Technical 100HP Rear Axle Beam - rot

[MarkPed]

I have read and re read most if the posts on this subject, but can't establish whether the beam axle is common across all 2007 model year Pandas or not - no doubt someone will be able to point me to a relevant post, if not please help me on this matter. :worship:

We have a 2007 100HP model, white with double sunroof, which we have owned some 12 of its 13 years - very happy once we sorted ride with proper dampers. I repainted the rear axle a few years back, but despite this it is deteriorating. I was in the process of removing rust when I broke through the vertical section close to the damper mounting and thought, this requires more than paint!

I could probably get it weld repaired, but would like to replace, if at all possible, as rest of car is pristine (only 55K miles too). Various parts suppliers (I haven't tackled Fiat yet) seem to differ, some list 100HP axle (but out of stock) others list one axle, seemingly for all Pandas of this age.

Only difference I can see in vehicle spec (apart from impact of track through wheel sizes) is the addition of disk brakes on 100HP and 4X4 models but callipers appear to be mounted on the hub carrier.... So should be no need for different part. Am I right or am I going to have to take the bitter pill and source from Fiat?

 

[varesecrazy]

Info should be mainly here:

https://www.fiatforum.com/members-motors/453779-mr-mrs-blus-panda-100hp-6.html

 

[jrkitching]

can't establish whether the beam axle is common across all 2007 model year Pandas or not

Probably not what you wanted to hear, but the consensus of the informed posts on this subject, across several different forums, is that the 100HP rear beam is unique to that model.

This needs further checking, but a quick search shows OEM part numbers as:

51856917 for all except 100HP; 4x4

51856918 for the 100HP

I'm not sure how available they are within the UK dealer network, but if you can still get one, the price will likely be around £1350 incl VAT.

Some, but not all, of the aftermarket rear beam resellers show the same (much cheaper) part as a substitution for both OEM part numbers. Others, perhaps better informed, state specifically in their advertising that it will not fit the 100HP or 4x4. It's confusing, to say the least.

You know what, I'd be tempted to 'phone the factory that's actually making these aftermarket beams and see what they have to say on the subject. If the change is minor (I have a sneaking suspicion the track may be slightly narrower to keep those wider wheels inside the arches), they might be able to rejig and run off a batch.

Do let us know how you get on with sourcing this; there are quite a few folks here who plan on keeping their 100HP's for awhile yet, and this can only become more of an issue as the cars get older.

 

[koalar]

As far as I know disc and drum models use the same centre part of the axle, and only the bolt on parts are different.


I did ask for someone to measure as they had both but never got back.

I don’t have the 100hp but can measure a standard axle on Tuesday

 

[irc]

It could be an urban myth, but I have heard the only differences are in the brake pipe clips, which are in different places for disc brakes.
Totally unverified and I can't remember who told me, other than he had a 100hp with a knackered beam and was looking for a replacement.
Never got back to me to tell me whether he had successfully swapped it, but it does sound logical.

 

[jrkitching]

I did ask for someone to measure as they had both but never got back.

That's what we need; if it's just a few clips, that should be easy enough to work around, but if the 100HP beam is indeed narrower, that could make using the other one problematic.

Running a tape measure between the hub bracket mountings should suffice. I've already done this for the 500 and standard 169; the pictures should be around here somewhere - we just need someone with a 100HP to do the same.

 

[MarkPed]

Yep, those replies just about sums it up... The offered thread includes the statement that the centre part is the same on all models, but the bolt on bits are different, but the other post says the beam is unique to the 100HP.

I will contact the sellers to find out what the differences really are and if they can be solved with a cable tie I am reassured that the part numbers are but one apart

I will also take up KOALER's offer of measurements and will do the same on mine... I have seen on one thread pictures of the 500 v 100HP and know the former has different welded brackets, so is a non starter.

I had seen the Fiat part quoted around £750, but £1350 puts a whole new complexion on my plans... maybe its a welding job after all.

 

[koalar]

That's what we need; if it's just a few clips, that should be easy enough to work around, but if the 100HP beam is indeed narrower, that could make using the other one problematic.

Running a tape measure between the hub bracket mountings should suffice. I've already done this for the 500 and standard 169; the pictures should be around here somewhere - we just need someone with a 100HP to do the same.

heres your original picture of a standard panda

saves me crawling under the car on Tuesday

 

[koalar]

It could be an urban myth, but I have heard the only differences are in the brake pipe clips, which are in different places for disc brakes.
Totally unverified and I can't remember who told me, other than he had a 100hp with a knackered beam and was looking for a replacement.
Never got back to me to tell me whether he had successfully swapped it, but it does sound logical.

That's was probably me

I post the manufactures of the replacement axles direct website not eBay

It lists the same part for all Pandas disc and drum. However it does not mention the 100HP by name.


If the OP measures and compares to jrkitching photo above we can put this one to bed

 

[varesecrazy]

I post the manufactures of the replacement axles direct website not eBay

It lists the same part for all Pandas

Does the website list 500 as the same as Abarth.. no crossovers to panda ?

 

[irc]

Not sure it was you, I seem to remember actually looking at his 100hp in my driveway and making an offer for his front bumper if he scrapped it (wasn't a great example...).
If it is only the brake pipe clips, then DaveMcT probably has details for changing to braided hoses which makes most of them irrelevant.

I've got a part-dismantled 100hp which I'm thinking of reassembling when the weather warms up a bit. Rear beam looked fairly scruffy when I took it off the trailer, so I am definitely interested in this thread. However, does need me to find engine/box and various other bits before starting work on it.

My other route was looking at modifying a 500 beam to narrow it, and use the springs/dampers off a 595, but I have lost access to my go-to welding expert so will probably never happen now. That is a shame, as I really don't like the ride on my own (almost totally standard apart from tyres) 100hp on most of Norfolk's roads.

 

[MarkPed]

Measurements on the 100HP are exactly the same as in KOALARs post, so the beam width is the same standard to 100HP.

The track difference of 10mm maybe a result of differing tyre sizes, as wheel offsets appear to be the same. I have some very nice looking Team Dynamics wheels (black with diamond cut rim), which ironically needed 5mm spacers to give the right offset, though looking at them there is plenty of clearance. I ought to try them without, as the loose spacers are a bit of a faff.

So, small bracketry apart, there are three possible differences to explore.
1) Beam material thickness (to create a stiffer beam and hence better roll control) - 100HP thickness is 4.5mm measured mid beam, bottom section
2) Spring Pan thickness (potentially to cope with greater loads from stiffer springs) but, there again, the maximum dynamic load is more dependent on weight over the rear axle than spring rates - rusty, so difficult to measure, but looks equivalent to the beam.
3) Hole spacings for the stub axle.

The last one is more tricky. I have read that the bolt on parts are pretty much interchangeable, has anyone got a disc brake and drum brake stub axle to compare the hub mounting bolt hole positions....

PS Thanks to all allowing this conversation to make progress

 

[Scotty100hp]

Not sure if this helps, a guy on the Facebook page bought one for his 100hp off a company called AM Car Parts on EBay. He was told it would fit but didn’t. This seemed to be the problem.

 

[Scotty100hp]

Edit - Just realised that is one of the companies that doesn’t say it is not suitable for the 100hp.

 

[MarkPed]

Scotty 100hp

I'm sure this is significant, but I just can't see what the difference refers to - is there anything more on the thread - it doesn't help that the pictures are from different perspectives. I guess the fundamental questions are:
Which picture is which?
Where is the lip?
If its on the one that doesn't work for 100HP, can it be ground off?

 

[koalar]

as suspected it looks like the rear axle is an off the shelf standard part.

its fairly typical for companies to just raid the parts bins

I have used a mixture of puntos parts to fix my cars air bag switch, starter motor, (granda), cigarette lighter, ignition coils and ignition switch.

I am not sure which way I would go. Some of the replacement new axles are advertised as being made of thicker metal. Which will alter the handling and ride probably not by much.

but scrap yards have plenty of decent axles. Not sure why some rot. I had a 05 and 06 both were in Good condition in fact better than my current 2011.

 

[MarkPed]

OK, just been under mine (again) and can now see the problem. Damn!

To answer my own previous question, both of the Facebook pictures are the new axle, the 'lip' is on top of the stub axle face plate.

This IS different from the 100HP because the lip is in the way of the handbrake cable run - which explains why the disk brake models (100HP and 4X4) require a different assembly - so it is not just minor bracketry...

A secondary issue is that the (speed?) sensor cut out is missing on the Facebook example - see my photos below...

At least the stub axle mounting bolts look the same

It seems eminently possible (if this is the sole issue) for there to be a universal beam axle, which is designed to cope with the disk brake models - and will do, just as well, for the drum brake variety. Maybe each of the current manufacturers have a different approach to the problem, which is why there are mixed messages - or looking on the bleak side, all only cater for the higher volume standard Panda and I have to go cap(s) in hand to Fiat....

The big advantage we now have is that we now know at least one thing to look out for.

 

[MarkPed]

Having looked at the link that is embedded in one of the KOALAR's responses contained within the thread he offered, it looks like the 'eurosubframes' version is without upper lip, which is why they quote it as being universal. This suggests that at least one manufacturer has followed my logic (pre-empted to be more accurate) and makes one which is suitable for both types, by leaving the original design's top lip off the stub axle plate.

Maybe we are getting somewhere at last.

Just need to find out what my local Eurocarparts people stock (they are quoted as having one) or order one of the eurosubframes ones...

 

[irc]

Having had a quick look at a replacement beam, it is clear to see the lip on the carrier bracket. The supplier for this one was "Small Parts" on eBay.
It does look like it could be "adjusted" to suit a 100hp, but definitely better to find one without the extra lip if possible.

My plan to convert a 500 beam basically involved cutting off the hub uprights and replacing with ones from a Panda beam, as this appears to be the only dimensional difference, and the track difference is accounted for by the Panda one being nearly flat, whereas the 500 one stands 20mm or so further out... pictures below.

The scabby one is a 500 beam, and the brand new one is a replacement Panda beam. Apologies for the rubbish pictures - neither is in a good place to photograph.

 

[09 johno]

This one dosn't seem to have the lip
https://www.imaxle.co.uk/new-fiat-panda-axle
and their 500 axle

https://www.imaxle.co.uk/new-fiat-500-axle