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:

FEATURE STORY

Hot Off the Press

Using voltage to locate electrical faults

Locating the cause of an electrical fault can be a challenge even for the most experienced professional. I’m not referring to open circuits or even short circuits. These are relatively easy to find. In either case, the component, or load, won’t work. But the most...

How do you handle billing shop supplies?

When I first began writing service at an indie auto repair shop, one line item on the bill was “shop supplies.” We tacked on some percentage of the bill, capping at $19.88. Shows you how long ago that was! Customers would ask about it, and many were angry about the...

Tool Review: FNIRSI DSO152 Oscilloscope

Disclaimer: I purchased this tool at full retail price. In fact, I actually purchased two so I could try out the version with a high-voltage lead.If you’ve met my fellow Shop Press contrib Pete, seen his videos, taken his classes, or read his articles, you’ll know...

Making custom coiled wire is easier than you think (VIDEO)

Description Coiled wire is a smart idea for adding service loops or mechanical strain relief on automotive electrical jobs or other projects. In three easy steps, you can make your own coiled wire sections for all kinds of applications.

Choosing the right brake fluid

You know topping off brake fluid is generally a no-no, but when a customer’s brake fluid needs to be flushed completely, knowing what to put in the reservoir isn’t as clear-cut as it once was. The master cylinder cap may say the vehicle uses DOT 4 brake fluid, but are...

Square drive: make or buy before you need ‘em

by | Mar 7, 2024

As a new tech, all I did was borrow tools from mechanics who were good to me. They usually lent and trained me on etiquette just after. (If you need to borrow it more than once or twice, maybe you ought to buy your own.) It’s not that often that I find myself without a tool these days in part due to having most of what I need and also in part to not being so pressed for money. But recently I found myself under a car needing something I didn’t have, so I thought I’d send out a little PSA for those of you who could end up in the same boat.

I was about to perform a service that doesn’t come up very often: a manual transmission fluid exchange. I’ve written before about my good friend the drain plug, so this was an interesting development: I had some trouble removing one recently, but that was no fault of the plug. Here’s what transpired on the Nissan that found its way onto my lift.

I can’t speak for you, but I personally always crack fill plugs before drain plugs. The fill plug was a little plastic butterfly affair. Easy-peasy; I spun that out and it was no problem.

See all that tire mounting compound? Getting sloppy here also helps when trying to index the valve stem; a slippery tire can just be held while the table spins to the correct spot.

Hmm. Not as straightforward as I thought. Photo: Lemmy.

Moving along, I readied the drain pan and spied what I thought was your standard 3/8” square drive slot broached into the plugs. I waltzed over to my box, grabbed a 6” extension, and when I inserted it, it was not fitting. No go. Maybe it was 1/4”?

Nope. Way sloppy.

I thought I knew what was going on, so I walked over to my lathe, which is imported, and grabbed the chuck key, an 8mm. I’ve only ever seen metric square stuff on Asian three- and four-jaw lathe chucks, but happily I had a tool on-hand to deal with them thanks to that. I popped it in, and bingo! That was it. I proceeded with the service uneventfully.

See all that tire mounting compound? Getting sloppy here also helps when trying to index the valve stem; a slippery tire can just be held while the table spins to the correct spot.

An unlikely solution to my problem was fortunately close by. Photo: Lemmy.

So today’s PSA is to grab (or make) yourself some tools to deal with these little things. Order some square stock, file down some junker hex keys or grab a set of sockets. I bought a set for my drawer; it was oddly cheaper than buying the stock to make my own.

This 8mm was on a Nissan, but Suzuki uses this style of plug on their cars and light trucks, too. Engines, trannies, and diffs all might have similar plugs on BMWs, Fords, Renault products, and Toyotas. (This depends on the vehicle model and market.) Through the grapevine I’ve also heard lots of domestic T-cases make use of this plug, too.

See all that tire mounting compound? Getting sloppy here also helps when trying to index the valve stem; a slippery tire can just be held while the table spins to the correct spot.

Ordinarily, I’m not a tool junkie. But fluid exchange happens a lot. I’m certain I’ll get my money out of these sooner rather than later. Photo: Lemmy.

Evidently, 10mm squares are also in use on some oil drain pans, and Honda uses them in their auto transmissions and diffs. I imagine a 3/8” might stand in for those in a pinch—with a caveat. I personally chose to purchase a tool since these plugs are shallow. The chamfer that makes it easy for us to pop a socket onto a ratchet or extension offers reduced bite in the shallow square broached into the plug. I like making do with what I have as much as the next fellow, but for the low cost of entry and high probability of servicing or checking a fluid level, spending some coins here seems like a no-brainer.

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.

Subscribe
Notify of
guest
0 Comments
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.