Oil pan drain plugs?

[CalG]

I was just reading over on the Kubota forum of a tractor that had lost it's oil sump drain plug while in the field. Engine troubles followed.

There seems to be quite a difference of opinion on how drain plugs are to be installed. Some are saying you MUST use a torque wrench on the Aluminum pans.

Is there some change in methods where sealing /compression washers are no longer used, and the torque setting is making the seal?

I've never heard of it. Can you check your operator's manuals and see what is advised ? I'm sure any change must be in the past few years . I wouldn't expect anything new or novel before 2010. But Hey, What do I know?

 

[CalG]

36 views and no one has an operator's manual? ;-)

 

[ericm979]

Most drain plugs use copper or aluminium washers (actually they're small metal gaskets). Less common is an o-ring in the plug. Either way the seal is made by the washer or o-ring. The torque ensures that the plug won't come loose, and that the washer is sufficiently compressed to effect a seal. The drain plugs with o-rings that I have seen are made so that the o-ring is compressed the appropriate amount when the bolt shoulder is hard against the pan.

Using a torque wrench is always a good idea, especially in an aluminium pan where it's easier to strip threads. Some people tend to over torque bolts, others tend to under torque them. Over torquers can strip threads. Under torquing can lead to plugs coming out.

All operators manuals list a torque value and expect you to use a torque wrench.

 

[herringchoker]

I checked my B7800 Operator's Manual and it says:
"After draining reinstall the drain plug."
No help there.

 

[CalG]

Using a torque wrench is always a good idea, especially in an aluminium pan where it's easier to strip threads. Some people tend to over torque bolts, others tend to under torque them. Over torquers can strip threads. Under torquing can lead to plugs coming out.

All operators manuals list a torque value and expect you to use a torque wrench.

eric

Your generalized information is very clear. And using a torque wrench is a great method to match material requirements to assure a functional seal

Unfortunately, your last statement does not prove as a fact, as it pertains to sump drains. I have four tractors, Not one operator's manual states a torque spec for the sump drain plug. And the general torque values for fasteners of that size are grossly in excess of prudent.

Does the Branson literature specify a value?

 

[CalG]

Here is an interesting comment snagged off the web regarding "torque specifications" for sump drain plugs.

There isn't one, because it's not known if the drain plug is being removed/reinstalled with the engine hot or cold. Such as at a quick-lube place.
And because the threads in the oil pan are coated with oil, it has to be a wet torque spec.
So, the drain plug is tightened by feel.

[End quote]

Several important consideration there.

 

[ruffdog]

Been doing it "by feel" since the 70's with no issues.

 

[CalG]

Been doing it "by feel" since the 70's with no issues.

Yes, me , from the late 60's ;-)

But there seems to be a movement afoot that would replace feel with a torque spec. Something I have yet to reconcile.

I was just looking for examples of operators manuals that describe replacing "feel" with blind and dumb numbers on a click wrench. ;-)

Are the advocates of the "scientific approach" missing some important aspects, like wet torque?

 

[ericm979]

Does the Branson literature specify a value?

Yes. It is in the maintenance chapter but not the engine chapter with the other engine specs. I've seen that in other manuals.

In all the shop manuals I have the general section at the beginning that no one reads says to use a torque wrench. It's on page 4 in the Branson manual.
I've never seen a manual say to do it by feel. Even when there is no torque value for a fastener you're supposed to follow the general values.

I don't use a torque wrench for everything but it's there for anything critical. Sometimes I use it on oil drain plugs, sometimes I don't. I understand that while the manufacturer gives a single number the actual practical range is often fairly wide- tight enough to stay in and to compress the metal washer, not so tight as to strip the threads. If it's in an aluminium or magnesium block (not the pan that can be replaced) I use a torque wrench for sure.

I did once do an experiment to check my personal torque calibration on a range of fasteners by tightening them to what felt like the target torque and then checking with a torque wrench. Turns out I'm in the ballpark on small fasteners and too light on larger ones. Figures since I don't have a lot of upper body mass. I've worked on motorcycles previously owned by big brawny guys where every small fastener was tightened to where it was just starting to strip the threads.

 

[ruffdog]

I've worked on motorcycles, ATV's, chainsaws, jet skis, snowmobiles, and lawn equipment at dealers and have had to repair threads in aluminum. Back in the day, most people worked on their own equipment and stripped threads, now, most work is done at a shop and thread repair is not as common.