Trunnion loads

Message Topic Search Topic Options Post Reply Create New Topic Printable Version Translate Topic

   Working on a 69 AMX and have a question regarding the loads (forces) applied between the steering knuckle and the trunnion cone.  
So there is the obvious downward force that the spring exerts on the thrust bearing.  However it appears, from looking at the components after disassembly, there is also a side load exerted on the vertical bushing by the knuckle (or cone)?

Looking at the rubber vertical bushing, there is some slight wear on the one side of the "waffle" pattern compared to the other side which still looks new.  This is the same on both bushings and I didn't notice it until I cleaned all the old grease off, so I don't know the original orientation of bushing in the cone.  

So, is the direction of this side load inward, toward the inner fender, or outward and away from the inner fender?  

Any insights would be appreciated.  Thanks

Author	Message Topic Search Topic Options Post Reply Create New Topic Printable Version Translate Topic
jsejamx Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Apprentice Joined: Aug/31/2007 Status: Offline Points: 101	Post Options Post Reply Quote jsejamx Report Post Thanks(0) Quote Reply Topic: Trunnion loads Posted: Aug/12/2022 at 12:32pm
	Working on a 69 AMX and have a question regarding the loads (forces) applied between the steering knuckle and the trunnion cone. So there is the obvious downward force that the spring exerts on the thrust bearing. However it appears, from looking at the components after disassembly, there is also a side load exerted on the vertical bushing by the knuckle (or cone)? Looking at the rubber vertical bushing, there is some slight wear on the one side of the "waffle" pattern compared to the other side which still looks new. This is the same on both bushings and I didn't notice it until I cleaned all the old grease off, so I don't know the original orientation of bushing in the cone. So, is the direction of this side load inward, toward the inner fender, or outward and away from the inner fender? Any insights would be appreciated. Thanks

TX390AMX Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: Dec/27/2012 Location: Indiana Status: Offline Points: 803	Post Options Post Reply Quote TX390AMX Report Post Thanks(0) Quote Reply Posted: Aug/12/2022 at 8:15pm
	Jeff, I believe the load you're referring to on the trunnion bushing would be toward the inner fender. Since the weight of the vehicle is supported by the wheel/tire, which is outboard of the trunnion bushing, the steering knuckle would be pivoting on the lower ball joint, pushing the upper part of the trunnion toward the inner fender. If you've still got waffle marks on your trunnion bushings, I'd turn them 180 degrees and reinstall them! That is if the rubber still looks good after this many years. I've had some trunnion bushings literally fall out in chunks after removing the nut on top of the steering knuckle, others almost as good as yours. Water seems to be the enemy of suspension bushings, and the steel sleeves and bores they sit in. Hope this is what you needed. Terry Sumter
	Terry 68 AMX 390 4 Sp Rally Green 68 AMX 390 4 Sp Matador Red 68 AMX 390 4 Sp Calcutta Russet 56 Chevy Sedan Delivery 2016 Can AM Spyder 55 Chev pickup

jsejamx Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Apprentice Joined: Aug/31/2007 Status: Offline Points: 101	Post Options Post Reply Quote jsejamx Report Post Thanks(0) Quote Reply Posted: Aug/12/2022 at 8:42pm
	Terry, Thanks, makes sense. I was thinking of turning the bushings also, as you suggest, but just wasn't sure which way they were in there originally. With the exception of the minor wear on one side of the pattern, these are in really good shape and I've decided to take my chances with the original rubber. Jeff

BU1 Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: Aug/11/2016 Location: MN Status: Offline Points: 2012	Post Options Post Reply Quote BU1 Report Post Thanks(0) Quote Reply Posted: Aug/12/2022 at 8:44pm
	I can't believe you got the bushings to slide off of the knuckle pin. They are usually rusted tight for me.
	AMO #2726 #1 1968 AMX Rally Green 343 Z code 4spd since 1975 #02642 #2 1968 AMX Rally Green 290 N code 4spd since 2019 #02959