Slide creeps in, not out.

[D_E_Bishop]

Earlier this year our HWH pump died and we had a Mobil Tech in Oregon replace it for us. Now the slide is creeping in about two inches.

The hydraulic lines were not opened and only the pump motor was replaced. I did have to crank the slide in by hand, something I would gladly pay to have done if another failure occurs.

I read somewhere in the HWH literature that the system was self bleeding, I can't find any info on bleeding the system.

Any ideas?

Update of sorts from 11-14, I have a limited education in hydraulics and I am not criticizing anyone's answer but I just don't understand how there can be pressure in a hydraulic system when the pump is off. Okay, with a check valve in place and when a system is pressurized there will be some static(I believe that's the right word) energy in the system but isn't it expended as soon as the system is operated with the pump off? My understanding is that a liquid(hydraulic oil in this case) cannot be compressed so, shouldn't even an itty bitty leak release the static energy instantly? How can there be enough energy to move my dinette/sofa slide 2 to 4 inches?

I truly do not understand.

[D_E_Bishop]

Well I lied, I couldn't take the rig back to storage until I found the problem. I had to vacuum the insides to get rid of the sand so when I extended the room I looked underneath. I saw a damp spot and crawled under to get a better look. There is a tee that is connected to the cap end of the room cylinders and to the manifold. It is both the extend and retract line. I cleaned the fittings on all three hoses and the Tee itself and cycled the room a couple of times. Crawled back under and saw a drip forming. Cleaned off the drip and cycled again, checked and another drip forming at the same place.

We've got a good mobile tech that does a lot of work at the storage yard and I'll get a price from him. It's a two hour job and the hose should be $125 to $150. If it's more thaan $350, I'll bring it home and do it myself but it is worth $350 not to have to do it.

Here is a diagram;

[D_E_Bishop]

First off, thanks everyone for the help, I truly appreciate all of it. We are sitting in a fantastic campground on the coast in Santa Barbara County and I'm not comfortable being under the RV in soft sand and messing with the hydraulic system. Today is going home day and tomorrow is Grandson helping the "G" Dude move stuff in the garage day. When we refurbished the house, we had the popcorn ceilings removed and smoothed out and the entire interior repainted. About 80 percent of our belongings went into the garage and we are going to sort and get rid of most of it this next week while the daughters and grandkids are off work and school. We have photo albums and slides going back to 1959 and those will all be converted to digital images. That alone is a huge undertaking but must be done.

On Monday after turkey day I will level the rig, put the jackstands in place and let the levelers retract, at that point I will try the flush out instructions Doug gave me and then go from there. I will post the results of each thing I try as I go along.

It is also time for the annual preventive maintenance inspection of every system and function of the MoHo. So that will take another two or three days. So if you don't hear what I did to correct the slide problem for a couple of weeks, it is because the family will be at the house and I just won't have time.

Thanks again, have a great Thanksgiving and we'll talk again in couple of weeks.

[ChuckSteed]

If the tech did not properly bleed the hydraulic system after pump replacement then yo7 most likely have air in the system..

It takes about 5 complete cycles...cycle being In and Out for the slides and the landing gear to properly purge the hydraulic system..Repalc8ng the pump most certa8nky did put Air into the entire system and bleeding properly ma6 fix issue..

If problem perisi5 after tha5 I’d have t8 be look8ng st the retract solenoid for that slide. If he replaced pump was it just the pump or was it the pump and manifold.

[77rollalong]

you could also put in a pressure releaf valve/check valve on the extend side of the cylinder for about 150lbs so that the fluid cannot escape back through the spool valve untill pressure is applied to the retract side of the cylinder

[dougrainer]

D.E.Bishop wrote:
Okay Doug I got it. I will be doing what you sugested on Saturday when I'm home. What still bothers me is with the pump off, where is there enough pressure stored to cause the room to move 2 to 3 inches?

That would seem like a lot of movement.

HWH rooms have static pressure ALL THE TIME. Whether extended or retracted. So, if you have an external or internal leak, the difference in pressure on one side will cause the room to move slightly. To see how much a room will move, just release BOTH extend and retract solenoid quick release tabs on the end of the solenoids. Doug

[D_E_Bishop]

Okay Doug I got it. I will be doing what you sugested on Saturday when I'm home. What still bothers me is with the pump off, where is there enough pressure stored to cause the room to move 2 to 3 inches?

That would seem like a lot of movement.

[dougrainer]

D.E.Bishop wrote:
Thanks to all, unfortunately we are in a somewhat remote area and I don;t want of crawl under the rig in the sand to attempt any repairs. We'll be home on Friday afternoon and I'll try Doug's suggestion and maybe replace the "o"ring in the poppet valve but I don't think that will have any effect.

Don't attempt to replace the o-ring's. There are a few not just one. When you remove the solenoid, it will shave/cut some of the O-rings. While HWH sells the O-rings, they never advise to replace them. They replace the complete solenoid under warranty. It is NOT the O-rings causing your problem. It is the needle valve that is allowing the fluid thru. Doug

[D_E_Bishop]

Thanks to all, unfortunately we are in a somewhat remote area and I don;t want of crawl under the rig in the sand to attempt any repairs. We'll be home on Friday afternoon and I'll try Doug's suggestion and maybe replace the "o"ring in the poppet valve but I don't think that will have any effect.

[dougrainer]

mikestock wrote:

rk911 wrote:

donn0128 wrote:
You have a bad check valve which is part of the valve. Replace it.

agreed. we had hydraulic slides and jacks on a previous motorhome. for each slide and pair of jacks there were two solenoid valves.. in/out and up/down. you likely have a leaky "out" valve on your slide.

If it would be more convenient you could even add another check valve in line. In other words, if the check valve is part of another component just add another. Can't hurt.

Can't do that on HWH systems. The solenoid is NOT a Check Valve. It just opens and closes as fluid has to run BOTH ways. Doug

[mikestock]

rk911 wrote:

donn0128 wrote:
You have a bad check valve which is part of the valve. Replace it.

agreed. we had hydraulic slides and jacks on a previous motorhome. for each slide and pair of jacks there were two solenoid valves.. in/out and up/down. you likely have a leaky "out" valve on your slide.

If it would be more convenient you could even add another check valve in line. In other words, if the check valve is part of another component just add another. Can't hurt.

[dougrainer]

Replacing the pump motor would not cause your problem. Yes, HWH systems are self bleeding. Just extend and retract 4 or 5 times and that will remove any air. Replacing the Pump Motor would not cause air in the system. Creeping out or in with no visible leaks is one of the extend or retract solenoids. They are leaking internally. You can manually open both extend and retract and run the room for 15 to 30 seconds and if there is any trash on the needle valve , that usually removes it. If not you replace the retract valve. Doug

[rk911]

donn0128 wrote:
You have a bad check valve which is part of the valve. Replace it.

agreed. we had hydraulic slides and jacks on a previous motorhome. for each slide and pair of jacks there were two solenoid valves.. in/out and up/down. you likely have a leaky "out" valve on your slide.

[donn0128]

You have a bad check valve which is part of the valve. Replace it.