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Discussion Starter · #1 ·
Hemmo wrote:

BTW. Whats the size of the oilplug? 13 mm?
That would be the closest size you'll find in metric. A 14-mm Allen wrench is a tiny bit too large and 13 mm just a tiny bit too small. Some have purchased a 14-mm and then ground it down a smidgen.

If you tire of trying to get the sump plug out and having to keep a supply of aluminum crush washers, you might want to consider buying a Quick Oil Drain Valve so you'll never have to take the plug out again. The FG-5 or FG-5N sizes (The 'N' version has a nipple on the end of the valve) are the ones for Rolls-Royce and Bentley motorcars from the Cloud/S period up through the SZ series cars.
 

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Brian --

The FG5 says it has a 25mm - 1.5 thread. I assume our sumps are really imperial?

25mm-1.5 is 0.98"-17; would 1"-18 UNF (Fumoto part T-203) be a better fit?

-- Jeff.
 

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Discussion Starter · #3 ·
Jeff,

I would have to think you are correct. All of these cars, with the exception of the SZ series, predate the conversion (or partial conversion) to metric. I took this number directly from someone who's using FG-5Ns. He's got this size on his Bentley S.

I have an extra sump plug hanging around here but have no idea where I'd go to confirm the thread size.

If anyone is able to confirm the actual size/threads-per-inch configuration on a UG 526 Oil Sump Plug please do so and post it here. I'll change my info so that it is precisely correct, not approximately.
 

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Nasty oil plug

I've been busy with my oilplug for a while, but then i just had it.

Just i ordered an "oil change transfer pump" on EBAY.
USD 5,95 (shipping USD 9,95 :? ).

Hemmo
 

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Oilplug tool

I saw the oilplug tool just on EBAY.UK.
About 16 GBP.





:idea:
 

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Discussion Starter · #6 ·
From someone I consider an unimpeachable source:

"The UG 526 drain plug is sized 1 inch UNS (Unified Special)at 16 TPI.

It is almost certain that the alloy sump pan (I am presuming it is an alloy one) will have originally been tapped 0.0025 inch undersize. That is 1 inch UNS x 16tpi - 0.0025 inch.

Most probably the thread will be about standard now due to extended use.
"

It should not be difficult to remove the oil sump plug if you have either the original Brittool tool in the kit in the trunk or use a 13mm Allen socket.

I'm trying to decide whether to go to a neoprene washer, which should be easier to source (and have a life much longer) than an aluminum crush washer.
 

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Brian,

That's kind of funny: so the metric thread -is- a better fit, even though the original wasn't metric. ;)

Jeff.
 
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