Foretravel Owners' Forum

Foretravel Motorhome Forums => Foretravel Tech Talk => Topic started by: pugmom on November 07, 2019, 01:40:36 pm

Title: Air bladder seal tolerances
Post by: pugmom on November 07, 2019, 01:40:36 pm
Question, the air bladder that is on our drivers side bedroom slide has been leaking apparently for a while. Our super RV tech and I have cleaned the underside of the seal and removed a small twig, a few more fir and pine needles, a piece of black electrical tape and gritty grime. In the process of doing this, we noticed that between the side of the slide and the middle of the slide there was about 1/4 inch difference, perhaps a bit less.  How much tolerance does this bladder seal
have?
My concern is that it will continue to seap water in.  Do we need to have the bladder replaced and if so, is Mot the best place to go?
Title: Re: Air bladder seal tolerances
Post by: DavidS on November 07, 2019, 04:49:16 pm
Before you go to deep into the rabbit hole... try adding air pressure (add gauge first) check to see what it is set at..New one is able to be set up to 16psi I believe.. see if that fills it in.. if not, Might need to adjust the slide (not sure if you can or not).

After I had my bladder in the bedroom replaced it would do some weird stuff.. Sometimes close off and sometimes not... but would always close off after I drove... I have pics and video .. no one could explain it.. now it works perfectly..
Title: Re: Air bladder seal tolerances
Post by: Travelin' Man (RIP) on November 07, 2019, 05:29:34 pm
I remember reading somewhere that the bladders seal 3/8" to 1/2" normally.
Title: Re: Air bladder seal tolerances
Post by: Dave Dunington on November 09, 2019, 02:09:02 pm
I just recently had a new bladder installed. The new one is considbly stiffer than the old one. There was slight irregular bump on the slide, where the side of the slide joins the roof section
 I sanded it, lightly and it looked pretty good. In a heavy rain it leaked again.
I installed a pressure gauge and increased the pressure to about 18 lbs. Yeah no more leaks.
I am hoping that the stiffer bladder lasts even longer than the original..The bladder has about one half an inch the way mine is adjusted.
Safe Travels
Dave
Title: Re: Air bladder seal tolerances
Post by: DavidS on November 09, 2019, 02:14:44 pm
Keep in mind that if you put to much pressure in the bladder it will crush the fiberglass.. if you do turn it up above what's recommended keep an eye on it before it destroys the shell.. so a gauge is a good start
Title: Re: Air bladder seal tolerances
Post by: pugmom on November 09, 2019, 04:52:38 pm
Thanks, I think we will make a trip to Nac and MOT for assistance in this process. Appreciate all the help in explaining what is going on. I would rather let them work it over than me or our RV tech accidentally mess it up. There may be more to meet the eye than an under deflated bladder.
Title: Re: Air bladder seal tolerances
Post by: Travelin' Man (RIP) on November 09, 2019, 05:07:13 pm
Keep in mind that if you put to much pressure in the bladder it will crush the fiberglass.. if you do turn it up above what's recommended keep an eye on it before it destroys the shell.. so a gauge is a good start

David I think too much pressure will pop the bladder,  not the glass. The reason I think so is because HWH told me that the new bladders can take 16 lbs and the old ones about 12 lbs with no mention of glass damage at those numbers.
Title: Re: Air bladder seal tolerances
Post by: DavidS on November 09, 2019, 05:11:24 pm
Negative... without the gauge I had mine at 22lb psi.. cracked the slide fiberglass.. I had to patch mine up.. thanks for making me admit it .. lol
Title: Re: Air bladder seal tolerances
Post by: Travelin' Man (RIP) on November 09, 2019, 05:23:21 pm
Wow!  I stand corrected.
Title: Re: Air bladder seal tolerances
Post by: pugmom on November 10, 2019, 08:19:07 am
Help me to understand something, once the bladder fills with air and seals, does anything check to see if it needs an occasional tweak to stay at the same pressure? Why I ask, is if the bladder fills up on a warm day, then temp drops down cold ( as it can do here in Texas)the air in the bladder shrinks a bit. Does anything trigger the little compressor to inflate or is everything pretty much one way only. X AMT of air inflates the bladder and that is it.
Title: Re: Air bladder seal tolerances
Post by: turbojack on November 10, 2019, 08:45:38 am
From what I understand  the pressure stays the same continuous.  If  the hwh air talk's pressure goes down the air compress comes on to buildup pressure.
Title: Re: Air bladder seal tolerances
Post by: Travelin' Man (RIP) on November 10, 2019, 08:54:33 am
The adjustable valve for the bladder allows the air pressure to remain constant at whatever it has been set at.
Are you sure the bladder is leaking and not the slide opening itself where the fiberglass edge isn't properly sealed?  Have you tried removing the inside trim on the slide and having someone spray water from the outside while looking for water intrusion from inside with a flashlight? I had a leak that went through the bottom wall to the floor and only appeared as a wet floor.
Title: Re: Air bladder seal tolerances
Post by: Michelle on November 10, 2019, 09:42:26 am
Slide bladder inflation is maintained at all times.  If you develop a leak in a slide bladder, the aux compressor may not shut off.
Title: Re: Air bladder seal tolerances
Post by: pugmom on November 10, 2019, 08:38:00 pm
Thanks for the additional information. I have seen moisture seeping under the bladder edge. When I pressed on the bladder it seemed softer than when it originally filled about 12 hours prior. I have not heard the aux compressor going on except when I cycled the slides. So perhaps I may have a compressor malfunction or a malfunctioning sensor?
Title: Re: Air bladder seal tolerances
Post by: rbark on November 11, 2019, 01:23:31 am
Your pressure switch for the compressor could be bad.
Title: Re: Air bladder seal tolerances
Post by: Michelle on November 11, 2019, 10:17:41 am
There is a manifold for the slide bladder that has a regulator on it as well.