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how to get the gearbox sealed on the selector shafts?


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Hi Marco, I had a look at your concern of the selectors rods being outside in the dirty environment under the car. I have come up with a shape/design that is functional but not overly pretty

Hi Folks, I have revisited this topic. In order to stop/reduce the oil leak at the end of the selector rods I fitted new 'O' rings and then 'Q' seals. Neither of these worked as well as I wo

L-O-V-E-L-Y ! But.. ( not negativ) One question ( not asked yet) gave me a different idea: what to do with the oil collected there? You know, the selector shaft housing vertical on the workb

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Hi Marco,

               you are a clever little sausage (that is a compliment)   

When you fitted the interlock balls you did also fit the small bar between them - please say yes.

Roger

Edited by RogerH
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Yesss,

I did it, as you told me, thank you. And I checked if the interlock works - it does.

This I did because I could have lost one ball without realising this in the chamber between.

Also checked this be shaking the hole assebly as strong as I'm able to - with everything quiet inside.

Ciao Marco

Edited by Z320
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Hi folks,

I am very sorry to tell you, one of my little helpers died a lonesome dead in my workshop - the spring loaded clamp.

She served me since surely 25 years without any complaint, always helpful and patient.

Me and my wife realized it by a very loud noise when the spring killed the plastic and the broken pieces have been flying through the workshop.

Luckily I was not next to here (afraid of fingers and teeth) and the gear box cover was positioned balanced in the squared timber.

So RIP dear spring loaded clamp. The next generation will be made of aluminium.

Ciao Marco 

Edited by Z320
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Ready, last photo,

P1110895-b.JPG.cddb498e6ef463febce4b18e3cce777e.JPG

all (6) plugs around in the housing I coated with 2K glue for the case they are not sealed, that already works well on the shaft of my old pertol pump.

I used no paper seal but "Dirko grau" (Dirko grey), that comes lovely with aluminium, and glues all 8 bolts in with Loctite medium to got the threads sealed (for the case oil comes up).

See how it works this summer....

Ciao / Cheers, Marco

 

Edited by Z320
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  • 1 year later...

Hi Folks,

I have revisited this topic.

In order to stop/reduce the oil leak at the end of the selector rods I fitted new 'O' rings and then 'Q' seals. Neither of these worked as well as I would have expected.

It may be that the counterbore is too slack for the rings.

I found an answer but it is a bodge and have always wanted a definitive answer.

Marco's engineering wizardry was perhaps a bit too much for the ordinary fiddler.

So I did a search for bits and pieces. I found the seals that I wanted  3/4"OD x 1/2"ID x 1/8" thick (3mm).  P/No.NBR07505013A  from Brammer Bearings and Seals.

I also found on ebay a very nice 3/4" end mill with 1/2" pilot - perfect.

The other day TRevor advertised an old GB on the buy/sell/swap forum - so I went for that as I needed the top cover.

The attached photos show the process -

Pic 19A shows the top cover firmly attached to the work bench

Pic 20A shows the cutter inserted and sitting on the steady

Pic 21A shows the drill attached

Pic 23A shows the centre hole counter bored

Pic 26A shows all 3 seals insitu and the metal remaining

I will set the seals in with Loctite 638

 

The process is very simple and requires no serious machinery apart from a decent cutter.

The above cost outlay including the gearbox was apprx £30. - result.

 

PS - in order to drive the cutter I needed to get my electric drill working (new lead required) having done this I found the chuck was not true - rats.

 

Roger

 

19

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26

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Edited by RogerH
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Posted (edited)

Hi Roger,

congratulations for this,

it is alway a good idea to give something a second thought how to make it more simple and for "everyone".

(I'm not jealous but count them, you got more likes - also one from me -

for only one post than me for the whole thread)

I suppose after testing you will realize what I did some week ago (sorry, I did not report) with my seals: it works fine, is better sealed but not completely.

On my gearbox the right side selector shaft leaks more than the two others, it might be the quality of the shafts surface is not good ennough.

Anyway I'm pleased with the result.

For a better result the shafts and lower end of the leaver stick must not be outside the gearbox but covered with a seald housing from below.

Ciao, Marco

Edited by Z320
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49 minutes ago, Z320 said:

 

(I'm not jealous but count them, you got more likes for only one post than me for the whole therad)

 

Ciao, Marco

Marco i am sure we all read your posts and envy your skills and thinking . Always interesting and i should have pressed the like button to keep you inspired .

Keep posting  ROY

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1 hour ago, Z320 said:

 

For a better result the shafts and lower end of the leaver stick must not be outside the gearbox but covered with a seald housing from below.

Ciao, Marco

Hi Marco,

indeed the weathering of the shaft, where the seals sit, is a problem.  I think it is possible to box that area in. I'll have a look.

I looked at the little hole in the shaft. It doesn't go anywhere and isn't fed with oil. Most odd!!

 

Roger

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On 6/27/2020 at 7:37 AM, Z320 said:

For a better result the shafts and lower end of the leaver stick must not be outside the gearbox but covered with a seald housing from below.

Ciao, Marco

Hi Marco,

I had a look at your concern of the selectors rods being outside in the dirty environment under the car.

I have come up with a shape/design that is functional but not overly pretty

I wanted to make the cover with a rounded end - a demi-hemi-sphere (1/4 sphere) and then add the sides to it but there is just not enough room to play with.

The first and second  pic shows the position of the central rod with 1st gear selected - there is actually 1/4" spare.

The third pic shows the cover attached.

It would certainly work with a thin smear of sealant around the edges

Not pretty but out of sight.  Also as it is sealed it would probably catch all the oil from the leaky seals.

 

Roger

 

P1060847a.jpg

P1060849a.jpg

P1060854a.jpg

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I like that “enclosing” a lot well done Roger.

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Roger,

If you cleaned up the welds you could take a mould and produce them in fiberglass.

As you say if it seals properly there would be no need to mess about with the rod seals. I guess they could leak as much as they liked because, eventually, the level of the oil in the “Cover” would be up to the bottom of the rod holes and so it would drain back.

A real “Thinking outside the box” idea.

(Yes… “Thinking outside the gear-box”)

 

What a quick and easy fix it would be if it works.

 

Charlie.

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Hi Charlie,

I thought about the cover acting as a seal for the dodgy 'O' rings that are fitted but that isn't really the best engineering practice.

Also I would then have a nice cutting tool going redundant.  I like the lip seals.

 

I like the idea of the fibreglass option  although it would be apprx 2mm too big but would probably  bend enough to compensate.

 

Roger

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Posted (edited)

L-O-V-E-L-Y ! But.. ( not negativ)

One question ( not asked yet) gave me a different idea: what to do with the oil collected there?

You know, the selector shaft housing vertical on the workbench is indeed wedged the rear end down in the cars frame with the gearbox!

So all oil that is collected on the rear end of your cover. It's shape is perfect! And if you drain it with a hose back to the gearbox - you don't have to seal it!

I think of the filler plug drilled and a 1/8" pipe glued in there, ready to fit a hose, the other end on your cover.

Edited by Z320
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Roger ,

If you took the mould from the INSIDE of your steel cover you would end up with an exact replica of what you have when you put fiberglass on the OUTSIDE of that mould. You could make it as thick as you liked and the cover to gearbox dimension would always be the same.

Easier still, pour Plaster of Paris into your steel cover (using a release agent) and you have a nice solid mould to vac-form a plastic cover. Cost less than a pound each and you could knock out 20 an hour.

(You do have a vac-forming machine I guess….)

 

Marco,

I feel bad for not giving you any of the credit for this idea. After all, it was YOU who put the idea in Roger’s mind.

Charlie.

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Hi Marco,

stop inventing :D

I think with the lip seal and the boot,  leaks will only be a distant memory :o

Hi Charlie

No, I do not have a vac-forming machine.

 

Roger

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9 hours ago, RogerH said:

Hi Marco,

I had a look at your concern of the selectors rods being outside in the dirty environment under the car.

I have come up with a shape/design that is functional but not overly pretty

I wanted to make the cover with a rounded end - a demi-hemi-sphere (1/4 sphere) and then add the sides to it but there is just not enough room to play with.

The first and second  pic shows the position of the central rod with 1st gear selected - there is actually 1/4" spare.

The third pic shows the cover attached.

It would certainly work with a thin smear of sealant around the edges

Not pretty but out of sight.  Also as it is sealed it would probably catch all the oil from the leaky seals.

 

Roger

 

P1060847a.jpg

P1060849a.jpg

P1060854a.jpg

Good thread both Marco/Roger for a long standing problem I knew nothing about.

My gearbox has been rebuilt with all the usual weak spots addressed apart from this one. While its under the bench I think I'll drag it out and box in the area in as you suggest Roger as I hate oil leaks as our two house cats like walking it all over the house and I get earache from the wife! I'm thinking of using Ali as I have a mate who is a dab hand with the TIG. 

Out of interest how much oil leaks in practice. Is a drain back to the GB really needed given the mod/catch tank stops any escape will it not simply find a level and return back and if so are any seals required at all?

Andy

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