WOW! My axle broke free... - Montana Owners Club

mailmanguy · 10-13-2010, 03:20 PM

Has this happened to anyone else?

Coming home from the Smokey Mountains on Interstate 76, our 3400 suddenly "jerked" and as I looked back into the mirrors I found myself pulling a jackknifed trailer! Oh Dear! Smoke billowing out from under the rig and I'm trying carefully to get out of the center lane and off to the side of the road.

Well, long story short, we got off the Interstate and halfway down an offramp. Upon inspection, none of the tires blew (Goodyear 614's

)but the furthest rear axle on the passenger side had a pin (which goes down through the leaf springs) shear off which allowed the axle to slide (via the "U" bolts) along the leaf springs. So now picture this, I've got the front axle in tact with the second axle at maybe a 30 degree angle. The rear axle must of had a bit more weight on it because it was trying to dictate the trailer's line of travel.

Luckily, since this wasn't really a tow-able unit now, our insurance company was able to find us someone that could come to us and provide a temporary fix (on site) to get us home.

The RV is now at our local dealership. My only thoughts on why this may have happened is, rough roads. Just prior to this event we passed through a construction zone that had some rough areas, but nothing extreme. We were traveling at about 52MPH (55 speed zone).

I asked the dealer if this was common. He said he's never seen this before (that made me feel better because I don't want a trailer if this is a known event!)

Thoughts?

pvcoach · 10-13-2010, 03:36 PM

We had a somewhat similar occurance this past summer due to loose U-Bolts. I'll PM you with the description I posted.

Bill-N-Donna · 10-13-2010, 03:41 PM

Wow! That sure would be a scary event to say the least. Several people on here have changed and up-graded their bolts for the springs, etc… but I’ve never heard of the axle breaking loose. There have been a few cases of broken shackles which could have led to similar problems. Perhaps they averted the disaster that you had. Glad no one was hurt, it certainly could have been a lot worse.

Exnavydiver · 10-13-2010, 03:54 PM

This has been an ongoing discussion for the past year or two. Loose U-bolts have caused this situation several times. The pin that sheared is only there to align the springs during the assembly process. The problem has been addressed several times and the only remedy seems to be checking the torque on all your U-bolts periodically. There will be multiple folks along shortly I am sure. Richfaa had his shift on him last year right after the Glakes Rally. because of reading about the situation on here I checked mine and found all loose to some extent and two with the nuts almost off the u-bolt... Dave

pbahlin · 10-14-2010, 01:17 AM

I talked about this with the Dexter guy at the rally. He showed me how the old style U-bolt (round profile) has tiny surface area contacting the axle and contrasted this with the new style U-bolt (flattened profile contacting the axle going to round at the threads).

What happens with the old style is that vibration will eventually wear a flat on the bolt over time. When this happens; bolts are no longer torqued to spec. It doesn't take much because you're talking about stretched steel holding the torque and steel doesn't stretch all that much.

You can order new style bolts from Dexter. He said you'll need to give them the axle model # from the label on your axles. This lets them get you the correct bolt. I'll be getting mine when I get to my winter digs.

Every single time I torque my bolts I find some out of spec. I do it about every thousand miles.

Tom S. · 10-14-2010, 02:39 AM

Dave (exnavydiver) is right on. As long as the u-bolts are torqued properly, there is no stress on the pin. If the u-bolts loosen up, then the pin is subjected to stresses and can snap or wear off. The pin was never meant to hold the axles in place, it only there make sure they are properly aligned. Once it's gone, chaos ensues.

richfaa · 10-14-2010, 04:53 AM

Same thing happened to us last year. We never checked the torque on the shackle U bolts as the manual says to do resulting in the shackle loosening, causing the axle to shift causing the spring pin to break . We lost 3 tires but the fix was easy and cheap at a Dealer..all because I was to smart to read the manual...lesson learned....read the manuals and do the maint..

corncob · 10-14-2010, 08:04 AM

Experienced the same on our 2008 Montana. However, it was the second spring to be replaced, same right rear spring. Tightening the U Bolts may a good thing to do, but I donot buy the necessity to do that as routine maintenance. I think it may have something to do with the flex on the aft spring (axle) when hitting some New England Potholes on I-95. Lot of weight/length aft of the axle on some models. That is a small bolt in the spring center to hold the flex/force. It would be better served to make it stainless steel.
Just my 2 cents.

Tom S. · 10-14-2010, 08:16 AM

Quote:

quote:Originally posted by corncob

Experienced the same on our 2008 Montana. However, it was the second spring to be replaced, same right rear spring. Tightening the U Bolts may a good thing to do, but I donot buy the necessity to do that as routine maintenance. I think it may have something to do with the flex on the aft spring (axle) when hitting some New England Potholes on I-95. Lot of weight/length aft of the axle on some models. That is a small bolt in the spring center to hold the flex/force. It would be better served to make it stainless steel.
Just my 2 cents.

You may not want to believe it's part of periodic maintenance, but if you don't do it, you wish you had. The first time I checked ours, they were way under torqued. Since then, I check mine yearly and still find one or two that will take a slight amount of torque to bring them back to specs. I have included it with my brake check/adjustment and wheel bearing maintenance.

mailmanguy · 10-14-2010, 09:09 AM

It's always good to hear from other people who experienced similar circumstances. I was wondering, can anyone see any harm in "double nutting" these "u" bolts?

By the way, I'm here a lot but I don't post much as one can see ... ha! ha!

I want to say thanks for all the input.

Blessings,

ratfink11 · 10-14-2010, 10:50 AM

I was interested too in double nutting the u-bolts. I would think it would affect the proper torque on the original nut making contact. I also thought it might hold the original nut from loosing torque, but if the round u-bolts create a flat spot resulting in "slack" then why bother.

Tom S. · 10-14-2010, 10:59 AM

Adding an extra nut will stop the nut from backing off if it's loose, but the reason they get loose in the first place is the bolt stretching. So even though you add the extra nut, you should still check the torque, which gets a little more involved with a second nut in place. BTW: when adding an extra nut you have to make sure that you are holding the first properly torqued nut stationary. Otherwise, you run the risk of changing the torque.

Champ_49 · 10-15-2010, 03:35 AM

I will say that Rich and Tom have it right on. Its the ubolt that is the culprit here. It loosened up and allowed the axel to move. It is a maintenence thing like it or not. Its not just a Keystone problem its the whole industry problem. I now have a SOB unit and although the ubolts are bigger in diameter they were loose when I first got the unit and after just 250 miles there was a couple more loose. In time they will seat and take hold and then it will be none as you check. But not checking is a disaster waiting to happen. You will learn through time how often you should check them. It only takes about 15 min. to do. Its worth the time!!

Dave

Illini Trekker · 10-15-2010, 04:34 AM

Just a reminder the dexter manual says 45-70 for a 1/2 inch u bolt and 65-95 for a 9/16 u bolt, most are using 60 for 1/2" and 95 for 9/16" u bolts.

richfaa · 10-15-2010, 05:16 AM

Here I am a maint kind of guy and I never read the Dexter manual for their recommended maint. It is all in the book and had I followed the maint we would not have had the failure and the expenditure. Had to buy 4 new tires..no small expense. Delay in trip, etc. The failure was all on me...most embarrassing.

Note that at the time of the failiure we had over 35K miles on the 3400 so it took awhile for the bolts to work loose enough to fail. Others bolts were also loose.

pineranch · 10-15-2010, 05:18 AM

Follow up maintenance is a must. When I found my bolts loose I contacted Dexter (I'm mad as hell and won't take it anymore) sort of thing. They took full responsibility and stated that Keystone was not to blame since Dexter delivered the complete unit and all Keystone did was attach it to the frame.
Mike

Tom S. · 10-15-2010, 06:41 AM

Quote:

quote:Originally posted by pineranch

Follow up maintenance is a must. When I found my bolts loose I contacted Dexter (I'm mad as hell and won't take it anymore) sort of thing. They took full responsibility and stated that Keystone was not to blame since Dexter delivered the complete unit and all Keystone did was attach it to the frame.
Mike

I agree Keystone wasn't at fault but...

It sure would be nice if Keystone provided a comprehensive list of maintenance items and mileage/time frames in a simple chart so we wouldn't have to thumb through everything. Something similar to what car manufactures provide in their owner's manuals.

I would also like to see that list include the names and contact information to the various vendors who manufacture the components.

Sigh, maybe some day.

capn chris · 10-15-2010, 11:12 AM

Tom et al,
There is a pretty comprehensive list of contact numbers and vendors on the Home page, Courtesy of Glenn Adams.

Sierra 117 · 10-15-2010, 11:45 AM

I think they lose torque because the U bolt stretches, not because the nut backs off.

Champ_49 · 10-15-2010, 02:44 PM

I agree Barry. Its the bolt stretching and probably not nut backing off. I think that these houses on wheels are not maintenance free by any means. After running down the road with these monsters on wheels and the great roads we have in America it only stands to reason that something has to give somewhere. But its time the industry take a little more to heart as to what the customers want. It isn't that difficult to compile a list of maintenance items that must be watched and a time basis. Its time for more regulation on these things also, but.............more regulation also will end up costing us, not the manufacturer. Its the way its always been.

So I find it my responsibility to compile my own list from my experiences, my failures, and my information I receive right here and anywhere else we can get it. It don't cost me a dime to ask here or anywhere else for that matter. I know I have gotten plenty of info here in itself. And,I thank you all!!!

Dave

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