Main Hydraulic Slide Fatigue Failure

[d2reid]

I bet you guys think I am the Sad Sack of RV ownership. Could be true. Just pulled in from another 3000 mile run and went to open the main slides. On the Momentum 376 these are the big slides in the middle of the RV, kitchen slides, one side dining table and the other refrigerator/stove. They use a rail/gear system and are pushed/pulled with a hydralic jack. In my 12 years of full timing I have never had one fail. Until now... The first noticeable symptom was the slide would not fully extend, stopped about an inch short. First thought was something was behind it restricting. Couldn't find anything. So started looking at the workings.

Taking a look at the picture below you will notice the steel bar with the red box around it.. That is supposed to be flush with the floor, not seperated. It is bolted to the floor of the slide. Just below that you will see the yellow arrow saying bent. There are two braces that the rail system is attached to and the ram is attached to. They are bent.

Anyone know how that black bar is fastened to the floor of the slide? Do the bolts go into some type of frame? I am thinking about getting a peice of flat iron, drilling holes through the bar and the floor, then through bolting. I would cover the flat iron with a peice of flooring trim. Feedback is appreciated.

[Country Campers]

d2reid

From what I have seen at the factory the bottom of the slide room is attached to the side walls, side walls sit on top of the floor of the slide room, with screws that go up from the bottom and into the slide walls. The aluminum framing in the slide walls have wood blocking inside the tubing, not much but it is there, that is supposed to help with the attachment of the floor. This same system is used for the outer wall where the steel tube that is in your picture is attached, larger screws for the steel tube. My guess is that over the usage of the slide the screws holding the steel tube in place has become stripped or loosened in the aluminum framing. I would think that if you bring the slide completely in you could remove the tube and drill new holes off to the side of the existing holes and reinstall the screws that you removed, not sure how practical that is but it sounds doable. If you do this take note of the mounting places of the slide mechanics so you get them close to the right place afterwards. You should be able to see the screws from the bottom of that tube.

Brian

[d2reid]

d2reid
You should be able to see the screws from the bottom of that tube.
Brian

Brian I can see the screws from the bottom. They are actually lag bolts. I tried taking one out and twisted it off. Knowing that they go into a peice of aluminum back frame is good to know. My current plan is to purchase 4 new lag bolts of the same size. I will drill holes in the black metal bar and smaller pilot holes into the slide frame. I don't plan on removing it. I am planning to brace the slide in the open position. I will put probably 2.x4's across the kitchen floor and supporting 2x4's against the wall and opposite side. I don't think it will take much pressure to pull that bar back into place. Once there, 4 new bolts go in. Then we will see....

[Jlawles2]

If it's like my kitchen slide, the slide itself is supported by the rollers and the rails (there should be one driven by the tube actuator and the follower (i see both brackets are bent). Adding supports could create other issues.

I'd try the manual over ride on the opposing side to slowly move the bar and see if it pulls back and gets aligned. If it does, then install the new bolts.

In the mean time, don't forget to check your rollers on the bottom of the slide and along the camper cutout to ensure none of them are broken, damaged or locked up.

[Country Campers]

Jlawles2 This is a hydraulic operated slide, I am not sure if it has a manual override similar to the electric thru frame.

d2reid

Dallas,

I am wondering if the bent tube is caused by holding the extend button on the slide too long. If I recall the slides will either operate together or separately, depending on the valves in the propane tank area. With the tube being twisted outward it would seem that the hydraulic actuator is putting extra force on the slide tube connection after the slide trim on the inside contacts the interior wall.

Brian

[TedS]

Just operating to retract for a second or two should pull the brackets back and rotate the tube as the hydraulics start to retract the slide.

d2reid you will also need to straighten the bent plates.

[Jlawles2]

d2reid Being Hydraulic, it may be worth pulling the 4 bolts in the bent plates, retracting the slide actuator (this is where you will need the supports you mentioned) then by means of a pipe wrench (this will put the handle parallel to the floor of the slide for easier operation, straighten the plate. You may want to make another support for the slide support arms since you will be pulling down in an attempt to straighten the plate.

You may find that the slide side support bracket at that time then will move back into position.

Lastly you may need to see if there is a limiting device that is out of adjustment putting extra stress on the bracket(s) if they are over traveling.

[d2reid]

I'd try the manual over ride ...
In the mean time, don't forget to check your rollers on the bottom of the slide and along the camper cutout to ensure none of them are broken, damaged or locked up.

On this slide system there is one controller that activates the hydraulic pump and switches the correct bypass valves so just the slide move. There are some cutoff valves in the front right propane compartment that isolates the two slides. Currently I have the refrigerator side locked off so it doesn't move at all. Only the broken kitchen table slide moves.

When the slide moves there is no restriction or dragging, so I think rollers, gears, bars are ok. Rusty and worn for sure, but functional.

Dallas,
I am wondering if the bent tube is caused by holding the extend button on the slide too long.
Brian

I believe you are supposed to hold the button an extra heart beat once the slide is extended. This adds pressure the hydraulics and holds it in place. The ram below extends fully when the slide is extended, unless it becomes out of correct alignment. This may be the case, as there is a gap between the extend lock nuts and retract lock nuts.

Or, it could be the time the metal cup we keep in the bathroom bounced out of the bathroom, down the stairs, and got in behind the trim when I opened the slide. Or maybe the time that the broom fell down and got wedged in behind the slide. (That was the last time I got fancy with the phone app extending the slides from outside). Or, it just could be the 6 years of moving that slide in and out once or twice a week.

Just operating to retract for a second or two should pull the brackets back and rotate the tube as the hydraulics start to retract the slide. d2reid you will also need to straighten the bent plates.

Oddly enough just retracting the slide a few inches does not straighten the bar and brackets out. It's going to take a greater counter force. I think locking the slide in place and then retracting will apply sufficient force to move things back in place. Or, it'll rip the whole thing out and I really will have a mess.




I thought about fully retracting the slide to see if the bar/brackets align correctly. But I am not sure if I can then get to the bar/brackets. Plus, it's weak. The more I fuss with it the more likely it is to really break. I am going to take it slow and easy, inches at a time.


= = = = = =

The plan; Tomorrow I am going to talk with GD and try to confirm the wood backed aluminum slide frame that the lag bolts go into. It kind of boggles my mind that the lag bolts are the only thing the hydraulic system pushes against. They look to about 3/8”, so kind of strong. I have a mobile tech that is coming Tuesday to replace my wet bolts. I am going to run everything by him also. By Wednesday I should have my ducks lined up. I will update after Thanksgiving.


Happy Thanksgiving.....