Hi,
I need to know the difference between the rear axles on grande puntos.
I need a new one and the only difference I can spot is the bracket to hold the brake lines for calipers wheeras the drum versions dont have the bracket, but still have the holes to rivet it in, this leads me to believe all the rear axles are the same...
However, on a new version of EPER I have found, it says they are different http://cerivensrl.com/navi?SGS_COD=...ROUP_7&SB_CODE=-1&WINDOW_ID=1&ALL_LIST_PART=0 It says my car is an M89 but says the one for a 1.4sporting is a different part number.

Is there actually a difference?
I refuse to believe Fiat would put different beams on the car just because of a different engine, springs and shocks yes but not the whole rear axle.

I have found a 1.4sporting that is being broken due to a front end smash and I may be able to get the rear axle off of it, but I need to know if it will be ok on my 1.9mjet.

Thanks for reading
Adam

if you compare the M20 (1.4 turbo 120CV) part compared to the M89 (1.9 turbo 130CV) part, the petrol version is lighter :s

anyone?

Of the 2 part numbers shown, the M89 axle (51804553) weighs 23Kg whereas the M20 axle (51804554) only weighs 20Kg. A 3Kg weight difference is likely to be more than just brake pipe brackets.

Perhaps the torsion beam is thicker for the diesel versions.

Why would they produce it like that though? the back end of a diesel must be a similar weight of a petrol

Bear in mind that it's not just a solid girder linking both sides. It's specifically engineered to act as a kind of anti roll bar through controlled twisting of it's structure.

So it's likely the mJet Sporting axle has less material removed which makes it stiffer, and therefore resists roll more, leading to "sporty" handling. There may also be subtle differences in camber and toe for better handling geometry.

It says in the GP eLEARN manual referring to the torsion bar "with different thicknesses depending on the version". This could account for the weight difference.
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D4nny8oy said:

Bear in mind that it's not just a solid girder linking both sides. It's specifically engineered to act as a kind of anti roll bar through controlled twisting of it's structure.

So it's likely the mJet Sporting axle has less material removed which makes it stiffer, and therefore resists roll more, leading to "sporty" handling. There may also be subtle differences in camber and toe for better handling geometry.

Click to expand...

Davren said:

It says in the GP eLEARN manual referring to the torsion bar "with different thicknesses depending on the version". This could account for the weight difference.
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Click to expand...

@ Davren : yeah, I've just been looking and seen that

@Dannyboy : Exactly, the sporting one is designed to be thicker and sportier, so I can't help but think that they should be the same on all sportings, 1.4 or 1.9

I have seen a complete rear axle for a petrol sporting cheap cheap, but can't find any for a diesel

Just done a bit more digging on this new eper I have found, the two main axles I am looking at are 51804554 and 51804553, 4554 weighs 20Kg and 4553 weighs 23Kg, so then I went on to look at the same product code, and it turns out 4553 is shared between models, LV6 (van), M11 1.4 8V CF4 (1.4 8v active/emotion/dynamic 77CV), M73 1.3 Mjet (1.3 Mjet 75CV Active/Dynamic/Emotion), M72 1.3 Mjet (1.3 Mjet 90CV Active/Dynamic/Emotion/Sport), and M87 M88 and M89 which are the 1.9 diesels but in various guises and powers.

SO...
Am I right in thinking I can go and find myself one of the above cars, I have already found a few actives and take the rear axle off of it? even if it has drum brakes? I can just rivet the bracket onto the replacement axle for the calipers and unbolt the hubs?

Thanks for any help on this guys, it still seems wierd that they haven't just used one axle :s especially when the basic 1.4 car has the same as a top of the range sport :bang:

I'd speak to someone in your Dealer parts dept and get them to check part supercessions on the latest online ePer and compare, as it's not unusual for the disc copies to be badly incorrect in places (as you know, the GPS has disc brakes with some extra spot-welded brackets for the flexi's, which the base-spec 1.4 doesn't... so the data doesn't make sense).

If the GPS shares it's axle with other models, it'll list alternatives or part numbers that can be cross-referenced and give a clearer picture.

The brackets aren't spot welded, they are rivetted. And on inspection of a photograph from a 1.2 axle, the holes are in place already for the bracket

I've been into Platts (fiat) today and asked the parts depot for some help with this, after going through the eper records and csps (tech infor or something) he came to the conclusion that the 23kg one is probably thicker than the 20kg one ... but I had already guessed this (and read on eLearn), csps said they both weighed 20Kg but eper stated differently. He said fitting the 20Kg one, found on most Grande Puntos would probably be fine and I wouldn't notice the difference, but the heavier one is obviously the one to try and find.

But for the mean time I will see how the tyres scrub and act accordingly, I may hold out for the heavier one which will be more rigid for my heavy weight diesel. Or I may have no tread left on my tyres next week and I will get whichever axle I can find

Thanks for your help, especially Davren