Bill,
Yep, your stuck piston sounds just like my stuck piston.
There may be a better way to free the thing, but I did it more-or-less
in this manner.
Jack up the back axle so that you can turn the driveshaft.
Put your fingers up inside the OD so that you can feel the cam on the
output shaft rotating as you turn the driveshaft. This will give you an
idea of the dimensions and spaces involved here.
When you know that the cam is away from the piston roller, using a
short dowel as a cushion, gently tap the piston back up. You are trying
to get the thing straight in the bore. When it is up somewhat, but with
the roller clear of the output shaft, turn it with the smallest pliars
you have.
After 200-300 attempts to do this, then it will suddenly fall right out
in your face.
When you reinstall, the piston should move easily in and out. I tested
the orientation by pushing it in place with a finger and then turning the
driveshaft to test the action before I buttoned it up.
I did not find any evidence of damage. There were no scores on the
piston or the cylinder, or on the output shaft or roller. It probably got
shoved out one time and became stuck, after which it was immobilised.
One tip--jack the car way up so that you can focus your eyes on the
unit. You will be looking at it for a long time, and you will need room
to tap with a hammer.
I sure hope that this works for you. OD is nice to have.
Bob
'72 GT also
On Tue, 19 Jan 1999 10:04:58 PST willsmg@excite.com writes:
>On Sat, 16 Jan 1999 14:52:34 EST, Bob Howard wrote:
>
>> While you are replacing them (O-rings)($20) check that the
>orientation of
>the
>> pump piston is correct. If it's 180 degrees out, it will push down
>once
>> and bind in the bore of the pump. Look carefully at it--the roller
>> carriers are not quite identical, and that's how one determines the
>> different sides.
>
>Bob:
>
>You may have diagnosed the problem with my '72 overdrive. It has not
>worked
>since I purchased the car. I checked out all the electrical
>connections and
>all is working fine. I then went at replacing the O-rings. I was
>able to
>replace all - except for those on the pump piston. I was not able to
>remove
>the pump piston. I thought there should be enough spring pressure to
>push
>it out with the retaining plug removed. It didn't come out. It appears
>to be
>stuck in the down position. Does this sound like the reversed piston
>problem you described? How does one go about removing the piston when
>it is
>stuck down? What is the damage likely to be?
>
>Hope you can enlighten me on this.
>
>Thanx
>
>Bill
>72 MGB GT
>
>
>
>
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