Technical Rear axle rust

[Danoid]

So last 2 years had an advisory for rear axle slightly corroded.

I wanted to sort this last year but couldn’t for various reasons.

The paint has pretty much flaked off but so far looks structurally sound.

I’m going to wire brush the area, remove the lower rear suspension, which I’ll then be able to remove the springs to do the plate. then use either Bilt Hamber Hydrate 80 and Dynax UB or Dinitrol RC800 and 4941.

The question is should I use Bilt Hamber or Dinitrol? I’m guessing someone has experience with both

Thanks

 

[Ralf S.]

Those look like a rust killer/converter followed by a cavity/wax over the top, combo'

In my experience, rust converters never kill all the rust, or it soon comes back again... but there's no solution to that really, apart from removing as much rust, paint and flakey surface as possible, so it can get to the first layer of good metal. To make it come back later rather than sooner, I would also apply some paint to the surface once the converter has done it's converting.

If your surface is relatively smooth and you like to lie underneath the car admiring the engineering, then an aerosol Hammerite or similar would give it an extra barrier to the atmosphere. If your surface is pitted and you never spend time under the car, then brush-on paint will do. You can apply by brush more thickly but aerosol is better for nooks and crannies. Don't use underseal type products, since in my experience these can dry out, crack and lift.. allowing moisture underneath,

Then it seems to be a preference between Dinitrol or Bilt Hamber products. Dinitrol seems to be more popular in terms of stockists.. but my feeling is that Bilt Hamber probably just edges it on performance. However, I've only ever used some Bilt Hamber UB and not long enough ago to give you any meaningful feedback on how it performs.

In any case, either treatment is better than no treatment. Just visit it again next year to see how it's survived and if necessary, apply more wax.


Ralf S.

 

[John202020]

So last 2 years had an advisory for rear axle slightly corroded.

What age is the car ? Take a good look at the spring pans these can literally crack off due to rust it can get to the point of a new axle (I had to replace ours for that very reason )

 

[Baglady1990]

I do my 2011 rear axle every spring! Knowing it’s prone to corrosion..the spring pans are always full of crap after winter
Try using genolite it works very well for me then a good coat of waxoyl pay attention to all areas of the spring pans & keep the little drains unblocked

 

[jrkitching]

I don't recommend using any kind of paint for chassis protection on a car in regular use in the UK climate. Moisture will inevitably penetrate the paint layer, and corrosion under the paint will soon see it flaking off.

Any of the proprietary self-healing wax-based underbody protections will work much better than paint. Checking the condition of the protection, and topping up or cleaning and reapplying as necessary should be done regularly, preferably annually before the start of the winter.

 

[typecastboy]

I've got a complete rear beam with hubs that I intend to put on one of my project cars. I've already removed loose paint/rust and use Jenolite rust killer and then painted with stone chip Hammerite. I did that last summer and it's still sitting at the bottom of the garden and has been out in the weather and it's pretty much as good as it was 6 months or so ago when I done it. I should be putting it on the car soon, hopefully.

 

[jrkitching]

and has been out in the weather and it's pretty much as good as it was 6 months or so ago when I done it

Don't be fooled. Being out in the weather, and being under a car driven on salty roads isn't the same thing.

 

[typecastboy]

That's very true.

 

[Pugglt Auld Jock]

For a couple of years - maybe it's been longer? - I've been meaning to treat the rust on Becky's (2010 Panda) rear axle. She's just passed her MOT again, with no advisories, so this summer I really must bite the bullet and get on with it. In the past I've used both Curust and Jenolite with good results but I've known about Fertan - this stuff: https://www.frost.co.uk/fertan-rust-converter-spray-1l/ for some years and I'm going to give it a try. Once stabilized I will be painting over with this stuff: https://www.frost.co.uk/frost-chassis-black-paint/ which I've used before and had excellent results with.

I hear what jrk is saying about wax vs. paint for these kinds of jobs and his thinking is sound. However the problem with wax type products is that if you want to subsequently do more repairs later then you've a devil of a clean up job to do before you can start work and most of the rust converters don't like oily/greasy/waxy surfaces, so I prefer to paint. Have to say though that I find Hammerite, whilst very good for some applications, I find it chips too readily when attacked by road stones etc. Frost's chassis paint is an enamel and I think has a wee bit more plasticity? Certainly I've found it much more resistant to chipping on the likes of motorcyle frame tubes etc.

Here's a couple of pictures of her rear axle/spring pans taken when I first thought about doing the refurb:

We're a couple of years on since these pics were taken and the corrosion has got a wee bit more of a grip but there doesn't seem to be any signs of cracks and I've had a good poke around with a screwdriver, which dislodged some slightly alarming "crusty bits" but it all seems pretty solid still. The plan is to disconnect the bottom shocker bolts, swing the axle down, clean everything up with a wire wheel and chipping hammer before applying the Fertan and painting. If it all goes well I'll buy new springs when I reassemble it. In the meantime I'm periodically spraying Plus Gas into the outer, threaded, ends of the securing bolts. I've done a lot of other work on her to bring her up to a good standard, most of which I've done posts about on the forum, and this is the last "big" job I know of which still needs to be done so I'm actually quite looking forward to getting stuck in. I can hardly wait for the good weather to come in.

 

[John202020]

For a couple of years - maybe it's been longer? - I've been meaning to treat the rust on Becky's (2010 Panda) rear axle. She's just passed her MOT again, with no advisories, so this summer I really must bite the bullet and get on with it. In the past I've used both Curust and Jenolite with good results but I've known about Fertan - this stuff: https://www.frost.co.uk/fertan-rust-converter-spray-1l/ for some years and I'm going to give it a try. Once stabilized I will be painting over with this stuff: https://www.frost.co.uk/frost-chassis-black-paint/ which I've used before and had excellent results with.

I hear what jrk is saying about wax vs. paint for these kinds of jobs and his thinking is sound. However the problem with wax type products is that if you want to subsequently do more repairs later then you've a devil of a clean up job to do before you can start work and most of the rust converters don't like oily/greasy/waxy surfaces, so I prefer to paint. Have to say though that I find Hammerite, whilst very good for some applications, I find it chips too readily when attacked by road stones etc. Frost's chassis paint is an enamel and I think has a wee bit more plasticity? Certainly I've found it much more resistant to chipping on the likes of motorcyle frame tubes etc.

Here's a couple of pictures of her rear axle/spring pans taken when I first thought about doing the refurb:

View attachment 404331

View attachment 404332

We're a couple of years on since these pics were taken and the corrosion has got a wee bit more of a grip but there doesn't seem to be any signs of cracks and I've had a good poke around with a screwdriver, which dislodged some slightly alarming "crusty bits" but it all seems pretty solid still. The plan is to disconnect the bottom shocker bolts, swing the axle down, clean everything up with a wire wheel and chipping hammer before applying the Fertan and painting. If it all goes well I'll buy new springs when I reassemble it. In the meantime I'm periodically spraying Plus Gas into the outer, threaded, ends of the securing bolts. I've done a lot of other work on her to bring her up to a good standard, most of which I've done posts about on the forum, and this is the last "big" job I know of which still needs to be done so I'm actually quite looking forward to getting stuck in. I can hardly wait for the good weather to come in.

Zoom in on the spring cup, is that a crack starting ? Just like mine?

 

[chris3234]

Zoom in on the spring cup, is that a crack starting ? Just like mine?

Certainly looks like the start of one?

 

[Danoid]

Cars a 2009 with about 22k miles, it only goes to Lidl 1.2 miles once a week the poor thing, on average really.

I’ll try the hydrate 80 and dynax ub I think, worth a shot but first I’ll check over the best I can to make sure the area is actually sound.

I wish I had a lift or inspection pit, make life so much easier

I’m likely to do this in the next couple of months, I will be back here once I’ve done it with pictures. I hate it when people never get back when they say they’ll do something then I end up thinking “RIP”

 

[Pugglt Auld Jock]

Zoom in on the spring cup, is that a crack starting ? Just like mine?

Yes, it nearly gave me heart failure too! However it's just the paint cracking with the rust underneath pushing it up. I chipped away at it with my "pointy" welding hammer and the paint and rust flaked away to expose sound uncracked metal underneath. That picture was taken some 2 years ago and it's still ok today (or it was when I checked it before it's MOT a couple of weeks ago. Phew!!

 

[Baglady1990]

Yes, it nearly gave me heart failure too! However it's just the paint cracking with the rust underneath pushing it up. I chipped away at it with my "pointy" welding hammer and the paint and rust flaked away to expose sound uncracked metal underneath. That picture was taken some 2 years ago and it's still ok today (or it was when I checked it before it's MOT a couple of weeks ago. Phew!!

dodged that bullet jock! I’d have done the same ..whoosh straight under the car another reason I strip mine back come spring though I probably make more work for myself..I just don’t really want to be in a position like John found himself…
Changing the rear beam over …ok I could BUT I don’t really want to

 

[Piccolo Nero e Bella]

Looking at the horror photos above made me realize I've not seen my rear axle for years so I popped the little camera underneath tonight and fired off a few 'blind' snaps. Obviously no issues with corrosion but can anyone please tell me if the apparent rust on the white components is significant?

 

[Baglady1990]

Looking at the horror photos above made me realize I've not seen my rear axle for years so I popped the little camera underneath tonight and fired off a few 'blind' snaps. Obviously no issues with corrosion but can anyone please tell me if the apparent rust on the white components is significant?View attachment 404349View attachment 404350

I swear you just posted this to make me super SUPER JEALOUS what corrosion?! Pha! If your on about those things inside the springs? Bump stops ..are you sure it’s rust!? When I changed mine I presumed they were plastic n rubber!?

 

[Baglady1990]

I swear you just posted this to make me super SUPER JEALOUS what corrosion?! Pha! If your on about those things inside the springs? Bump stops ..are you sure it’s rust!? When I changed mine I presumed they were plastic n rubber!?

Your climate! Oh how I wish I lived where you do!!!

 

[Pugglt Auld Jock]

I probably make more work for myself..I just don’t really want to be in a position like John found himself…
Changing the rear beam over …ok I could BUT I don’t really want to

Anxiety about "what if I don't" is always making extra work for me! As you say, changing the rear beam? Yes I could, but at my age and with my arthritis I really don't want to!

 

[Piccolo Nero e Bella]

I swear you just posted this to make me super SUPER JEALOUS what corrosion?! Pha! If your on about those things inside the springs? Bump stops ..are you sure it’s rust!? When I changed mine I presumed they were plastic n rubber!?

I'm with Jock on this one - I wasn't getting under there to check 'em out! If I did I'd need to call the wife to drag me out and help me get up again!!! Quite honestly I have no idea what they're made of - I'm just going by the colour. If they're just part of the bump stops I'll assume there's no problem.

Your climate! Oh how I wish I lived where you do!!!

Gotta be some compensation for living on the arse-end of the planet - but remember the spiders!

 

[Baglady1990]

I'm with Jock on this one - I wasn't getting under there to check 'em out! If I did I'd need to call the wife to drag me out and help me get up again!!! Quite honestly I have no idea what they're made of - I'm just going by the colour. If they're just part of the bump stops I'll assume there's no problem.

Gotta be some compensation for living on the arse-end of the planet - but remember the spiders!

Oooooh sh*t yeah the spiders 🕷 now …if I got under my car and there was a big bugger …I’d not be doing any work saying that by the looks of thins…..I wouldn’t need to!