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 > Relationship between jacks and slides?

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dedmiston

Coast to Coast

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Posted: 01/24/23 12:57pm Link  |  Quote  |  Print  |  Notify Moderator

In most regards I feel like a captain who knows every inch of his ship and knows what sounds it should make and can intuitively tell when something's awry. But there's one system that I just can't understand, and that's the relationship between my slides and my jacks.

I had a blowout almost two years ago, and the flapping of the tire shreds severed one of the hydraulic lines to my Lippert 6-point jacks. I changed the tire and made it the rest of the way home. When it was time to unhitch, it dawned on me that the line had been severed and it was just bleeding fluid instead of deploying the jacks. So I kinked the line, tied it off with zip ties, and added more fluid to the reservoir so I could get the jacks down and unhitch the trailer at the storage yard and go home.

This was the beginning of the end of the motor that runs the jacks and the slides. From then on the motor was weak and strained. And worse, it would intermittently fail and just make a "clunk" sound of the solenoid instead of running the motor. It finally died completely before we were supposed to leave for our New Year's trip, but I finally got the parts to fix it.

Yesterday I replaced the motor and everything works fine again. Yay.

I wasn't even positive that the problem was the motor until I replaced it, but I was certain it was the motor the moment I removed the old one. I've never smelled something so fried before. Worse than Satan's armpits. I left the old motor on my tailgate while I was working on it, but I could smell the stench of the burned out grease standing by my front bumper.

[image] <<--- Satan's armpits (or worse)
[image]

So my question to the world is... What does this motor have to do with my slides?

It's obvious to me how it operates the jacks: The motor turns, either pumps or sucks fluid through the lines to deploy or retract the jacks, and the fluid visibly rises or falls in the reservoir like a high or low tide.

But running the slides in and out has no effect on the fluid in the reservoir. I suppose I should put my finger up there on top to feel if the motor even spins while deploying the slides, except my arms aren't long enough to control the slides inside the coach and fool with the motor at the same time.

I just can't for the life of me envision the relationship between the two systems. It makes no sense to me why that dead motor would kill the slides too.

What am I missing? Someone please enlighten me.


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fj12ryder

Platte City, MO

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Posted: 01/24/23 01:03pm Link  |  Quote  |  Print  |  Notify Moderator

I assume you have hydraulic slides and hydraulic jacks?

Simply put, it's not really two systems, it's one system that does one thing: the motor runs a pump that pressurizes the hydraulic system. What that hydraulic system does depends on the particular valve that is opened, i.e. slide system, or jack system. The pump/motor doesn't care, it's just pumps fluid.


Howard and Peggy

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dedmiston

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Posted: 01/24/23 01:06pm Link  |  Quote  |  Print  |  Notify Moderator

Is the fluid for the slides just recirculating then? Why isn't the level in the reservoir affected when I run the slides in and out like it is with the jacks?

fj12ryder

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Posted: 01/24/23 02:13pm Link  |  Quote  |  Print  |  Notify Moderator

Yes, the fluid just circulates between the slide pistons and the jack pistons. Where the pressurized fluid goes is determined by the solenoid valves opening and closing hydraulic valves directing the pressurized fluid from the hydraulic pump.

Actually the level should vary as the slides go in or out. The volume is going to be less for the slide pistons, so it may not be as noticeable.

dedmiston

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Posted: 01/24/23 02:41pm Link  |  Quote  |  Print  |  Notify Moderator

I'm going to have to bust out a sharpie to mark the reservoir and check your work. [emoticon]

fj12ryder

Platte City, MO

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Posted: 01/24/23 03:07pm Link  |  Quote  |  Print  |  Notify Moderator

dedmiston wrote:

I'm going to have to bust out a sharpie to mark the reservoir and check your work. [emoticon]
LOL I can tell you, our last 5th wheel had just the hydraulic slides, and the level did raise and lower. But all three slides were hydraulic.

phil-t

Ogdensburg, NY

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Posted: 01/24/23 04:20pm Link  |  Quote  |  Print  |  Notify Moderator

dedmiston wrote:

Is the fluid for the slides just recirculating then? Why isn't the level in the reservoir affected when I run the slides in and out like it is with the jacks?

Likely, the level varies with jack deployment because they are pressure out (oil pumped into the jack cylinder), lowering oil in the reservoir; and spring return, raising the oil level. Slides are double-acting cylinders - (oil s pumped into one end to deploy, while the oil is pushed from the other end of that cylinder; opposit for retract. Thus the oil level does not change for the slides.
Slide Cylinders are like this


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Allworth

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Posted: 01/25/23 01:09pm Link  |  Quote  |  Print  |  Notify Moderator

Your original problem is because the hydraulic fluid is used to lube the bearings in the pump. A common practice on construction equipment.

Very low fluid = cooked bearings.


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Previously: 2008 Titanium 30E35SA. Currently no trailer due to age & mobility problems. Very sad!
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dedmiston

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Posted: 01/25/23 03:17pm Link  |  Quote  |  Print  |  Notify Moderator

That makes sense for how the motor fried.

I'm still having a hard time visualizing the role of the hydraulic fluid in a rack and pinion system. It looks like the motor turns the pinion that moves the slides in and out.

The belly is inclosed and there's a limit to what I can see from the outside, but I still feel like I need someone to whiteboard the whole thing out for me.

MFL

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Posted: 01/25/23 03:48pm Link  |  Quote  |  Print  |  Notify Moderator

I know and understand my rack and pinion electric slide system, but not the sharpest tack, on the several other types. [emoticon]

Is it possible that your system is hydraulic jacks, but slides are simply operated by the electric motor? You did say the fluid level does not change, while moving the slides.

You may get better response by posting in the tech section?

Jerry





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