Broken S/O

[mobilrvn]

Traveling in Mexico makes you a better Montana repair tech. After a hard day's drive, was looking forward to putting the house together, putting my feet up and having a local brew---not so fast! I usually watch the S/Os when they go out and in. The main S/O only started to come out at the rear---my wife was faster than my voice, so we were spared any damage, but now how to fix it since we were about 300 miles from the US and help.

It wasn't hard to figure out what had happen. A pin had sheared which holds the connecting rod between the front and rear rams. Looked like Keystone used a cheap Chinese bolt (wonder how much money they save? Also have had the landing gear connecting rod bolt shear). There were two things that you needed to align to get the new bolt in the hole. First the rams need to be equal distance. I measured the amount of track space sticking out on the broken ram and by just clicking the IN/OUT switch, got the rear one aligned more or less (a process I had to do again). I couldn't find the hole, but discovered that the connecting rod can be slid to the rear which exposes the hole, making the alignment easy. Also once you know, the pin which runs through the ram gear, is the same on both sides. The exposed part of the pin has a hole which is a mirror image of the other side, so you can figure out where the hole is without sliding the connecting rod. Of course, the alignment for the hole will probably cause the need for more in/out aligning of the rams. Used a sturdy screwdriver in the outside hole and a wrench on the connecting rod to make the fine adjustment. All I can say is that it is working.

[RVWheels]

mobilrvn,
This has happened to a number of folks and there is an extensive thread on it. You may want to do a search and see what was discussed earlier. The slide mechanisms are made by Lippert. If you have any questions about this issue MIMF is a good person to ask.

RVWheels

[OntMont]

Call Dale (MIMF2) at Lippert Componets in Goshen (574) 537-8900. He will probably be able to help you get it fixed.

[DHenry]

At the Reno rally Dale addressed this problem and the solution is to install a longer bolt as the original bolt is a little to short.

[richfaa]

Since the solution is to install a longer bolt..Has Lippert replaced the short bolt with a longer bolt???

[mobilrvn]

Think the solution should be to install a stronger, not longer bolt. The original bolt broke in the middle. It still seems to be working OK with my repair. Will track the thread. Didn't have internet at the time it happened.

[MIMF2]

mobilrvn,

That bolt needs to be a 1/4-20X2" grade 8 hex head bolt. It uses a nylok 1/4-20 hex nut. If possible, puchase zinc plated ones to protect against rust and corrosion. In fact, purchase several and keep them as spares. You can purchase these any where. Lowes, Menards, Home Depot or any hardware store.

Any of you folks that where at the Reno Rally probably got some of those as I had them there for hand-outs.

The reason those are grade 8 is because, these are designed to be weak points. They shear before something more expensive and time consuming to repair is damaged.

If you have any further questions or need help, feel free to call me at the number shown above or call our toll free number, 866-524-7821. My extension is 4542.

[Trailer Trash 2]

Where are these bolts that you guys are talking about does anybody have a picture that the could put on this topic or a PM.

Thanks

TT2

[MIMF2]

TT2,

These bolts are located under the slide room at each end of the cross shaft. The cross shaft is a 1" square tube that extends from one gear pack assembly to the other. The shaft runs parallel to the main "I" beam of the frame just 4 or 5 inches out. You will see that at one end of the cross shaft, it is 1" square while at the opposite end it is 3/4" square and telescopes. That is because one size of tube fits inside the other. Therefore, we are able to use this tube for different length rooms in the manufacturing process. Each end of the shaft fits over the round shaft of the gear pack assembly. The bolt we are talking about slips thru the tube and and gear pack shaft and is held in place with a nylok (plastic insert) nut. Some people refer to them as aircraft nuts.

When I get to my office later this morning and I have time, ( I have to deliver a Non Keystone product back to the manufacturer) I will attempt to post a picture of what we are talking about.

Talk to all later.

[MIMF2]

Hey gang, something else I just thought of. At any time ,you can go to our web site at Lippert Service and Maintenance Manuals to look at service and maintenance manuals. In those manuals, you will be able to find drawings or pictures and wiring diagrams of the most widely used slide mechanisms and products we make. Click on "Warranty" in the upper right then, click on "Owner Manuals" at the bottom of the list. Typically, you folks will click on Hydraulic slide out systems. For those of you with the Cambridge, click on Hydraulic slide rooms with HLG. And for those of you who have the humungus 3685 with the sofa slide outs up stairs and you want to see the system that moves those (electrically) in and out, click on Sofa slide out.

Feel free to print those at any time in any amount you wish.

Have a good day and, don't anybody freeze.

[Wrenchtraveller]

A grade 8 bolt will have 5 little slash marks on the hex head. A grade 5 bolt has 3 slash marks.

The grade 8 has more strength than a grade 5 but it is more brittle and will break where a grade 5 will stretch more so I can see why they use a Grade 8 if this bolt is designed as a shear pin.

Thanks for the post and I will carry a few of these for spares. Wrenchtraveller.

PS, If there is room to use a small line up bar, this makes this type of job very easy. A line up bar is a small bar with a tapered end that is used to insert into two holes to bring them into perfect alignment.
The taper gives you great leverage and these tools are inexpensive to buy and one of the tools that all mechanics use a lot. They come in a small enough sizes for 1/4 inch holes and one this small would only be about 6" long so hopefully there is room .

[thook]

Thanks for the info......just went out to my shop and found several grade 8 bolts and put them in my "to go" pile for when we hit the road in January. Tips like these are what make the MOC forum what it is. Thanks again.

[Illini Trekker]

Made a print out you suggested it will go in the Monty. I always turn an eye to your post Dale THANKS!

[Trailer Trash 2]

Dale said I could post this picture of the bolts I hope it isnt to big, if it is I will edit is so the picture can be taged OK.

http://tinypic.com/id53wg.jpg

[mobilrvn]

MIMF2, Thanks for the great info. Will get the right bolts when we get back to the US in a few months. Seems to me that if something is designed to break, then we should have some spares like fuses, etc. Didn't find any info on this with all the manuals, etc. we got when we bought the Montana.

Guess a follow up question would be, "what could cause the bolt to shear?" We have never run the S/O into anything and what do you do but push the IN/OUT switch? Was it a weaker than normal bolt or do we have some other problem out there waiting to attack us?

[MIMF2]

TT2, that is absolutely perfect!! Thank you very much for doing this!

mobilrvn, to answer your question. Most of the time these bolts break prematurely simply because we were using bolts too short. We were using bolts that were 1 1'4" or 1 1/2" long. That ment that the threaded section of the bolt was inside the square tube and the round shaft of the gear pack assembly. With the back and forth motion of the room being extended and retracted, the moving parts acted like a scissors to eventually cut the threaded section to the point of making the bolt weak enough that it would break. We have found that by going to the 2" long bolts the shoulder is stronger than the thread and they last much longer. In other words, the threaded section of the bolt was the weakest point.

[montanared]

MIMF2, Thank you for another outstanding bit of information.

Belonging to this group has been invaluable. Bless you all and I wish you all a very happy holiday season.

[Trailer Trash 2]

Everybody that see's that picture you see 2 arrows, and not knowing what it looked like under there, I took a peek, Guess what, after I went under my slide and looked at what I posted, I have to apoligise for the error please ommit the arrow on the left, it sure looked like a nut and bolt to me, but it's not, there is only one on each side of that square tubing, I hope I didnt confuse too many out there.

TT2

[William H. Collier]

Thanks MIMF2, while putting out the slides here in Mesa I noticed a squeeking when the big slide, living room, was going out. I crawled under yesterday to lub the gears and noticed that the nut and half the bolt in the slide shaft nearest the hydraulic cyclinder was missing. The bolt had broken and only half was still in place. It broke right where the treads stopped. It took a little doing to get the other half out as it was rusted in place.
Thanks to this forum and MIMF2 I was prepared for this situation. Prior to leaving home I purchased 6 of the above named bolts in case this should happen. I replaced both the bolts in the shaft with the longer ones. I cannot say enough about the help provided by the forum and its members.
Bill

[Charlie]

TT2-
What is the designation of the "grade 8"? Would stainless steel bolts be acceptable as replacements?