Lull 644B owners- Whats normal - whats not

[Roadoil]

Someone on a hydraulic cylinder repair facebook group I am in sent me this - which I found helpful.

The 51790 part number lead me to this place -

51790 from HUSCO - SEAL KIT

www.ironwingsales.com

They have the seal kit for 16 dollars. Hopefully its correct. I ordered it, but will be out of town for a bit.

Will report back if it is the right kit.



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It's prob a Husco 4545B like in mine.

But maybe the seal kit will work.

 

[Roadoil]

We have a hydraulic sales rep at the plant I work in. I shot him an email this morning asking for some advice. He also suggested Hercules and pointed me to a few seals I can try. I need to measure it and see what they have that might work. I'll report back in case it helps someone else. He also thought I can likely buy a $60 1800 PSI valve and put my spring in it. Like I told him, often there is some off the shelf solution for these old/obsolete/over priced parts - but sometimes its hard to get there without specific knowledge and experience.

Yes usually off the shelf parts such as Sun valves but I found on my 844C some were proprietary made for Lull by various companies I think one was out if business.

But these are common components for mechanical hydraulic systems and I am sure someone with knowledge could get a modern part in other brands that's the same.

 

[Andy1845c]

It's prob a Husco 4545B like in mine.

But maybe the seal kit will work.

Mine clearly has 5060 stamped into the side of it. The 4545 does look similar in the pictures online though.

 

[Roadoil]

Ok

 

[Roadoil]

Is the 5060 what's spec'd for your machine ?

I have seen some hackery with sun valves that fit and look identical to what's supposed to be in equipment but totally different valve messing up the functions.

Here is the 4545B old one I replaced.

 

[Andy1845c]

Update - I got the seal kit. Installed it tonight and now I can set the pressure for pump 2. Once I got this set the frame leveling and the fork curl work properly!

Does anyone know how to address low steering pressure? The manual tells me what it should be but fails to suggest causes and solutions.

 

[Andy1845c]

Getting to the end of my list of issues on this machine, but this one is odd - The boom hoist circuit is weak in the UP direction - at idle I am getting around 1000PSI at test port 1. At full throttle I get somewhere around 2800. It struggles to lift the boom at idle with the forks on.
If I bottom the hoist cylinders DOWN at idle I hit almost 3000 PSI.

Kind of at a loss. I get 3000PSI if I bottom the boom telescope IN too.

Is there a possibility the spool is worn or something? Anyone ever seen this?