Removing the filler plug from a GKN diff on a Chimaera
Discussion
I thought I'd share my method of removing the tricky filler plug from a GKN diff.
I recently bought a 95 Chimaera and decided one of the first things to do was to change the fluids all round. I soon found out the previous owner liked to everything up nice and tight such that just about every nut requires a breaker bar to undo and the diff filler plug was no exception. The diff on my car is the GKN one with fins and has the filler cap just above one of the rear cross members. Access is extremely tight with only 65mm approx from the filler plug to the boot bulkhead. Afer I'd cleaned up the diff to see the problem better I could see that previous owners had used plumbers grips on the plug thread and of course damaged it. No way it would budge with grips.
Next I bought a set of metric oil drain keys and the 13mm one is the correct one. These are often sold as a 8mm and 13mm square combination with a centre portion to take a 19mm spanner. The 13mm end fitted perfectly but I couldn't get sufficient purchase on the centre section to get enough leverage. Too tight between the diff case and the cross member and from the back, too much of angle to get sufficient purchase with the spanner.
Next attempt was to buy a small 100mm section of 1/2" key steel for <£4. Key steel is tougher than mild steel but can still be cut with a hacksaw and filed. I cut it to size and it fitted nicely from the plug to the rear bulkhead but the plug still wouldn't budge when I put a large adjustable to it.
I then changed tack again and went for another oil drain key, this time a socket version that I could attach to a 1/2" breaker bar. There were 3 options: 13mm Company 23 1/2" socket for Subaru diffs (length 45mm), 13mm Beta tools socket 1494Q (length 50mm) or the 13mm Koken 4110M-13 (length 32mm). The one I went for was the Koken as I could get the breaker bar head between the bulkhead and the cross member with the socket attached and then manoeuvre the end into the plug. The diameter of the socket is 24mm and the length of the tip is 10mm.
The tool fitted perfectly and with the exhaust still in place I could crack loose the plug with a 450mm breaker. I then used the piece of key steel to further undo the plug past the damaged threads and the finally span out the plug using a 1/4" ratchet with a 2 socket adapters going to 1/2".
Picture of the diff with the plugs removed and also of the tools used.
https://thumbsnap.com/nDqpBJOI
https://thumbsnap.com/UmRizBXL
The drain plug at the bottom was a 13mm square male which undid OK.
Replacement filler plug can be source from Landrover spares shops and the part number is 608246 for just over a £1.
Yes the oil that came out was black and sludgey. Next to fill it up!
I recently bought a 95 Chimaera and decided one of the first things to do was to change the fluids all round. I soon found out the previous owner liked to everything up nice and tight such that just about every nut requires a breaker bar to undo and the diff filler plug was no exception. The diff on my car is the GKN one with fins and has the filler cap just above one of the rear cross members. Access is extremely tight with only 65mm approx from the filler plug to the boot bulkhead. Afer I'd cleaned up the diff to see the problem better I could see that previous owners had used plumbers grips on the plug thread and of course damaged it. No way it would budge with grips.
Next I bought a set of metric oil drain keys and the 13mm one is the correct one. These are often sold as a 8mm and 13mm square combination with a centre portion to take a 19mm spanner. The 13mm end fitted perfectly but I couldn't get sufficient purchase on the centre section to get enough leverage. Too tight between the diff case and the cross member and from the back, too much of angle to get sufficient purchase with the spanner.
Next attempt was to buy a small 100mm section of 1/2" key steel for <£4. Key steel is tougher than mild steel but can still be cut with a hacksaw and filed. I cut it to size and it fitted nicely from the plug to the rear bulkhead but the plug still wouldn't budge when I put a large adjustable to it.
I then changed tack again and went for another oil drain key, this time a socket version that I could attach to a 1/2" breaker bar. There were 3 options: 13mm Company 23 1/2" socket for Subaru diffs (length 45mm), 13mm Beta tools socket 1494Q (length 50mm) or the 13mm Koken 4110M-13 (length 32mm). The one I went for was the Koken as I could get the breaker bar head between the bulkhead and the cross member with the socket attached and then manoeuvre the end into the plug. The diameter of the socket is 24mm and the length of the tip is 10mm.
The tool fitted perfectly and with the exhaust still in place I could crack loose the plug with a 450mm breaker. I then used the piece of key steel to further undo the plug past the damaged threads and the finally span out the plug using a 1/4" ratchet with a 2 socket adapters going to 1/2".
Picture of the diff with the plugs removed and also of the tools used.
https://thumbsnap.com/nDqpBJOI
https://thumbsnap.com/UmRizBXL
The drain plug at the bottom was a 13mm square male which undid OK.
Replacement filler plug can be source from Landrover spares shops and the part number is 608246 for just over a £1.
Yes the oil that came out was black and sludgey. Next to fill it up!
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