TOWING A M720 mobilizer is it me or ?

I just picked up what I thought was an older S280 shelter with the mobilizer mounts. KCCLAY and I did the recovery and he mentioned he had a M720 mobilizer that he had got in trade several years ago and if I wanted it, it was mine. Went over today to get it, got the tires and air bags up to stated pressure in the TM hooked it up and left to go home. His place is just off the Hwy and as I was speeding up to merge all of a sudden about 30MPH it started to sway back and forth thinking it would mellow out I kept going, by 40 it was like a drunk baby was driving at 45 I thought it would rip the receiver off the back of my truck. I dumped the speed got below 30 got off the next exit and back to his place. Has anybody else had this problem or is it just me, does this sort of thing not happen with the shelter attached? Tm states 50max highway 15 cross country did they get that backwards?

Shelter is bolted together per the TM btw.

I am going to do another thread on the shelter as that is another bag of worms.

We didn't have any problems with the M832 (next size up) on towing, but backing up is a whole different ball game (and not a pretty one either). Sounds to me like the bearings might be a tad dry one one of more wheels, or the brakes are dragging.

And if there was no shelter on the mobilizer at the time, with such a short wheelbase, and light(ish) wheight, and wiggly would quickly be amplified...

2 cents

I would love to say they suck and you need to give that beauty to me so you wouldn't have to deal with it. In reality, they suck empty. I had one fishtailing all the way back from Eglin to Atlanta on me. That turned a 4 hour trip into a 12 hour trip.

Get it home slowly and get the shelter on it. I've driven mine with a shelter mounted at 50 mph with very, very, VERY little sway. Keep the load as balanced front/rear/side to side as possible.

Thanks for the input guys, but I am pretty sure it's not the bearings after shelling one on a M101A2 GL 100 mile pickup last fall first thing on a new to me trailer PMS,check brakes/repack wheel bearings. I had another member email and said he had same problem with a recovery and ended up putting draw bar in stowed position, lifting front wheels off the ground attached front axle directly to the trucks pintle (used chains and binders to keep it square) and pulled it 300 miles as a 2 wheeler at highway speed. I only have to go about 20 miles so will just flat tow mid morning when traffic is light and stay off the HWY.

Has anyone towed an M720 (or other dolly set) successfully without a shelter on it and not have it sway all over the place? I can see there would be some wandering around since the fronts turn on their own.

How about more weight on it like strapping a couple of full water cans towards the front wheels? Too bad there is not a way to "lock" the front wheels strait so they don't turn.

thanks for any input. Looking at an M720 and would rather tow it home than find a trailer to put it on.

OD

I pull my SPAM around on a M720 regularly. With a shelter pulls smooth at speed(45-55), empty they can sway like a tree in a wind storm.

So far, I have towed three M832 sets without the shelter attached. Two of them pulled smooth and straight and I was able to do highway speeds comfortably (well, 55mph. That's highway speed to me with an MV).

I tried recovering the third one from Ft Worth. It towed great up to around 25mph, then began swaying badly, and by 29mph it was wagging the dog (1-ton Chevy pickup) in a most alarming way. I slowed down, sped up, no good - it acted the same way each time.
I traded it off before leaving town.

Cheers

OK thanks for the input guys. Looking at the TM there are a couple of things to check if it sways. Looks like the 720 has a LOT of toe-in, 1/4"... Hmmm. Odds not looking good on a 500 mile recovery trip.

Update, I ended up removing the draw bar, jacking up the front and chaining it to sit on top of and in the pintle hook, along with ratchet straps going to each side of the axle it then towed fine. When I got it hooked up to a S280 it towed like a dream.

Good job! A little of the Yankee ingenuity! As a note, most Dollies will sway, some more than others, even the larger 1022's when empty! It leeps you awake for sure!

I have M832. I towed it empty from AZ to MD with no issue at cruise speed of 55 MPH.

I towed the bigger cousin from Mobile to New Orleans in a light rain. Never, ever will I touch a dolly again........ It was acting just plain crazy stupid.

I won an M720 WAY out in Washington state and working to have a buddy pick it up and hold it for me...

A thought on the swaying issue. In the TM for maintenance on setting tow-in it shows putting a wood block under the hitch arm which pushes a lock pin to lock the front wheels in place to allow for tow-in adjustment... I am still thinking there is a way to lock those front tires in place. With no shelter on the dolly it wouldn't seem like too terrible of an idea with not much binding in turns while towing... Just a thought.

OD

Another tail wagger!!!

I am still waiting to pick one of these up. I haven't seen any on the east coast.

DanM7890 said:

I am still waiting to pick one of these up. I haven't seen any on the east coast.

Click to expand...

I saw a couple time in SC but the condition was not nice as I got. It is cheap, $125. You sell tires and you get your money back. Or you can sell tail lights.

Bad Robot please edit you profile per site rules to show which one of the "United State of America" you reside in or use as your home of record.

If anyone get's a model 4003 to part out let me know. I need a few parts off one.

I guess I was lucky when I towed a M720 from Ft. Meade for about 80 miles North without any problem, going as fast as the speed limit. But that also proves that there must be some adjustment (toe-in?) that prevents these things from wiggling. FWIW, the spring bags on my dolly were flat when I towed it.