C514.6 differential bearings

[Nuttynick]

Afternoon all, my wife has a C514.6 gearbox in her car and I need to replace the diff tapered bearings. I know plenty of you have this box, or have retro fitted it for 6 speeds, so thought you could help.
It looks from a quick inspection that the diff case can be unbolted with the trans in the car?
Any tips on removing and refitti g the bearings, along with checking end float?
Thanks in advance

 

[judderbar]

Afternoon all, my wife has a C514.6 gearbox in her car and I need to replace the diff tapered bearings. I know plenty of you have this box, or have retro fitted it for 6 speeds, so thought you could help.
It looks from a quick inspection that the diff case can be unbolted with the trans in the car?
Any tips on removing and refitti g the bearings, along with checking end float?
Thanks in advance

Palio Albea C514.5.15 Official Fiat Gearbox and differential repair manual

Comprehensive repair manual for the Fiat C514.5 gearbox.

www.fiatforum.com

The 5 speed should be identical apart from what goes on inside the steel cover which contains 5th and then 6th on your car.

The differential is 'easily' repaired from under the car providing you can manage the fact the crown wheel is like an axe if it falls on your face! I did this job on my own which was a bit stupid in hindsight. I will do it again but just be even more careful of the risks. When you reassemble you have to be able to hold the differential parts from above. so that when you put the cover back on you dont disturb your sealant. I used a broom handle tied from above and a socket extension. I used an anerobic sealant as the manual suggested. Silicone is too thinly applied on these machined faces.

I found my bearing splitter was unable to take the differential bearings off without laying down a line of weld onto the bearing to heat it up. I had no gas flame. Putting it back on was very easy by shrinking the differential in the freezer and putting the bearings in the oven.

For the 'end float' You do not need those special tools shown in the manual. The bearing has no end float or looseness but is rather tight or preloaded with the amount of tightness determined by finding how much gap you have without the shim in place. and then adding the thickness of the gap and the extra tightness amount (preload) to determine the desired shim size. I used the solder method. The idea being that solder does not resist being compressed but I found that is not exactly true once the roundness of the solder becomes completely flattened. So you just make a loop of solder in place of the shim being there and tighten up to spec and check the thickness of the solder. If the solder is spread out fully in contact with the contact surfaces of the differential you need to cut it in half so it does not fully cover the compressing area of the differential surfaces touching the solder. The solder does put up a bit of resistance once it is squeezed wider. In the end i reused the existing shim. I used identical timkin replacement bearings from a full gearbox kit supplied by one stop bearing shop.uk.

The preload torque is relatively tiny. I managed to strip one thread and miraculously because i had a right angled drill attachment I was able to drill the thing out and recoil it and kept the drill bit straight using the preload plate with the four holes bolted to the other 3 good holes with long bolts and spacers! Really you need a low torque torque wrench or use a suit case weighing balance on the socket handle to make absolutely sure you dont mess it up. I am never going to use my mickey mouse torque wrench for these low torque bolts again.

 

[Nuttynick]

That is a perfect reply and exactly what I was after! Cheers, that really is very much appreciated