Home Forums General Discussion Technical Questions Sanding piston

I’m getting mixed answers in the field if sanding pistons to solve stuck pistons on take off is good idea. We get a hard release in both directions .. a few guys told me it can cause more bad then good. But jack manufacturer and seal company are saying to sand piston horizontally no more then 45 degree angle. I don’t really get how a piston can basically stick because it’s too smooth. Any body have any thoughts on this ??

From my understanding the small grains of the piston traps oil and that’s what lubricates the seal. If a piston is "Polished" then no oil will get to the seal and cause the packing to stick to the jack. Sand with fine 300 grit (or MFG recommended) in a cross pattern. Just make sure you clean the piston with acidtone after and wipe the head.

I had a car one time that was like that. The manufacturer had made the inside diameter of the head too tight. Causing the packing to squeeze the piston too tightly. That car they replaced the head with one machined to the right tolerances.

Maybe just sand the piston where it will actually be touched by the packing when the cars at a floor. Might get just enough oil to be carried onto the packing without sanding the entire piston. That being said, I've never had to sand one to "fix" anything.

What about putting some Maxglide in the oil (add some to the jack/jacks directly)? I've had good success on cars with sticky packings with it. And if it doesn't work you won't have harmed anything.

I’d check with Gorman to see if they have an oversized packing expressly for this condition. Gorman also has a packing with a teflon ring in one seal for tight packings as well. Is there a possibility the reservoir oil is old? We had a Dover 5” jack that once we wiped the piston down with a solvent it ran fine, but several runs later the hard breakaways and chattering leveling was back. New oil was the answer. I’m no oil expert, but that experience tells me oils can loose their ability to lubricate.

We had an old Dover like that too. You could clean the piston and it would be fine for a week or so. This car ran really hot and we did end up replacing the oil. When we asked around just about every mechanic that takes duty had added soft stop additive over the years and some more than once. Just a theory but I think that was what was leaving the sticky film on the piston. Like there was way too much in there and it was breaking down from the heat.

Is Maxglide different then the soft stop additive. Adams sells a soft stop additive. But I was under the impression Maxglide was different

I've never used the Adam's soft stop additive. Maxton makes Maxglide, especially for stickslip and hard take off conditions. The few cars I've used it on its done its job. I agree with Dirt and elmcannic, if it's an old car the best bet may be replacing the oil. I should've asked, I assumed from how you described the original problem this is a new car so the oil should be new also?

https://maxtonvalve.com/products/index.php?route=product/product&product_id=108

Changed oil and seals And the hard release didn’t go away . Cleaned pistons and added 1 gallon of max glide into jack and one gallon into tank and the hard release disappeared. The piston had noticeable Pattern ingrained into rod so I did no sanding. The cleaning of the piston really changed the look and feel. I think that helped a lot ... and now I am a Maxglide fan. Thanks guys.

A unit I just started servicing seems to have the jack stick slip only in the down. Hard start accompanied with an unpleasant sound. I believe the power unit was replaced in 05. Gets heavy use at a motel.

Considered changing the oil but Maxton tech suggested just adding the additive Maxglide to the old oil. Obviously the quickest cheapest way out. The tank shows grime inside but ill probably do the maxglide 2 gallons and see if that does the trick. That will buy some time then swap the oil later and add maxglide again.

Jluff did you notice more lubrication to the piston after the Maxglide. The piston on this unit feels really dry. Its hard to determine if the cross hatch is polished out or not. I can visually see some grain but also seems polished out.

Alto, I would pull the head off the jack and siphon out a gallon of oil to make room for a gallon of Maxglide, and add a gallon of Maxglide to the tank as well. The stuff does work, but it helps to get it to where it needs to be vs just adding to the tank.