Experience is a great teacher. Here are some things I’ve learned over the years working on cars that may help you avoid hassles when working on your car:
* Remove the fill plug before you remove the drain plug –
This applies mostly to manual transmissions and rear axles, which typically have a drain plug mounted somewhere near the bottom of the case and a fill plug located higher up, often on the side of the case. A beginner’s mistake – one that can lead to extreme frustration (and possibly, expense) is to remove drain plug – and with it, all the fluid (gear lube/transmission fluid) and then discover that you can’t get to the fill plug.
Or can’t get it out.
Now, you can’t refill the transmission (or axle) with fresh lube. Which means… you can’t drive the vehicle.
Hence: Always locate – and remove – the fill plug first.
Usually, the fluid/lube level will be at or just below the level of the fill plug, so it will not come gushing out when you remove the fill plug. But it will facilitate faster/more complete draining once you remove the drain plug. And – most important of all – you’ll know you can refill the case before you drain the case.
Helpful extra: Many transmission/axle drain and fill plugs can often be removed using a 3/8 or 1/2 inch socket extender. The “boxed” shape of the extender exactly fits the drain plug bolt and is deep enough for a secure (non-wobbly) fit. Use the largest (longest) driver (or breaker bar) that’ll fit in the space available to loosen the drain/fill plugs. They are often very tight. Leverage is your friend. Dousing them with PB Blaster or similar penetrant about 30 minutes before trying to loosen them also helps.
But whatever you do, don’t force them – or you might end up with a truly hideous scene. A cracked/broken case, for instance – which will take many dollars to remedy.
* A light coat (or dab) of Vaseline –
Is just the ticket for holding a gasket in place while you line parts up. Particularly case covers with lots of bolts, such as differential covers and automatic transmission pans. In addition to making it easy to get parts together properly, it will also make it a lot easier to take them apart again, later on. The gasket will not have to be scraped off with a razor blade. Just peel it off.
No fuss, much less muss.
Vaseline can also be used to hold small parts in place during installation – such as the little check balls in an automatic transmission’s valve body – that would otherwise fall out of place and drive you nuts.
* Start all bolts/spark plugs, etc. by hand (and wiggle as you turn) –
Few things can ruin your day like cross-threading a spark plug or bolt. It hasn’t happened to me in years because I’ve learned to first make sure the threads are clean (you can use a wire brush for this) then begin turning them in (righty, tighty) by hand, wiggling them slightly at first to help seat the threads. You’ll soon develop an instinctive feel for proper (and improper) engagement. Only when you’re sure the spark plug or bolt is threading properly should you bring out the ratchet or wrench. Be extra careful when tightening a plug on an aluminum cylinder head. Just slightly tighter than hand-tight is usually safe – and even if it’s not quite there, it’s far better to leave it a bit loose than too tight.
Smart move: Invest in a torque wrench to be certain you’ve tightened whatever it is just enough … but not too much. A good one will cost you about $50-$75.
Much cheaper than pulling a head to fix a ruined thread.