Suspension Arm Shims

[OZM29C]

@Patrick Tipton@M29C3284 Patrick, This topic is reason enough to start a new thread so we don't hijack @darth_kitten's thread. I initially set my weasel up with one thick and one thin shim per bogey arm, similar to what M29C3284 had installed on his weasel. I found that after some testing (Both land and water) that the bogey wheels were pushing the track guides to the outside which in turn was hammering the track guide tops into the track sprocket guide plates. I then fitted 10mm (Approx 3/8"Inch), see attached photo, shims to the bogey arms and this had the reverse effect by pushing the track/guides back to the inside and chaffing the outer side of the track guides. So in my case the sweet spot lies somewhere in between. All of the adjustments were made with the suspension unloaded (weasel lifted off the ground) however the next adjustment I make will be with the suspension under load. Unfortunately I could find little information on this subject in the TM's but hopefully Patrick you may have access to more documentation. I did find a photo in the attached weasel brochure that shows some special tooling/jigs to set the suspension up in the factory. Interesting subject.

[Patrick Tipton]

Great idea John.  There is a lot of lost "art" in getting these machines to operate correctly.  Hopefully we can figure this piece out and get it documented so the process is easier for the next guy.

My LAR tracks on the unrestored M29 are running pretty well.  I would say the bogies are perpendicular under load (basic empty weight of Weasel without passengers/cargo).  I will put it on my list to remove one of them and measure the thickness of the shims.

Regards, Patrick

[OZM29C]

39 minutes ago, Patrick Tipton said:

Great idea John.  There is a lot of lost "art" in getting these machines to operate correctly.  Hopefully we can figure this piece out and get it documented so the process is easier for the next guy.

My LAR tracks on the unrestored M29 are running pretty well.  I would say the bogies are perpendicular under load (basic empty weight of Weasel without passengers/cargo).  I will put it on my list to remove one of them and measure the thickness of the shims.

Regards, Patrick

@Patrick Tipton Bizarre as it might sound, I am going to use a small spirit level and then lay against the outside of the bogey wheels to ensure that the bogey wheels are correctly orientated vertically after I make my shim adjustments. BTW I too am running the LAR tracks. 

[M29C3284]

@OZM29CAre all the suspension bushings and bolts on your weasel in as new condition? Just wondering if having too much play/wear in the support arm bolts and bushings would cause the angle of the bogie wheels to shift regardless of how many shims are installed. 

I noticed on mine, when I started installing the yokes and support arms, that there was a terrible amount of play in the whole assembly. So right now I'm making new bolts and bushings for the ones that are not avaliable.  

[OZM29C]

@M29C3284Thanks for your valuable suggestion. I can confidently say that all suspension bolts and bushings were replaced with NOS parts. I had to replace them all due to severe wear from lack of lubrication. That’s the Achilles heel of a weasel, the constant need to keep the suspension regularly greased. 

[DonM]

We have started removal of the bogies and suspension arms from our hull and one side is done. We found that the suspension arms were shimmed differently for each bogey set. Going from forward to aft, the shims were 1 thick + 1 thin for the first set, 1 thin for the second and third sets, and 1 thick + 1 thin for the rearmost set. 

 

[DonM]

Correction for my previous post........there is 1 thick and 1 thin shim on each of the 4 support arm mounts.

[Ronny68]

3 hours ago, DonM said:

Correction for my previous post........there is 1 thick and 1 thin shim on each of the 4 support arm mounts.

Same as with ours.

[F-D Zernia]

Please understand my set up has not been tested yet as I’m still working on the engine. 
When I picked up my LAR tracks the advice repeated was bogie wheel alignment. There was no mention of how many shims to use only the end result. I imagine like an automobile alignment the shims used are not uniform from vehicle to vehicle. Not all frames are perfect only close. 

1. Mike’s main instruction was to set the Weasel on the ground before track installation. I set mine on boards. 
2. Use a 1” square bar to slide between the bogies where the track guide will be. This bar should be long enough to engage all bogies and move freely from bow to stern. 
 

At first it did not fit at all. I did both sides a little different but the alignment was the same. I must warn in advance you will probably be on you knees for a long time so be prepared for that. 
I found 2 bogie sets that were not straight to begin with. Check each set of bogie with a good straight edge and be sure the steel rims all touch the straight edge on 4 points when checking across both bogie wheels. If you find one  just a little off it didn’t seem to matter. 
 

I put Jack stands under the hull but not to support the weight when resting on the bogie’s.   Then used a plumb bob on the inside of the slot of the drive sprocket and put a long screw in the board to use later. Then did the same with the return wheel. I use this as a straight line from front to back. 
 

Now lift all the bogies and support them with blocks like the manual explains for track work. The hull now is resting on the jack stands. Place the steel bar on the board and use 2 more screws to keep the bar on the center line of the drive and return wheels. 
 

One at a time lower the bogie set and adjust it to fit over the 1” bar. It worked best to fit the front and rear bogeys first. This helped to keep the bar on center. Every time a bogie set is lowered have the mounting plate with the shims loose. The assembly will rock from left to right and then find the sweet spot. Shim according. Keep doing this until all the bogies are resting on the ground supporting the weight and the bar moves freely. Sometimes to get alignment the mounting pivot bolt holding the assembly needed to be removed and inserted catching the thread differently to move the entire thing about 1/8” in one jump. 
 

I did check when finished and another steel bar pressed against all the bogie steel rims touched all of the rim surfaces . This will be my quick check when the track is on. Or if I do a field repair. 
 

As I stated my Weasel is not moving under power yet. When that day comes I will post. What I have learned the bogies can be aligned with each other. It takes a lot of patience and time. 
 

Another observation, it didn’t change with or without engine weight. I aligned without engine then placed 500 pounds of bag water softener salt in the engine bay. The suspension squatted and the bar still moved freely. 
 

I hope some of this helps

Fred