How to set a Marsden lock nut?

Gary Ash

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May 25, 2004, 9:20:06 PM5/25/04

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My M5 had a number of Marsden nuts on various parts of the suspension.
During the restoration I bought some new ones from Mr.G (www.mrgusa.com) and
some other places. They are sort of like castle nuts with narrow slits on
each face about halfway down, but I noticed that they don't really have any
holding torque when I put them on. Recently, I saw some mention of
"hitting" the Marsden nuts. I tried laying one of them on the top of the
bench vise and gave it a good whack with a 3 lb hammer on the face that was
slit. Now when I put it on a bolt it is tight. So, what is the right
technique for using these nuts on spring shackles, etc. ? I figured that an
all-steel lock nut was better than the nylon insert locknuts for car use.
Maybe the Marsden nuts are old technology and the deformed-thread type is
the new stuff. Any opinions? [As if the Stude news group didn't have
opinions, LOL!]

Gary Ash
Dartmouth, MA
'48 M5
'65 Wagonaire
www.studegarage.com

Sonny

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May 25, 2004, 10:19:29 PM5/25/04

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Funny you should ask about this Gary. It brought back some fond memories.
When I was a pup in the 'ol USMC, I didn't have a garage to pursue my habit,
so I ended up working at night in the old Quonset huts at the base Motor-T
area. I helped my buddy Jessie who worked there at night sometimes, and we
also turned out a bunch of '53 to '56 Furd pickup drive train conversions.
He used those nuts on some of the heavier frame stuff. He liked 'em, they
were free and I believe they were grade eight. He used a special tool, he
called a "brace" to set the nuts, (in fact, that's the first time I've ever
heard the proper name for those nuts, he just called 'em "castle nuts").

Anyway, the tool looked like a heavy-duty truck lug wrench, straight, solid
rod about 18 inches long, with a big, round, tapered socket looking deal on
the end. When we torqued the nut down, you put the tool over the nut and
whacked the end of the rod on the brace, like you're hitting a chisel. I
know for sure that they didn't loosen after that. <G> Oh, if I remember
correctly, some of the bolts were drilled for cotter pins too, like a wheel
nut.
--
Sonny
http://RacingStudebakers.com

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Gary Ash

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May 26, 2004, 8:53:15 AM5/26/04

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That explanation makes sense, though I sure can't figure out how I could get
such a tool into some of the spots where these nuts are and then swing a
hammer. I think I'll just use some modern lock nuts with deformed threads.

Thanks.

Gary Ash
Dartmouth, MA

Ron Butts

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May 26, 2004, 12:28:51 PM5/26/04

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Gary
The style nut with "deformed threads" you are talking about is called
toplock nuts. Not to be confused with the nylon insert locknuts. Get them
in grade 8, they have the gold colored finish on them. I use them all the
time and never had a problem.
Ron

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PwrHawk

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May 27, 2004, 7:35:02 AM5/27/04

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Quonset huts?? Now that's old Corps!

Semper Fi!

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