Shop Press

Shop Press is the news and idea hub for everything related to working on cars and trucks, focusing on repair, technology, and wrenching lifestyle.

From the creative minds at:


Hot Off the Press

Brake booster valve – ASE practice questions (VIDEO)

Description A customer states the brake pedal falls slightly when the brakes are applied while starting the engine. Technician A says that a faulty brake booster check valve may be to blame. Technician B says this can be caused by a leaking brake booster diaphragm....

The final days (and cars) of AMC

In the last days of AMC, two employees brought a video camera into the Kenosha, Wisconsin plant to document the end of an era. Billy and Danny take a thorough tour of the old AMC buildings and production line, which was producing its last L-body Plymouth Horizons and...

What is a core charge?

The article title is a question I asked when I was a young counterman, and most of you oldtimer mechanics and parts people of course know the story: the core charge is a way to be sure the smoked part makes its way back to the parts counter. A core charge is a deposit...

How do you inspect a serpentine belt for wear?

Performing a visual inspection of a car part is usually the first step in assessing its condition. In the case of the serpentine belt, any sign of physical damage to the belt means the belt should be replaced, and may indicate the need to more closely inspect the...

The importance of testing engine coolant (VIDEO)

How to test for blown fuses in a car or truck | Fast and easy methodDescription Dorman Training Center instructor Pete Meier explains why you should be testing engine coolant on vehicles in your bay. With a simple test strip, you can quickly check the coolant's health...

How to use a refractometer

I used to feel real dumb when I didn’t know what a tool was. After fixing things for a bit, I have come to learn that there are a lot of specialized tools and the only dumb thing is not learning about them. So when Dorman Trainer Pete Meier showed up recently with a...

Transfer cases: Married vs. divorced FAQ (VIDEO)

There is a paucity of divorced transfer cases fitted to vehicles traversing the roadways in 2024. In fact, some technicians—especially younger ones—aren’t even aware a setup beyond the married arrangement exists. If you’re unfamiliar with them, our own Technical...

How to get a little more (temporary) performance out of your air impact gun

by | Dec 21, 2023

I would like to start this article off by mentioning that yes, I know air impacts are slowly going out of style—which is exactly why you might want to keep this tip in the back of your head. Parts availability can be a challenge for some old impact wrenches, and even if they can be sourced, it’s often not worth the time it takes to renew the tool. So if you have a get-it gun that’s losing its mojo, there’s a half-baked method you can employ to coax some additional (albeit very temporary) life out of it.

Often impact guns lose efficacy when the rotor vanes wear. They’re really not unlike rotor tip seals in a rotary engine, or piston rings in a standard engine. Rust (from water that your inline filter didn’t catch) and debris in the air get into your gun and slowly wear away the vanes, which are often made of a phenolic polymer and seal against the metal housing. Or in your case, stop sealing.

The solution is a rebuild or a new tool. (Or jacking up the line pressure, but that might be part of what got you into this pickle in the first place.) But that doesn’t help much when you’re trying to nurse your ailing rattle-blaster through one more week of rotations until the nice man on the tool truck arrives at your shop.

So do the same thing we do for an ailing engine that’s getting a wet compression test: throw a shot of oil down the hatch. Skip the air-tool oil; that ain’t gonna help much. You want to shove some thick stuff into the air inlet. I work on a ton of Harley-Davidsons, so SAE 60 or 20W50 is always on the shelf, and that stuff usually bumps the power back up to acceptable levels to get by for a little longer.

The articles and other content contained on this site may contain links to third party websites. By clicking them, you consent to Dorman’s Website Use Agreement.

Related Articles

Shop Press Comment Policy

Participation in this forum is subject to Dorman’s Website Terms & Conditions. Please read our Comment Policy before commenting.

Notify of
Oldest Most Voted
Inline feedback
View all comments

Get Articles In Your Inbox

Subscribe to receive a monthly email summary of our latest Shop Press stories.

Shop Press

I agree to the above privacy statement and T&Cs

Thanks! You're now subscribed.