lift pumps seems weak
 

new here ya'll. Haven't lifted top of 1992 tow light in about a year. Replaced battery because old one was near dead. Pump will only lift top about one 1 inch but motor doesn't seem to strain any different thru entire motion. It comes down pretty fast when lift switch is released. Checked lowering switch at pump and it's only getting 12v when lower/raise switch is in lower. Fluid about 1 inch from top. Question ??? Could the fact my lowering switch is leaking reduce my pump pressure to were it's not providing enough pressure.
Is there a way to remove lowering switch for cleaning or would you recommed replacing with new

Hello stab - welcome!

I'm guessing, from your post that the lift motor does not stop when the top stops lifting? This implies that there is a loss in pressure at that point.

You could have bad seals in the lifting system, or, you might have a leak in the lowering valve as you suggested. Is it possible the valve is not fully closed? Try cycling it manually from full open to full closed. See if that makes it work. I DO think you can replace the lowering valve, but I have no information on this.

- Jack

Thanks Jack... It will hardly lift at all. Motor keeps running and doesn't make the sound as if it's under a lot of resistance as when reaches full height. I do not have the manaul pump option to isolate a weak DC motor etc.... Even swapped out new battery in hopes it was defective. No luck. Removed cable pullys from ram and ram fully extended so guide shaft is not binding. Plan now is to remove ram and install manual pump ram. If it works I have a work around while I'm getting lift system squared away. If it doesn't lift I have a binding upper trailer section. Then it's time to get a bigger ram lol. I wish I had a hydraulic pressure gauge to put in line going to Ram to check pump pressure. Thanks again

stab, you MAY have misunderstood my suggestion. There should be a pressure release valve at the pump. This is what is opened to lower the top when it has been raised. It is normally actuated electrically when you press the lowering switch.

It CAN be stuck in a partially open position, because it has a manual way to be opened too. I don't know how yours works, but the common ways are a lever that is pushed to the rear to lower the top or some kind of knob that you twist. Find that and try to cycle it full open and then full closed.

If that's not the problem, then I suspect your hydraulic seals have degraded, which is a common problem if a hydraulic system is not "exercised" now and then. (I think they sort of "dry out"). I've never had to replace mine, but I believe Treeclimber, another member here, has. if he doesn't notice this thread, you might send him a PM and ask him about it.

A manual lift option would probably not tell you a whole lot. Whatever is causing your top to not lift would stop it from lifting that way too. The fact that the top comes back down as soon as you release the lift switch tells me the system is not holding hydraulic pressure. I don't think anything is "binding".

- Jack

stab, Just caught me. So you disconnected the cable pulleys and the piston extended, yet it wouldn't go up when cables attached. Am I correct so far? As Jack suggested try fully cycling the manual valve open and closed. Try raising, also check the plastic hose returning from the piston end of the cylinder to the pump reservoir. Fresh fluid? If so, then internal seals have failed. Cylinder rebuild. Removal is tricky, but not real difficult. imagination.
By the way, welcome to your new forum!
Tree

Jack I believe your right about the valve or something reducing pressure. Will get inline pressure gauge and verify system reaches 3000 psi as manual specifies. It's that I'm in a time crunch and want to camp out starting Wednesday. I'll get that top up if it takes 10 min of pumping. Have a great weekend my friend!

-Stab

Tree 1st be safe these next few days. You all are awesome with your suggestions. Will check hoes to see if it is leaking thru ram. Thanks

Please be safe in Florida.
 

To all in the path of Dorian we pray for your safety. Wishing all our HiLo friends no ill effects or damage.

Stab; DO NOT adjust your pump to 3000 psi. My manual and other tech info I have on the pump says the pump is capable of producing 3000 psi but HiLo sets the max pressure to 1500 psi. You could do major damage if press is set at 3000 psi. Your problem could be debris stuck under the solenoid lowering valve. This debris can be cleaned out by a process called how to fix top half creep. For a good explanation of this fix, when you open the forum go to search and type in How to fix top half creep. When the thread opens pull down to find the post by Neal and Bev dated 04-04-2016 and you may find one dated 03-04-2010. If this does not work I would be willing to talk to you on the phone to help further.

stab, I must strongly AGREE with Jim. The max TESTING pressure for that CYLINDER is 1 and 1/2 times the working pressure. 1500 psi is the working pressure plus 750 is 2250 psi, that's MAX. My shop tests to 2600 psi. If your fortunate enough to install a gauge, bring the PUMP pressure to no more than 1500 psi. Higher than that and you won't like the results. An internal leak in the lowering (solenoid) valve may also be the problem.
An internal leak in the CYLINDER will show itself in the plastic hose or on the ground.
BTW a 3000 psi leak can CUT flesh, I've seen it!
Tree

mine was doing that ...i took the oil reservoir off the pump and it was full of sludge..the intake tube has a screen on it..it was also plugged...i cleaned everything out and it worked perfect