hyd cyl repair

fendmat · Aug 10, 2022

Hi i have a massey ferg 50A backhoe boom cyl have overhauled all seals but cant get the piston back in with new seals .Do you have to have some sort of ring compressor to fit ,have enclosed old seals on drum and new seals fitted on rod Thanks in advance Ted

LouNY · Aug 10, 2022

I have had luck with very thin shim stock, and I used a ring compressor one time.
I've heard of people using a hose lamp.

Chilliwack Murray · Aug 10, 2022

A hose clamp or ring compressor works but you should put a liner of soft material between the seal and the clamp. I’ve usually cut a strip from an old oil jug to protect the seal. Less important with a ring compressor but personally I’d still do it to avoid a nick on the seal face.

wdchyd · Aug 10, 2022

So, your V packing (chevron) sets are very peticular about stack height. Too much and it squashes out too much, too little and they don’t seal. V packing needs to have just a smidge of correct tension to perform right. Most OEM seal kits with V packing sets have the correct squish up (.50-.100”) Generic seal kits (or piece meal from a hyd shop) have to be tightened just enough, but not too tight (like yours pictured).
At work we mic up the bore and use a similar scrap piece of cylinder barrel stock, we insert the piston loose, then adjust the piston nut (preloctited) to a slam fit (my definition of slam fit is it has to move with the slam of a plastic hammer). Them tap off the scrap barrel stock and immediately insert in cyl barrel.
Viola……..perfect fit.
The way you are trying to do it will only ruin the V pkg set.
BTDT

ROUSTABOUT · Aug 10, 2022

First, it doesn't look oily enough.

Stand barrel on floor and put rod and piston on top of the barrel where it's supposed to go. Wiggle in a circular motion like it your waist spinning a hula hoop. Only about a half inch each way. Piston will drop right in. I've done thousands that way. If you want to squeeze it, use a pipe clamp. Cut a pop can for between clamp and plastic.