I’ve got a 45’ Eagle towable manlift and bottom boom is leaking down.

[Puppypunter]

Like I said before, I didn’t see this post until I thought I fixed it, once I realized it was still doing the same thing I decided to buy the valves, that is all we had really discussed up to that point. It’s ok though I just appreciate the Help, and if that means I wasted 250 dollars it’s not the end of the world, however I don’t want to waste anymore money, so based on my results it’s bypassing, which means I need to have the cylinder rebuilt, correct?

I quick way to find out if it’s the counterbalance valve or the piston seals…..raise the unit up off the frame, get it into the creep down mode, turn off the engine, then immediately support the structure with another piece of equipment just off the truck frame, remove the two cylinder hoses, then lower the support equipment. If the valves are compromised oil will leak out from one or more fittings at the cylinder base at the rate of descent. If no oil leaks out of fittings and still creeping then the piston seals in the cyl are bypassing.

 

[oldnslo]

Hey guys I appreciate all your help and I’m sorry if you feel your repeating yourselves, however I must have not have seen the leak down test before deciding in buying the valves, in post 22 I specifically asked what can I do to test it to isolate the problem, I didn’t see the leak down test until after I decided to buy the valves.

Si today I had a forklift hold the boom, turned off the engine and disconnected both hoses, the boom leaked down just as fast as he let it down with no oil coming from the ports whatsoever, does this mean it’s leaking internally? We did this with the new valves in, I didn’t have the old ones on me at the time and after reading oldinslo said that it should be adjusted to 3000 new and that should be close enough to 2500, we went ahead and tested it. My buddy asked could it be something to do with the pump, however it lifts and holds the top boom just fine. Again it’s not leaking externally and not a drop of oil came out when he set it down.

Thanks again for all your help

when you performed the leak test was the load extending the cylinder? If yes then yes it can leak internally without any oil leaving the cylinder out the hoses.

Reason for this is difference in oil volume since cylinder rod takes volume the blind or cap end can absorb all the rod end volume so no external leak is required.

 

[Puppypunter]

Yes it was extending the cylinder, so you’re saying because the rod is running through there it takes less oil to extend it as opposed to the other side which is just the top of the piston? So This would clearly make really all cylinders more powerful on kne side and faster and less powerful on the other? I’ve never really thought about that.

Ok one last question, because this company doesn’t sell parts anymore how would I measure (mic) it to order new seals? Is there a way I could do this before taking it apart, so I would have everything I need to do it all in one day?

I’ve actually got the spanner wrench and the inner seal installing tool (idk what they’re called) to do this myself. As I stated earlier there isn’t a good hydraulic shop within really 90 miles from me.

I’m just hoping the cylinder isn’t scored, as I stated earlier when I got this machine the oil was in bad shape, and it took me about 4 oil changes to get all the water and crap out of it. But this was probably 80 hours ago that I finally got it clean and dry snd stayed that way.

Again I really appreciate all of you in helping with this, this is the first hydraulic forum I’ve found with active members helping the community. I hope this thread can help a newbie in the future.

 

[oldnslo]

Puppy
I know of no method to verify seal style or size without dismantling the cylinder. Anything I would suggest would just be guess for diameter and there are multiple types of seals that could have been used so without parts diagram apart is the only way I know.

 

[wdchyd]

Don’t guess what the seals will be, strip it down and send them UPS to a hyd shop to match.
If you had water in oil and the lift has been idle for a spell don’t forget to inspect for water damage as the oil and water will separate and rust the barrel from the inside from the water. If you notice any pitting get that barrel honed and reinspected for corrosion damage.
Where are you located?

 

[Puppypunter]

I’m in Carlsbad New Mexico, right square dab in the middle of the Permian basin. Where at any one time there are approx 300 oil rigs running along with everything that goes with it. Along with 4 potash mines and the governments Waste Isolation Pilot Plant (WIPP) that’s basically another potash mine that they’re putting low level nuclear waste into because the salt is suppose to i capsulate it.

It’s really just astonishing we don’t even have a proper parts house much less a hydraulic shop. U think we would with 65,000 ppl here. But we don’t anymore. A guy told me today when i was running around town looking for a company I could potentially get a kit from said there’s one in artesia which is about 30 miles away.

So what is the best way to go about this? Im pulling it apart myself, should I just take pictures of it and post them on here? And what do I measure to get the right kit? Is there a sticky for this already somewhere? I will certainly make sure it’s not pitted because that’s precisely what im worried about. Thanks again guys.,

 

[oldnslo]

Puppy
Like wdchyd states you almost need to take all of the seal components with you to a hydraulic shop.

If just simple O-rings they are sized by ID and cross section (thickness).

If U cup or V cup style seal I am not certain how they are sized.

I live by a town of 150,000 people and no hydraulic repair shop anywhere around so feel your pain.

 

[davedj1]

If you are confident in taking the cylinder apart, take note of where the seals are along with wipers, O ring, glands etc, take them to the hydraulic shop and they will match them up. Don't forget there is one inside the piston so removing the big nut will be required. There will be seals, backers and make sure to note which way the cup points on the seals. If you establish a relationship with the hydraulic shop they may just rebuild if for you if you bring it to them while you wait.
Best of luck,
Dave