Technical Time for new axles, but....

[Damon500]

Hi Bob,
Good to hear there are still Bambinas around in Christchurch! Hope you survived the quakes ok- I was back over the ditch last Christmas, I successfully evacuated my Bambina but it was a confronting experience.
Don't be too scared about the dire warnings about diff preload when replacing axles- it is quite straightforward with basic mechanical skills.
I would say your axle setup is a great example of Kiwi ingenuity and I think it is unlikely that the differential has been modified - agree with the suggestion to convert it back to standard with 500R axles.
If you are looking for some advice in Christchurch you could pop in to my old work at Harman Motors in Sydenham and talk to David- he has owned a 500 for over 40 years and will certainly be able to give you some good advice.
Hope this helps!

 

[Toshi 975]

The diff may have been changed to get a more suitable ratio for the car. I am building a 126 box with a Bis dif to get the higher ratio with a tuned engine and a mate has asked me for a 500 lower ratio diff as he is building a sprint set up with a high reving engine.

 

[Nick Striker]

I have a thumping sound that I think comes from the axels. Do you really need to remove the transmission to replace the axels and boots?

 

[babbo_umbro]

I have a thumping sound that I think comes from the axels. Do you really need to remove the transmission to replace the axels and boots?

Since it only takes about fifteen minutes to remove the engine and gearbox there's no point in attempting to do this with the transmission in place.

 

[the hobbler]

I know that I am getting on a bit, but I have never managed to get a gearbox AND engine out in 15 mins!

 

[Nick Striker]

OK, and I doubt I could do it that fast either. I was thinking leaving the engine and removing just the transmission. Is that easier? Also do I have to be careful not to move anything important so the gears work when I put it back in?

 

[the hobbler]

It is a lot easier to renew the drive-shafts and boots with the transmission out. If you take the engine out first, the gearbox is 'a doddle' (as we say over here). Having the engine out also gives you the chance to give the clutch a good check-over. It is a real 'pain in the bum' to have to take the engine out again just a few months down the line to do this job. If you are not stripping the gearbox, there is nothing external that can affect the gear change mechanism internally.
If you DO have to replace the drive shafts this IS a gearbox out job. Not a difficult job in itself, but a job that requires a certain amount of care, noting where parts go and marking their position. If you do need to do this job, let us know and if required we can 'talk' you through it. When the gearbox is out, check the gear-change 'lollipop'---the metal/rubber gear linkage connector.

 

[babbo_umbro]

I know that I am getting on a bit, but I have never managed to get a gearbox AND engine out in 15 mins!

Put a jack under the engine; undo - outer driveshaft joints, gearchange, heater duct, starter cables (activation and electricity), throttle and choke cables, petrol feed, clutch cable. Undo rear chassis crossmember, push car away. Separating engine and gearbox takes another couple of minutes.

 

[The Whitakers]

I can feel a Pepsi challenge coming on..........??

 

[babbo_umbro]

I can feel a Pepsi challenge coming on..........??

Also note that the flanges at the outer end of the driveshafts (and which bolt onto the flexible couplings) are much softer than the splines on the driveshaft so it (really) only takes a few minutes to check that you need to replace the shaft or just the flange. When I had 500s years ago I reckon I probably changed three or four flanges for one driveshaft replacement.

 

[fiat500]

I have a thumping sound that I think comes from the axels. Do you really need to remove the transmission to replace the axels and boots?

Leave your engine and box in place.

The most likely problem is the aluminium/rubber, splined connectors to the hub. When the rubber deteriorates you get a "thump". Easy to check this without dismantling and if they do need replacing it's (I'll be careful what I say here ) a few milliseconds' extra work to replace the driveshaft boots whilst you're at it.

 

[The Whitakers]

???

 

[Nick Striker]

Oh sure now you tell me!I've got everything disconnected and trying to pry the car forward to expose the engine. At least I'll be able to inspect everything and give it a good cleaning.

 

[fiat500]

Oh sure now you tell me!I've got everything disconnected and trying to pry the car forward to expose the engine. At least I'll be able to inspect everything and give it a good cleaning.

It might even been that your gearbox rubbers are soft or detached but maybe you will know either way now.

 

[Nick Striker]

OK step one. I'll keep posting as I proceed and I really appreciate the help across the Atlantic and Pacific. :worship:

 

[fiat500]

OK step one. I'll keep posting as I proceed and I really appreciate the help across the Atlantic and Pacific. :worship:

Did you notice if there was a small, intact spring inside the drilling at the end of each driveshaft? On further thought, that item is actually there in order to prevent an abrupt bottoming out or "clunk" of the driveshaft against the inner hub-nut.

 

[Nick Striker]

There were no springs. Maybe that caused the noise? I also noticed the clutch shaft moves in and out maybe a quarter inch or so. Is that normal? There is no wear on the splines and the clutch itself looks good. On the axels the bearings inside the bearing housing at the differential case look fine. Maybe I just get the springs, and new oil boots. Anything else I should replace?

 

[fiat500]

Here we would benefit from some input from previous contributors to offer some thoughts. The clutch input shaft does tend to have a small amount of "slop". But it's hard to judge from your description. On balance, it's probably not related to any problem.
You definitely need the correct snubbing springs and obviously change the boots and the seals inside them.
At this stage have a good look at the splined, rubber connectors. They may seem ok but the central, steel "star" should be firmly embedded and bonded in the rubber. Check that the splined flanges are good by holding the shaft and trying to rotate them manually whilst slid back onto the shaft.
If you can find a way to lock up the input shaft and one of the driveshafts in turn, you should try to turn the opposite shaft manually to see if the driveshaft sliding blocks are damaged...I suspect very unlikely.
My main message is be absolutely sure about those metal/rubber drive connectors before reassembly.
Good luck.

 

[The Whitakers]

My main message is be absolutely sure about those metal/rubber drive connectors before reassembly.
Good luck.

This, when I had my 495cc lump and box in there I had a noise that was in between a thud and a clunk every time I took up drive......both the box and engine have been swapped out and the noise is still there!!


When I did the change over I checked the bushes in question and although they were old they were intact but with a degree of degradation. I could grip them and move the outer case slightly by hand and although not much more when a pair of grips were on there so I left them. I do think in hindsight though they are well deteriorated and that is where my 'thu-unk' is coming from...….They are not an expensive item either, VdL are offering them at 12.50- 29.50 depending on the quality...……..


Hope its an easy fix for you...….

 

[the hobbler]

The 'snubbing' springs, as mentioned by Peter (Fiat500) are important as they stop the drive shafts from moving in and out. If you DO have to replace the metalastic couplings,I have been advised by a (real!) expert that you do NOT have to replace the crushable spacer (between the bearings) if the bearings sound OK, BUT, you do have to do the big stub-axle nut up to the correct torque.
I have always been slightly bemused by the fact that Fiat only use 1/2 the threaded hole in the couplings for the bolts that secure the metalastic to the sliding flange, so I clean the thread all the way through the coupling (8mm x 1.25mm) with a tap and then obtain longer bolts and with the appropriate die, run a thread down the shank of the bolt leaving just about 19mm (3/4in) clear shank below the head of the long bolt. I think that the length for these modified bolts is 60mm, but they must not protrude out of the coupling