Trango

The use of slime to solve pinhole leaks...seems to work. I had a whole fantastic post put together earlier today during an idle 20 minutes, but tabbed browsing outsmarted me and I lost it all.

Last night, I shot some slime in an airbag. Based on some known physical qualities of slime (namely, the platelet-like action to cure leaks in tires), as well as little imagined possibility of damage to the shock assembly (aside from, perhaps, the hard chromed rod of the shock piston), I figured that Slime tire sealant would be a good way to add some life to a failing airbag (which currently has been draining out in a matter of hours).


I used a DOA takeoff airspring to perfect the technique, and then disconnected the airline and shot some slime into the bag. When you introduce Slime into the bag, you are trying to hit the circular "shelf" where the airbag folds over itself. If you shoot it in the middle of the assembly (center of the axis), it looks like it's just going to sit on the top of the shock, which is undesirable.

To get the slime in, I put the vehicle in jack mode, lifted the chassis, disconnected the airline, and slowly dribbled slime in (hoping it would stick to the walls of the airbag, and slide down to that shelf).

After I shot the slime in there, I used shop air and a blowgun to pressurize the airbag through the air port (and let it drain out) to make sure I wouldn't get any blockages.

Once the vehicle was lowered, I drove it up onto some wheel ramps to work on some other stuff (oil change, scope a placement for a wideband sensor, a nagging boost leak I finally found, etc). Right after putting it up on ramps, I inspected the airspring, and I saw where the leak was, which manifested itself as a small dot of green crud, say, the size of a 20-24ga wire. The green stuff was, of course, the slime. Around the dot was a small area of wetness, which presumably was the glycol carrier in the slime.

After doing all of the other tomfoolery I had planned for the vehicle, I looked back at the airspring, and it displayed no change.

For right now, it looks to have stopped the leak, and I have about 12 miles on the setup. This is Boulder, so that's 3 trips in the car.

Oh yeah, in retrospect, here is how I would have installed the Slime:
I would have taken an acutely crooked straw (similar that seen on to an irrigator bottle, if anyone's familiar with this piece of medical hardware), disco'ed the airspring airline, pulled the bottom of the airspring from the shock, and squirted the slime around this "shelf", and then letting the surplus drip out.

So, I learned some stuff. I expect to take it apart later this week and learn more, and I'll post up afterwards. But, in the meantime, this is how far I've gotten. I'm now on 20 hours of not-sagging, which is pretty phenomenal considering how bad this spring had
gotten.

Off to the weekend - my third to last day in the office this year is now over.

Sarge

There are many, many types of chemical 'dressings' out there that feed and protect various types of plastic materials, some of which actually insinuate themselves into the chemistry of the material to help keep it pliable, and thus prevent drying, rotting and cracking (i.e. leaking).

Just curious if anyone knows of anything that might be advisable? (and I'm not talking about armor all)

Trango

...would be to create an "outer" skin that the airspring would move within, sort of like the fascia for a muscle that stretches along with the airbag. So, maybe something articulated? It would have to be something that basically kept the grit away from the bag.

So, maybe something articulated, that had cinture above and below the bottom of the airbag, which is where the extension, debris entrapment, and ultimately, leaks all take place.

Well, aren't I just pulling out the medical terminology here.

powderlvr

I've too thought that debris, caught in the fold of the airspring, might be the source of pinholes.

Would it be conceivable to produce some sort of protective cover? One could simply lube up the clean air bladder to keep it from oxidizing, then cover it to keep debris out.

Also, instead of Slime, has anyone considered patching their pinholes using something like a bike tube repair patch, etc?

-Josh

grey-2002-ar-6sp

... keeps everything nice and snug once the tube is pressurized.

I do like the protective cover idea.

ryry

You beat me to it! Can't wait to hear how it holds up.

hockeypuck

You are not worried about the slime back feeding in to your valve assembly?

Trango

...first off, the slime would have to jump back through the airline port. I'd say that there are better odds for an earthquake causing a quarter to jump back out of a payphone coin slot.

Second off, if the slime does make it to the air hole, it will likely clog it first.

Some of that is wishful thinking (anything can happen), but if you look at the layout of the components, probability is low.

hockeypuck

what was the specific brand used?

hockeypuck

of their allroad running to the auto parts store and stuffing their leaking bags with slime. Oh boy.