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Overdrive cover bulging!!

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Overdrive cover bulging!!
#1
  This topic is about my 1966 MG MGB MkI
mgann Mike Gann
West Point, UT, USA   USA
Ok folks. I am the guy that left the overdrive switch on and now it is in-op. Wonderful suggestions from the forum. Thanks all.
Problem is I checked the oil level as a first step kind of thing and the dipstick was clean. Put in over a quart before getting an indication on the stick. Next I jacked up the car to check out the leak and the pictures are what I found. Looks to be like the solenoid got shot out of the gearbox and bulged out the cover. That is where the leak is obviously. What in the world happened? it has been working just fine. No leaks, worked everyday and then this!
My next step is to drain gearbox (yeah, the one I just filled up) and see what is under the cover. It looks like it actually bent the bolts too. I am a little freaked out at what I will find. Any ideas on this one. Thanks



Edited 1 time(s). Last edit at 2019-03-08 11:22 AM by mgann.

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albeegreen1 Avatar
albeegreen1 Gold Member bob tresch
bordentown, NJ, USA   USA
1972 MG MGB MkIII "ALBERT"
Looks like aliens.
I am sure The master , Dick Moritz can help.



"Only those who have patience to do simple things perfectly ever acquire the skill to do difficult things easily".

- James Corbett.

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dickmoritz Avatar
dickmoritz Platinum Member Dick Moritz
Philly 'burbs, PA, USA   USA
I suspect misassembly of the solenoid components. The area under the black/blue plate is not normally exposed to the 400-420 psi of pressure it takes to operate the overdrive internals, and I'd guess that it's just that kind of pressure that would cause the condition you show.

Since the solenoid area is not directly exposed to the gearbox oil supply, you can remove the black plate and solenoid assembly without draining the oil out of the gearbox. Suggest you do so and post a photo or two of the solenoid components in the order removed...

That condition would not be caused simply by leaving the overdrive switched on as long as the overdrive wiring is in the factory configuration.

Dick



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

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mgann Mike Gann
West Point, UT, USA   USA
Okay, here are the pictures. For a while I was not sure the bolts were going to come out.
First picture is just with cover off. Solenoid assembly is extending out of the hole almost 1/4 inch.
Next is the solenoid assembly hanging and the hole. The small ball bearing came out when this assembly was removed.
3rd picture is how the assembly went together. The piston was pushed right to the end or the brass cylinder and was protruding out the bottom about 1/16th. When disassembling this the piston did not move in the cylinder until forced up into the cylinder then moved smoothly.
Last picture is the deformed cover, which I suspect I will not be able to reform. I will try some heat and persuasion.
The only thing that I can think of that could be assembled incorrectly is the lower cap. It could be assembled 180 out. I thought that I had the correct orientation.
Also remember, this was operating just fine for about a month.
Thanks all for any help with this.


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dickmoritz Avatar
dickmoritz Platinum Member Dick Moritz
Philly 'burbs, PA, USA   USA
That appears to be correct. Can you measure the diameter of the ball with a micrometer or digital caliper?

Perhaps the pressure valve stuck causing dramatic over-pressurization. Suggest you remove the 3/4 hex plug and remove the pressure valve for inspection. There should be a small screen on the bottom of the valve, then the two-piece valve, possibly with some very thin shims on top, then a spring (not under tension, so don't worry about it...), a solid or perforated sleeve around the spring, and then a small funnel-shaped piece at the top. Suggest you post a photo similar to the photo of your solenoid disassembled...

Dick



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

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frnloth Avatar
frnloth Jonathan Lane
Greenwood Village, CO, USA   USA
1949 MG TC "The Blue Car"
1960 Austin-Healey 3000
1967 MG MGB Racecar "Race Car"
1971 MG MGB GT "BRiGT"
Not the first time I've seen this. Back in '88 I helped a friend build an MGB with overdrive for racing. He took it out for some test laps and after kicking it out of OD at high speed it started leaking oil and we noticed the bent cover. Seems to me that he thought that by not using the clutch when he took it out of OD it put a lot of pressure on the solenoid and thus the plate. My recollection is that we pulled it apart, replaced the cover and never had another problem, but that was a lot of years ago so I may have forgotten some details.

Not sure if that helps but there it is...

Jonathan

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chris Avatar
chris Platinum Member Chris Roop
Pendleton, OR, USA   USA
I never use the clutch to go in or out of o/d. Is that a mistake??


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frnloth Avatar
frnloth Jonathan Lane
Greenwood Village, CO, USA   USA
1949 MG TC "The Blue Car"
1960 Austin-Healey 3000
1967 MG MGB Racecar "Race Car"
1971 MG MGB GT "BRiGT"
In reply to # 3905239 by chris I never use the clutch to go in or out of o/d. Is that a mistake??

Neither do I, but in the instance in my past it was a pretty abrupt change and using the clutch might have helped to smooth things out a little.

Jonathan

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dickmoritz Avatar
dickmoritz Platinum Member Dick Moritz
Philly 'burbs, PA, USA   USA
Makes no difference at all... Most folks find engagement and disengagement of the overdrive a little more satisfying if they lift on the gas ever so slightly when engaging overdrive and applying a skinch more throttle when disengaging overdrive...

Dick

In reply to # 3905239 by chris I never use the clutch to go in or out of o/d. Is that a mistake??



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

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melbaver Avatar
melbaver Gold Member Chris Howells
Carrington, NSW, Australia   AUS
1968 MG MGB "Moneypit"
2012 Dodge Journey "Another Shopping Trolley"
For those of you who understood what Dick was saying, but were left in awe as to the origin

skinch verb
\ ˈskinch\
-ed/-ing/-s
Definition of skinch
transitive verb

dialectal, British : to be stingy or niggardly in respect to (material or a person)
intransitive verb

: to be sparing —usually used with on
tried to skinch on the food

The Australian equivalent would be a fly's dick of throttle (absolutely no pun intended).



Chris Howells

1968 MGB Purchased already dis-assembled but which is largely back together so I'm a lot less ignorant.

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albeegreen1 Avatar
albeegreen1 Gold Member bob tresch
bordentown, NJ, USA   USA
1972 MG MGB MkIII "ALBERT"
That's skosh in my shop. Another way of saying "a slight additional amount"

Dutch -German lingo.



"Only those who have patience to do simple things perfectly ever acquire the skill to do difficult things easily".

- James Corbett.

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dickmoritz Avatar
dickmoritz Platinum Member Dick Moritz
Philly 'burbs, PA, USA   USA
Thank you for translating, Chris... Although in my post it was used as a noun...



smoking smiley

Dick





In reply to # 3905276 by melbaver For those of you who understood what Dick was saying, but were left in awe as to the origin

skinch verb
\ ˈskinch\
-ed/-ing/-s
Definition of skinch
transitive verb

dialectal, British : to be stingy or niggardly in respect to (material or a person)
intransitive verb

: to be sparing —usually used with on
tried to skinch on the food

The Australian equivalent would be a fly's dick of throttle (absolutely no pun intended).



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

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Stu Rodger Avatar
Oliver, BC, Canada   CAN
1980 MG MGB "Dorian"
And here I was expecting mechanical jargon I wouldn't understand.

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Richard-Kloss Avatar
Richard-Kloss Richard Kloss
Boise, ID, USA   USA
Just a thought here, in looking at your dismantle it appears that there might be part of the solenoid housing missing. I do not see "both" of the metal end pieces that are in my solenoid housing. You do not picture the solenoid either. The new replacement one from Moss does not look like the original. First photo original second replacement.


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mgann Mike Gann
West Point, UT, USA   USA
Yes, I do not picture the steel housing as it is still in the gearbox. It is being difficult to remove. I think the over-pressure expanded it a bit.
I have removed the control valve and attached the assembled and expanded view in the pictures. There are five (5) shims in the assembly at the bottom of the spring. It all seems to be ok. Not sure what else to do. Reassemble and test?


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