While change my salon slide seal found the rear slide lock leaking from the plunger/pin area. Decided to try replacing the seals (see image below for part numbers) mainly to see If it is possible.
Removed the switch housing on top of the lock and pushed the slide pin out. The internal seal was completely deteriorated and retained by a snap ring. From what I could tell that seal was an squared "U" shaped seal, not an O-ring, The "U" was facing the pressure side of the chamber. Using my Dial Calipers I came up with dimensions for the internal seal and the others as well. The closest McMaster-Carr had to the square "U" was a X profile and Double X-Profile seal. I chose the double x profile as it is designed for a dynamic installation. I was able to fit the seal into the channel without having to remove the internal snap ring after cleaning it out thoroughly.
The next item to note, on the slide pin is two Teflon backing rings on each side of the O-ring. Those are solid and not split like most backing ringsI made a tool to take it apart but did not bother as they looked great to reuse as is.
Checked the operation of the switch with an OHM meter all good there.
Reassembled the lock assembly and installed into the coach for leak and operational checks. Happy to report no leaks and works great!!
In December of 2020, the coach went into the shop for a winter’s rest and repairs. As the slide went in, fluid started running down the valance dripping on the dining table. Months later After several other repairs and additions, it was time to look into the leak. I was not looking forward to working on the hydraulics. However, I was lucky as @land yachts was here ( he works for food lodging and beer). You can’t get the valance down by yourself so his help was quite welcome.
The slide has to come in a little to get the valance down. The light rope gets moved and a quarter round piece covering the wall to ceiling junction. This gives access to the locking ram. The next step is very important. Deflate the seals and open a few hydraulic solenoids manually to relieve pressure. Turn off the air to the seal solenoids and unplug. Now you are ready to remove hydraulic lines. We took the ram to a vice and found the nut on top (used to cover the bore for the ram) had a blown o-ring. Easy fix, new o-ring and job done! Here is a picture of the locking ram still installed.
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The rest is reverse of the removal process. Operated the slide several times to purge air, no need to bleed lines besides, it is very dangerous. This system works at 3500psi.
My thanks to Mike Ginn, without him this would have been much too difficult.
Gordon,
Thanks for pointing out to deflate the slide seal. I was in the middle of changing my slide seal so it was deflated and the air shut off anyway. Mine was leaking so bad that by the time I disconnected the hydraulic lines there wasn't any pressure at the lock assembly. As a PM I will be rebuilding the rest of the locks in the near future. I will make a note to accomplish the steps you pointed out.....thanks
All,
We took a trip to St Augustine for the week. Once parked went to extend the slides. Front had no issues....the bedroom's rear slide lock developed a massive spewing leak upon activating the extend mode.. The interesting thing to note here.....absolutely no warning of impending failure, no leaks drips runs or smells....nothing! The "Blind hog finds an acorn" analogy here was I stop the extend cycle immediately. The intense urge to continue was almost unbearable but I resisted. Once back home, pulled and disassembled the rear slide lock....found the seal had come apart due to small amounts of foreign matter collecting on top of seal as its a low point in the flow of fluid. Also found out that the seal is a "Loaded U-Seal".....the same size as the shaft seal I used on the on the slide actuator (The O-ring Store, P/N UL125-0.875-125 Polyurethane U-Seal). This seal is slightly harder than the original and should be more robust but, will require the removal of the internal snap ring with a pair of articulating needle nose snap ring pliers. The seal I had used on the salon slide lock and identified in the previous picture can be installed with out removing the snap ring and works just fine.
WYIT mind set I rebuilt the bedroom's front slide pin lock as well. Since I have already rebuilt the salon's rear slide pin lock assembly I'm going after the front slide pin lock assembly next!
Given the fact this failure gave no warning I would highly recommend rebuilding these locks. Especially if you have the time and access.
Another note to add. I had tried to order the loaded U-seal and several other o-rings from McMaster Carr back in November they had six week lead time. Then in December they notified me that due to supply chain issues my order was cancelled. The O-Ring Store had them in stock and prompt shipping to boot.
Thanks for that Steve! I guess since I have the salon slide room torn apart I should do this R/R on the hydraulics… another thing on the list! You think that part number will fit my coach (#478 HWH slides)? Will order it today if so… I also have to order a bunch of new screws and RivNuts from McMaster Carr but will make sure they have it all in stock…
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