Freel2,

As most of you know Land Rover (and Volvo) didn't install a drain plug for the power transfer unit.

I recently drilled and tapped a hole for a drain plug on my PTU (Power Transfer Unit).

The surface of the casting is very rough so I initially used a small belt sander to smooth the surface.
Unfortunately I wasn't able to keep the surface flat enough and I developed a very small leak.
Weeping would describe it better than leaking.
But it needed to be fixed.

To fix the weeping PTU gear oil I did the following.

I purchased a grinding stone and I used my air drill to remove some aluminum. https://www.amazon.com/DEWALT-DWA4972-Alum...mp;sr=1-11

Grinding stone in Air Drill





Finished surface
Here is what it looks like post machining
Note: I did use a tap covered in grease to collect the aluminum shavings visible in the threads prior to installing the drain plug.





Drain Plug installed
This is with the magnetic drain plug installed and two copper washers and a Dowty steel washer in the middle.







I'll post here if it still weeps gear oil.

Thanks

Paul

PS the grinding stone that I bought is 1.0" diameter if I were to do it again I would try to find a 0.75" stone so that I didn't have to remove as much aluminum. And to make sure that the surface was flat I covered it in red sharpie and grinded away the sharpie mark.


PPS Here is the before picture

Click image to enlarge

What size is the drain plug ie, what size thread have you drilled and tapped? Landrover - turning owners into mechanics since 1948

2014 Orkney grey Freelander SD4 GS.
2004 Zambezi silver Discovery 2 Td5 (Gone)
1963 Surf blue Morris Mini Minor Super de Luxe (my little toy)

i used a 10mm P1.25 on mine just as an FYI and I could have gone slightly smaller.

@p_gill,

Last edited by MotionInc on 27th Jun 2021 5:12 pm. Edited 1 time in total

I was able to do this with a brass NPT plug, easier mod to execute but does require some finesse to tighten it properly without over-tightening and stripping (or splitting ) the hole.

I went easy on the torque and simply inspected it (and checked the torque) frequently for the first year to ensure it wasn't working out.


https://www.freel2.com/forum/post409510.html#409510

Also I did drill out a straight-thread drain hole in the rear diff, had to do some grinding there to get it level but that was much more accessible than the PTU hole.

Still leaked just a bit, ended up solving that with two washers and RTV sealant (letting it cure overnight before refilling)... that might be an option for the PTU as well since you don't change the oil very often.

hey @merlinj79,

Where did you drill and tap the rear diff, which bolt hole? I was thinking of drilling from the bottom but just not sure where........yet.

Bobupndown wrote:

What size is the drain plug ie, what size thread have you drilled and tapped?

Merlin and Motion,

I thought both of you would be interested in this modification.

Thanks for the replies and encouragement.

I am slowly turning my LR2 into the vehicle that I think it should have been when new.

Take care

Paul

MotionInc wrote:

Update to drilling & tapping my PTU:

I used a M10x1.25 drill, tap and motorcycle magnetic bolt. In retrospect, an M8 would have been better

MotionInc wrote:

hey @merlinj79,

Where did you drill and tap the rear diff, which bolt hole? I was thinking of drilling from the bottom but just not sure where........yet.

Freel2,

Plan A didn't work (it is still weeping gear oil)

Time for Plan B











The O-ring is an actual Land Rover part, it is used at the drain for the automatic transmission. I did add an over sized copper washer also as a supplemental seal and to prevent me from applying too much compressive force to the O-ring. The copper washer is about half of the thickness of the O-ring. When the O-ring is compressed by 50% the washer will act as a stop to prevent me from compressing the O-ring further.

I will post here if I get to Plan C

Thanks

Paul

PS the Drain Plug is a M8 and the casting is aluminum so the maximum Torque that I fee comfortable applying is 10 Ft*Lbs. (If I could apply more torque I would crush the copper and it would seal without the O-ring)

Success!!!! Not a drop coming out.

Here is the proof-----completely dry





I did add a Torque Stripe and I checked to see if the O-ring had relaxed and it had very slightly.




I don't know if you can tell from the picture but the bolt did move slightly when I applied 10 FT*LBS




I would estimate about 1/10 of a turn which is about 0.125 mm of compression on the O-ring.
I wasn't surprised that it had relaxed a little, I expected it to. Note: I don't think that I will torque it again not until its time for the next gear oil change.

If I keep torqueing the bolt either the copper washer will deform or the O-ring may break.

It is possible that my LR2 knew that the O-ring was a Land Rover part and that's why it worked. (or is that me being paranoid)

Take care

Paul

No, if its a proper landrover seal it should be leaking, I'd take that seal back and complain. 🤣 Landrover - turning owners into mechanics since 1948

2014 Orkney grey Freelander SD4 GS.
2004 Zambezi silver Discovery 2 Td5 (Gone)
1963 Surf blue Morris Mini Minor Super de Luxe (my little toy)

p_gill wrote:

Success!!!! Not a drop coming out.

Here is the proof-----completely dry





I did add a Torque Stripe and I checked to see if the O-ring had relaxed and it had very slightly.




I don't know if you can tell from the picture but the bolt did move slightly when I applied 10 FT*LBS




I would estimate about 1/10 of a turn which is about 0.125 mm of compression on the O-ring.
I wasn't surprised that it had relaxed a little, I expected it to. Note: I don't think that I will torque it again not until its time for the next gear oil change.

If I keep torqueing the bolt either the copper washer will deform or the O-ring may break.

It is possible that my LR2 knew that the O-ring was a Land Rover part and that's why it worked. (or is that me being paranoid)

Take care

Paul

Bobupndown wrote:

No, if its a proper landrover seal it should be leaking, I'd take that seal back and complain. 🤣

Bob,

LOL

That would make for an interesting conversation!!!!


"Yes I do want to return it. No it can't be a genuine part. I know this for certain because a genuine part would leak and provide a protective layer of oil for adjacent parts. This is clearly per the original design intent. If that's not the case then why does every other sealing surface leak oil. I want my money back for this counterfeit part."



Paul