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Repairing a Generator Slide


Keamyinc

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This spring when I took my 2002 Monaco Windsor out of storage the generator slide would not extend despite being able to hear the electric motor and hydraulic pump running but sounding strange compared to normal operations. Bleeding lines and tapping on the valve block assembly changed nothing. We then removed the electric motor hydraulic pump unit and took it to a hydraulic repair shop where they confirmed that both sides of the hydraulic pump were putting out the required 500 psi pressure. We then disconnected the remaining hydraulic lines from the aluminum hydraulic block assembly, removed the side fittings then removed the hydraulic block assembly from the end of the ram. The fittings on the side of the aluminum hydraulic block must be removed with the block in place as there is not enough room for the aluminum block to make complete turns with the fitting in place as it won’t clear on the side of the generator. Note: Even though all hydraulic lines were disconnected from the aluminum hydraulic block assembly we were unable to move the generator slide with pry bars until the aluminum block valve housing  assembly was loosened enough to bleed trap pressure out of the ram. Only at this step were we able to fully extend the generator slide manually with pry bars. Again not an easy task with not many convenient spots to pry. Once we had the aluminum valve housing on the bench we blew the one and only valve assembly out of the aluminum housing. As previously mentioned in an earlier post, wrap the housing in a rag to catch the valve assembly or you may not find the two part valve assembly that will blow across your shop if not caught in a rag. Also note, when you manually pry the generator slide out, ATF fill shot up and out of the ram, estimated at 2-3 cup fulls of it will shot out all over the undercarriage and your floor or driveway so be prepared. Have lots of rags on hand.  We examined the valve parts, o-rings etc and could not find a problem. Took the housing and valve to the hydraulic shop.  The pros had never seen a unit like this before. Regardless they cleaned it up, put the valve back in with a little grease for installation. With the slide fully extended now we had lots of room to work on reinstalling all the components of this system. Once finished with the installation the oil reservoir was filled with a little over a quart (1.25 litre) of ATF Dextron III once all the air was bled out of the system. Upon activating the switch the slide began to move in both directions.  Note: the first time the reservoir is full run the motor for a minute or two then top up the reservoir again. After a half dozen complete in and out cycles of the slide all the air had automatically purged itself out of the system and the slide was rolling quite smooth and the hydraulic pump was sounding normal once again.Then recheck the oil level.

Conclusion: Must have been some debris in the valve assembly in the aluminum block.

Cost: 2 quartz of ATF.

Reward: My slide working again and the knowledge above to share with everyone else should they run into a generator slide not moving with the motor and pump still working.

Thanks

Keamyinc 

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I have had this problem intermittently since I've owned the coach.  I have taken the cylinder out and completely cleaned trying to get rid of all contamination.  I have had to remove the valve block multiple times to get the lock valve free and  I even purchased a new lock valve.  

What I have found is that when I put the slide in if I continue to hold the button in it seems to purges hydraulic fluid through the valve and it reduces the chance of it sticking.

I also found that if the slide does get stuck, I can take the 2 nuts off the cylinder ram and move the slide manually and for some reason when I put it back the slide works, no idea why but this is the last thing I do before diving into the valve block itself. 

 

So don't get too excited yet as I predict the problem will come back eventually. 

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2 hours ago, jacwjames said:

I have had this problem intermittently since I've owned the coach.  I have taken the cylinder out and completely cleaned trying to get rid of all contamination.  I have had to remove the valve block multiple times to get the lock valve free and  I even purchased a new lock valve.  

What I have found is that when I put the slide in if I continue to hold the button in it seems to purges hydraulic fluid through the valve and it reduces the chance of it sticking.

I also found that if the slide does get stuck, I can take the 2 nuts off the cylinder ram and move the slide manually and for some reason when I put it back the slide works, no idea why but this is the last thing I do before diving into the valve block itself. 

 

So don't get too excited yet as I predict the problem will come back eventually. 

 

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I recently had intermittent issues getting mine to extend. The one time when it did extend out again to the stop I noticed the fluid level was not quite at the extend full mark. It took maybe 8oz or more to bring it to the line. So far it’s been working. It makes a loud shake and rattle noise when I start while in the closed position however, but not while extended. I figure it’s the tray on the rollers. I will need to check those at soon. 

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  • 1 month later...
On 7/8/2021 at 8:24 AM, jacwjames said:

I have had this problem intermittently since I've owned the coach.  I have taken the cylinder out and completely cleaned trying to get rid of all contamination.  I have had to remove the valve block multiple times to get the lock valve free and  I even purchased a new lock valve.  

What I have found is that when I put the slide in if I continue to hold the button in it seems to purges hydraulic fluid through the valve and it reduces the chance of it sticking.

I also found that if the slide does get stuck, I can take the 2 nuts off the cylinder ram and move the slide manually and for some reason when I put it back the slide works, no idea why but this is the last thing I do before diving into the valve block itself. 

 

So don't get too excited yet as I predict the problem will come back eventually. 

Can you explain the lock valve?

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10 hours ago, tmw188 said:

Can you explain the lock valve?

The lock valve moves under pressure to allow hydraulic oil to extend/retract the generator slide.  With no pressure it is suppose to move to block the hydraulic oil from letting the slide extend.  When I've had problems with my slide not moving and have taken the valve block out the lock valve was stuck and I had to blow it out with air.  I replaced it thinking that would solve my problem, it didn't.  Any contamination in the system eventually works it way to the lock valve, there is not filter on the system, since it is a reversing motor/pump system you can't install one.

I had attached a parts schematic for the valve block and also a manual for the slide. 

Dr4Film actually fount a place that rebuild his pump and cylinder.  The pump is obsolete. 

Edited by jacwjames
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Ok well I may need to try that. There is no pressure on the lines unless the pump is running correct? The pump and system I assume is self purging of air after opening since it has a vent on the reservoir? This all started immediately it seems when extended I notice the extended fluid level line showed it was low so I filled to the line with maybe 4-6oz of ATF

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  • 2 weeks later...

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