Renovating a hydraulic cylinder

   / Renovating a hydraulic cylinder #1  

Volp

Silver Member
Joined
Jun 14, 2002
Messages
110
Location
Stockholm and Raskarum, SWEDEN and Porreres Mallor
Tractor
Massey Fergussom MF35, Kubota B6001, JD LX186 Lawn tractor. Ford Super Dexta 3000
With this posting I would like to share my experiences renovating a hydraulic cylinder and maybe learn a better way of doing it!
The problem started when my backhoe stopped swinging. I examined the swing cylinders and discovered that the piston rod no longer was connected to the piston! The reason for this could be that the cylinder support was loose due to a defective weld. I removed the cylinder expecting that a replacement was necessary but decided to first try to renovate it myself.
The first problem was to remove the piston. After unscrewing the cylinder end I managed to screw back the piston a few turns (the threads were damaged) and then attach a chain hoist to the rod end and draw out the piston. I don’t have the tools for rethreading so I used a “Dremel” type tool with a small cutoff wheel to clear up the threads. The rod could then be screwed back in the piston and secured with a new spring pin.
But first I replaced the old piston packing with a new.
Second problem: How to pass the rod through the cylinder end without damaging the new packing on the sharp edge before the threads at the end of the rod. The solution was “gaffa tape” (gaffa tape can mend everything except a broken heart or bad haircut) tightly wound and greased.
Replacing the piston seals was easy, just noting the positions of the old seals an replace them with the new.
Third problem: how to insert the piston in the cylinder without damaging the seals on the inside threads at the end of the cylinder. Thinking of a piston ring compressor I cut out a piece of brass plate 0.5-millimeter thick covering the threads then placed on the inside of the cylinder. With a rubber hammer I then drove the piston down into the cylinder. Screwed on the cylinder end after replacing the O-ring.
I tried to do most of this on a clean sheet to avoid contamination.
After reinforcing the cylinder mounts I mounted the cylinder and it worked!! Saved myself the cost of a new cylinder.
Any suggestions as to what I did wrong or could have done in an easier way?
 
   / Renovating a hydraulic cylinder #2  
Sounds like you did a great job, hopefully the end results were good /w3tcompact/icons/grin.gif. An inexpensive (and very helpful) tool is to get what is known as a "thread file", it is available in both SAE and metric pitches, it sure would be a lot less nerve racking than using a dremel /w3tcompact/icons/eyes.gif
 
   / Renovating a hydraulic cylinder #3  
Ditto on the thread file. You won't use it often but the first time you fix a buggered up thread with a few strokes of a thread repair file you will wonder how you managed to live this long without one in your file drawer.

<A target="_blank" HREF=http://www.cornerhardware.com/hardware/iteminfo.html?action=iteminfo&item=038728312365&cat_id=554>Here is a picture of one.</A>
 
   / Renovating a hydraulic cylinder
  • Thread Starter
#4  
Thanks for the input!
I will try to find a "thread file" but will it renovate inside threads?

traktor2.jpg

<font color=red>Anders</font color=red>
 
   / Renovating a hydraulic cylinder #5  
Anders
<font color=blue>but will it renovate inside threads?</font color=blue>

A thread file will only repair external threads. Repairing inside threads would require a tap. Northern Tool has a thread repair kit. That uses a nut type tool for the external threads and a tap for internal threads. to view this kit. If the internal threads were badly damaged a coil insert could in installed. <A target="_blank" HREF=http://www.emhart.com/products/helicoil.html>Click Here for an illustration of these inserts.
 
   / Renovating a hydraulic cylinder #6  
<font color=blue>(gaffa tape can mend everything except a broken heart or bad haircut)</font color=blue>

I'd give the gaffa tafe a crack at a bad hairdo I reckon /w3tcompact/icons/laugh.gif

Welcome to TBN Volp.

Us non-US members are few and far between.

Thanks for helping "Keep the Balance of the Force"

Cheers
 
   / Renovating a hydraulic cylinder
  • Thread Starter
#7  
Neil
Thanks for the greetings from "the other side"!
Nice signature! /w3tcompact/icons/wink.gif
 
   / Renovating a hydraulic cylinder #8  
Anders

Your sig is 100% better than mine.

Know why??


Cause you made yours. I had to get help frim MikePA to make mine. (Well if you can call uploading all his hard work help /w3tcompact/icons/laugh.gif)

Cheers
 
   / Renovating a hydraulic cylinder #9  
Hi Volp,

Congrats on your hydraulic reapir. You must of done it right, giving the way hydraulic systems delight in drenching you with fluid if you don't treat'em with respect.

Just popped into this thread with some info on the thread file question. They're a little hard to find, but you can get thread files that restore internal threads. Here is one company that handles them. They have a catalogue online. I can't post a link to the specific page where thread files are listed but if you go to thread restoring tools under the machining catagory you'll see them.
http://www.mcmaster.com/

HTH,
Dave Perry aka karmakanic
 
   / Renovating a hydraulic cylinder
  • Thread Starter
#10  
The McMaster-Carr company (http:// www.mcmaster.com )realy seems to have every conceivable tool for renovating threads both external and internal.
Thanks for pointing to this source for tools!
 
 
Top