<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META content="text/html; charset=utf-8" http-equiv=Content-Type>
<META name=GENERATOR content="MSHTML 8.00.6001.23588">
<STYLE></STYLE>
</HEAD>
<BODY
style="WORD-WRAP: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space"
bgColor=#ffffff>
<DIV><FONT size=2>The main difference between the earlier black label on all
chrome bumper cars and the later blue label ODs on all rubber bumper cars is
speedo gearing - the black label is 1280 turns per mile and the blue label is
1000 turns - a very significant different to speedo reading if you use the
'other' one. This change was made on RHD cars as well and they always had
OD on 3rd and 4th. OD was restricted on North American spec cars only for
the 1977 year on as part of emissions reduction, tied in with the 4th gear only
vacuum advance system.</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>But never mind swapping the OD, it beggars belief that they
could give it back with it still not working after having it all that
time! You could take it back, but I wouldn't based on previous
experience. You can check for electrical continuity by putting an ammeter
in series with the manual switch. With the ignition on, in 4th gear, and
the manual switch on, you should see about an amp flowing. If not then you
will have to check for 12v on each side of the gearbox switch to see where you
have 12v and where you don't. As they had the gearbox out to change the OD
it's quite likely they mucked up the connections there. You can get at the
switch by lowering the rear cross-member and going in through the top of the
tunnel, exact method depends on which of your cars is involved. But first
peer up from below to check the wire from the solenoid cover is attached via a
bullet connector to the sub-harness that goes over the gearbox, and both spades
are on the switch, it should be just visible.</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>If you DO see an amp, then the problem is mechanical or
hydraulic. First thing would be to drop the solenoid and check that the
plunger moves into the central position freely when powered, and the little ball
bearing is present between plunger and cap <A
href="http://www.mgb-stuff.org.uk/lhod.htm#5">http://www.mgb-stuff.org.uk/lhod.htm#5</A>
Check all seals are sound, the one on the plunger is essential to develop
pressure. After that really it needs a high-pressure gauge to measure the
pressure. You could remove the pressure relief valve assembly and check it
is complete and correctly assembled <A
href="http://www.mgb-stuff.org.uk/goc.htm#3">http://www.mgb-stuff.org.uk/goc.htm#3</A>,
ditto the pump, but you would still need the gauge to see if you have pressure
or not.</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>PaulH.</FONT></DIV>
<BLOCKQUOTE
style="BORDER-LEFT: #000000 2px solid; PADDING-LEFT: 5px; PADDING-RIGHT: 0px; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV><FONT size=2></FONT><BR></DIV>The only difference is that the blue label
unit only functions in 4th gear, not 3rd and 4th. Maybe you should try
disabling the lockout switch.</BLOCKQUOTE></BODY></HTML>