Shell will not raise. Hydro Cylinder?

[BarkAtTheMoon]

1999 26' Hi-Lo
History:
Had trailer raised, in driveway, for 2 weeks. Went to lower shell and could not get the safety bar to release. After many attempts it finally released but as soon as it did, the shell slowly fell to it's tow-low position on its own. (No pump) it just dropped on its own as if it blew a pump or cylinder seal. At that point it would not raise back up. It would move about 1/4 of an inch, but fell back down. Using the manual pump, it did the same thing. Thought the pump had blown an internal seal because there were no external leaks visible from the cylinder area. Adjusted the pump pressure screw (back-side of pump) to increase pump pressure...no help. Pulled pump and had a Machinist friend test it. It tested fine.
Now, I assume there is a cylinder seal isuue??? I assume this because when I engauge the pump I can see the fluid flowing back through the return tubing into the resevoir. This issue has become too much for my level of mechanical skill. I cannot find ANYONE in the Houston, TX area that will touch this thing. HELP!!!!!!!!

 

[C317414]

Now, I assume there is a cylinder seal isuue??? I assume this because when I engauge the pump I can see the fluid flowing back through the return tubing into the resevoir. This issue has become too much for my level of mechanical skill.

The return tubing attached to the Hi-Lo cylinder is a vent line. Is is OK to see some fluid in it, but not a lot. If you are seeing steady fluid flow in this line when the pump is operating, the cylinder's seals may be bad. Here's a diagram of a single-acting cylinder like the one on our Hi-Lo trailers:
http://www.pirate4x4.com/tech/billavista/PR-Hydro_Steering/images/10-5-6.jpg
Note a couple of things: 1- the Hi-Lo cylinder does not have an internal return spring. The weight of the top forces the piston to return. 2- The Hi-Lo cylinder has a line attached to the vent.

The Hi-Lo pump and cylinder are of the types used on farm machinery, snow plows, etc. A farm machinery place should have people that can troubleshoot and repair the components.

Raul

 

[BarkAtTheMoon]

Thanks for the quick reply, Raul. Unfortunately, the link you provided wont pull-up. "HTTP 403 Forbidden" So I am unable to view the diagram. That would be very helpful.

 

[C317414]

Thanks for the quick reply, Raul. Unfortunately, the link you provided wont pull-up. "HTTP 403 Forbidden" So I am unable to view the diagram. That would be very helpful.

Interesting, I just clicked on the link and it worked fine.

 

[C317414]

See if this works. It's a link to a totally different diagram. It shows the complete system, similar to that installed in a Hi-Lo. The blue line coming from the cylinder to the reservoir is the vent line.

http://www.mech.uq.edu.au/courses/metr3100_2005/hydraulics/s7_f03.gif

 

[RCREYES]

Interesting, I just clicked on the link and it worked fine.

Didn't work for me either, Raul.

 

[C317414]

Didn't work for me either, Raul.

Did you try the second one that I posted? Did that one work?

 

[BarkAtTheMoon]

Did you try the second one that I posted? Did that one work?

Yes, that 2nd link worked. Thanks. I think I understand how the cylinder works. If I'm seeing fluid flow back to the resevoir thru the vent line then I probably have a seal leak inside the cylinder. Can anyone refer me to someone who can do the cylinder rebuild/replacement near Houston, TX? Also, is Midget R/V the only place to find the OEM Hydro Cylinder, found here for $499.34: Hydro Cylinder - Midget RV & HiLo Service & Parts

 

[JIM L-HILO]

Any tractor repair shop can put in new seals. This is a very easy repair and reasonable cost. No reason to replace. The biggest part of the job is removing and reinstalling the cylinder. If a shop does not want to do the job ask them for the name of a good hydraulic repair shop. There would be many in your area because of the oil industry, an aircraft industry also.

 

[C317414]

Yes, that 2nd link worked. Thanks. I think I understand how the cylinder works. If I'm seeing fluid flow back to the resevoir thru the vent line then I probably have a seal leak inside the cylinder. Can anyone refer me to someone who can do the cylinder rebuild/replacement near Houston, TX? Also, is Midget R/V the only place to find the OEM Hydro Cylinder, found here for $499.34: Hydro Cylinder - Midget RV & HiLo Service & Parts

This is a pretty standard cylinder. You should be able to get it fixed or find a less expensive replacement locally. I just googled "Houston, TX hydraulic" and a number of places came up; try that.

Check this thread: http://www.hilotrailerforum.com/f22/cylinder-removal-repair-replacement-part-i-528/

 

[RCREYES]

Did you try the second one that I posted? Did that one work?

2nd one worked!

 

[BarkAtTheMoon]

Good News! I was able to find Williams Hydraulic & Machine in Dickinson, TX. They had no fear of this job, even though they had never seen this type of hydraulic set-up. They took good care of me and got my Hi-Lo back on the road. They had to cut the slide-bar out to get the cylinder removed for re-seal work, but that ended up working to my advantage. When they reinstalled a new rod, they drilled a port-hole through the frame, on the door side of the camper, slid the rod through and secured it. They also installed a port-hole cover plate, so if I ever need to access the rod again I can just remove the plate and slide the rod out through the port-hole. Awesome!
The total price for parts and labor? $345. That's a number I could handle given the task at hand. Very reasonable. Williams Hydraulics (281-534-6100) earned my business. If you ever need a shop you can trust, I highly recommend these guys!