Adding a Second Hydraulic Ram to Kitchen Slide

[smo99]

I have a 2008 FR Berkshire 390QS. After purchasing it used, I realized the kitchen slide had been repaired at some point. It uses one hydraulic ram and a system including a transfer shaft/rack and pinion gears to transfer the motion from the rear slide post (with the hyd ram) to the front post. It's nearly impossible to explain in words. If you don't understand what I'm talking about, don't worry...probably only Berk owners can understand...maybe others use this method (I have no idea).

ANYWAY! The front end of the slide moves unevenly--the gears sort of pop and bind a little..it works, but I'm very nervous every time I use it.

I'm considering asking me local RV repair shop to put in a second hydraulic ram to push/pull on the front end. I'd leave the gears and transfer shaft in place so that they move in unison. My thought would be to Tee off the existing line to the rear ram, and just have the second ram be fed by the same pump line...it would probably move slower and take a bit longer, but we're only talking 30 seconds. I'm not sure you can run rams that way...maybe each ram needs a specific line direct from the pump (?).

Anyone done or had similar issues/problems/solutions?

[nwtraveler]

That is a fairly common setup. I've heard of a second ram being installed
by NuWa on a few slides. I'm not sure what your installation looks like so
couldn't comment on whether it would be possible for you. Have you looked
at the gear packs closely? I've also read threads about broken/missing teeth.
I don't see why you couldn't T the existing hyd line with a pressure equalizer
valve to run two rams. But, I'm not an expert in that field.

[tmmar]

Smo,
Your slide may just need to be adjusted so that the slide moves out evenly. You should give Equalizer a call and explain to them your problem and see if they can give you a procedure to adjust the slide mechanism. Just a thought.

[smo99]

I've checked the gears--no missing teeth--looked good. I actually had the rack (the flat gear inside the post) break loose from the rear post. I was able to drill out the old welds and get a prof welder to come in and weld the rack back into position...I've got a hunch that that last repair may have messed up the synchronization of the two sides...

I've also considered drilling a couple grease zerks into the bottom of the slide post to keep it well lubed.

[silver]

My buddy had a 2008 390 with two rams installed by equalizer on the kitchen slide. I would never do it as the slide wobbled so badly they never used it. A better solution would be to have the factory fix your current solution.

If you look at equalizer web site you can find instructions on the two ram setup. I have seen them in the past. It was specific to Forest River.

[BooBoo23]

Right, you will need an equalizing valve to balance the pressure or else the one with the least resistance will move before the other.

[smo99]

Thanks guys. This a big help. Esp. the equalizer--that makes total sense.

At least now I know what to look/ask for. I live in NW Montana, so going to the factory isn't a great option for me, but I'll keep it in mind. I would have thought that by leaving the rack and pinion system in place, it would have minimized the "wobbling" that Silver mentioned.

Knowing that it can/has been done is comforting...any other stories/successes or failures are appreciated.

[dan-nickie]

Have you read the manual on that system? I believe it is called a timing shaft / gears. They should be adjusted to synchronize them. If work has been done on it, it sounds like they just might be out of adjustment.

[tmmar]

Originally Posted by dan-nickie

Have you read the manual on that system? I believe it is called a timing shaft / gears. They should be adjusted to synchronize them. If work has been done on it, it sounds like they just might be out of adjustment.

This is why I suggested contacting Equalizer. They may be able to tell him how to adjust the system.

[dan-nickie]

Originally Posted by tmmar

This is why I suggested contacting Equalizer. They may be able to tell him how to adjust the system.

Yeah Tom, I read the manual about the procedure and not sure that I would actually try it myself without calling equalizer.
I just thought the manual would show him that there may be an issue that can be adjusted without adding a second Hydraulic ram.

[Iwannacamp]

Interesting...




Sent from my iPhone using Forest River Forums

[silver]

Originally Posted by smo99

Thanks guys. This a big help. Esp. the equalizer--that makes total sense.

At least now I know what to look/ask for. I live in NW Montana, so going to the factory isn't a great option for me, but I'll keep it in mind. I would have thought that by leaving the rack and pinion system in place, it would have minimized the "wobbling" that Silver mentioned.

Knowing that it can/has been done is comforting...any other stories/successes or failures are appreciated.

I believe Equalizer had to remove the timing shaft otherwise the two systems would fight each other. I would sooner say you have a broken tooth or the timing gear out of position on the front shaft. There is a union for the front shaft where they come apart to set timing. Perhaps it is as simple as adjusting there.

first attachment is double piston. Second is Timing shaft adjustment

[smo99]

This is all great information--thank you! I didn't have the attached docs in my doc set (maybe the former owner lost them--but they were pretty meticulous). Thanks for posting the PDFs Silver!!!

I do know all about the timing shaft--and I'm hoping it just needs adjustment. The gears all looked pretty good. I'll keep you posted...she's going in tomorrow to the repair shop.

[silver]

I was thinking, the slid runs on rollers. If you look under the slid from the inside you can see them. I wonder if one of the rollers has broken or is out of adjustment so the slid is no longer making contact. This has happen in the past and would effect movement. The rollers are not that big or numerous. Slide needs to be out to see rollers. Like small rolling pins.

You might be able to lift rubber seal from outside and look under and see them. I have never tried that.

[I-RV]

smo99 - I have a 2012 with the same problem. The front timing gear rumbles half way on going out and is smooth as silk on the way in. I crawled all around trying to pin point the problem and now believe I have a sound theory as to the problem.

The idea of the two timing gears to keep the slide from racking when being moved is good, only if implemented with a good mechanical design. The gears are held against the two rack gears by the timing shaft. On mine, the rearmost gear has a shaft bearing block only a couple inches away. However, the front gear's bearing is about 22 inches away from the gear.

My kitchen slide has more weight on the aft end, due to the kitchen counter. Pushing it with one piston in the center means naturally that the slide may not want to move evenly. That's where the timing gears come in place. To keep the movement in check there is a lot of torque transmitted between the gears via the timing shaft. But if the front gear is held in position at the end of a wet noodle, it is going to bounce because the shaft flexes. The front bearing block needs to be closer to the gear and playing around with phasing the gears is not going to help.

Most probably FR decided where the front bearing block was to be installed
FR does not have a single engineer - LOL.
Hank

[John Hagen]

I had similar issues with my 2014 Trilogy 5th wheel. The roadside slide is about 25' long and only has one piston, mounted near one end of the slide. Of course, the piston is not at the heavy end. I was grinding teeth and popping teeth like you wouldn't believe. I ended up taking the Trilogy into the Lippert service center in Goshen.

The technician listened to what I had to say, including all of the work I had already accomplished, to include 3 gear packs. The bottom line is the slide was riding too high on the gear pack near the piston. This caused it to crunch and grind teeth when it was pushing the slide to the out position.

He rebuilt the frame where the piston bolted to the slideout, added gussets, and did a total realignment to the slideout. This resulted in the slideout sitting about 1-1.5" lower that when it was delivered. Since then, no more nashing of teeth!

Look to see how high the teeth are when they are pushing out the slide. You may need to adjust the slide so it sits a little lower, so it better engages the teeth on the gear pack.

John

[I-RV]

[QUOTE=John Hagen;
Look to see how high the teeth are when they are pushing out the slide. You may need to adjust the slide so it sits a little lower, so it better engages the teeth on the gear pack.

John[/QUOTE]

The gear naturally wants to pop off the rack when it has a lot of torque on it. The gear needs to be held firmly against the rack, but if the gear's shaft bearing block that holds it in position is 22 inches away, the shaft will flutter. - Hank

[smo99]

Update:
For once a happy update! My shop here in Kalispell, MT (Gardner's) was able to adjust my slide. One of the shims was either missing or shot and the pinion gear was skipping (not making proper contact with the rack gear --as some of you diagnosed. They got the unit sliding almost perfectly...the best part is that it closes fully (it used to stick out by about 1/2" in the front). Thanks for all your input!!!

[5456Mich]

Smo, good news !

[tmmar]

Originally Posted by 5456Mich

Smo, good news !

X2!! Happy to hear that it was not something major and that they were able to fix it for you.