Car lift problem

[mike48130]

Interesting.

 

[ovrszd]

Sounded normal the first push. Couldn't tell if it was raising the lift?

Definitely locked up on the second push.

 

[leveled]

Sounded normal the first push. Couldn't tell if it was raising the lift?

Definitely locked up on the second push.

yes it raises from the ground, or when I engage the lowering valve to temporary lower pressure.

 

[ovrszd]

And, I assume, it will lift a load if started with no load???

If so, that would say the pump is fine. And that the motor will run with a load.

If so, the issue is getting the motor to start with a load?

I can't see anyway that's a valve problem or pump problem. Certainly sounds like a motor problem.

Very curious to see the outcome of this problem.

I wonder if the guy that worked on the motor was able to test it under load?

 

[mike48130]

I keep going back to the motor or capacitor. Have you looked around for a used pump? My lift was 3 phase and I bought several used ones from a guy that were cheap, that's how I ended up with a spare motor.

 

[ovrszd]

I keep going back to the motor or capacitor.

Yeah, I think so too Mike.

Really has my curiosity up....

 

[leveled]

I keep going back to the motor or capacitor. Have you looked around for a used pump? My lift was 3 phase and I bought several used ones from a guy that were cheap, that's how I ended up with a spare motor.

We tested the motor and it draws 60 amps when stuck, which we decided that it was not a motor problem, because it is using 6 times the regular working amps. When running it only uses 11 amps. I tested this with a clamp meter. I keep going back to the hose being the problem. I am still waiting on the manufactures opinion. I am really not sure but i learned a lot so far.

 

[ovrszd]

I'm a curious guy. If I thought it was a hose problem I would have came home with a new hose by now. My curiosity would just have to know.

The only reason I won't discredit the hose theory is that I've saw rubber flexible brake lines on cars separate internally and collapse causing the caliper to stay engaged.

 

[leveled]

I'm a curious guy. If I thought it was a hose problem I would have came home with a new hose by now. My curiosity would just have to know.

The only reason I won't discredit the hose theory is that I've saw rubber flexible brake lines on cars separate internally and collapse causing the caliper to stay engaged.

I am getting pretty close to doing that, my set back is not having any response from the lift manufacture. I am probably going to order on discount hydraulics online. Have you guys used them?

 

[ovrszd]

Yeah, I've used them with good results.

Surplus Center is a good one too.

My local Farm/Home store has a good stock of hydraulic hoses in various sizes and lengths.

My local JD dealer builds what you want.

 

[Peter 315]

I think the check valve is not working , Just a guess....

 

[leveled]

Yeah, I've used them with good results.

Surplus Center is a good one too.

My local Farm/Home store has a good stock of hydraulic hoses in various sizes and lengths.

My local JD dealer builds what you want.

my local shop wants 175 bucks for a 12 ft line with two 90's with 37 Jic fittings on it. Its like 60 bucks online.

 

[leveled]

I think the check valve is not working , Just a guess....

I took the check valve out it looks fine, it moves freely.

 

[ovrszd]

Possibly. The check valve is simply a one way valve. Fluid can flow away from the pump but can't flow back. So if it's working the pump has to pressurize and overcome the valve to raise the lift. By starting at the lowered position or with the "down" valve activated he is starting the pump with no load against the check valve and/or in the system.

By starting the pump with load on the check valve the motor has to overcome that load and open the check valve. That's what normally happens when you lift, then stop, then resume. So we know the system is designed to do that.

How could the check valve malfunction so badly that the pump can't push it open and it locks up but with load removed open easily?

 

[Peter 315]

If the valve is staying open then the pressure would be on the pump . I have a small air compressor one day it shut off and would not start motor binding drained the tank it started filled the tank shut off would not start the check valve had crap in it ,When the compressor shuts off it dumps the air out the switch just a little so it will start with no load

 

[leveled]

when the check valve is closed it stops the fluid from being returned, when the release lever is engaged it allows the pressure to open the check valve to return fluid. Common failure to a check valve is the lift drifting down. Same for the lowering valve.

 

[mike48130]

I would put a tee in at the pump out put with a pressure gauge. Then you will know if you have a hose or cylinder or lift issue after the pump.

There is always a chance the pump is worn and binding under load. But the hyd pressure should be on the check valve and not the pump.

What happens when you take the lift to max height while the pump still running? Does the pump still run against the pressure releif?

 

[leveled]

I would put a tee in at the pump out put with a pressure gauge. Then you will know if you have a hose or cylinder or lift issue after the pump.

There is always a chance the pump is worn and binding under load. But the hyd pressure should be on the check valve and not the pump.

What happens when you take the lift to max height while the pump still running? Does the pump still run against the pressure releif?

I do not have pressure gauge, tomorrow I will check the lift at the top. but I am pretty sure it pushes past the relief valve when it maxes out the lift. i think it runs out of power though. I would check it tonight but its 50 mph winds here and my cold blooded Gehl skid steer with its deutz diesel engine is staying warm and preparing to move snow here in 22 degree weather. I will pull off the hose also and blow some air through it, the guy at the local hydro shop said the plastic cheap hoses can collapse internal. I must say i am not impressed with bendpak response time. Thank all you guys for helping out, all your suggestions are appreciated.

 

[ovrszd]

when the check valve is closed it stops the fluid from being returned, when the release lever is engaged it allows the pressure to open the check valve to return fluid. Common failure to a check valve is the lift drifting down. Same for the lowering valve.

Correct.

 

[ovrszd]

What happens when you take the lift to max height while the pump still running? Does the pump still run against the pressure releif?

Mine does.