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Rich, I believe I have checked all the electrical connections , perhaps there is one hiding from me.

Hi, thats correct, all four jacks extend and makes contact with the ground however will only lift the coach at most 1/4”. And room slide barely moves. yes indeed the HWH system automatically dumps the air and this portion is working correctly, in fact I crushed my wash bucket in the process because I placed it just under the side. there is also a manual air dump button on the panel. The manufacturer recommends to use the leveling system with the Engine OFF due to vibrations causing issues with the leveling sensor. But I’m right with you on this point ,,,,,,I tried the system anyway with the engine running to rule out low electrical input power

Rich the front room slide is hydraulic as is the generator slide and of course the leveling jacks. My hydraulic system is an HWH system The bedroom slide is electric

Rich, Wolfe 10, actually it’s quite easy to open the generator slide out in order access the fuel filler cap. Simply locate the correct solenoid valve for generator slide. It is one of several solenoids on the valvebody. The four large solenoids are for the individual leveling jacks. There is only four solenoids for each of the four jacks. A second solenoid for each Jack is unnecessary because the retraction of each Jack is accomplished by the two return springs located on each Jack. that being said,,, the room slide out and generator slide out are both extended and retracted under pressure. There is a separate solenoid for both directions. On the end of each solenoid in the center is a 1/4” nut. First confirm which two are related to either the room slide or generator slide (which ever you are having trouble with) then turn the 1/4” valve nut counter clockwise to manually open the hydraulic flow. This allows the cylinders to move in and out freely without hydraulic pressure. The generator slide was easy to manually open the 6” necessary to add diesel fuel. It did not want to open beyond 1foot by hand so I simply rolled the coach at 5 MPH and depressed the brake Quickly ,,,the forward momentum and sudden stop caused the generator slide to fully open , about 3 feet. Closing was easy to simply push back closed. It’s important to close those little 1/4” valves,,,this creates the “hydraulic lock” necessary to prevent the slide from re-opening. There is also a manual winch with strap and hook located just under the coach next to the generator for closing and keeping the slide closed. Same is true for the room slide.

11.0 -12.2 VDC at the pump motor relays during pump “ON”. 12.7 - 13.9 VDC when pump motor is off.

Hi Rich, yes sir I removed and cleaned every wire connection that I could find related to the system. It is possible of course that there are additional connections between the power sources and the pump/valve body. There are also two 15 amp in-line fuses on 18-20 gage wires connected to the pump/valve body which are in good order. When I get to my shop tomorrow I can connect a pressure gauge in order to confirm existing main pressure. Also I confirmed this morning the generator slide is also weak. It did fully extend and retract, although very slowly. One design I’m not too thrilled with is the fuel filler is located in the fire wall area on the drivers side. It is necessary to extend the generator slide in order to access the fuel filler cap. If the hydraulic system failed completely it would create a difficult (not impossible) situation getting diesel fuel into the tank.

Also I know the connection is still good between the electric motor and the pump due to the attempt to push the slide open and the fact that the leveling/stabilizing jacks deploy down and makes light contact with the ground.

Yes sir, that was the first thing I did. Indeed the components are located where you remember. The jackets were already lowered to ground level consequently The fluid level did not indicate on the stick so I raised the jacks back up (which does not require any hydraulic pressure due to the return springs) and the level showed normal. The electric motor seems to making the normal and expected sounds while running. No binding or struggling while running. Actually there is plenty of room to add fluid with a quart bottle of ATF with a small funnel. The dipstick is integral with the breather cap. I build Allison transmissions and hydraulic pump PTO’s for fire apparatus and I’m familiar with the expected sounds of most pumps. I visually inspected the hoses associated with the jacks and slide out while my son activated the systems, I did not see anything unusual in the movement of the hoses when pressure was applied. I saw the expected “stiffening” of the hoses when pressure was applied. My instinct is that there is an obstruction in the suction circuit, perhaps in the reservoir. Perhaps there is a screen that is clogged. With all the valves and solenoids and wiring it may be possible that one is not operating correctly or perhaps not at all. If there is hydraulic schematic available I could isolate the hydraulic flow of main pressure to the components. Its the intermittent aspect that has me believing the pump has not failed. Dave

You said it!

You are absolutely correct, thank you

Thank you all for the much needed advise! I did exactly as suggested and also flushed the brake system and filled with Dot 5.1 brake fluid. I just returned to California from a trip to Utah which took me through MANY steep grades. My brakes worked perfectly! Another thing to note,,, I removed the Pacbrake exhaust valve assembly to check the condition of the valve disc,,,sure enough the normally flat disc was bent considerably! So instead of being flat like a plate it was rolled or bent like a Pringle’s potatoe Chip. This issue caused a tremendous amount of exhaust flow to go around the valve instead of up against it during engine braking. I installed the new upgraded design with the spring loaded pressure relief valve. During engine braking The Allison system worked normally by preselecting downshifting and I could feel the Pacbrake working but I thought maybe not as well as it did originally. As the Pacbrake valve slowly bent over time more and more brake pressure was necessary to slow the rig. Amazing how you don’t notice the Change in performance when it deteriorates over long periods of time. I just purchased the coach earlier this year so I suppose I didn’t have much in which to make a comparison. Again thank you Dave

Greetings recently while on a trip my leveling jacks and slide out stopped working properly. I have a 2004 34’ Alpine Coach. When I turn the hydraulic system on I can clearly hear the electric over hydraulic systems engaging, when I set the system to auto level the coach I see all four jacks extend until they each contact the ground however there is insufficient force to lift the coach or to complete a thorough leveling cycle. Also when I attempt to extend the slide out it seems to be making a little effort to do so by the extending an inch or two however will not continue beyond that. My instinct Is that the hydraulic pump has lost the necessary amount of pressure to perform its purpose however This issue began as an intermittent malfunction, it would work one day then not the next therefore I suspect the pump itself is working so perhaps the malfunction is related to valving or solenoid or perhaps a clogged filter/screen in the suction side of the hydraulic passage. Currently it is in a non-op state. Does anyone have advise or service manual as to troubleshooting this issue? I am a Diesel mechanic so I have a fair amount of technical skill but I have not worked on this system in the past. Thank you in advance Dave

Wolfe 10. Thank you for the welcome and too for the prompt response. Your diagnosis sounds very well thought out and reasonable. I was not aware of the heat conversation into a gas with brake fluid. That makes great sense considering the pressure behind the fluid coming out of the master cylinder. I own a diesel repair shop in AZUSA California, we specialize in diesel Engine and Allison transmission repair. Obviously we rarely do brake work. My guys just put it on the lifts to do exactly what you recommend. Thank you again sir! Dave

Greetings, I have a 2004 34’ Alpine coach. Recently we made a trip to the mountains, on return we made it safely down the mountain with no braking issues. Once we landed on a flat level roadway we came to a stop at an intersection, at the next stop the coach had ZERO brakes! Fortunately the coach was traveling only 10 miles an hour. Upon investigation we found brake fluid coming out of the master cylinder under pressure. I walked two miles to an auto parts store and returned with brake fluid which I promptly put into the master cylinder reservoir, we bled the brakes and were motoring down the road and made it safely back home about 100 miles away. The engine is 350 HP cummins with a properly functioning exhaust brake. During exhaust brake function the Allison transmission preselects a lower gear properly. Any ideas as to the cause? Dave