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Diff drain plugs; which are compatible? - Engine & Ancilliaries/Gearbox - The Lotus Forums #ForTheOwners Jump to content

Diff drain plugs; which are compatible?

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I'm looking to replace the drain plug on my diff (once I get the damn thing off!), if possible with a magnetic plug. The problem is finding what plug will fit.

Both drain and fill plug currently are the square head type which look like these ones that SJ Sportscars sell (and which they sell as drain and fill plugs).


My understanding is that the diff in the Elite/Eclat is a Salisbury 7HA, the same used on a Morgan and some Land Rovers. I've found a Morgan 7HA drain plug listed here which may fit, but it's not magnetic. Looking at Land Rover ones seems to be a bit if a minefield though as I'm not exactly sure which this diff was fitted to. Also, the Land Rover diffs have an inverted square head and sites seem to say that the filler and drain plugs are not the same.

Does anyone have any idea which plugs are compatible and if there's a magnetic drain plug alternative we can get for our diffs?

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Would it be possible to use/stick/bond a Neodymium magnet like these

to the existing plug? That way you would not have to buy a new one

just a thought.


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11 hours ago, EXCEL V8 said:

It's 3/4" BSPT.  Should be readily available for a couple of quid each.  I'd be OK gluing a magnet to one so long as it's counterbored first - use a good epoxy.


Thanks, Pete. Just the info I needed. Have found Land Rover Defender plugs will work, and also an interesting article on diff plugs (never thought I'd write those words!) from an E-Type forum here

I'm probably going to get a pair of these magnetic plugs:

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3 hours ago, EXCEL V8 said:

To remove these plugs I use the square drive end of a 1/2" drive socket by putting a short piece of hexagon bar stock into it and driving with a second socket of the same size - does that make sense?


Very good idea but unfortunately I've tried it and it's not worked. Even if I put pressure on it from the bottom, it looks like it might be lifting the diff as it pushes the socket off. I did try turning it tighter a degree or two and it did move so it's not completely seized; just nothing I have can get leverage on the rounded head. I'm thinking my two options are:

  1. Get my garage to do it when they're cutting the track rod to bring alignment back into spec, possibly welding a nut onto it or something to get it off
  2. Live with it stuck on for now and do a diff oil change using my suction pump to suck the oil out of the fill hole..
Edited by soldave
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31 minutes ago, EXCEL V8 said:

You've had the stilsons out again I assume?  When stilsons are new they have very sharp teeth - do yours?


I have, and I've quickly realised my stillsons from Halfords aren't very good!

Edit: Just went out and got a good grip on the head of the plug. All it's going is pulling chips of metal out of the head which is getting more and more rounded. Think I might have to accept defeat on this one :(

Edited by soldave
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