On Thu, 19 Jun 1997 22:27:25 -0400 "Richard A. Boris"
<borisri@earthlink.net> writes:
>Hi Everyone:
>
>A fellow member of the MG Car Club-Long Island Center (MGCC-LIC) has a
>79B roadster with a recently installed LH overdrive. The basic
>overdrive
>unit prior to installation had "o"ring replacements and basic pump
>check-out. The unit functioned for approx 1,000 miles and now will not
>engage in the overdrive position. Checked out the solenoid with normal
>car wiring and direct 12 volts, and the solenoid functioned. Also a
>replacement solenoid was tried with same results. The car was on a
>lift
>with rear wheels turing approx 25 MPH to see what happens when the
>electric power is applied, solenoid clicked in but the unit still
>failed
>to function. Anyone out there have any suggestions? and, can the LH
>unit
>be removed from the car on a lift without removal of the entire engine
>and gearbox to faciltate bench repairs?
>
> Thanks: Rich
>Boris 67B roadster
>
Rich,
In the factory manual is a test with a pressure gauge. Car on the lift,
fourth gear, 30 mph or so, the pressure should indicate 400-420 psi. The
adapter to the relief valve plug is 18G 251E. You might, however, just
put your thumb over the hole to see if there is "any" pressure. My guess
is that you don't have any. Suggestions--replace all the O rings again,
replace the springs in the non-return valve and the relief valve, and
replace the little ball in the relief valve. While you have the thing
open, check that the pump itself is free to move up and down. If you are
working on the car when it's low to the ground, it's easy to get
disoriented and replace the pump piston 180 degrees out. There are front
and back to it. It will then work for a while but then stick in one
position. If yours is doing that, it's just a 180 turn to get it right,
(once you get the piston out) I ended up putting small flat pieces of
metal on the top of the roller, then turning the prop shaft by hand to
push the piston, then a thicker piece of metal, etc until the thing
dropped onto my face, just as the manual says it does.
Best of luck with this.
MGBob @ juno.com
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