This morning I tried to undo the oil *filler* plug of my BMW's ZF
6-speed automatic gearbox so I could change the oil and filter. I
managed to find an allen key that was an excellent fit (8mm) but the
plug was so tight I had to resort to thumping the key with a club
hammer in an attempt to loosen it. At first it seemed like the plug
was loosening but it turned out it was only the key twisting! The plug
remained resolutely in situ and the key now has about a 45 degree
twist in it. Fortunately it doesn't seem to have chewed up the plug.

So I have the following questions:
Is it normal for keys to twist like that under heavy load?
Is it normal for gearbox plugs to be so obstinate?
What's the best approach to getting the plug out going forwards?

In article ,
Mike McLeod wrote:
This morning I tried to undo the oil *filler* plug of my BMW's ZF
6-speed automatic gearbox so I could change the oil and filter. I
managed to find an allen key that was an excellent fit (8mm) but the
plug was so tight I had to resort to thumping the key with a club
hammer in an attempt to loosen it. At first it seemed like the plug
was loosening but it turned out it was only the key twisting! The plug
remained resolutely in situ and the key now has about a 45 degree
twist in it. Fortunately it doesn't seem to have chewed up the plug.

So I have the following questions:
Is it normal for keys to twist like that under heavy load?
Is it normal for gearbox plugs to be so obstinate?
What's the best approach to getting the plug out going forwards?

could it have a left hand thread?

--
from KT24 in Surrey, England
"I'd rather die of exhaustion than die of boredom" Thomas Carlyle

On Thursday, 13 August 2020 19:26:36 UTC+1, charles wrote:
In article ,
Mike McLeod wrote:
This morning I tried to undo the oil *filler* plug of my BMW's ZF
6-speed automatic gearbox so I could change the oil and filter. I
managed to find an allen key that was an excellent fit (8mm) but the
plug was so tight I had to resort to thumping the key with a club
hammer in an attempt to loosen it. At first it seemed like the plug
was loosening but it turned out it was only the key twisting! The plug
remained resolutely in situ and the key now has about a 45 degree
twist in it. Fortunately it doesn't seem to have chewed up the plug.

So I have the following questions:
Is it normal for keys to twist like that under heavy load?
Is it normal for gearbox plugs to be so obstinate?
What's the best approach to getting the plug out going forwards?

could it have a left hand thread?

Would not appear to be the case - if this is the right box.

https://youtu.be/4eWnnNdoFoE

On Thu, 13 Aug 2020 11:36:09 -0700 (PDT), polygonum_on_google wrote:

What's the best approach to getting the plug out going forwards?

could it have a left hand thread?

Would not appear to be the case - if this is the right box.

Still worth giving at whack or three clockwise even if it's a RH
thread.
And a squirt of plus gas.

--
Cheers
Dave.

On Thu, 13 Aug 2020 16:37:36 +0100, Mike McLeod wrote:

This morning I tried to undo the oil *filler* plug of my BMW's ZF
6-speed automatic gearbox so I could change the oil and filter. I
managed to find an allen key that was an excellent fit (8mm) but the
plug was so tight I had to resort to thumping the key with a club hammer
in an attempt to loosen it. At first it seemed like the plug was
loosening but it turned out it was only the key twisting! The plug
remained resolutely in situ and the key now has about a 45 degree twist
in it. Fortunately it doesn't seem to have chewed up the plug.

So I have the following questions:
Is it normal for keys to twist like that under heavy load?
Is it normal for gearbox plugs to be so obstinate?
What's the best approach to getting the plug out going forwards?

Allen style insert for a socket wrench.

Example (probably not the right size):

https://www.amazon.co.uk/Teng-M12151.../dp/B0001P0WMU



--
My posts are my copyright and if @diy_forums or Home Owners' Hub
wish to copy them they can pay me £1 a message.
Use the BIG mirror service in the UK: http://www.mirrorservice.org
*lightning surge protection* - a w_tom conductor

Mike McLeod wrote:
This morning I tried to undo the oil *filler* plug of my BMW's ZF
6-speed automatic gearbox so I could change the oil and filter. I
managed to find an allen key that was an excellent fit (8mm) but the
plug was so tight I had to resort to thumping the key with a club
hammer in an attempt to loosen it. At first it seemed like the plug
was loosening but it turned out it was only the key twisting! The plug
remained resolutely in situ and the key now has about a 45 degree
twist in it. Fortunately it doesn't seem to have chewed up the plug.

So I have the following questions:
Is it normal for keys to twist like that under heavy load?
Is it normal for gearbox plugs to be so obstinate?
What's the best approach to getting the plug out going forwards?

Righty tighty, lefty loosey, or t'other way ?

The video here, at around 5:15, the gentleman is using a
socket wrench. And for whatever transmission this is,
it looks like lefty loosey. He was turning counter-clockwise
to open it up. He had the car tipped a bit, to make the
video, which affected the fill level.

https://www.youtube.com/watch?v=h2ckC-epJhs

Later in the video, he checks the fluid level one last
time, and he seems to be removing more than one
fastener at that point. A bit of fluid slops out
after he has it open again for access.

I'd just make sure I was cranking the correct thing,
and that's not a structural fastener keeping some
gasket compressed.

My last car, I had the proper shop manual, and
what a difference that makes :-) Not a Haines.
The instructions can still be imaginative, but
at least the pictures of stuff are good.

And I don't want the manual just because I want
to fix all the stuff myself. Sometimes, the pictures
help just to understand how large of a job a
certain repair might be. Like pulling everything
off the top of an engine, just to be able to access
a small steel tube with coolant in it, nestled
underneath. With a mirror, I could see the general
area of the leak, but I never expected to find a
plumbing network behind that point. I thought
something screwed right to the block and I just
couldn't see it. But there was a right angle turn
after that point. The people at the shop didn't
seem to know what was under there either,
which is why the repair took forever.

When the user manual for your car says:

*This car uses a special coolant solution*

they weren't kidding. Follow the instructions!
It's unbelievable the **** the engineers pull
on this stuff.

Paul

On 13/08/2020 20:33, Bob Eager wrote:
On Thu, 13 Aug 2020 16:37:36 +0100, Mike McLeod wrote:

This morning I tried to undo the oil *filler* plug of my BMW's ZF
6-speed automatic gearbox so I could change the oil and filter. I
managed to find an allen key that was an excellent fit (8mm) but the
plug was so tight I had to resort to thumping the key with a club hammer
in an attempt to loosen it. At first it seemed like the plug was
loosening but it turned out it was only the key twisting! The plug
remained resolutely in situ and the key now has about a 45 degree twist
in it. Fortunately it doesn't seem to have chewed up the plug.

So I have the following questions:
Is it normal for keys to twist like that under heavy load?
Is it normal for gearbox plugs to be so obstinate?
What's the best approach to getting the plug out going forwards?

Allen style insert for a socket wrench.

Example (probably not the right size):

https://www.amazon.co.uk/Teng-M12151.../dp/B0001P0WMU



That link is for a 17mm hex - which the illustration definitely *isn't*!
[The picture looks more like a 7mm or 8mm hex to me]

One of those of the right size plus a decent impact wrench should shift it.
--
Cheers,
Roger

Paul wrote:
My last car, I had the proper shop manual, and
what a difference that makes :-) Not a Haines.
The instructions can still be imaginative, but
at least the pictures of stuff are good.

Yes, it's worth seeing if there's a way to access the dealer manual. Some
manufacturers allow you to pay for a short access period to their online
manual (a tenner for a weekend kind of thing), or there might be an
'unofficial' way described on a forum somewhere. It's a lot better than a
Haynes as it's designed for dealers troubleshooting and maintaining things.

Theo

On Thu, 13 Aug 2020 16:37:36 +0100, Mike McLeod
wrote:

This morning I tried to undo the oil *filler* plug of my BMW's ZF
6-speed automatic gearbox so I could change the oil and filter. I
managed to find an allen key that was an excellent fit (8mm) but the
plug was so tight I had to resort to thumping the key with a club
hammer in an attempt to loosen it. At first it seemed like the plug
was loosening but it turned out it was only the key twisting! The plug
remained resolutely in situ and the key now has about a 45 degree
twist in it. Fortunately it doesn't seem to have chewed up the plug.

So I have the following questions:
Is it normal for keys to twist like that under heavy load?

Good ones, no.

Is it normal for gearbox plugs to be so obstinate?

They can be but I've not had one beat me yet. ;-)

What's the best approach to getting the plug out going forwards?

I have a range of short and long, 1/4, 3/8 and 1/2" sq drive socket to
hex (and spline etc) bits and I would have probably started with the
1/2" sq dr one if the bits went down small enough.

I would use the shortest bit I could.

I would set myself up to be able to put the best focused effort on it
possible (ideally pulling at 90 degrees).

If it didn't move with the std length ratchet handle, I'd try a T bar
(push pull as a T then right at one end) and then an 1/2" sqdr breaker
bar, keeping in mind the size of the hex and once absolutely sure it
was the right way.

If it still won't move then, if it uses a crush / flat washer I might
try some Plus Gas (*not* WD40) but if it's an 'O' ring I'm not sure
that would help.

If there is anything like a shoulder you can get some *good* Mole
Grips on, you could try those along with the ratchet handle.

If that doesn't work (and assuming you have a spare plug and *are*
sure you are turning the right way, see if you can knock it round the
right way with some tangential taps to a cold chisel, cutting into the
outer corner (not hitting it too hard for risk of damaging the gearbox
casting (fins etc)). Bothering wrong with a few taps in the other
direction during any of this.

If you are single handed and can do it easily, the hex bit in 1/2"
drive supported in place and tensioned against something with a
ratchet strap (or a mate pushing / pulling on it) *and* trying to tap
it with the chisel / hammer (making sure the ratchet can't fall onto
your head if it does break free).

'Pre loading' whilst tapping is a very powerful combo.

Then about all you have left is some heat (you don't want to soften
the steel) and / or weld a nut / bar onto it?

If you don't have any good (round jaw) Mole grips and there is a
shoulder you can grip, than you can get some very big pump pliers
fairly cheap and again, could be used to apply a pre-load or
additional load, along with the hex etc.

Cheers, T i m

On 14/8/20 1:37 am, Mike McLeod wrote:
This morning I tried to undo the oil *filler* plug of my BMW's ZF
6-speed automatic gearbox so I could change the oil and filter. I
managed to find an allen key that was an excellent fit (8mm) but the
plug was so tight I had to resort to thumping the key with a club
hammer in an attempt to loosen it. At first it seemed like the plug
was loosening but it turned out it was only the key twisting! The plug
remained resolutely in situ and the key now has about a 45 degree
twist in it. Fortunately it doesn't seem to have chewed up the plug.

So I have the following questions:
Is it normal for keys to twist like that under heavy load?
Is it normal for gearbox plugs to be so obstinate?
What's the best approach to getting the plug out going forwards?

Get tha allen key type that fits your socket spanner.

On Thu, 13 Aug 2020 16:37:36 +0100, Mike McLeod
wrote:

This morning I tried to undo the oil *filler* plug of my BMW's ZF
6-speed automatic gearbox so I could change the oil and filter. I
managed to find an allen key that was an excellent fit (8mm) but the
plug was so tight I had to resort to thumping the key with a club
hammer in an attempt to loosen it. At first it seemed like the plug
was loosening but it turned out it was only the key twisting! The plug
remained resolutely in situ and the key now has about a 45 degree
twist in it. Fortunately it doesn't seem to have chewed up the plug.

So I have the following questions:
Is it normal for keys to twist like that under heavy load?
Is it normal for gearbox plugs to be so obstinate?
What's the best approach to getting the plug out going forwards?
Have a look in here https://www.bimmerpost.com/ for the most
appropriate forum and then ask in there (you'll have to register).

On 2020-08-13, Jethro_uk wrote:

On Thu, 13 Aug 2020 16:37:36 +0100, Mike McLeod wrote:

This morning I tried to undo the oil *filler* plug of my BMW's ZF
6-speed automatic gearbox so I could change the oil and filter. I
managed to find an allen key that was an excellent fit (8mm) but the
plug was so tight I had to resort to thumping the key with a club hammer
in an attempt to loosen it. At first it seemed like the plug was
loosening but it turned out it was only the key twisting! The plug
remained resolutely in situ and the key now has about a 45 degree twist
in it. Fortunately it doesn't seem to have chewed up the plug.

So I have the following questions:
Is it normal for keys to twist like that under heavy load?

Not if they're made properly

At least part of the allen key has to be no wider than 8 mm --- what's
the limit on torque that any affordable alloy of that size can take?


Is it normal for gearbox plugs to be so obstinate?

I know some are slightly tapered to ensure they can't work lose ..

What's the best approach to getting the plug out going forwards?

When I was in trade I'd weld a bolt into the plug and replace it.

Sadly you've fallen victim to the "buy cheap, buy twice" approach to
life. It doesn't take much imagination to work out how the manufacturer
manages to keep their factory busy ...

Best tools I have ever used by a country mile were made by (or for) FIAT.
DF is still using the spanners over 60 years after he "acquired" them.

US tools are also pretty good. Snap-on may be ****ing expensive, but you
only ever need buy one.

In article ,
Mike McLeod wrote:
This morning I tried to undo the oil *filler* plug of my BMW's ZF
6-speed automatic gearbox so I could change the oil and filter. I
managed to find an allen key that was an excellent fit (8mm) but the
plug was so tight I had to resort to thumping the key with a club
hammer in an attempt to loosen it. At first it seemed like the plug
was loosening but it turned out it was only the key twisting! The plug
remained resolutely in situ and the key now has about a 45 degree
twist in it. Fortunately it doesn't seem to have chewed up the plug.

So I have the following questions:
Is it normal for keys to twist like that under heavy load?
Is it normal for gearbox plugs to be so obstinate?
What's the best approach to getting the plug out going forwards?

I have a cordless impact driver. Often called a rattle gun - the sort of
thing tyre shops use on wheel nuts. It works a treat on stubborn fixings.
It has a standard square drive, so my socket allen keys fit. And being
short, not so likely to bend.

Of course there may not be access room for one of these on your box.

--
*Modulation in all things *

Dave Plowman London SW
To e-mail, change noise into sound.

On 13/08/2020 16:37, Mike McLeod wrote:
This morning I tried to undo the oil *filler* plug of my BMW's ZF
6-speed automatic gearbox so I could change the oil and filter. I
managed to find an allen key that was an excellent fit (8mm) but the
plug was so tight I had to resort to thumping the key with a club
hammer in an attempt to loosen it. At first it seemed like the plug
was loosening but it turned out it was only the key twisting! The plug
remained resolutely in situ and the key now has about a 45 degree
twist in it. Fortunately it doesn't seem to have chewed up the plug.

So I have the following questions:
Is it normal for keys to twist like that under heavy load?
Is it normal for gearbox plugs to be so obstinate?
What's the best approach to getting the plug out going forwards?


Thumping with a club hammer is definitely the wrong approach, you are
then applying moments to the interface which will result in local
loadings and deformation, usually of the socket. You need a cheater
pipe, and try to apply a reaction force at the bend in the allen key so
as to apply a fairly pure torque. Also easier to do with a hex bit in a
socket wrench, or better still an impact driver, if there is room for one.

Twisted key sounds like incorrect heat treatment.

Gearbox filler/level plugs can be difficult to remove: they tend to be
put in with high torque, and they are not disturbed often.

Mike McLeod wrote:
This morning I tried to undo the oil *filler* plug of my BMW's ZF
6-speed automatic gearbox so I could change the oil and filter. I
managed to find an allen key that was an excellent fit (8mm) but the
plug was so tight I had to resort to thumping the key with a club
hammer in an attempt to loosen it. At first it seemed like the plug
was loosening but it turned out it was only the key twisting! The plug
remained resolutely in situ and the key now has about a 45 degree
twist in it. Fortunately it doesn't seem to have chewed up the plug.

So I have the following questions:
Is it normal for keys to twist like that under heavy load?
Is it normal for gearbox plugs to be so obstinate?
What's the best approach to getting the plug out going forwards?

Now, what could possibly go wrong there ?

https://i.postimg.cc/NfLf6SpT/drain.jpg

It looks like the fill plug matches the thing it
screws into. It might not be caused by dissimilar
metals. It it's an aluminium alloy, maybe the
surface could pit a bit, but would that cause
it to stay put ?

The thing it screws into, would be an expensive place
to make a mistake.

Paul

On Friday, 14 August 2020 11:15:06 UTC+1, Adam Funk wrote:


At least part of the allen key has to be no wider than 8 mm --- what's
the limit on torque that any affordable alloy of that size can take?


I have a small hex-key torque wrench - includes 3 to 10 mm. And torque settings 2 to 24 Nm. I'd be a bit surprised if I came across something it was unable to manage - unless there is a problem such as corrosion.

Most Allen Keys I've tried to use beyond their abilities tend to just break
somewhere.
Brian

--
----- --
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please
Note this Signature is meaningless.!
"Mike McLeod" wrote in message
...
This morning I tried to undo the oil *filler* plug of my BMW's ZF
6-speed automatic gearbox so I could change the oil and filter. I
managed to find an allen key that was an excellent fit (8mm) but the
plug was so tight I had to resort to thumping the key with a club
hammer in an attempt to loosen it. At first it seemed like the plug
was loosening but it turned out it was only the key twisting! The plug
remained resolutely in situ and the key now has about a 45 degree
twist in it. Fortunately it doesn't seem to have chewed up the plug.

So I have the following questions:
Is it normal for keys to twist like that under heavy load?
Is it normal for gearbox plugs to be so obstinate?
What's the best approach to getting the plug out going forwards?

In article ,
Brian Gaff \(Sofa\) wrote:
Most Allen Keys I've tried to use beyond their abilities tend to just
break somewhere.
Brian

I'm rather surprised to see them in a relatively new car part. Most are
Torx these days.

--
*Isn't it a bit unnerving that doctors call what they do "practice?"

Dave Plowman London SW
To e-mail, change noise into sound.

On Fri, 14 Aug 2020 06:20:19 -0700 (PDT), polygonum_on_google
wrote:

On Friday, 14 August 2020 11:15:06 UTC+1, Adam Funk wrote:


At least part of the allen key has to be no wider than 8 mm --- what's
the limit on torque that any affordable alloy of that size can take?


I have a small hex-key torque wrench - includes 3 to 10 mm. And torque settings 2 to 24 Nm. I'd be a bit surprised if I came across something it was unable to manage - unless there is a problem such as corrosion.

More likely a reaction between the alloy of the gearbox and the steel
of the plug. Not the least uncommon.

On Fri, 14 Aug 2020 20:30:04 +0100, "Brian Gaff \(Sofa\)"
wrote:

Most Allen Keys I've tried to use beyond their abilities tend to just break
somewhere.

As they should, if they're hardened steel. The fact that the key bent
shows it's poor quality and the force of the hammer blows is being
absorbed by it instead of the plug. You need to *shock* the plug into
releasing which won't happen if they key is prone to bending. Get a
better quality tool and try again.