On Apr 9, 2011, at 10:05 PM, Wayne <wmc_st at xxiii.com> wrote:
> On 4/9/2011 8:07 PM, David Scheidt wrote:
>> ....... The reason it's eaten
>> the seal (whether it's an oring or a cup seal) is because the
>> machining sucks. My experience with cheap chinese jacks is that
>> it's
>> the main seal on the piston that fails. It's bigger than what's in
>
> Would something like a brake cylinder hone clean it up well enough
> to work for a while?
>
> I have a Sears 3 ton floor jack that is starting to fail after about
> 18 years. Wish I knew more about fixing the things. The jack
> saddle on the thing is so dang high, it has trouble getting under
> most new cars anyway. But I worry a new low-profile one will just
> expire quickly anyway. Hmmm.
>
A jack thAt's lasted 18 years is probaly just worn seals. These jacks
have an oring or cup seal (sometimes a set), either on piston (most
common, I think) or the bore. The surface w/ the seal doesn't have to
be perfect, because the seal is there. The surface without the seal
needs to be smooth, because it's what the seal rides on. Even with
good machining seals simply wear out. If you can get a kit (and I bet
you can), I'd just look at the bore and replace the seal if the
bore's good. (parts kits usually have the main piston seal, o rings
for the pump and maybe a release valve needle.). So
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