Bob,
Test that you have 12v to the solenoid with the car in 4th gear,
ignition on and OD switch on. If not, then test that there is power to
the OD side of the 3/4 gear switch. Work backwards until you have 12v
somewhere, the forward until you get 12v at the solenoid wire (the little
black one entering the OD).
At the OD, if there is power to the solenoid, it may or may not work.
The early ODs would click when the solenoid moved. The LH types do also,
but it's so soft you can't hear it unless your ear is on the OD. Don't
go replacing the solenoid until you are sure that it's at fault. They are
expensive, but have only one moving part, so there isn't a lot to go
wrong.
Then pull off the bottom bits of the OD, using the shop manual as your
guide. Replace all the little rubber parts. They perish with age, and the
OD requires 400 psi + to work. Be sure that the pump plunger moves. It's
quite possible to install it 180 degrees out (check the drawing very
carefully and see the offset of the roller) so that it pushes once and
jams in the bore.
If, after all is done, you have electricity to the OD, solenoid works,
all rubber bits are new and the pump works, the problem is greater than
most mortals can solve. But, odds are that you can get it working with
just a few bucks and lots of time invested.
Bob
On Sat, 29 Apr 2000 08:12:07 -0700 grhacker@wfl.fha.dot.gov (Gary R
Hacker) writes:
> I have been too busy to participate lately, but I wanted to share a
> few
> things I have been able to work on with my 75 B.
>
> I have seen a few comments on u-joints and vibrations lately. I was
> working on the vibration/shaking at 60+ mph myself. I started
> trying to
> replace the u-joints on my car but ended up going to a professional
> auto
> machine shop. Lou was kind enough to allow me to watch as he
> replaced
> my old u-joints and balanced my drive shaft. He showed me why I
> would
> still be chasing my tale with drive shaft vibration if I had just
> replaced the u-joints myself. Drive shaft was straight (lucky
> there)
> but very much out of balance. After he finished, he professionally
> marked the proper orientation of shaft and yoke for the next time
> this
> operation has to be done. $50 and I was able to drive the B at 80
> mph
> for the first time. It isn't perfect yet and there is still wobble
> but
> I am taking it step by step. I then attacked the stay rod that
> hooks
> the transmission to the bell housing. After cleaning what seemed
> like
> tons of old oil and grease away from the area, I unbolted the stay
> rod
> and brackets. The rubber spacers were like mush. I haven't got
> replacements for them yet, but it may improve things when I do.
>
> The next surprise was finding that I do have an overdrive
> transmission.
> The serial number of my car indicates that this must have been put
> in by
> one of the many POs. I never thought to look that close at the
> transmission before. The overdrive does not work when I tried to
> engage
> it at the wiper switch. The wires I could find from under the car
> are
> all connected, so I am not sure where to begin troubleshooting to
> get
> the o/d to work. Any ideas?
>
> For anybody in the greater Portland, Oregon area, Club T MG's annual
> swap meet is tomorrow starting at 9 AM at Montgomery Park.
>
> "Safety Fast"
>
> Bob Hacker
> 1975 MGB
> Vancouver, Washington
>
|