Aquired a 1974? Hi-Lo from father in law-need help
 

Hello, all! Im completely new to the Hi-Lo scene(i didnt even know such a thing existed)and i have a couple of questions. First, the pump seems to work just fine, however, it seems to be stuck in the up position. I cant get it to raise in order to unlock it and lower it. I under stand theres a manual method to operate it, but its not completely obvious and i cant figure it out. Secondly, i had to add about 2 1/2 qts of ATF(i work for a Mobil distributor so fluids aren't an issue), so i was wondering if maybe there is some air in the system and if so, is there a way to bleed it out? And lastly, is there a better fluid that can be used? AW 32? AW 46? Maybe universal tractor fluid? I wouldnt think there would be an issue seeing as how theyre all hydraulic fluids and the only real differance i can see is viscosity and the additive package each fluid contains. I greatly appreciate any help. I cant get this thing to go down!

Usually, the pump is a little low on fluid and the top can't lift high enough to unbind the safety release. How did you know 2 1/2 guarts of ATF was enough? What I'm getting at is that you still may not have enough fluid in there but if you have added that much, there is definitely a leak somewhere. You are pulling the safety release cable while trying to lower the unit right?

Also, by adding that much fluid, you may have overfilled the resevoir and it will come gushing out when you get thing to lower finally.

I went by the markings on the side of the gallon jug i was using and by the filling instructions elsewhere on the site in that the fluid level should be about an inch from top. I did that and the top still wont rise. The pump made a high-pitched squeal and i adjusted the pressure relief screw like the instruction manual for the 1977 camper( closest to my year on this site) but it made no difference except for the sound. I doesnt sound like its straining anymore, but it still doesnt move.

The hydraulic system should work fine with ATF.The newer trailers use Dextron. Can you take a pic of the screw that you adjusted? Was the top up when you got the trailer? Or did it go up after you added fluid? You can't lower the top by any method unless you can get the safety bar to release. The hydraulic cylinder is near the axle under the trailer, the safety bar is above the cylinder ram and blocks it from returning to the in position. After the safety bar is released the the top goes down by gravity, when the hydraulic lock valve is opened, it is mounted on the pump.

The fluid should be an inch from the top when the camper is in the DOWN position

The top was up when we got it. My dad said that ur supposed to lift the top up just a bit so that you can unlock to saftey in order for it to go down. The screw i adjusted was a large flathead and had a cap on it. When the top is up, you just have to pull the release and it comes down?

No. You pull the release cable which pulls back the release block. You then push down on the switch (Up lifts, down dropps) which opens a valve and allows the hydraulic fluid back into the resevoir.

It helps to first lift the top a bit to release the cable. Then you pull the cable outward while pushing the switch down.

Thats what i was told, but it wont go up anymore. It wont budge at all

You best check the hydraulic cylinder, see if it looks ok and also look for leaks. Not sure about that screw that you adjusted. If the manual release valve on the pump is open it won't go up. There are a couple different kinds, without knowing which one you have, can't tell you what to do to check it.
A couple pictures of the pump would help.

Im doing all my browsing and posting with my phone and im not sure how to post pics. However, my setup is precisely like the one in the owners manual for the 1977 camper in the manual section on the forum. Ive tried loosening the electric manual release valve, but nothing changes. Thanks for everyones help by the way! It just dawned on me that i havent said that! Thanks again!

HiLo won't go down
 

Welcome to the forum. We love questions -so just ask.

On page 4, item #2 the manual release valve has to be turned all the way in snug for the top to go up when you push the up button, if this valve is open the fluid just by passes and nothing will happen.
You must also have a fully charged battery, the pump is ran by an auto starter motor and takes a lot of amps to run.

Poprichie has the best suggestion, make sure to turn that manual release valve completely clockwise to close it (Item 2 on page 4 of manual). Also you may have a bad solenoid or losing 12v to the lowering valve on the pump. If you Press the down switch and test to see if 12v is on the the lowering valve should tell you if your good there.

If I understand his problem correctly, he can't get the top to raise off the safety bar as he can't pull the cable to release it. The solenoid valve has to work also but first he has to be able to pull the cable to release the safety bar.

Yep, I was being proactive, if the safety is released and then the top still didn't go down it might help knowing the next steps.:D

Is the pump supposed to run when u lower it? Also, if i turn the manual release valve all the way to the left as to release pressure,and pull the safety release, it still does nothing. If the solenoid is bad, could i just use an old Ford solenoid? Thats kinda what it looks like

I found the owners manuals after some snooping! According to the manual, the pump SHOULD run in the 'down' position. Am i reading this right?

Don't know what you are reading but your reading something out of context. Yes, the pump will run when the top is in the down position, it runs to lift the top but it does not run when lowering the top. When the top is up you must run the pump to lift the top a very small amount to get the weight off the safety bar so that you can pull the release cable at the same time. You must pull the safety release cable and hold it in the released position before pushing the down button or turning the hydraulic manual release valve. Doing it backwards puts the full weight of the top on the safety bar and makes it impossible to pull the cable to release the safety bar. It seems that for some reason you are only making things worse. You had best stop changing things. I have nothing left to offer you, sorry.

Post you location and maybe someone with a Hi-Lo may live near you and come help.

Rich is right in describing how the pump works, I used to own an automotive repair shop and I had 6 automotive lifts, 4 were 9000 lb and 2 12000 lb, they work exactly like the system on the Hi-Lo, the pump only works in lifting up position, in the down position all that the pump does is release the hydraulic fluid back to the reservoir tank and the safety lock has to be pulled to get it down, we used to think it was designed that way so you use 2 hands, one on the safety lock and one on the down switch so as one's hand does not get caught in lift arms, or cables resulting in major injury, of course in the hi-lo trailers I don't believe there is a chance of arms get caught in cables. but the concept is identical.