4 post auto lift hydraulic cylinder noise

madmaxx · #1 (**permalink**) 03-12-2009, 05:49 PM

If you have a 4 post lift and you get a vibration, noise, squeal when you raise your lift or lower it very slowly the solution may very well be catapiller hydraculic cylinder anit-chatter additive. I would start with a 1/4 quart for a 4 to 5 quart system.

I also strongly suggest you bolt to the ground. I found a video where a guy was raising a vehicle and the front pulley bolt fell off, pulley slid back, cable popped out and the car fell forward and to the right bending the front post out. The car was left in a very precarious position. If it would have been bolted the mechanical stops would have caught it. The lift had been in service for 8 years and a simple inspection would have found the loose bolt and prevented the whole scenerio IF it would have been inspected on a regular basis. I noticed the bolts on mine have little tach welds. Just a heads up.

Bobcat · #2 (**permalink**) 03-12-2009, 07:08 PM

One of the Divisions I used to work for made single acting hydraulic rams ... which these lift cylinders are . The chattering/squealing is caused by the seals grabbing the rod tightly , then breaking loose , grabbing etc . This happens very quickly , and normally under light loads . As the load increases , the system pressure required to move the load also increases , which reduces or eliminates the problem . If the seal material was changed or the seal squeeze/preload reduced , this would eliminate it .... the anti chatter additive also works as it reduces the friction between the rod and the seal . Rod surface finish also has an effect on this . I`ve seen it so bad on some presses that you could hear it from 30 yards away in a factory and feel the floor vibrate from about 6 feet away .

madmaxx · #3 (**permalink**) 03-13-2009, 07:27 PM

Bobcat,

The difference was nothing less than incredible, the smallest quantity CAT sell is 1 quart. I put 4 oz in my 3 gal reservoir and within two cycles the noise, vibration was complety gone. I have tested for the last couple of weeks and I am pretty sure the problem is solved. Funny thing is CAT appears to be the only company which makes such a product so it is kind of a pain to find. I am tempted to put teaspoon in my floor jack reservoir and a couple onces in my lift pump for my boat outdrive cylinders.

Interstingly enough at work we have a couple very very large catalyst cylinders which exhibt similiar behaviour. We have been fighting for years, once I check compatibiilty of the system I may very well test there. The sytem at work is about 100 gallons and a quart of the additive is $28 bucks but one day of lost production is $300K so it is well worth the try if it will even extend a rebuild a couple weeks.

Bobcat · #4 (**permalink**) 03-14-2009, 07:58 AM

Cat also makes most of their hydraulic cylinders .... and their specs and quality are among the highest in the industry ( I used to be in Parker`s Mobile Hydraulics Group ) .They are also very tight on their seal standards and cylinder rod finish .... their rod surface finishes used to be less than 8 microns .... which is extremely smooth . One possible side effect of this is that you can get some squeal due to the interaction between the seals and rod under some conditions , ( the rod surface can be wiped so dry that there is virtually no oil film between the seal and rod ) ,which is probably why they have this additive . Yes , it works and works very well .
You`re going at it the correct way by checking compatibility of the additive with your existing hydraulic fluid ... which is something 99% of the people out there don`t do . I used to see everything from STP to ??? dumped into systems with no regard for what it would do to the fluid , pump seals , wearplates , valve seals , temperature ratings , hose etc .
BTW , you might check with Cat and also see what they say .
Good luck ... hope it works out for you at work .

madmaxx · #5 (**permalink**) 03-14-2009, 06:09 PM

Thanks Bob, I work in a petrochemical plant and it always bewilders me why more people do not get killed or harmed around the house. In my line of work we have 5 or 6 safeguards and all have to fail at the same time for an incident to occur. Yes at times all the holes in the circle line up and accidents happen. Sad but true most of our safety sytems and procedures are written in blood.

Case in point, I decide to look over my 4 post lift for a squeal noise. Since I put the additive in it is so quite the smallest sounds annoys me. I find one of the shafts which supports a pulley on one side and the mechanical latch on the other is missing a set screw allowing the shaft to turn in the cross member. No big dea, Wrong, if the shaft would have pulled out either the cable and pulley would have fallen off, while lifting, i have seen a photo of that mess or the mechaical arm would have fallen off, once again big mess.

I really do not think 4 post lifts are for everyone, if you do not fully understand the mechanics of the lift, serious injury and likely death will occur.