Michelin jack won't lift a load

[10WSmuckers]

Hi all. I have a 3 1/2 ton Michelin floor jack that has the quick lift feature but it has now rendered itself useless. It will raise and lower itself without any weight on it but anything like a car is out of the question. It will just stay under the car and squeak loudly with every pump. There are 3 screws behind the pump cylinder and I don't want to risk adding more air into what I suspect isn't the oil fill plug. In fact they say "DO NOT ADJUST" around these 3 plugs and this isn't something I want to mess up completely. How can I bleed the air out thoroughly?

 

[Ducked]

It IS messed up completely. It doesn't work.

How do you imagine you are going to make that worse?

 

[wdn]

Good reason why top brands should never license their brand name to put on other random stuff that is not made by them. I hope my Kubota shop vac holds up.

 

[eljefino]

Take it all apart and look for shot o-rings.

 

[spasm3]

Originally Posted by eljefino
Take it all apart and look for shot o-rings.



You have nothing to lose by doing this. Its shot either way.

I'd watch this and give it a try.

 

[jkasch]

If you haven't yet, try this first.

Bleeding
1. Remove the Cover Plate.
2. Loosen the Fill Screw.
3. Turn the Handle counterclockwise to open the Release Valve.
4. Pump the Handle up and down quickly several times to purge air from the system.
5. Check oil level and add as explained below, if needed.
6. Tighten the Fill Screw and replace the Cover Plate.

 

[CT8]

How old is the jack?

 

[Trav]

I would even try to fix it, its a cheap Chinese jack with a brand name from a company that doesn't even make jacks. Return it of toss it IMHO.
Jacks can be dangerous if they fail. If it were a good brand I would have the cylinder serviced by the company.

 

[funflyer]

Originally Posted by Trav
I would even try to fix it, its a cheap Chinese jack with a brand name from a company that doesn't even make jacks. Return it of toss it IMHO.
Jacks can be dangerous if they fail. If it were a good brand I would have the cylinder serviced by the company.


China can copy and produce hard parts pretty well, it's the rubber compounds they have trouble with. I bought a cheap Chinese jack back in the 80s and within the first year it started to fail/leak, not surprising. So, being an aircraft mechanic, I headed over to see my friend in the hydraulics shop. He fixed me up with new o-rings, seals and backups and that jack is still going strong today. Now, do I trust my life with it? Heck no! I never crawl under a vehicle without jack stands in place and the weight relieved from the jack.