LAC - harbor freight hydraulic jack

Ben Swann benswann at
Mon Apr 23 20:54:03 EDT 2007

Well sounds like some of what I said is true, but not a good idea to fill
through the check valve port.


Based on what I understand reading this is - you have a defective jack.
Return it and don't waste your time trying to fix it.  Harbor Freight has a
good return policy and they may even do an exhange at the local store.  





From: thejimrose [mailto:thejimrose at] 
Sent: Monday, April 23, 2007 6:03 PM
To: Ben Swann
Cc: quattro at; gtq at
Subject: Re: LAC - harbor freight hydraulic jack


Thanks Ben I'll give that a try. I also found this out there on ye olde web:

it's really amazing what's out there... 

On 4/23/07, Ben Swann <benswann at> wrote:

The instructions, if any have surely been deep-sixed or in stashed  some


Usually when I have bled jacks - and they are mostly the same this is what I
do.  Probably having an assistant help would be good.


Hold the bottle spout just above the fill port.  Have assistant slowly lift
the jack arm which will draw in fluid.  As the fluid level goes down, add
fluid.  When fully extended,  close the fill port.


The bleed port is to let out any XS air.  You may want to use this first.  DO
NOT pump jack with this open.  Instead lift jack to highest point with the
lever.  Springy when you push on it?  If so - you have air.  Now here is the
somewhat tricky part.  You need to hold the jack with the bleed port up in the
air - tilt jack and rest in vertical position.  


Now, slightly open the bleeder and press down on the lift arm and expel any
air - you don't want to let the fluid out any more than necessary.  If air
comes out, see if this has fixed the problem.  You may need to repeat the
process.  You may even need to add fluid and sometimes the bleed plug can be
taken out allowing to fill through it - I think this is better than using the
fill port, which probably is used only when adding fluid the first time.


Keep expelling air until all you get is fluid and jack get to highest travel
point by adding fluid - essentially sucking it in through the bleed port as
applicable.  If this does not work, then there may be a problem with the jack
- usually a bad O-Ring seal or piston seal.  This should not be happening on a
new jack.  Probably got a little air in being shipped all the way from China -
gotta love Harbor Freight, as you sometimes get some pretty good stuff for the
$, but you takes your chances.


This all came from me experimenting and I never read any instructions, so
there may be a better or more proper way.  I'd be happy for someone to set us
straight if the above is not correct, because I have never seen any
instructions on how to do this.  Just my daddy showing me how to fill a bottle
jack when I was really to young to understand what was going on.







From: thejimrose [mailto:thejimrose at] 
Sent: Monday, April 23, 2007 3:35 PM
To: Ben Swann
Subject: Re: lac - harbor freight hydraulic jack


thanks Ben. I'm hoping it just needs a bleed, it's how to bleed it that has me
baffled. have you read your instructions? they're pretty bad. 

On 4/23/07, Ben Swann <benswann at> wrote:

I just used mine without doing anything to it - no problems - works great.  I
wish everything worked like that.

It does sound like yours may need bleeding, but should not have come that way.


[Date: Mon, 23 Apr 2007 10:24:55 -0700

From: thejimrose <thejimrose at  <mailto:thejimrose at> >

Subject: lac - harbor freight hydraulic jack

To: "Quattro List" <quattro at  <mailto:quattro at> >

Message-ID:< 298352bd0704231024k3f38d3d6rd34b8edafecfdd4d at
<mailto:298352bd0704231024k3f38d3d6rd34b8edafecfdd4d at> >

Content-Type: text/plain; charset=ISO-8859-1; format=flowed

anyone have any experience with the HF jacks? i bought their 'rapid pump'

aluminum racing jack:

and can't seem to get it to work properly. it has limited hydraulic effect,
won't extend to max saddle height [14 vs 17"], etc. i think because the
instructions to bleed it are very poorly written or translated.

it seems to be pretty well made, and i don't want to deal w/ returning it.



God was invented to explain mystery.

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