Kingpin Bearings

<body topmargin=0 leftmargin=0 marginheight=0 marginwidth=0> <table cellpadding=0 cellspacing=0 border=0><tr> <td valign="top" colspan=2 height=90 BGCOLOR="#006633" TEXT="#F7F7FF" bgproperties="fixed" background="079005a0ddvuru.png"> <div> <A HREF="http://www.vernco.com/index.htm" TARGET="_top" TITLE="http://www.vernco.com/index.htm"><U><B>home</B></U></A><B>     |     </B><FONT SIZE="5" COLOR="#FFCC66" FACE="Arial" ><B>Vern</B><B>co.com</B></FONT></div> <div> back to<B>  </B><A HREF="index.htm" TARGET="_top" TITLE="Front Axle Rebuild"><U><B>Front Axle Rebuild</B></U></A></div> <bR> <div> <A HREF="http://www.vernco.com/id173.htm" TARGET="_top" TITLE="http://www.vernco.com/id173.htm"><U><B>Site Map</B></U></A></div> <div> </div> </td> </tr><tr> <td valign="top" width=150 BGCOLOR="#669966" TEXT="#080000"> <div> <A HREF="id372.htm" TARGET="_top" TITLE="Front Differential and Housing"><U>Front Differential and Housing</U></A></div> <div> <A HREF="id404.htm" TARGET="_top" TITLE="Spindle Bolt Upgrade"><U>Spindle Bolt Upgrade</U></A></div> <div> <B>Kingpin Bearings</B></div> <div> <A HREF="id374.htm" TARGET="_top" TITLE="Bendix Joints"><U>Bendix Joints</U></A></div> <div> <A HREF="id460.htm" TARGET="_top" TITLE="Spindles, etc."><U>Spindles, etc.</U></A></div> <div> <A HREF="id461.htm" TARGET="_top" TITLE="Hubs and Drums"><U>Hubs and Drums</U></A></div> <div> <A HREF="id495.htm" TARGET="_top" TITLE="Front End Alignment"><U>Front End Alignment</U></A></div> <bR> </td> <td valign="top" height=390 BGCOLOR="#FFFFFF" TEXT="#080000"> <div> With the new bushings in the axlehousing and ready to go, let's look at the kingpin bearings, which allow the knuckles to turn.  Here is a scary detail I found on this "rebuilt" axle.  Check out the remains of the bearings.  The bearing on the right had all of the individual rollers loose from the cage and scattered within the knuckle.  I'm glad I decided to check them out.  Due to flat spots and missing rollers, it was obvious these bearings were never even touched during the rebuild:</div> <bR> <div> <A HREF="id368.htm" TARGET="_top" TITLE="Remains of kingpin bearings"><U><IMG SRC="5a4af460.jpg" border=0 width="175" height="70" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></U></A></div> <div>  <A NAME="bearing_cups"><IMG BORDER="0" SRC="1x1.gif" HEIGHT="1" ALIGN="bottom" WIDTH="1" HSPACE="0" VSPACE="0" ></A></div> <div> Oddly enough, the bearing cups were in perfect condition with the trashed bearings shown above.  Gary Hunt graciously sent me a picture, showing the opposite condition that he found.  His bearings looked fine, but the races had heavy indentations from the individual rollers.  The worst dents were on the inboard side of the upper bearing cup, probably from shock loads encountered during bumps.  Since the bearings never rotate in a full circle, the contact area on the race is concentrated.  Remember that bearings and cups must be replaced as a set.  Never mix and match new and used components:</div> <bR> <div> <A HREF="id494.htm" TARGET="_top" TITLE="Kingpin bearing cup Gary Hunt"><U><IMG SRC="7ea964b0.jpg" border=0 width="150" height="75" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></U></A></div> <bR> <div> Here is a close up of the new kingpin bearing cup, on the ball at the end of the axle housing.  Note how the cup fits against a shoulder at the bottom of the recess.  Carefully inspect the ball end around the bearing cup for any signs of distortion or other damage.  If the bearing cup has any gaps around the edge, the thin crescent on the outboard side of the ball end has stretched.  This is more likely on the bottom, since that bearing is pulled outward by the vehicle's weight.  The presence of any damage is a dangerous situation and the axlehousing must be replaced:</div> <bR> <div> <A HREF="id365.htm" TARGET="_top" TITLE="Kingpin bearing cup and housing"><U><IMG SRC="5a6af470.jpg" border=0 width="175" height="71" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></U></A></div> <bR> <div> To replace these cups, don't just start pounding them out with a bearing driver set.  It would be easy to bend or crack the relatively thin ball end.  In this picture, a socket is being used to catch the bottom of the bearing cup.  The kingpin cup sits flush with the ball end but is part way out in this image.  The outside diameter of the socket must not exceed 1.430" to fit inside the shoulder:</div> <bR> <div> <A HREF="id366.htm" TARGET="_top" TITLE="Kingpin cup part way out"><U><IMG SRC="5a8af4d0.jpg" border=0 width="175" height="77" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></U></A></div> <bR> <div> This picture shows how the cup was pulled.  A large socket is used on the outside.  The socket must clear the 1.690" outside diameter of the bearing cup.  By tightening the bolt, the cup is pulled free of the ball end into the large socket.  You could use any handy item such as a short piece of pipe, old bearing races, etc.  The important part is not to hammer on the cups which could damage the ball ends.  A similar process will be used to install the new cups.  Since the unmachined inner surface of the ball end casting is not parallel with the shoulder, use caution that you don't pull twist the new cups during installation:</div> <bR> <div> <A HREF="id367.htm" TARGET="_top" TITLE="Kingpin cup with both sockets"><U><IMG SRC="5aa7d640.jpg" border=0 width="125" height="100" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></U></A></div> <bR> <div> Before installing new cups, lightly clean up any crud or rough surfaces on the outside of the ball end.  ScotchBrite pads work well.  A smooth surface is needed for the knuckle seals.  If you don't want to spend the time cleaning up the sealing surface, you can pour the lube directly on your garage floor instead of filling the knuckles.  The end result is similar, and the knuckles won't be messy when you go back and disassemble them to polish the ball ends.</div> <div>  <A NAME="kingpin_bearing_cap_studs"><IMG BORDER="0" SRC="1x1.gif" HEIGHT="1" ALIGN="bottom" WIDTH="1" HSPACE="0" VSPACE="0" ></A></div> <div> Here is an exploded view of the kingpin bearings inside the knuckle casting.  Shims under the bearing caps control the bearing preload.  Later version knuckles used shims only at the top, with a thicker boss at the bottom to compensate.  Studs were originally used to secure the bearing caps for two very important reasons.  The studs can be installed to the very bottom of the threaded hole to engage the maximum number of threads.  That is an important consideration with the relatively weak threads of the cast iron knuckle.  If you look at the top of this picture, bolts were temporarily installed to show a second reason in favor of studs.  If the bolts are approximately 1/8" too long, they will hit the bearing cage.  Unless the bolt length is carefully calculated, a shorter bolt may not engage enough threads.  The casting is only about 1/2" thick here, so if the bolts are an 1/8" too short that is a 25% loss of engaged threads.  At some point, Willys did switch over to bolts instead of studs.  Should you decide to use bolts, choose bolt length carefully and don't forget to include the thickness of the <A HREF="id460_brake_hose_guard.htm" TARGET="_top" TITLE="Spindles, etc."><U>brake hose guards</U></A> if so equipped:</div> <bR> <div> <A HREF="id417.htm" TARGET="_top" TITLE="Kingpin bearings exploded"><U><IMG SRC="68daf540.jpg" border=0 width="175" height="84" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></U></A></div> <bR> <div> The studs are not readily available except through a <A HREF="http://www.public.asu.edu/~grover/willys/parts.html" TARGET="_blank" TITLE="http://www.public.asu.edu/~grover/willys"><U>vendor specializing in Willys parts</U></A>.  These studs have fine threads at both ends.  The type often found on engine blocks, etc., have coarse threads on one end, and fine threads on the other.  Here is a picture of my close, personal friend Mr. Loctite preparing to hold the studs in place after they are threaded flush with the inside of the knuckle.  (Add the Loctite before assembly, not after the stud is started in this staged shot.)  Willys trucks, wagons and the very early CJ-2A used a different knuckle with a separate steering arm attached to the kinpin bearing cap.  Longer fasteners were used to secure the steering arms:</div> <bR> <div> <A HREF="id418.htm" TARGET="_top" TITLE="Kingpin stud with loctite"><U><IMG SRC="68faf5b0.jpg" border=0 width="175" height="91" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></U></A></div> <div>  <A NAME="knuckle_changes"><IMG BORDER="0" SRC="1x1.gif" HEIGHT="1" ALIGN="bottom" WIDTH="1" HSPACE="0" VSPACE="0" ></A></div> <div> To verify the proper preload, an ordinary fishing scale is used.  (If you are married, you may have to hunt around a bit to find it, considering the last time you actually used it.)  For the CJ-2A, 12-16 pounds of resistance is the desired range after the bearing caps are torqued in place.  This value may be different on other vehicles, so consult your manual.  (Early versions of the manual specified a lower resistance value, but that was superceded in later versions of the manual.)  Do this check before the knuckle seals are installed.  </div> <bR> <div> <B>NOTE:</B> The resistance will increase substantially when the seals are installed, but that is normal.  Don't reduce the bearing preload to compensate.</div> <bR> <div> Keep the combined shim thickness the same for the top and bottom, unless you have the later knuckles designed for shims at the top only.  If the preload is not enough with all shims removed, thin hardened washers can be added at the shoulders for the bearings:</div> <bR> <div> <A HREF="id419.htm" TARGET="_top" TITLE="Fishscale on Knuckle"><U><IMG SRC="6a996480.jpg" border=0 width="150" height="72" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></U></A></div> <bR> <div> After the preload is set correctly, don't forget to disassemble the knuckle to pack the kingpin bearings with grease.  The bottom bearing gets plenty of lube when the knuckle is filled.  The only additional lubrication for the top bearing is in 4WD when the axleshafts are churning up the lube.</div> <div>  <A NAME="knuckle_plug_caution"><IMG BORDER="0" SRC="1x1.gif" HEIGHT="1" ALIGN="bottom" WIDTH="1" HSPACE="0" VSPACE="0" ></A></div> <div> Before proceeding to the seals, this is a good time to check clearance for the fill plug on the aft side of each knuckle.  Due to normal manufacturing variations with tapered pipe threads, it is possible for the tip of the plug to extend too far inside the knuckle and contact the ball end at the end of the axle tube.  Contact marks may even be present on the ball ends.  If needed, grind some material from the tip of the plug to avoid interference.  Don't overlook this check because the steering could bind if inadequate clearance exists.  In extreme cases, the steering could jam at full travel.  If the plugs aren't installed until after the completed axle is reinstalled and filled with lube, such interference may not be obvious until it is too late.</div> <bR> <div> Here are what the original knuckle seals looked like.  These seals are cast metal, with a replaceable felt insert that fits in a groove.  The flag shaped ends of the felt pieces butt together when assembled.  I don't know if these felt pieces are available any more:</div> <bR> <div> <A HREF="id420.htm" TARGET="_top" TITLE="Old Knuckle seal"><U><IMG SRC="6ab965c0.jpg" border=0 width="150" height="92" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></U></A></div> <bR> <div> When I ordered new knuckle seals, I received a newer style.  This is a rubber seal with an embedded metal ring.  The inner sealing lip has a step to it.  Even though the metal ring has a slit, the rubber portion was made in one piece.  A razor saw is being used to cut the rubber lip for installation:</div> <bR> <div> <A HREF="id421.htm" TARGET="_top" TITLE="New knuckle seal with razor saw"><U><IMG SRC="6ad96450.jpg" border=0 width="150" height="69" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></U></A></div> <bR> <div> The rubber seal is held in place by a pair of stamped metal retainer plates.  A felt dust seal is sandwiched in place under the plates. If installed before the knuckle, the felt dust seal can be passed over the bare ball end of the axlehousing, otherwise it will need to be cut with scissors:</div> <bR> <div> <A HREF="id422.htm" TARGET="_top" TITLE="Felt dust seal and plates"><U><IMG SRC="6af96650.jpg" border=0 width="150" height="101" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></U></A></div> <div>  <A NAME="knuckle_seal"><IMG BORDER="0" SRC="1x1.gif" HEIGHT="1" ALIGN="bottom" WIDTH="1" HSPACE="0" VSPACE="0" ></A></div> <div> The rubber seal is a bit of fun to install.  I had to slightly bevel the outer edge and grease it to get it to fit inside the shoulder of the knuckle.  These new seals didn't come with any instructions, so initially I wasn't positive which direction they should face.  Some research by a friend with a newer manual (Thanks Mike) confirmed the embedded metal ring faces the knuckle as shown:</div> <bR> <div> <A HREF="id423.htm" TARGET="_top" TITLE="Knuckle seal without felt"><U><IMG SRC="b05af460.jpg" border=0 width="175" height="70" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></U></A></div> <div>  <A NAME="seal_caution"><IMG BORDER="0" SRC="1x1.gif" HEIGHT="1" ALIGN="bottom" WIDTH="1" HSPACE="0" VSPACE="0" ></A></div> <div> Here is a shot of the installed seal assembly.  The rubber seal is not visible under the felt dust seal and retainer plates.   With the knuckle at full travel in either direction, look in from where the spindle will be mounted.  This will let you verify that the rubber seal is fully seated in the shoulder of the knuckle.  <B>Caution</B>: Until the turn limits are adjusted and the tie rods are connected, it is possible to turn a knuckle too far.  The seal can travel past the ball end and get trapped.  The seal will have to be removed before the knuckle can be straightened.  (Don't ask)  Note how the turn limit bolt makes solid contact with one of the retainer plate bolt heads:</div> <bR> <div> <A HREF="id424.htm" TARGET="_top" TITLE="Knuckle seal at turn limit overhead view"><U><IMG SRC="6b1af500.jpg" border=0 width="175" height="80" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></U></A></div> <bR> <div> If that retainer plate bolt is tightened the turn limit will change.  If possible, wait a couple of days after installing the felt dust seal before adjusting the turn limit.  The felt will have time to fully compress and the retainer bolts can be retorqued before setting the turn limit.  Lockwashers cannot be used on the retainer plate bolts.  Applying enough force to compress a lockwasher will distort the retainer plates.  Loctite is preferred, but the bolts could not be retorqued after the felt has compressed.  To get around this Catch-22 situation, the retainer bolts should initially be installed dry.  After a suitable waiting period, remove each bolt individually, apply the Loctite and then reinstall.  Since the felt is absorbent, apply it from the backside of the knuckle before each bolt is threaded in place.  One bolt hole at the steering arm is not open on the backside, so there won't be much choice here but to apply it to the bolt:</div> <bR> <div> <A HREF="id425.htm" TARGET="_top" TITLE="Loctite on knuckle seal retainer bolts"><U><IMG SRC="6b3af4e0.jpg" border=0 width="175" height="78" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></U></A></div> <div>  <A NAME="turn_limit_with_seal"><IMG BORDER="0" SRC="1x1.gif" HEIGHT="1" ALIGN="bottom" WIDTH="1" HSPACE="0" VSPACE="0" ></A></div> <div> The turn limit bolt is being set to factory specifications in this picture.  (<A HREF="id374_turn_limit_caution.htm" TARGET="_top" TITLE="Bendix Joints"><U>The Bendix Joint section</U></A> has more details about a potential error in the service manual.)  The axle has been rotated with the driveshaft yoke pointing straight up and the differential cover mounting surface resting on wooden blocks.  This allows the use of an angle finder to check the turn limit.  To measure turns from a neutral point, shim the axle level from end to end.  You may find the turn limit bolt and lock nut factory welded in place.  Grind out the weld if needed to adjust the bolt.  Even without the weld, expect to find it frozen in place since it most likely hasn't been touched in years.  Don't ask how I know this, but it is a lot easier to remove a frozen turn limit bolt before installing the knuckle.  After breaking the bolt free, I cleaned up the threads and applied anti-sieze compound so it should be good if my grandchildren have to readjust it another 50 years from now: </div> <bR> <div> <A HREF="id426.htm" TARGET="_top" TITLE="Angle finder with knuckle seal"><U><IMG SRC="6b5af500.jpg" border=0 width="175" height="80" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></U></A></div> <bR> <div>  <A NAME="turn_limit_on_vehicle"><IMG BORDER="0" SRC="1x1.gif" HEIGHT="1" ALIGN="bottom" WIDTH="1" HSPACE="0" VSPACE="0" ></A></div> <div> The turn limits can be checked even if the axle is already installed on the vehicle.  The following pictures show the left turn limit being checked.  The edge of the leaf spring is used as a reference plane for the straight ahead position.  The steering wheel is turned fully so the knuckle contacts the turn limit bolt.  The shoulder of the tire will be compared with the leaf spring.  The difference will be used to determine the angle.  It is very important that the tape measure be held at a right angle to the leaf spring.  Looking aft, the distance from the tire's shoulder to the leaf spring is being measured at the front:</div> <bR> <div>   <A HREF="id556.htm" TARGET="_top" TITLE="Turn Limit Front Measurement"><U><IMG SRC="90c96590.jpg" border=0 width="150" height="89" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></U></A></div> <bR> <div> Repeat the process at the rear of the tire, with the knuckle still against the turn limit bolt.  Measure against the edge of the leaf springs themselves and not the clips:</div> <bR> <div> <A HREF="id557.htm" TARGET="_top" TITLE="Turn Limit Rear Measurement"><U><IMG SRC="90e96580.jpg" border=0 width="150" height="88" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></U></A></div> <bR> <div> Record the difference between the two measurements.  Then measure the tire's diameter for the next step:</div> <bR> <div> <A HREF="id555.htm" TARGET="_top" TITLE="Tire Diameter for Turn Limit"><U><IMG SRC="91096430.jpg" border=0 width="150" height="67" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></U></A></div> <bR> <div> Here is a diagram, in TooMuchFreeTimeVision(tm), showing the calculations needed to determine the steering angle.  Also included are details on the specified angles for the three different types of axle shafts and an example based on my CJ-2A.  This is a simplified top view of the front left tire:</div> <bR> <div> <A HREF="id558.htm" TARGET="_top" TITLE="Turn Limit Diagram"><U><IMG SRC="91296710.jpg" border=0 width="150" height="113" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></U></A></div> <bR> <div> With the proper difference determined, adjust the turn limit bolt on the rear of the axle as needed.  Doublecheck that the turn limit bolt is contacting the knuckle by attempting to pull a strip of thin paper from the contact area:  </div> <bR> <div> <A HREF="id559.htm" TARGET="_top" TITLE="Turn Limit Bolt w/ Wrench"><U><IMG SRC="91496450.jpg" border=0 width="150" height="69" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></U></A></div> <bR> <div> Repeat the entire process for the other side, with the wheel turned fully in that direction.  The type of axle joints used need not match side-to-side, but the turn limit for both knuckles must be set for the most restrictive type of axle joint installed.</div> <bR> <bR> <bR> <bR> <bR> </td> </tr></table></body>