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how to get the gearbox sealed on the selector shafts?


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Hi there,

my gearbox has two breather drills, anyway it looses oil on the selector shafts.

O-rings and cover plate are there and the bolts are tight - but it is not sealed there.

Any idea to get this sealed without dismantling the gear box top cover?

Ciao / Cheers, Marco 

P1110826-b.JPG.bfd73d4144e826d73d8e04d2d796b7dd.JPG

Edited by Z320
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Hi Marco,

  in simple terms no.

The Top cover needs to come off.

Essentially this is easy but there are three little problems.

Remove the top cover and gear stick.

The rods are held in place by taper screws - use a 4 or 8 point socket to undo them. WARNING these can be very tight and may shear off.

Remove the three sets of detent balls/springs and keep them separate.

Remove the reverse rod.   and remove the interlock ball and shaft.

Remove the 1st/2nd rod and its interlock ball.

Remove 3rd/4th (central) rod.

You now have access to the three seals.

Remove the seal plate and the seals.

You can use the original 'O' ring seals but they will probably leak.  I use the Q seals - these have a 4 leaf clover cross section

When that are in place ensure you have a snug packing washer to stop them floating in and out.

I installed my Q rings with a little coating of Silicon gasket Goo around the outside  https://www.moss-europe.co.uk/gasket-maker-silicone-sealant-black-200ml-ggl1009.html

https://maydayseals.co.uk/search?controller=search&orderby=position&orderway=desc&search_query=Quad+seals&submit_search=

Fit the seal plate

When you install the rods coat them in a smear of oil to stop the gasket goo adhering.to the rod.

INSTALLATION

fit the centre 3/4 rod - fit the small interlock rod and ball to the 1/2 rod side install the 1/2 rod

Install the rev rod interlock ball (make sure the interlock rod is in place).

Fit the detent balls/springs

Tighten the gear fork taper screws (I wired locked mine) 

Take plenty of photo's to ensure you have everything the right way.

 

It is easier than it sounds.

 

Roger

PS - the above comes from the excellent Buckeye website

 

 

 

Edited by RogerH
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Hi Roger,

thank you for your anser, I had a closer look and indeed this seems to be the way.

Sound like it loses it's amazement after the first time doing it.

Buckeye tells the O-ring size 1/2" x 11/16" x 3/32", which is 12.7 mm x 17,5 mm x 2.4 mm.

What about fitting a modern radial seal ring 12.0 x 18.0 x 5.0 mm?

Is 12 mm to tight for the shaft 12,7 mm? Did anyone do this?

Ciao / Cheers, Marco

 

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Hi Marco,

                  I looked into the lip seal (radial seal) idea.

12mm ID will not fit at all.  If you go down the 18mm OD then you will need to counter bore the three holes in the top cover.  I considered this also.

I purchased a very nice milling cutter that had a 1/2" pilot.  I think it is 3/4"OD 

 

To go with my 'Q' seals I also did another fix - I noticed that many of our gearboxes have a plate on the top that gives access to a cavity behind the gear area.

I cut a hole in this cavity and put a plastic tie wrap on each rod.  This causes the oil to drip off into the cavity

I have left as is at present as this is enough to stop the leaking from the rear of the rods.

Eventually the cavity will fill up to the rod holes and may start leaking again.  I can either drain the cavity or build in a drain pipe back into the GB !!

 

Roger

 

P1060608a.jpg

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Hi Roger,

I own a lathe but unfortunately no milling machine. So I'm limited in my possibilities.

So one idea is to make 3 adaptor rings, 

one end suitable to press/clue in where the O-rings should be,

the other ends suitable for the new lip seals, without any cover anymore.

What do you think about this.

Ciao, Marco 

Edited by Z320
reduced type size
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Hi Marco,

           the adaptor rings will have some depth (fore/aft dimension) and there is not much room there when the rods are pushed forwards.

it would be worth experimenting with.

The rectangular hole in my top cover was done by hand.  Drill 4 holes for the corners. Chain drill the sides and then file/burr to shape.

Roger

 

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19 minutes ago, RogerH said:

Hi Marco,

...

The rectangular hole in my top cover was done by hand.  Drill 4 holes for the corners. Chain drill the sides and then file/burr to shape.

Roger

 

Hi Roger,

if in this forum there would be a hand-clap emoji - you would get it for this post.

Indeed the challenge is always: how can I make it with my limited possibilities or a minimum of more of tools or help.

This evening the gear box top cover will be out from the car.

Ciao Marco 

 

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Hi Marco,

            on the gearbox top covers that have the access panel, I was expecting to find all sorts of stuff inside the cavity - micro switches , oil pumps, interocitors etc.

But it is empty. I wonder why it is there.

 

Roger

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Hi there,

the top cover was out very fast and I guess it will also be in pieces very quickly (have no time now).

What I noticed immediately was a little damage on the selector shaft of gear 3/4, like a center punch to make a drill there.

That will never be oil sealed because this damage always goes through the seal by going from #4 to N to #4.

With a gloser look and a piece of wire I realized IT IS A DRILL THROUGHT THE SHAFT (d about 1.7 - 1.8 mm, fortunately mainly filled with grease).

This can not be there by accident, I guess it's a "oil pump" to lubricate the outer parts of the shafts and the gear stick!

This will never be oil sealed this way and this was not the plan of the ingeneurs of the car due to their time..

Any ideas?

P1110836-b.JPG.ff81bf501c03fda2b3f923e87977b4b4.JPG 4th gear in

P1110830-b.JPG.63aa029964486c059ac420b57f4abcf5.JPG N in and oil out

Edited by Z320
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Hi Marco,

       I've just had a reply from another forum.  The chap suggests it may be to stop hydraulic problems !!!. 

He has noted it on a number of rods especially on the small chassis GB's.

If it was me I would fill the hole and forget about it.

Roger

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I had this oil leakage from the selector shafts a while back, getting progressively worse, and last year decided to follow Rogers advise and install the two part seals from Mayday Seals  (01242 241022). They were an "X" section which required a spacer - AE 122 and the seal Q-112. Since fitting them around 24 months ago the leaks from that area have dried up completely. However, the joint from gearbox to overdrive has started leaking much more since- I shall be removing the gearbox next year but in the meantime resorting to attempting to plug the leak with some form of adhesive from outside. I know- sounds dodgy, but it is temporary, hopefully!

Does a dry gearbox actually exist?

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1 hour ago, signalredshaker said:

I had this oil leakage from the selector shafts a while back, getting progressively worse, and last year decided to follow Rogers advise and install the two part seals from Mayday Seals  (01242 241022). They were an "X" section which required a spacer - AE 122 and the seal Q-112. Since fitting them around 24 months ago the leaks from that area have dried up completely. However, the joint from gearbox to overdrive has started leaking much more since- I shall be removing the gearbox next year but in the meantime resorting to attempting to plug the leak with some form of adhesive from outside. I know- sounds dodgy, but it is temporary, hopefully!

Does a dry gearbox actually exist?

I didn't know about the spacer and made my own.

I also had the increased leak from below. I suspect it was always there but being drowned by the leaking rods from above.

I tried to stem the flow by applying  a significant layer of silicon sealant. It worked for a short time 2 - 3 weeks until the oil found a way out.

I suspect I will be removing the box in the spring.

 

Roger

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Hi Roger,

thank you for your detailed description.

For 7/16 square head bolt I own a single 13 mm “Gear Lock” socket.

This was the moment to buy a set of them, the 9 mm socket fits perfect on the 5/6 (8 mm) square head.

P1110847-b.JPG.dd309717e0e973fe7bb2bfb579301352.JPG

I also ordered some types of modern shaft seals 12 mm and 13 mm for the 1/2" shafts, problem is there is only about 20 mm (outside) space for each.

First idea was to put the 12/19 mm (ID/OD) seal in a suitable “cup” with OD 20 mm, but the 12 mm seal is too tight (inside 11 mm) on the shaft and I damaged the outer lip.

P1110848-b.JPG.93bb65b1283ff2eb7ef725ab296ca795.JPG

The 13 mm seal measured inside 12 mm and fits perfect on the 1/2" shaft, with a bit of challenge to put it over a smaller “cup”.

The rim is 0.4 mm tall, fits between the seals outer body (is inside rubber coated) and the spring compressed lip – also when the shaft goes through.

P1110851-b.JPG.49077fd83c486ea8ff813b9fcd3c347d.JPG

The left one is the way I go, now I’m waiting for 2 more seals….

Ciao / Cheers, Marco

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Hi Marco,

                    that looks very impressive.  I was considering doing something similar but decided on using the Q seals as recommended by another forum poster quite a while ago.

 

Now here is another challenge - the original seals leaked eventually. The oil comes along the rods from front to back.

The oil will still move along the rods even with the new seals in place.

Where does the oil end up?

On my set-up, the oil is gathering in the front cavity where some top covers have an access panel.

Given time this will need draining.   maybe a pipe in there running direct into the GB 

 

Roger

Edited by RogerH
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Hi Roger,

the shafts are no one way direction, what ever oil comes up will go down again, I do not worry about that.

You are the man who can check that: open your inspection cover, fill it up with oil and see the next morning about the remainig level.

Ciao Marco

 

Edited by Z320
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OK, here ist comes,

glued a "bar" made of brass with Loctite 638 (I love it) in the "oil pump" drill and smoothed the surface.

P1110866-b.JPG.3f8258a654ea9162a78aba9b05beb4cc.JPG

Also glued the adaptor rings in the old seal seats, removed all Loctite 638 that went out below very proper.

P1110871-b.JPG.2765e27f7caea30680acb95109c5600f.JPG

Some kind of "unusuall": the shaft lip seals sit not in the new seal seats but on the tall rim, which goes in the gap between sprink loaded lip and seal housing.

P1110875-b.JPG.71aaf2302b0f234a11df77bf6f40022c.JPG

Here you see why: no space left for normal use. The seals have been "pressed" in position with gently punches (used a suitabe nut and an extecion).

P1110876-b.JPG.4fdb8c13dad551972b73dd9b0e3ede40.JPG

Ready, 6.2 mm high, I hoped for 6.0 mm, that should fit anyway for the reverse gear (that's the critical one).

P1110879-b.JPG.8f9a4cb0c5b5da1db4e0c7affe5e880e.JPG

To bring the interlock balls in position I used a little helper, a M12 rod, 106 mm long, easy job with him.

Below you see two other little helpers, a piece of square timber in the vise and a spring loaded clamp.

P1110883-b.JPG.0c9c799f641261dd9e3e7c22d2cb3792.JPG

Last photo, you see the remainig parts, everything seem to be in, reverse gear works, gap is still 0.35 mm, I hoped for 0.50 mm.

P1110884-b.JPG.09ad8e6c71059730ec09f17348f2781d.JPG

I hope that works, if not - I will not let you know. :)

Ciao / Cheers, Marco

Edited by Z320
my bad english writing
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