Look at the shock absorber bracket and on the front (far side) of the pan about 1" to 2" inboard from the weld. My old axle is generally rusty around the spring pans but these two areas are by far the worst. They are both relatively high stress points so maybe that's part of the problem.

Mechanical stress - ok. General corrosion - ok. Both together - Not OK.

tinmar49 said:

The PJI chain spray is so thin when it is first applied that it penetrates by capillary action even better than Waxoil can. It will go straight under flaking paint and soaks into rust, you wouldn't have to dismantle anything, just keep it away from the brakes.

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Thanks Tinmar! - is this the stuff?

http://motorcycleparts-uk.co.uk/pj1-...lue-label.html

(Almost) Any of these will do the job just avoid the dry lubes.

For metal protection you don't care about it lubrication ability so get the cheapest.
http://www.mandp.co.uk/index.php/default/catalogsearch/result/?q=chain+lube. But its not intended to soak through rust which is why people use Waxoyl.

http://www.ebay.co.uk/itm/CarPlan-T...101000?hash=item2ef2ce4908:g:DJQAAOSw5ZBWGEVu

I've not used this stuff but the trade like it.
http://www.frost.co.uk/dinitrol-metallic-underbody-wax-500ml.html

Also here
http://www.ebay.co.uk/itm/DINITROL-...063596?hash=item2a6c81aaac:g:KwoAAOSwayZXi-29

Thanks Dave, so if I use PJ1 or similar will it just cover over / protect existing metal and rust but not actually inhibit it as such - whilst waxoyl/dinitrol also helps to react to existing rust and stop it getting worse. Hard to know whats going to be best! I won't be able to get the rear axle off but I might be able to drop the shocks off to allow better access to the spring pans..

Hi all....I've an '07 plate 100hp showing the usual signs of rusty rear axle especially around the coil spring cups. I want to do what I can to slow down it's deterioration but am slightly confused as to what to do....

EITHER

1.) Thoroughly sand/wire brush all metal and repaint with something like hammerite

OR

2.) Remove all loose rusty metal with wire brush and then spray or brush paint with waxoyl/dinitrol.

I'd prefer the second option as it would seem to require less fastidious cleaning prior to finishing.

Your thoughts??!!

You are dead right. Even with really fussy cleaning (almost impossible under the car) you will struggle to stop the tin worm continuing its evil ways.

Scrape off the loose metal and treat with a product that soaks into the metal and later thickens in some way. The chain lubes do this but the likes of Waxoyl do it better.

The spring pans get pretty badly rusted. They really need a hole in the rim at the lowest point. The central hole wont allow water from escaping from around the spring itself. Take off the spring to do the job properly.

DaveMcT said:

The spring pans get pretty badly rusted. They really need a hole in the rim at the lowest point. The central hole wont allow water from escaping from around the spring itself. Take off the spring to do the job properly.

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Would drilling one hole in the rim of the spring pan at the lowest point, of the same diameter as the central hole, result in any weakening of the pan?

SPORTPACK50 said:

Would drilling one hole in the rim of the spring pan at the lowest point, of the same diameter as the central hole, result in any weakening of the pan?

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Maybe but the rust will do an even better job. A 6mm hole would be ample drilled in the middle of the spring landing area.

DaveMcT said:

Maybe but the rust will do an even better job. A 6mm hole would be ample drilled in the middle of the spring landing area.

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OK...I'll investigate the feasibility of hole drilling when I'm next underneath the car, maybe tomorrow if it stays dry.

While under there vacuum out the flaking rust and squirt in some anti rust stuff to your taste.

I use ACF-50 on the bike. It flows very easily so a little goes a long way. Something like Waxoyl or some such brushed over the top would add a thicker layer of protection. Black underbody waxes show where it's covered (or not).

http://www.ebay.co.uk/itm/ACF50-Ant...386882?hash=item3d0e2628c2:g:DkMAAOSwYIhWhoiY

The ACF-50 looks ideal and pleased to see no problems with any overspray (apart from keeping it off the brakes).
I have a tin of Waxoyl underseal stuff...do you think this would be OK to use on top of the ACF-50?

IMO a good corrosion proofer will do a better job of protecting an already-rusting axle than paint; it'll be near impossible to get what's left of the metal into a good enough state to stop it from continuing to corrode under the paint.

Dave is right in saying you want something that will flow easily to get under any rust you can't remove and to flow back into any areas which may subsequently become chipped. What you don't want is to get salty water under a hard layer - that will accelerate corrosion until the hard layer peels off in chunks. Commonly seen on cheaply painted parts, including the finish Fiat originally applied to these axles.

I beg to differ about Fiat's original paint finish. Mine seems to have simply dissolved.

ACF50 will soak onto the metal surface and Waxoyl will go over the top. Use black and you can see where it's gone (& not gone).

I wire brushed and waxoyled the whole axle yesterday, as well as is possible with the axle still in place and the car up on stands - decided to use black waxoyl in the end, messy job but has covered pretty well. After getting rid of the flaking paint it confirmed my axle is in pretty good nick and the spring pans are solid. I also have some ACF 50 which I plan to spray in the spring cups to soak into any areas underneath the springs that might have been missed. Not sure if it attacks the waxoyl or not though?

Taking the axle off to do the job just wasn't practical for me and doing this is better than doing nowt hopefully!

Stonefish71 said:

Taking the axle off to do the job just wasn't practical for me and doing this is better than doing nowt hopefully!

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What you've done is probably enough to protect it against further corrosion for at least as long as the car is still economic to keep using.

Dave's solution looks prettier, though .

Not overly fussed about what it looks like under there as long as it remains solid, it doesn't look tooooo bad though tbh! In an ideal world it would have been off, blasted, powder coated etc etc yep - but in an ideal world I'd have a fully pre waxoyled Lancia Delta Integrale collection so hey ho, I'll keep dreaming and fettling!

jrkitching said:

What you've done is probably enough to protect it against further corrosion for at least as long as the car is still economic to keep using.

Dave's solution looks prettier, though .

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My 169 axle isn't broken but was heading that way so the only option was to take it off the car for cleaning and repair where necessary. That would leave the family without transport so an axle swap was the only realistic option.

I now have a better handling car and a 169 axle to strip, rust proof and sell.

Did mine today. Horrid job but worth it by all accounts. 1 can of galvanising primer, 1 can of acryllic black and 1 can of dinitrol wax.

THIS LOOKS LIKE DELIBERATE BUILTIN OBSOLESCENCE to me! It looks like another pair of dampers is also needed. I will not be buying Fiat ones ever again as the off side is clearly now much weaker than the near side; after relatively few miles and they were both so badly rusty after 18 months I decided they required cleaning and repainting..... At least they were very cheap.

Bump stops re stuck with 25 year mastic and some ivy wood. Peace and quiet restored again.

Dampers are not built to stop the axle on full bump so a missing or loose bump stop will soon take out it's damper/shock absorber.

The original dampers 0on my 57 (35K miles) Panda were ok and not especially corroded. The new axle (2015 F-500) came with springs and dampers (and brakes) so I fitted the whole lot. It rides a lot better but IMO all dampers will be well past their best after 35K miles.

BTW, I will be putting the original Panda springs back on the car. The lower ride height with 500 springs could be sorted and I like the more compliant ride but any load really drops it down so I'll have to go back to the stiffer ride.

Does anyone have a workshop page or link for removal of the rear axle or failing that a step by step?