Keeping a rust-free sunroof... rust-free

[Kepes 231]

Evening,

It seems like every E30 sunroof rusts at some stage in it's life. Mine is no different, now severely rusted to the point where water leaks through it.

 I have here a nice rust-free panel, even the same colour. How can I ensure that it stays this way? Unfortunately my car does not live in a garage. There are products like Por 15 etc which people use on the body itself, would this be suitable? The reason I ask is it just seems like the factory seal/paint doesn't protect it well enough from corrosion long term. 

Appreciate the help!

Toby

Edited March 13, 2017 by Kepes

[Olaf 3249]

when I've needed to ensure steel stays rust-free, my old-school approach has been:

- remove any scale

- prep with rust kill (neutraliser)

- prime with appropriate metal primer

- ensure drainage functions as intended (in the case of old japanese & english cars add more drainage

- two liberal coats of fishoilene (yes, it's made from fish), brushed in, with time to leech into seams, and bake dry in the sun.  Yes it stinks.  Yes for a couple of weeks cats will hang around your car.

My brother fishoiled a mid-70's 180B that had been flooded.  When he sold it in '83, no rust - remarkable for one of the 70's best-known self-recycling cars.

My $0.02 for free.

 

PS:  have a good think about the design, and why they rust out where they do.  Is it the sunroof drains blocking?  If so, can you make 'em larger?  or is it just the outlets?

Edited March 13, 2017 by Olaf
PS design

[nick496 268]

I split my sunroof into its 2 pieces, saw all the rust hidden between. Then got them acid dipped and repainted before putting back together. 

[Kepes 231]

23 hours ago, Olaf said:

when I've needed to ensure steel stays rust-free, my old-school approach has been:

- remove any scale

- prep with rust kill (neutraliser)

- prime with appropriate metal primer

- ensure drainage functions as intended (in the case of old japanese & english cars add more drainage

- two liberal coats of fishoilene (yes, it's made from fish), brushed in, with time to leech into seams, and bake dry in the sun.  Yes it stinks.  Yes for a couple of weeks cats will hang around your car.

My brother fishoiled a mid-70's 180B that had been flooded.  When he sold it in '83, no rust - remarkable for one of the 70's best-known self-recycling cars.

 

PS:  have a good think about the design, and why they rust out where they do.  Is it the sunroof drains blocking?  If so, can you make 'em larger?  or is it just the outlets?

Seems like a good approach, as for the fish oil, doesn't it leave a residue, somewhat sticky too? My brother has his Land Cruiser fish oiled (I think) and it is like a hard goo is on the metal.

I think the reason is like nick says, to the sunroof is actually 2 pieces and water get trapped in there and causes the corrosion. The drains themselves do occasionally get blocked.

I didn't actually realise it was two pieces until I looked just now. I think I'll take the same route as you, Nick. How do you get the 2 panels apart?

 

23 hours ago, Olaf said:

My $0.02 for free.

Always grateful for your inputs!

Edited March 14, 2017 by Kepes