Technical Driveshaft oil leak

capers626 · Sep 30, 2008

Hi there,

Uno 60, 'J' reg, 1992, 1108cc, 5 speed manual gearbox, single point injection, hydraulic clutch, CAT

I've got a slow but steady oil leak which I've traced to the gearbox area (smells of gearbox oil too). On closer examination the oil is seeping from around the driveshaft boot, even though the boot is held firmly in place with a metal clip and is in reasonable knick. The outer boot contains grease so any oil would appear to be dripping down from the inner driveshaft boot (?), which consists of a bush and seal.

I thought maybe just the seal needed replacing but after speaking to a Fiat dealer, I am a bit confused by the info I was given.
The dealer used my chassis number but came up with 2 alternatives:
"either a seal inside the diff or a bearing inside the boot".
However, after confirming the gearchange linkages are connecting rods not cables said that what I needed was a complete new boot. Apparently, this has a lip which acts as a seal. (?). I'm not sure if he was referring to an outer or inner boot on the driveshaft.

As I'm unsure of the exact set up on my car

(model details as above), can anyone else help?

Thanks,

Andy

Chas Uno · Sep 30, 2008

capers626 said:
Hi there,

Uno 60, 'J' reg, 1992, 1108cc, 5 speed manual gearbox, single point injection, hydraulic clutch, CAT

I've got a slow but steady oil leak which I've traced to the gearbox area (smells of gearbox oil too). On closer examination the oil is seeping from around the driveshaft boot, even though the boot is held firmly in place with a metal clip and is in reasonable knick. The outer boot contains grease so any oil would appear to be dripping down from the inner driveshaft boot (?), which consists of a bush and seal.

I thought maybe just the seal needed replacing but after speaking to a Fiat dealer, I am a bit confused by the info I was given.
The dealer used my chassis number but came up with 2 alternatives:
"either a seal inside the diff or a bearing inside the boot".
However, after confirming the gearchange linkages are connecting rods not cables said that what I needed was a complete new boot. Apparently, this has a lip which acts as a seal. (?). I'm not sure if he was referring to an outer or inner boot on the driveshaft.

As I'm unsure of the exact set up on my car (model details as above), can anyone else help?

Thanks,

Andy

Older Unos used driveshaft gaitors that were 'wet', meaning that the driveshaft inner gaitors held the gearbox oil in. If a gaitor failed then gearbox oil would rapidly disappear. Later gearboxes, such as Cinq Sportings, used a different arrangement where the driveshaft spiders were contained in grease filled cups and the cup itself had a seal where it went into the gearbox. This may be the type that was fitted to the later mk2 models but I'm not sure. I've always had mk1s with the wet type gaitors.

On the wet driveshafts the gaitors do have a seal that covers the bearing from both sides. The bearing itself also acts as a seal and these too can fail leading to gearbox leakage.

There are a number of different gaitors available for the Uno driveshafts depending on year and gearbox fitted. You need to identify exactly which gearbox you have to determine which gaitor/ bearing you need. Maybe you could take a picture of the driveshaft inner gaitor and we might be able to tell from that?

Louie Bee · Sep 30, 2008

Yes the later Uno gearboxes have dry drive shafts

Couple of pics from when I did my clutch on the L reg Uno 1.0ie on this thred
https://www.fiatforum.com/uno-technical/130044-louie-s-first-clutch-job-2.html

This Uno has the C514 gearbox which you need to press the gearlever downwards to select reverse. There is 1 incar linkage and 2 cables - no under car gear linkage if that helps. Oh you can’t see carpet below the radio in front of the gear leaver.

However, our Brava which also has dry shafts had gear oil gushing from the diff seal this time last year. it's still a reiveshaft off job to fix, but the seal was only about £3 IIR.

capers626 · Oct 1, 2008

Yes, thanks, it is the C514 type 5 speed transmission. According to the Haynes manual (supplement), "modified inboard joint boots have been fitted to the differential ends of the driveshafts on non-Turbo models after September 1987. The new boots incorporate a seal/bearing assembly....".

I'm still not sure though whether this means I can replace just the seal or have to buy the whole boot. Guess it will make more sense after removing the old boot

Will be in touch soon.

Cheers,

Andy

capers626 · Oct 25, 2008

Just a quick update. It turned out that the oil leak was due to the metal clip on the inner driveshaft boot being fitted incorrectly (even though it had been checked by another garage!). This may not sound like it would cause much of a leak but the oil soon mounted up. However, it was soon dwarfed by a massive leak in the (probably original) oil sump. Drive has now been recoloured and resurfaced to kill any weeds and moss!

Cheers, Andy

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