M923A2 Shaking at 55-60

[buggyman]

I've read allthe replies, In my opinion, one or more of the tires are out of balance. I hadthis same problem with my 923A2; when I removed the CTS and weights I got ridof almost all of the shake. Good luck, Paul

Hi my 923 shakes badly at 55ish to 60ish. Doesn't shake at all before and really after these speeds. It does sometimes go away all together. But for the most part, its a pretty regular shimmy during those speeds. Changed rear tires and still doing it exactly as before.


Should I get a new set of tires? - No -

Is this a balance issue since its certain speeds. Since I figured low spots would shake throughout 0-65.

 

[OktobrVega]

I've read allthe replies, In my opinion, one or more of the tires are out of balance. I hadthis same problem with my 923A2; when I removed the CTS and weights I got ridof almost all of the shake. Good luck, Paul

Gatta be tires, for one reason or another. Bad thing is tires I have have 80% tread. And CTIS works perfect. I would hate getting whole tire set and it still...shake. Doh!

 

[plode]

I've read allthe replies, In my opinion, one or more of the tires are out of balance. I hadthis same problem with my 923A2; when I removed the CTS and weights I got ridof almost all of the shake. Good luck, Paul

Not to hijack the thread, but what did you use to plug off the hole in the hub after removing the CTIS valve? I've searched on here and there isn't a clear answer as to what size plug it is.

 

[buggyman]

This is a good question The rear hubs have a 5/8" pipe stud and the front axle has a 1/2" pipe stud. I had to buy 2 different plug cap kits to get both sizes.
Paul

Not to hijack the thread, but what did you use to plug off the hole in the hub after removing the CTIS valve? I've searched on here and there isn't a clear answer as to what size plug it is.

 

[whiskey357]

May I suggest that you take it to a commercial truck repair shop and have them check it out and get a front end align there also....Have a m35a3....Same thing and I took it in...300 bucks later she comes good as new no more problem at 50-55 mph...,,, Loose nut on the drive shat and wheels out of alignment.....Have to watch the potholes around Chicago I guess...Good hunting ...Hope this might help with your problem.............Life is short laugh often heheh

 

[OktobrVega]

Thank you guys, Guess gonna try to get it into a shop. Check alignment and check driveline issues. Then is it still persist. Tires. I want to be able to enjoy the vehicle. Not have it shake to pieces from under me. Shes a dream till 53. LOL

 

[Over]

Bad Shimmey on a M923A2 with 14r20's at 55-60. Tried fluid balancing

I too just picked up a M923A2 with 14r20's. The rear are Michelin XZL's and the fronts are Goodyear AT2A's. Just did a recover from Ca to AZ about 380 miles. We contended with a bad shake/shimmy that was side to side between 55-60. It felt like the front end was going to fall apart! Before and after was fine. We ended up staying at 65-70 most of the way home. Now I saw the fluid balancing method here and after the ceramic balls wouldn't go in, direct into tire valve stem NOT CTIS valve stem. I proceeded with the Anti freeze solution. Did the air down on a jack and put a hose on and jack up method. The main offender seemed to be the drivers front as coming back I took a turn in the chase care and video taped. The front tire and the farthest rear on the drivers side seemed to be jumping. So after 64 oz in the front went for a test drive and was much better and the steering wheel didn't try to go side to side. Still vibration just less. So got back and put 64 oz in each of the drivers rear and added another 32 oz up front. Also added 64 oz to the pass front. Aired everything to 60 lbs. As a side note on the recovery I ran 80 up front and it seemed to ease it a little but was still pretty bad. OK test run...now the vibration has moved down to 50-55 mph, not as bad but still too much. Even starting slow it feels like my tires are oval. It is pretty smooth up to 50, dang near enjoyable! There is no slop in the steering that I can see. Any thoughts?

BTW it was posted here on SS but I was keeping track of it on Craigslist. Bought it from a great guy that had modded it a bit with a straight pipe and some bumping up of the pump. Plus from some photos he took it to the desert where that rear travel really shines. Actually I bought it because he threw in a cup holder from "those military guys"! I have one in my M923A0, an accessory must have!

In the video at 60+ still a pretty noticeable shimmy but 55-60 you really had to hang on. Felt like the wheels where ready to fall off. After fluid balancing a lot better but still very noticeable.

https://www.youtube.com/watch?v=18O80GWquKA

 

[M35A2-AZ]

That is a A2 thing, with all the CTIS weight and valves they are bad about shimmy and balancing.

 

[helomech]

That is a A2 thing, with all the CTIS weight and valves they are bad about shimmy and balancing.

My A2 with CTIS rides just fine at over 60. Only time I had a bounce was when I had a flat and could not move the counter weight over to the spare, and anything over 45 was horrible.

 

[M35A2-AZ]

My A2 with CTIS rides just fine at over 60. Only time I had a bounce was when I had a flat and could not move the counter weight over to the spare, and anything over 45 was horrible.

My M932A2 rides just fine also, but I have driven some that are very bad. I think it is all about the tires, if they are round and in good shape.

 

[Over]

That is a A2 thing, with all the CTIS weight and valves they are bad about shimmy and balancing.

Is there a way to adjust the counterbalance weight or is it what it is? I now have ant freeze in the tires so maybe keeping the CTIS isn't a good idea. Bummer as when I hit the super crappy (understatement) mining road I could air down. Not so much to soften the ride but to get ride of bounce over the rocks.

 

[M35A2-AZ]

I think with the CTIS and ant-freeze or beads is not a good thing.
I have seen people add lugs nuts to the wheel half bolts to balance them or you could try to rotate the wheel and move the
CTIS things around the wheel (but that would a lot of work).
Could check out a big truck tire place to see if they can balance them.

 

[Ford Mechanic]

I removed all the ctis from my M923A2 if anyone is interested in the weights, they're for sale in the classifieds. I had no shimmy before and none now and I run up to 72 MPH in mine.

 

[MuleMac01]

In the video is your ABS light on?? and what about the Over Speed light? Don't they light up about 50+ on a side note try to get em balanced or rotate the tires, and or put 1,000 pound weight in the back of the truck should smooth it out nicely. Mine had a death wobble on the front turns out some dude put the CTIS counter weight on the wrong lug on one of the tires.. go fig huh? now it's almost gone. One thing we all need to understand is that these tires have been on the trucks for years and just siting and some times there flat causing damage and a flat spot inside the tire

 

[Over]

In the video is your ABS light on?? and what about the Over Speed light? Don't they light up about 50+ on a side note try to get em balanced or rotate the tires, and or put 1,000 pound weight in the back of the truck should smooth it out nicely. Mine had a death wobble on the front turns out some dude put the CTIS counter weight on the wrong lug on one of the tires.. go fig huh? now it's almost gone. One thing we all need to understand is that these tires have been on the trucks for years and just siting and some times there flat causing damage and a flat spot inside the tire

Yes the ABS light is always on, something to trouble shoot later. I personally never have liked ABS and on the M923's it's for a soldier in a panic stop. I have to rehook the panel plug as the owner unplugged because of the low air buzzer. I double checked the weights and there in the right position. I am going to play around with the lug nut balancing to see if I can figure it out. I still have the passenger rear tires to fluid balance. I have another Goodyear on a rim that I can move around to see if one tire is the issue. I may just for S&G's throw a 275 gallon cube in the back and fill it up, 2200 lbs should do something. I know 2 cubes at 4400 make my old PowerStroke F350 crew cab long bed ride where I can actually make a call without saying OLGA is giving me a massage!

 

[M35A2-AZ]

I think the lug nut thing is a good place to start. Let us know how it does.

 

[swede69]

go to a truck shop and spend the money and get it done right. because where do you start? if you hit it right you are the balancing king with all the fuel burn and aggravation you'll be money and time ahead, a lot of liability with golf balls, airsoft pellets and extra lug nuts spinning in tires at 60mph.it is a mother lode for a lawyer, just saying

 

[Over]

Decisions, decisions........

 

[bricksrkids]

What's the counter weight for the ctis look like?

I sometimes have bad vibs at these speeds if I haven't driven the truck in a few days. Mine smoothes out after a while so I think it's the tires flat spotting from sitting. So maybe some of you guys have flat spots that won't go round because of age or sitting for way too long.

 

[Over]

Funny, hopped in the "Patrol" M9230 today and I have to say I LOVE the way it just goes thru the gears, a little early but down the road non the less! No stomping it to the floor thinking SHIFT now, or then letting off to make it shift. No bad vibration coming off the front 11r20's or the 8 tires in the rear! Takes a little longer to hit 55 but other than the louder engine a beautiful ride. I imagine with 14's or 16's it would have a higher top speed with a little less oomph on crappy roads or uphill. The A2 would be great if it could take a couple of hints from the old AO! Just my thoughts. Will continue to see what can be done for the A2 as I think the trannies are the same so I don't understand the totally different shift patterns? I know the torque is different but the 2 trucks feel like they have different model trannies and aren't even related.