Lancia Motor Club

Model Technical and Interest => Aurelia => Topic started by: Dikappa on 16 January, 2017, 07:55:07 PM

Title: transmission/clutch question
Post by: Dikappa on 16 January, 2017, 07:55:07 PM
Is there anyone on the forum with experience in transmission/clutch assembly on early cars?

I'm currently preparing a B21 gearbox, that seems fine, and has no play on differential bearings, as opposed to the one currently under my car.  I cleaned the box, and intend to put new oil seals all around.  What particularly cworries me is that i found the complete clutch disk soaked in oil.  I removed the front casing to reach the oil seal, but now wonder on a few other items:

Behind the tubular part (part n18 tav 31) there is a steel ring (part n39), and behind that is a rubber o-ring , part n24, (I guess as there nothing there on my box, so measurements welcome on the ring)

Then the axle itself is hollow, and open in the front which is puzzling me as it seems to carry oil through it for lubrification purposes.
There are holes, one of which seems to be filled with something, (item 44 in tav 31, called 'stoppino lubrificazione cuscinetto dinnesto frizione)
I wonder what the material should be. 

The only reason I can guess for the shaft to be open in the front is for lubricication of the small bearing in front of the clutch, and I would think it better to use a sealed bearing there and plug the shaft.

Any opinions/advice on this?

Thank you,


Title: Re: transmission/clutch question
Post by: GG on 16 January, 2017, 10:58:09 PM
Oh we went through this very same issue recently. The shaft is hollow to bring "oil" to the clutch bearing and throwout arm on a shaft; it is supposed to be plugged with a small felt piece. Apart from not being one of the very best Lancia ideas, we also found that as the shaft went through the clutch using only that "felt ring" (part no. 24) wasn't enough. So what we cut a small chamfer in the end of the steel piece to fit an O ring (instead of the felt ring) that would be more securely in place. Then we plugged the end hole of the shaft with something more solid. I also think behind the steel ring, we put a second o-ring, replacing what we found as silicone just kind of wedged in there.

I don't think the small holes in the shaft are the main issue. Its oil either coming out the end of the shaft, or oil getting past the felt seal. The rubber O ring seems to be doing the trick. The fact that all this is buried inside is a remnant of the 1940s design of the gearbox, and was changed later to something a bit more serviceable.

The photos below show first, the shaft and the metal ring, and the steel tube. The steel tube is cut at the ends (hard to see in the first photo), more evident in the second one.


Title: Re: transmission/clutch question
Post by: Dikappa on 17 January, 2017, 07:05:41 AM
Thanks for that Geoff!

Were you able to deduct what the material of part n44 was?  It looks like a semi-dissolved wooden toothpick on my car....

Title: Re: transmission/clutch question
Post by: DavidLaver on 17 January, 2017, 10:16:02 AM

When I first got my B20 (alas no longer with Jason and Louise Kennedy) it had horrible clutch slip.  We blamed the tuned engine and fitted a paddle clutch.  Still got slip so uprated the springs.  Still got slip.  Tim Burret plugged the hole where the oil was getting in and put the rest back how it was...

Title: Re: transmission/clutch question
Post by: on 17 January, 2017, 02:25:15 PM
The big question now popping up in my mind is ... Do Jason and Louise still run it in that state, ie is that fix still working? The answer might affect what I do with mine in the rebuild!!!!!!!


Title: Re: transmission/clutch question
Post by: Parisien on 17 January, 2017, 02:28:57 PM
I recall Kevin MacBride having similar issues, will try and retrieve link, but as it turns out it was an article he did in the club magazine VL, anyone know which one?


Title: Re: transmission/clutch question
Post by: GG on 17 January, 2017, 05:01:19 PM
Thanks for that Geoff!

Were you able to deduct what the material of part n44 was?  It looks like a semi-dissolved wooden toothpick on my car....

Mine had been replaced by silicone. We put in nicer silicone. I think it was a felt plug originally. Doesn't do much, just holds back a dripping flow....

And yes, it was oil on the plate that was the issue. Slipping clutch got solved this way. Never had to change the springs.

Just to be clear, the steel tube was chamfered on the inside lip, so the O ring was compressed and held in by the sleeve.

Title: Re: transmission/clutch question
Post by: Dikappa on 18 January, 2017, 07:16:47 AM
Thanks for the replies, in the parts catalogue there is some sort of spiral inside the main shaft, I guess working as some sort of oil 'pump'.  On the end (forward side of gearbox) is a sort of 'plug', that feels rather soft now (only 'felt' it with a long screw driver)  My guess is that this material deteriorates over time, and that it lets by more oil than it was originally intended to do.  Has anyone taken his box far enough apart to get to this item?  My feeling is that there lies the cause of the problem.  It takes however quite a bit of dismantling to get to it, what was not my intention originally....

Title: Re: transmission/clutch question
Post by: Niels Jonassen on 19 January, 2017, 10:20:42 PM
All very interesting. Useful knowledge. I think that - while everything is taken apart - it is worthwhile to take a look at the clutch plate. I suffered from a badly slipping clutch, an on taking it apart discovered that the clutch plate was slightly concave, so that only the outer part of it was in firm contact. It was not visible concave, but grinding it helped.

Title: Re: transmission/clutch question
Post by: Dikappa on 05 February, 2017, 04:22:49 PM
This afternoon I searched together my courage and removed the back cover and side cover (with diff) in order to be able to dismount the oil pump housing of the gearbox.  As expected the input shaft is hollow, and containing some twisted metal strip.  On the end of the strips are is sitting a felt 'seal', some 8-10 mm diameter,  and about 30 mm long.  It seems to have consisted of three 10mm thick felt washers.

In the center of the pump house is a hole that allows gearbox oil to fill the shaft.  The problem is that the normal oil level of the gearbox is above the hole and the shaft, and so if the felt seal inside the shaft does not stop the oil, half of the gearbox oil will be allowed to drain through the clutch housing.

I feel however Lancia designed the whole seal to leak a little bit, in oder to lubricate the little bearing in front of the cluch and the clutch release bearing.

Still I think the best solution will be to find a suitable replacement for the felt seal (completely soaked in my case), to plug up the shaft in the front, and to use a modern sealed bearing for the little bearing.  Remains the lubrication of the clutch releas bearing, hope to take that one appart in the next few days, but fear for that a little oil should be allowed to 'escape'

Any hints/advice for a replacement felt seal welcome!

Title: Re: transmission/clutch question
Post by: Dikappa on 13 April, 2017, 07:41:07 PM
Finally some progress as yesterday I got a call the machinist had done his job!

In order to try to prevent my new clutch disk to become soaked in oil I did the following:

The felt 'seals' inside the main shaft where replaced.
The nose of the main shaft was tapped M10 and sealed with a set screw and locktite 542
In the separate bushing on the main shaft we machined a groove for an O-ring, so that there is a sealing between the bush and shaft.
In the nose (on which the clutch release bearing is sitting) we machined a small additional oil seal to seal between housing and bushing.
The little bearing in front of the clutch was replaced with a sealed one, so no oil needed there anymore.

I retained the felt bushings as they are intended to leak (or feed) a bit of oil to the clutch release bearing.

It the same time having the differential out I replaced the outer bearings, which looked a bit dry, with new sealed ones.
I also provided an air vent on the left hand main diff bearing

Off course all oil seals were renewed (quite a few)

Title: Re: transmission/clutch question
Post by: Dikappa on 17 April, 2017, 05:27:57 PM
I've a question regarding the pot joints, does one -put the two filling taps horizontally and then fill colmpletely untill they 'overflow'.  The manual says EP140 oil, but in the LMC workshop manual it says in the tekst on the joints to use EP 90 oil.  Any suggestions?


Gearbox is now re-assembled ready for mounting.  Shifting my attention to shock absorbers and rear suspension and wheel bearings.  Christo's car has had Houdialle shock's mounted in a faraway past, with a lot of welding to the rear supension brackets, and would like it to be original again...

Title: Re: transmission/clutch question
Post by: Sliding Pillar on 17 April, 2017, 05:31:22 PM
Koen, you are correct about the way to fill the pot joints.
I have always used Penrite transoil 250 in them.

Title: Re: transmission/clutch question
Post by: Brian Long on 18 April, 2017, 11:22:21 AM
I also add about a 'tablespoonful' of molybdenum based additive ideal application for this type of lubricant.

Title: Re: transmission/clutch question
Post by: Charles T on 23 April, 2017, 04:57:43 PM

I also used Penrite Transoil 250 recently, from Classic Oils at Bicester Heritage.  The consistency is more like treacle and a lot of work was required on the pump to get sufficient oil in to fill it up! I assume that the consistency will change as it heats up with running.