial I am trying to show a simple disassembly and assembly procedure and instill the basic concept that the clutch release plate connected to the pressure plate by retaining bolts and spacers acts as a solid unit.)

AC_STRRG_CL_19.JPG (420334 bytes)   AC_STRRG_CL_20.JPG (392410 bytes)   The final picture shows the assembled clutch and the recessed clutch release plate in relation to the inner driving drum.  It is this difference in height that provides the important measurement that will tell you if you have a clutch that will work.  This distance, or depth, should be 3/16" of an inch (plus or minus 1/16")  If the distance is greater than 3/16" inch then remove a steel disc.  If the clutch release plate is not recessed then your stack height is too low and you will need to add discs.  Quoting from the service manual below:

if clutch was assembled correctly and stack height is within specifications, and pressure plate and hub friction surfaces, seem OK to use, ADD one steel plate next to pressure plate and re-assemble. If measured distance (stand-in) is more than specified maximum distance, remove one steel plate from next to pressure plate (at least one steel plate must be used next to pressure plate) .

I'll put together some future pix showing you how to assemble the discs both with a brake drum and without the use of a brake drum.   It is almost intuitive and you can probably figure it out but it may still be helpful to see it done.  (remember..........Keep everything centered!!)


The latest service manual covering the HD5-HD6-HD9-HD11 steering can be seen and downloaded by clicking the link (HERE)   Earlier parts and service manuals can be retrieved below.  Reviewing the different types of literature may be helpful as there are points and examples in one that may not be in the other.






Click HERE to view all of our new steering clutch discs.


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General Gear and Machine, 733 Desert Wind Rd.,
Boise, Idaho, 83716  US
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