An easier way to replace the check spring
(AKA thread take-up spring)
on a Singer 99K26 through to 99K31
Most service instructions advise that the upper tension check spring
be replaced from the front like the diagram above, however, I believe
my method is simpler.
Breaking down a later model 99K26 through to 99K31 class tension
A — Check spring regulator
B — Check spring
C — Tension post
D — Tension release pin
E — Tension plates
F — Tension release disk
G — Beehive spring
H2 — Stop washer
H1 — Indcator dial
H — Tension nut
Comparing the check springs from early and later model 99 class
The #32758 is no longer in production, but the #32575
can be used if you follow my instructions
"A" is a new check spring made in Taiwan to
the specs for the Singer part # 32575 (the check spring required for
early model 66 and 99 class machines. "B" is Singer part #
32758 taken from a later style 99K.
Loosen off the set screw to the side of the tension
(there is no need to remove completely)
Remove the complete tension assembly from the machine
Loosen off the cap screw
(there is no need to remove completely)
Pull the check spring regulator from the main tension, then slide off
the check spring.
Part #32757
(complete tension)
Part # 32758
(original check spring)
Part #32759
(check spring regulator)
Check spring #32758 original but slightly bent out of shape, still okay,
but a really damaged spring will need replacing
Note the position of the spring
If the tail of the #32575 check spring curls around on itself like this,
it is a good idea to trim about 5mm off with a pair of side cutters
Note the position of the spring
The check spring regulator may not sit flush with the
end of the tension stud if you don't trim the #32575 check spring, and
this may affect the effectiveness of the tension release pin (the 25mm
long rod which runs up the centre of the tension stud).
This is how you want it to look, check the spring moves freely
Retighten the cap screw when it looks correct
The top of the regulator slot should sit about even with the end of
the minus sign on the tension indicator and the arm of the spring should
rest against the top of the slot
Replace the tension with the presser foot in the down position (tension
release inactivated) and ensure the centre mark is at 12 o'clock
Tighten the set screw to the side of the tension and check the tension
is released when the presser foot is raised
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