Hydraulic Tip

[hydraulicman]

Cylinders are less complicated than most other types of
hydraulic components and are therefore relatively easy
to repair. As a result, many hydraulic equipment owners
carry out these repairs themselves.

An important step in the repair process that is often skipped
by DIY repairers, is the checking of rod straightness. Bent
rods cause distortion, and ultimatley premature failure, of
the rod seal(s).

Rod straightness should always be checked when a cylinder is
being re-sealed or repaired. This is done by placing the rod on
rollers and measuring the run-out with a dial gauge. The rod
should be as straight as possible, but a run-out of 0.5
millimeters per linear meter of rod is generally considered
acceptable.

[bgott]

The less sophisticated among us can use a flat table top. Lay the rod on it and roll it. You can easily see whether it's straight or if it wobbles. I kept a flat side window out of a van around for stuff like this and for checking cylinder head flatness and sanding flanges flat.

[edt]

Hi Hydraulicman i bent my cylinder on my back hoe last year
replaced it with a new one my question is can i have the bent one straighten to with in 0.5 mill. from a machine shop and use for temp until new one is picked up
thanks EDT

[hydraulicman]

In most cases bent rods can be straightened in press - although rechroming will usually be required afterwards.

If the rod has an "s" bend in it, then its harder to straighten
and may need to be scrapped.

[mrcaptainbob]

For 'a' reason, the swing cylinder shaft got bent on the bh. I turned it 180* on it's pin and swung the bh 'till it straightened out. The second step was to put a stop in place to prevent the overswing. That's been about 2 years ago and much use. I think I got lucky.

[edt]

Thanks hydraulicman i think i will have it straightened and see how it looks
Thank EDT

[dourobob]

Hi mrcaptianbob
How far was the swing on your cadplan digger. I remember you wanted to get it up to about 180 degrees - a little more than the plans called for. Is that what caused the problem or was this before you made any adaptations. My buddy and I are just beginning to assemble the pieces of an 821 digger we have been working on over the winter and I am wondering if we should consider a 'stop' on th swing cylinder.

Douro Bob

[mrcaptainbob]

Unfortunately, I haven't done the 'remodel' yet. We're now in the throws of lookin' for another dwelling, so many of my projects are on hold. I did, however put a stop in place to keep it from bending the shaft again. It happened only when swinging to the right and hitting the center post before the shaft wasw fully extended. Swingin' left is no problem. I lost maybe five degrees.