Technical Leaky Gearbox

[doogal]

To continue my master class in very slow Fiat mechanics, tonight I undid the LH driveshaft - 6 bolts 6mm Allen key. As I undid them oil/thin-grease started to seep out of the joint between CV joint and gearbox flange. I've now moved the driveshaft out of the way and tied it up but in order to do this, I had to compress the CV boot which forced grease out of a little hole in the gearbox end of the CV joint (does that make sense??)

This is the end of the CV joint on the driveshaft with hole from whence the grease came circled in red (sorry - poor photo editing with MSPaint):



This is the gearbox output shaft flange covered in grease from the CV joint:


Do I now need to rebuild the CV joint/boot? Or can I just take the boot off and fill with grease? Is there supposed to be a seal to stop grease coming out of the little hole? Or should the be a gasket between CV joint and g/box output flange? This would appear to be the source of the original leak, anyway.

All advice appreciated as always.

Doog.

 

[docorangepeel]

Hi, you can pull off the CV boot and replace the CV grease. CV grease did not come out of mine when I removed the drive shaft on my B. I removed the brass colour back plate thats in the first pic with a pair of ring pliers.(see pic) once removed you can see the condition of the CV joint bearings.

I dont remember the CV join having any oil seal inside but I could be wrong. (sorry)

 

[Alan.D]

I'm struggling to understand this to be honest and can't think why there would be a hole in that flange? there are seals on the inner cv joint as per pics below which seems remarkably over engineered?

Just to make me understand a little better is the gearbox output stubs sealed so the gearbox oil doesn't come out when the driveshaft is removed?

If you need any part No's let me know.

 

[Alan.D]

Starting to make sense again seems like the dif is sealled from the drive shaft so that hole must be to assist lubricate the other part ?

While the drive shaft is off it seems a good time to replace the rubber boots.

 

[doogal]

Thanks, Alan and Doc. Excellent info as always.

Doc - you say that no grease came out of the hole in the brass coloured plate on the g/box end of the CV joint. I reckon this is correct - no grease should be coming out of the hole.
Also, how did you get the brass plate off with the circlip pliers? did you just use them to lever it off? I can't see anywhere where I could use circlip pliers on it.

Alan - thanks for the drawings and info. As you say I should probably replace the inner boot whilst I'm at it. Definitely no hole in the gearbox flange to let oil out. I think the leak I have been seeing is CV grease coming out of the hole in the end of the CV joint and seeping out of the joint between CV and gearbox flanges. I reckon I need to either replace the brass plate or a seal inside the CV.

Doc - Did you get a new brass plate and some oil seals with the CV repair kit from Fiat?

Getting there slowly... :bang:

Cheers
Doog.

 

[Alan.D]

The circlip will be used to remove item 9 the inner CV roller joint if the cap is No 13 in the first pic it should just pop off but may be held in place by the gasket fusing to the surface and will be held in place when re bolted to the output flange on the box.

Once one Joint is off both CV boots can be replaced by sliding them both from the one end.

 

[doogal]

Thanks, Alan. Looks like the cap is 13 in the pictures, so presumably 14 is the circlip holding 9 onto the driveshaft. 3 (in two places) looks like an o-ring or gasket and that is what I think I need to replace.

Can I tap 13 off the end of the CV with a soft faced mallet? What do you reckon?

Doogal.

 

[docorangepeel]

Hi,
To get the (13) brass cap off, place the tool I told you about above on the black part (9)just behind the cap, when you spread the pliers the ends of the pliers will hit the lip of the brass cap and the other lip (6) on the other side of the CV joint giving you a spreading force, thus pushing off the brass cap without damaging it. Do this 3 or 4 times around the cap and it will come off.
(The brass cap is only pushed on)

The pliers must be the close grip spread tip type.

Doc Orange Peel

 

[Alan.D]

Doogal could you take a side pic of the driveshaft when your next out just for curiosity and the other side as well when you get to it, but only if you are doing that side. Mine is well tucked in in the garage.

 

[doogal]

Thanks, Doc. Will try that tonight.

In an earlier photo in this thread it looked like you had your driveshaft out on the bench. Did you take it out of the car to work on the CV joint? If so, can you give me any advice on getting it out at the hub end?

Alan - photos to follow tonight when I get home.

I owe you both (and Dangil as well) a pint or 2 when I get to the end of this little "project".

Doog.

 

[docorangepeel]

Hi,
Yep I removed the drive shaft from the car, just undo the main nut. Then hit the end with a rubber hammer and out it will come. Please see number 1in the diagram.
You will trash the nut so order a replacment from Fiat
Doc Orange Peel

 

[DanGil]

When I changed my box I wondered about the small in the end of the driveshaft, my dad said it was something to do with air and letting it escape?

 

[doogal]

DanGil - That is my guess as well - it's supposed to be an airhole but on my driveshaft it also serves as a handy grease escape route.

I've come to the conclusion that I need the driveshaft off the car and onto the bench, so I need to beg borrow or steal (or maybe even buy ) a 32mm socket to undo the hub nut.

Alan, photo of the LH driveshaft disconnected from g/box but still connected to hub. Hope this shows you what you need to see. If not, let me know and I'll get some more pics...



Pic of RH to follow. I'll also post a pic of the LH when its out.

Tonight I have mostly been drilling and re-tapping the holes for the airbox and resonator mountings following the shearing bolt incident before Christmas.

TTFN
Doog.

 

[Alan.D]

Spot on thank you, I take you have ABS.

BTW with the end of the driveshaft off it will be neigh impossible to get the hub nut off as it will just spin the driveshaft round

 

[docorangepeel]

Alan D is spot on, you will need to put one or two bolts back in the brass end of the drive shaft so you can undo the large nut thats holding the wheel side of the driveshaft on.

The large 32mm nut has a locking part on it so tap that out before having a go at getting it of.

A bit of inspiration for you Doogal. Below is a picture of my B just after I finished the pain it the backside job of fitting the oil cooler. If I was going to do it again, I would take the rad out first.

Keep at it m8, I know it can be a real pain.

 

[doogal]

Nice photo, Doc. Keep me thinking of better times when I get back on the road.

Alan - yes I have ABS.

Alan and Doc - it did occur to me that I may have trouble getting the hub nut off. Even if I reconnect driveshaft to gearbox, won't the diff still allow the driveshaft to spin (bearing in mind that I have the whole front of the car off the ground on stands and the the g/box is in neutral with the linkage disconnected)?

What about if I get an assistant to put a foot on the brake? May need to temporarily put the mcpherson strut back on as well to hold the hub in place.

Cheers
Doog

 

[Alan.D]

Yep that may work BUT the nut is put on at 280nm so you will have to be carefull of the ammount of pressure used so it don't fall off the stands. Torque wrench and a scaffold pole will make it easier, and whoever is putting their foot on the brake will really have to stamp on it.

 

[doogal]

Torque wrench and a scaffold pole will make it easier

Doog.

 

[Alan.D]

 

[doogal]

Doc OP - can you remember what size the front hub nut is? I bought a 32mm socket but that's too small. Swapped that for a 34mm impact socket (32mm is the biggest 1/2" drive normal socket you can get ) tonight and that is still too small. Is it a 35mm?? Have I got different hubs?

I'l update progress when I finally get the hub nut off.

Cheers
Doog.