CVR(T) Gearbox Shaft Seal Leak advice.

[martinwcox]

My Scorpion has an oil leak which looks like its from the output shaft at the gearbox in this case on the right hand side, anyone replace these seals and got any tips? It's not bad but bad enough to cause hard steering due to the oil film on the steering brake disc.

 

Cheers,

 

Martin

[Richard Farrant]

My Scorpion has an oil leak which looks like its from the output shaft at the gearbox in this case on the right hand side, anyone replace these seals and got any tips? It's not bad but bad enough to cause hard steering due to the oil film on the steering brake disc.

 

Cheers,

 

Martin

 

Martin,

There is an inner and outer seal at that position that I recall. Only the outer one was supposed to be changed by 4th line workshops, but when I was working on them, I found a way of changing the inners as well but needed to be done carefully and I think a tool had to be made. Going back about 18-20 years now, so cannot recollect exactly. Also the seals were special and where made for the gearbox. When in service if the inner seals were leaking the box was supposed to go back to base workshops for rebuild.

 

regards, Richard

[robin craig]

Having just swapped a gearbox in a CVR(T) earlier this year I honestly think that some of the restrictions on who can do what that Richard is talking about is derived from a series of decision making reasonings that should not exclude mere mortals as ourselves from attempting or doing.

 

Frankly gearboxes are one of the main assemblies about which there is created a huge aurora of complexity and doom and gloom as it is a bit of a specialist subject.

 

Once you break into that world and meet and know some of the people in it you will realise that it is a specialised world but honestly it is basic to them. We have a gent like that locally. He is second generation owner of a shop that rebuilds both manual and automatic units and he is not afraid of items that are considered odd ball by todays standards.

 

We have 3 CVR(T) gearboxes being readied for his attentions.

 

Honestly Martin I think that sane reasoning and some skill will replace those seals and as Richard says you may need to make some tooling but it may be just as much aggravation to find the seals.

 

Having the parts manual for the gearbox will help identify what you are looking for to begin with, the one I have has about 138 pages for the gearbox, is that the one you have? I know others who have had some of the CVR(T) seals made.

 

R

Edited December 6, 2013 by robin craig

[martinwcox]

Hi Robin,

 

I have a parts list that covers most of the sub assemblies, I have attached a scan of the end covers section that I believe applies in this case. I have asked my previous parts supplier for availability of the seals etc.

endcovers.pdf

 

I plan on removing the gearbox over the winter and fixing what I can given a supply of parts.

 

Cheers,

 

Martin.

[martinwcox]

If I had some seals made would there be enough interest for a "group buy" I wonder?

 

I have made some inquires here in the US so will see if its even a possibility.

 

Martin.

[sirhc]

If you are making the seals you'd need to be careful with the material selection etc.

 

They are about, but fairly expensive...

 

http://www.thexmod.com/item_detail.asp?id=7148

 

Chris

[martinwcox]

Thanks Chris.

 

From the parts list they are steel case, plastic PTFE element BUT they are directional as in the Rh side is for anti clockwise rotation and the Lh side is clockwise.

 

These are not straight lip seals but helical maybe?

 

I just love Google:

 

MONO-DIRECTIONAL HYDRODYNAMIC OIL SEAL

 

Used for oil sealing where the shaft rotation is mainly in one direction such as automotive line application.

This seal has designed into the lip a series of helical raisers that create an uplifting action, thus, effectively reversing the oil flow. This gives a longer seal life in the more critical applications.

The mono-directional hydrodynamic seal is used to great advantage in Timing Cover Seals - Crankshaft Rear Seals - Gearbox Input and Output Seals - Pinion Seals.

[Richard Farrant]

Thanks Chris.

 

From the parts list they are steel case, plastic PTFE element BUT they are directional as in the Rh side is for anti clockwise rotation and the Lh side is clockwise.

 

These are not straight lip seals but helical maybe?

 

I just love Google:

 

MONO-DIRECTIONAL HYDRODYNAMIC OIL SEAL

 

Used for oil sealing where the shaft rotation is mainly in one direction such as automotive line application.

This seal has designed into the lip a series of helical raisers that create an uplifting action, thus, effectively reversing the oil flow. This gives a longer seal life in the more critical applications.

The mono-directional hydrodynamic seal is used to great advantage in Timing Cover Seals - Crankshaft Rear Seals - Gearbox Input and Output Seals - Pinion Seals.

 

Hi Martin,

They appear to be the same as a normal lip seal, but from memory the was a slight scroll moulded into the lip. The maker's technical blurb was that they were "PDR rotary shaft seals (PTFE type - direction of rotation biased)".

 

I am sure that originally they were normal seals and these were introduced later on.

 

Richard

[martinwcox]

Hi Martin,

They appear to be the same as a normal lip seal, but from memory the was a slight scroll moulded into the lip. The maker's technical blurb was that they were "PDR rotary shaft seals (PTFE type - direction of rotation biased)".

 

I am sure that originally they were normal seals and these were introduced later on.

 

Richard

 

Richard,

 

As usual you are a fountain of knowledge!

 

I will see what transpires re get any made etc.

 

If I was in the UK I would try and cull a few bad gearboxes and dive in, probably like a Swiss watch, comes apart, now what :shocked:

 

Martin.

[Richard Farrant]

Richard,

 

As usual you are a fountain of knowledge!

 

I will see what transpires re get any made etc.

 

If I was in the UK I would try and cull a few bad gearboxes and dive in, probably like a Swiss watch, comes apart, now what :shocked:

 

Martin.

 

Martin,

This might be of interest;

http://www.tss.trelleborg.com/remotemedia/media/globalformastercontent/downloadsautomaticlycreatedbyscript/catalogs/turcon_varilip_pdr_gb_en.pdf

 

There is a list of sizes near the back of the document, you might strike lucky and find it is a stock size.

[martinwcox]

Martin,

This might be of interest;

http://www.tss.trelleborg.com/remotemedia/media/globalformastercontent/downloadsautomaticlycreatedbyscript/catalogs/turcon_varilip_pdr_gb_en.pdf

 

There is a list of sizes near the back of the document, you might strike lucky and find it is a stock size.

 

Richard,

 

I actually had found that trelleborg made the seals, found this in a NSN cross-reference and emailed them asking about seals referencing this info:

 

Trelleborg Part# 835-163-7280-21 / 835-163-7280-29 or FV792974

 

Lets see what I get back.

 

Martin.

[martinwcox]

Well my seal hunt is yet to produce anything for the outer seals. This original supplier quoted a cost so high that I may as well buy another gearbox or two!

 

If anyone here have a few stuffed in the mattress let me know.

 

Happy Christmas all.

 

Martin.