> It worked for a while and quit again...back under the car I found
> the plunger resting on the bracket ear.
Resting on the bracket ear is definitely wrong. There should be either an
adjustable bolt or a rubber bumper that limits the plunger movement. Early
manuals specify 1/4" between the stop and the engaged plunger; apparently
that specification was later reduced to .150"-.155" (per Nelson Riedel, I
don't have my manuals handy to check). Nelson recommends drilling and
tapping the ear for a 1/4-28 setscrew & locknut to add the adjustment to
units that lack it.
Note that having this adjustment too large is hazardous ... if the solenoid
cannot lift the plunger, it will burn itself up in short order. However, if
the adjustment is too small, the OD may not disengage.
> Question: Is there a way to check the position of the actuating
> lever?
Yes there is. What you do is measure how far the ball that forms the actual
valve gets lifted off of it's seat. This is becoming a necessity on many
units, because wear in the cam, the valve spindle and the ball seat has made
the hole in the side inaccurate. In addition if any of those parts have
been replaced, the hole will also be inaccurate.
Opinions vary somewhat as to what the "correct" ball lift is, some people
recommend as little as .010" at the ball, to soften the engagement of the
OD. I personally don't believe that was the factory's intent ... the
engagement is controlled in other ways and in fact the accumulator design
was changed for the IRS cars just to soften the engagement (IMO) ... so I
believe it should be set to 3/32" or roughly .100". Actually, anywhere
between 1/16" and 1/8" will work fine.
Basically, you remove the plug, spring and plunger above the valve. Then
with the solenoid not engaged, measure the distance from the plug seat to
the top of the ball. This can be done with the depth probe of vernier or
dial calipers, or a regular depth micrometer if you happen to have one, or
with a dial gauge and a suitable plunger. (Nelson Riedel reported that some
1/8" od hard brass tubing from the hobby shop worked well as a plunger for
the dial gauge.) Then lift the solenoid plunger by hand (to keep from
launching the ball), engage the solenoid, and measure the new ball position.
The difference is the ball lift. Watch that the ball stays centered in the
hole (and hence on the end of the valve spindle).
> If this is so, then I'd like to get a dimension between the bottom
> of the plunger and the bracket ear when the plunger is at rest so
> I can set the actuating lever correctly.
Not sure I understand this question. IMO measuring the ball lift is the
only correct way to set the actuating lever. How far the plunger drops is a
different measurement, since the lever does not limit how far it can drop.
> Bob Stahlbush, pres., bmcne
I'm not familiar with your club, Bob, do you have a web site ?
BTW, I have a copy of the Laycock A-type OD service manual that has been
converted into a MS Word document in searchable text format. It's about
3MB. If you would like a copy emailed to you, just let me know. I just
found an OCR error, so the PDF version I distributed before has a mistake in
it. One of these days I'll get it up on a club website somewhere, but it
hasn't happened yet.
Randall
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