Leaky Lift Cylinder Bolt

[bmarshall1]

Hey All, I have an odd problem here. I have an older Ben Pearson LAS 7 (lift cable on the floor type).

Used consistently, it has very little fluid leakage, after sitting for a month, there was a LOT of fluid on the floor upon the first use and actually squirted across the floor to the wall, which really puzzled me.

I have come to determine that after sitting, the pistons or fluid settle down in the cylinders and upon pushing the 'lift' button, it runs for a moment until the cylinders fill back up (the pistons aren't rising yet, no load on them).

While this refill/no load situation is going on, I discovered fluid literally squirting out of a bolt at the upper end of the cylinder. ( had assumed it was a air bleed screw/bolt). I removed the bolt and it is drilled out to allow fluid to pass through (I don't understand this). Maybe it is a air bleeding bolt, but why the hole and why the fluid coming out? Maybe upon developing pressure there is an internal valve or the piston covers the port on the bolt?

I am considering replacing this 'holey' bolt with a solid bolt but I assume it is the way it is for a reason. Any thoughts?

 

[575cat]

Its a vent cylinder is bypassing need to replace cylinder .

 

[bmarshall1]

@575cat - I'm not sure I understand. Does that mean I have a bad cylinder and this is fluid that is leaking past the internal seals and is venting?

I assume replacing the bolt w/ the hole w/ a solid bolt is not advised.

Would a rebuild help.

Short of a rebuild, is there any way to eliminate this (store the car in the lowest position eliminating the pressure on the lift?).

Now that I know what is going on I can work around it, but I would like to have it working properly if possible.

 

[575cat]

yes bad seals , cylinders are not rebuildable , keep it on the locks to relieve load it will probably still bleed by .

 

[CJseven]

It’s a single acting cylinder, fluid is bypassing the piston seal and leaking into the vented side of the cylinder and out the vent plug.

 

[CJseven]

Here is a parts list for that lift.

 

[bmarshall1]

OK All, thanks for the replies, this all makes sense. I always leave it on the locks, I may try an experiment and leave it just off of the locks ( 1/8-1/4 inch) and see if the pressure pushes out against the seal and makes it more effective.

@575cat - what makes these particular cylinders un-rebuildable? Aren't people rebuilding their cylinders all the time?

 

[bmarshall1]

I just checked with AEPN and found rebuild kits for $40. I watched a video as well and it doesn't seem overly difficult. Having said that, I know a fellow who had his rebuilt for @ $75 and that would be well worth it for me.

 

[575cat]

Thats what Bend pack said , now I see your,s is Ben pearson so maybe . When I pulled mine apart you could see the bad bore .I have another one hear that weeps real slow .

 

[nadogail]

It is apparent that hydraulic fluid is leaking past the piston seals. How to replace those seals will depend on how easy it is to open the cylinder and access those seals. If you have tie rod cylinders, or threaded end caps the access should be only routinely difficult. If you have welded cylinders disassembly and reassembly will be significantly more difficult.

A hydraulic shop can advise you.

 

[bmarshall1]

@nadagail - they are quite dirty at the caps, but it appears there is a threaded cap that has (2) set screws going thru side of the cap into the cylinder. Also, I see a wiper/seal for the piston. So... my guess is that once the cap is unscrewed, the wiper seal can be pried out and below that is a "C" clip holding the piston in place. I believe I'll take it to a rebuild place, I *think I have 2 different cylinders as one is yellow and one is blue. my buddy did his for $75 each, for that I'm not messing with it!

 

[brownbagg]

you say one is yellow, one is blue, that how they tell which o ring kits, but where are the colors, I never found them

 

[nadogail]

@nadagail - they are quite dirty at the caps, but it appears there is a threaded cap that has (2) set screws going thru side of the cap into the cylinder. Also, I see a wiper/seal for the piston. So... my guess is that once the cap is unscrewed, the wiper seal can be pried out and below that is a "C" clip holding the piston in place. I believe I'll take it to a rebuild place, I *think I have 2 different cylinders as one is yellow and one is blue. my buddy did his for $75 each, for that I'm not messing with it!

IMHO, A Hydraulic Shop would be a good bet, I will PM you with the name and phone number of the shop I worked for 21+ years ago.

 

[bmarshall1]

@brownbagg - sorry for the confusion. One of the cylinders is blue, the other yellow. I can't see any reason they would have come from the factory like that so my assumption is that one has been replaced.

 

[nadogail]

IMHO, A Hydraulic Shop would be a good bet, I will PM you with the name and phone number of the shop I worked for 21+ years ago.

PM Sent, if you did not find it, PM me with a number and I can call you on the phone.

 

[bmarshall1]

@nadagail - thanks, I received the info you had sent.

Well... yesterday was a disappointing day. I went to work in the car a bit and spent more time working on the lift. What used to be a small amount of leakage turned out to now be stream of fluid shooting out. Since the bolts in the upper portion of the cylinder are hollow, I decided to take them out and simply run a hose to a catch can. Well one cylinder quickly overfilled my catch can and went all over the floor, as did the other to a small degree. I finally ended up running the hose to my oil change pan and quickly filled up 2 gallons. So- now i have a car 6 feet in the air and a lift that won't lift. At this time I will have to leave the car as-is and remove the cylinders to be rebuilt. UGH - what a pain!

 

[Jswain]

Sometimes its a blessing to have a complete failure like that rather than just a small leak that you decide to trust until the inevitable happens.

Now you've got no choice but to fix the problem. Leaking that much oil it will pay itself off in oil in a few uses lol