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Blue label LH O.D.Solenoid

Moss Motors
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naturbar Avatar
naturbar Buz Natur
Asheville, N.C., USA   USA
1977 MG MGB
Another question about the solenoid. I am attaching a pic of the solenoid disassembled - I understand how a typical one operates but I can't figure out how this one works. When the plunger is placed into the cap and seated, I can't see how it can move. With it assembled, I grounded the case and applied 12 Vdc to the wire - nothing happened (a small arc when applying power) . There is 14.3 ohms thru the coil. Also is the an orientation to the hole in the o'ringed shaft? I just can't see how this device can mechanically operate. I know we have some very knowledgeable people on this forum ...help wanted.

Buz



Buz

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dickmoritz Avatar
dickmoritz Gold Member Dick Moritz
Philly 'burbs, PA, USA   USA
Buz,

The "Off" position for the solenoid plunger is with the plunger in the down position. When the solenoid is energized, the solenoid pushes it up to seal off one port of the Y connector. The Y connector directs oil pressure to one of two passages. One goes directly back into the overdrive sump, the other goes to the passages that lead to the area behind the operating pistons, such that they push the pistons out against the bridge pieces, pulling the cone clutch off the annulus and locking it to the I.D. of the brake ring.

When you switch the overdrive off, there is no longer upward electromagnetic pressure on the solenoid plunger, so oil pressure pushes it back down, uncovering the drainage port so that the oil pressure that is continuously generated by the overdrive oil pump is directed straight back into the sump for recycling.

There is no particular orientation to the plunger, other than the fact that the little end points upward... grinning smiley

Dick



Errabundi Saepe, Semper Certi
(Often wrong, but always certain)

course2kid Jeffrey Johnson
Fountain Valley, CA, USA   USA
1979 MG MGB "Lucy (Lucifer)"
x2 what Dick said

The reason you don't see much, if anything on the bench is because the plunger only moves a tiny bit to seat the ball bearing and redirect the oil flow.

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naturbar Avatar
naturbar Buz Natur
Asheville, N.C., USA   USA
1977 MG MGB
In reply to # 3514785 by course2kid x2 what Dick said

The reason you don't see much, if anything on the bench is because the plunger only moves a tiny bit to seat the ball bearing and redirect the oil flow.

Ball bearing? Rut Roh.. Did not see a ball beating come it w/ solenoid. I don't see It listed either on Moss site ? What I am I missing?



Buz

ohlord Avatar
ohlord Gold Member Rob C
North of Seattle, N.W., USA   USA
1957 Land Rover Series I "EYEYIYI"
1971 MG MGB
1971 MG MGB "Bedouin 2"
Properly operating which they do near 100% of the time
The solenoid when energized snaps with very noticible force and easily noticed movement
While not much it is very noticible especially when tested in hand at the workbech on an LH Overdrive solenoid.
Tested on a bathroom scale energized the plunger shouldn't move with anything less than about 8 pounds,which when energized , in hand rocks your hand sharply
Remove Ball bearing to prevent loss while testing at bench.
In reply to # 3514785 by course2kid x2 what Dick said

The reason you don't see much, if anything on the bench is because the plunger only moves a tiny bit to seat the ball bearing and redirect the oil flow.



"I'm a long way gone down this wild road I'm on
It's gonna take me where I'm bound
It's a long way around"



"These are the days that must happen to you"

RD2 Radar/ Electronic Warfare Technician
Vietnam 1969-1972

naturbar Avatar
naturbar Buz Natur
Asheville, N.C., USA   USA
1977 MG MGB
In reply to # 3514769 by dickmoritz Buz,

The "Off" position for the solenoid plunger is with the plunger in the down position. When the solenoid is energized, the solenoid pushes it up to seal off one port of the Y connector. The Y connector directs oil pressure to one of two passages. One goes directly back into the overdrive sump, the other goes to the passages that lead to the area behind the operating pistons, such that they push the pistons out against the bridge pieces, pulling the cone clutch off the annulus and locking it to the I.D. of the brake ring.

When you switch the overdrive off, there is no longer upward electromagnetic pressure on the solenoid plunger, so oil pressure pushes it back down, uncovering the drainage port so that the oil pressure that is continuously generated by the overdrive oil pump is directed straight back into the sump for recycling.

There is no particular orientation to the plunger, other than the fact that the little end points upward... grinning smiley

Dick

Dick,
Is there a way to confirm if solenoid is functional? I also forgot to post pic, will with this post. I know about clutching your anus while trying to I.D. some of these parts..seems to always be a lot of clutching when learning new stuff...



Buz


Attachments:
image.jpeg    57.5 KB
image.jpeg

ohlord Avatar
ohlord Gold Member Rob C
North of Seattle, N.W., USA   USA
1957 Land Rover Series I "EYEYIYI"
1971 MG MGB
1971 MG MGB "Bedouin 2"
See my hand test above.
The ball bearing sits atop the solenoid plunger.
Missing it is one of the chief causes of complaints of OD failure to operate.
With an ohm meter solenoid operation can also be verified.

In reply to # 3514825 by naturbar
In reply to # 3514769 by dickmoritz Buz,

The "Off" position for the solenoid plunger is with the plunger in the down position. When the solenoid is energized, the solenoid pushes it up to seal off one port of the Y connector. The Y connector directs oil pressure to one of two passages. One goes directly back into the overdrive sump, the other goes to the passages that lead to the area behind the operating pistons, such that they push the pistons out against the bridge pieces, pulling the cone clutch off the annulus and locking it to the I.D. of the brake ring.

When you switch the overdrive off, there is no longer upward electromagnetic pressure on the solenoid plunger, so oil pressure pushes it back down, uncovering the drainage port so that the oil pressure that is continuously generated by the overdrive oil pump is directed straight back into the sump for recycling.

There is no particular orientation to the plunger, other than the fact that the little end points upward... grinning smiley

Dick

Dick,
Is there a way to confirm if solenoid is functional? I also forgot to post pic, will with this post. I know about clutching your anus while trying to I.D. some of these parts..seems to always be a lot of clutching when learning new stuff...



"I'm a long way gone down this wild road I'm on
It's gonna take me where I'm bound
It's a long way around"



"These are the days that must happen to you"

RD2 Radar/ Electronic Warfare Technician
Vietnam 1969-1972

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naturbar Avatar
naturbar Buz Natur
Asheville, N.C., USA   USA
1977 MG MGB
Rob,
To be clear, the plunger is the second part from right in my pic...ball bearing is captured atop the plunger, inside the cap? Happen to know diameter of ball ? Why isn't ball bearing shown in Moss?



Buz

dickmoritz Avatar
dickmoritz Gold Member Dick Moritz
Philly 'burbs, PA, USA   USA
Buz,

14-18ohms through the solenoid coil is about right. There needs to be a ball above the solenoid plunger, Moss 329-820. This ball is specific to the task.

You can bench test the solenoid assembly by fitting the lower cover plate to the solenoid with the plunger inserted down into the solenoid. Apply 12 volts to the solenoid, positive to the solenoid feed wire, negative to the metal body of the solenoid housing. When you apply voltage, the plunger should pop up, not dangerously so. It will likely not drop down without very slight hand pressure, since there will not be hydraulic pressure to push it down. That being said, if the solenoid measures within the proper range of ohms, it is not at all likely to be faulty.

Do check inside the top hat to see if the little check ball is present. If not, the overdrive will not engage. The ball from Moss is only about twenty cents, but it probably comes with thirty or forty bucks in shipping charges... eye popping smiley If you find you need one, let me know. I always keep several on hand and would be happy to mail you one...

Dick

In reply to # 3514825 by naturbar
In reply to # 3514769 by dickmoritz Buz,

The "Off" position for the solenoid plunger is with the plunger in the down position. When the solenoid is energized, the solenoid pushes it up to seal off one port of the Y connector. The Y connector directs oil pressure to one of two passages. One goes directly back into the overdrive sump, the other goes to the passages that lead to the area behind the operating pistons, such that they push the pistons out against the bridge pieces, pulling the cone clutch off the annulus and locking it to the I.D. of the brake ring.

When you switch the overdrive off, there is no longer upward electromagnetic pressure on the solenoid plunger, so oil pressure pushes it back down, uncovering the drainage port so that the oil pressure that is continuously generated by the overdrive oil pump is directed straight back into the sump for recycling.

There is no particular orientation to the plunger, other than the fact that the little end points upward... grinning smiley

Dick

Dick,
Is there a way to confirm if solenoid is functional? I also forgot to post pic, will with this post. I know about clutching your anus while trying to I.D. some of these parts..seems to always be a lot of clutching when learning new stuff...



Errabundi Saepe, Semper Certi
(Often wrong, but always certain)

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dickmoritz Avatar
dickmoritz Gold Member Dick Moritz
Philly 'burbs, PA, USA   USA
Buz,

If you're lacking the ball atop the plunger, I can also give you the dimensions. You can likely get one from an industrial bearing supply house...

Dick



Errabundi Saepe, Semper Certi
(Often wrong, but always certain)

naturbar Avatar
naturbar Buz Natur
Asheville, N.C., USA   USA
1977 MG MGB
Dick,
I found a ball which is .197 diameter.... fits nicely. When assembled w/plunger deactivated, I can blow air thru the small hole atop the hat...when activated I can see the ball thru the side holes and only a small amount of air can be blown thru top hole. If you have time to measure your ball (oh boy I can hear it now) I'd appreciate it, thanks.


Thank you Jeffery and Rob for your inputs, greatly appreciated!

Buz



Buz

ohlord Avatar
ohlord Gold Member Rob C
North of Seattle, N.W., USA   USA
1957 Land Rover Series I "EYEYIYI"
1971 MG MGB
1971 MG MGB "Bedouin 2"
0.1875 diameter. 3/16th in.
Yes 2nd from right is plunger.



"I'm a long way gone down this wild road I'm on
It's gonna take me where I'm bound
It's a long way around"



"These are the days that must happen to you"

RD2 Radar/ Electronic Warfare Technician
Vietnam 1969-1972



Edited 1 time(s). Last edit at 2017-05-19 04:29 PM by ohlord.

dickmoritz Avatar
dickmoritz Gold Member Dick Moritz
Philly 'burbs, PA, USA   USA
Caution is in order here. There is no ball in the overdrive that measures 0.197 or close thereto. Rob is correct that the ball above the solenoid plunger should be 3/16,which is 0.1875. Coincidentally this is the same size ball that is used to index the oil pump drive cam on the gearbox third motion shaft.

The only other ball in the overdrive is the one at the non-return valve at the bottom of the pump assembly. This ball should measure 0.218. It is not uncommon for this ball to inadvertently get swapped with the ball from the solenoid plunger, since they are fairly close in size to each other. If they are swapped, the smaller ball will disappear down into the spring in the non-return valve, and the larger ball will not seal properly above the solenoid.

I suggest you measure the balls with a 0-1 inch micrometer unless you're really good with a digital caliper, and assure that you have the proper balls ( eye popping smiley ) for both the solenoid plunger and the non-return valve...

Dick




In reply to # 3514917 by naturbar Dick,
I found a ball which is .197 diameter.... fits nicely. When assembled w/plunger deactivated, I can blow air thru the small hole atop the hat...when activated I can see the ball thru the side holes and only a small amount of air can be blown thru top hole. If you have time to measure your ball (oh boy I can hear it now) I'd appreciate it, thanks.


Thank you Jeffery and Rob for your inputs, greatly appreciated!

Buz



Errabundi Saepe, Semper Certi
(Often wrong, but always certain)

naturbar Avatar
naturbar Buz Natur
Asheville, N.C., USA   USA
1977 MG MGB
In reply to # 3514961 by ohlord 0.1875 diameter. 3/16th in.
Yes 2nd from right is plunger.

Thank you Rob, it's nice to have such helpful fellow enthusiast .



Buz

naturbar Avatar
naturbar Buz Natur
Asheville, N.C., USA   USA
1977 MG MGB
Dick,
I had the oil pump out at a different time, so I know the balls weren't crossed up. I measured the oil pump ball it's .218. When I took solenoid apart it was on my bench and I really believe there was no ball in there. So I'll try to source the 3/16 ball. Really appreciate your assistance.

Buz



Buz

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