About time we got into some serious stuff.
What is the collective “expert” opinion about “self-locking-nuts” as used on
I have identified three distinct design/types and have an opinion about
chronological sequence of use, but like to hear other opinions.
I note the commercial suppliers like to now supply slotted-nuts for
split-pin use in most applications, but some were originally a self-locking
nut - eg Tie-Rod end bolts were secured by self-licking nuts - NOT
slotted-nuts with split pin.
Roger Payne - XK140MC OTS; E-Type 4.2 S.1 OTS; DSV8.
From: email@example.com [mailto:firstname.lastname@example.org] On Behalf Of
Sent: Friday, 18 July 2008 10:30 PM
To: XK mailing list
Subject: Re: [xk] Red Nuts, Purple Bolts
I don’t think it is anti-seize, since it is spread all the way along some
very long bolts for the rear suspension. This stuff sure looks to me like
paint, but very thinned out like what’s left on a paint brush after you give
it a quick clean in turpentine, or like kids water color paint. Something
that doesn’t build up thick at all anyway.
My current belief, and always being glad to have corroboration or
contradictory evidence, is that it was a marker for ANF threaded fasteners,
so they wouldn’t get mixed up with BSF threaded stuff at the factory.
Remember the Mark V and XK120 were built at a time when British industry was
just starting to change over from BSF to ANF, and Jaguar seems to have done
it gradually according to component groups. The front suspension was all new
design in 1948, and is all ANF threads. So is the XK engine, but the pushrod
engine was still all BSF threads. I found red bolts holding the oil pan
baffles of my XK120 engine. I have not found one single red fastener on my
Mark V pushrod engine, which is all BSF, but I’m finding red on all the
front suspension, all the brake backing plates, the rear shocks, and the
front end of the leaf springs, i.e. anything that was a new design for 1948
and not a carry-over from the Mark IV.
The exception would be components bought in whole from an outsider like
carbs and gearboxes, still all BSF and no red bolts.
I suspect the BEES and AUTO bolt makers dunked their ANF products in a
thinned out solution of 1 part red paint and 9 parts turpentine before
sending the order to Jaguar, possibly at Jaguar’s request.
This would hold true for Mark VII as well, as Ed says about his, since it
was nearly all ANF threads like XK120. I suspect that after the BSF stuff
was mostly cleared out of the factory, say by the mid 50s, that the need for
red on the ANF stuff would be mitigated. We hear of fewer red bolts on XK140
The torsion bar reaction arms look to me like forgings, not sand castings,
and I did not see any red on them, nor in fact any paint at all, but the
clamping bolts for them were red. The arms would not be Glyptal, since there
are no ball bearings and oil involved here. You remember that Glyptal was
only important on the INSIDE of the differential.
Charles, you might want to organize your bolts and nuts according to
diameter, length and thread pitch, and then go through the fasteners list in
the back of the parts catalogue and see if you can identify part numbers for
some of them. Anything with an unusual feature like a castle nut or a bolt
with a hole in it for a cotter pin will be a C part number, so set them
aside for later. For example 4 of the 8 bolts holding the lower wishbone
shaft to the chassis are special shoulder bolts, and the other 4 are
ordinary fully threaded bolts (all 8 are red) and the nuts for them are a
special self locking nut. I’ve been pretty careful about keeping mine
separated and identified, so I can probably help you out there on specific
Rob Reilly - 679187