Coupe Boot Rust

[Anonymous]

So I just discovered some rust on the inside of the tailgate of my coupe :headbang:

I was looking for some solutions to this problem and the general consensus seems to be that it’s caused by “birdbath” (pooling of water) on top of the boot.

However Steve84N claims BMW said that birdbath has nothing to do with it” and that the rubber seal is purely cosmetic and the glass is bonded. (Not sure what it’s bonded to? )
(If true I’d like to remove the rubber since it would serve no functional purpose)

Has anyone come up with any solution to this problem?

Perhaps applying silicone sealant around the rubber lining?

 

[j3nks79]

Yes the rear glass is bonded just like the windscreen at the front.

You would need to get the rear glass removed. Then cut out the rust and replace with good metal. Prep paint and then re fit glass.

 

[Anonymous]

.Cheers j3nks79. I think I’ll bite the bullet and just order a new hatch from BMW.

The labor or love huh. :roll:

So if the rust isn’t coming from the rubber seals where could it be coming from?

I have a theory that it’s the rubber trim pieces around the windows that trap water underneath and then cause it to rust.

If I’m right I’d rather just get rid of the rubber trim and prevent these issues in the future.

 

[-Tom-]

Is this rust on the underside of the hatch, above the plastic light housing ?

 

[Mr Tidy]

I remember in my earlier years on here a few members reported getting their tailgates repaired or replaced under the 12 year corrosion warranty.

But I don't think the corrosion is related to the famous birdbath! My 2nd E86 looked like it had corrosion coming through from inside the frame when looking at it while it was open about a foot up from the bottom. Maybe water got inside the frame higher up through the rubber seal? Or maybe starting it's life in Manchester meant it got wetter than some!

By then the warranty had expired and I sold it when it was 13 and thankfully my current one seems to be OK so far.

 

[beanie]

.Cheers j3nks79. I think I’ll bite the bullet and just order a new hatch from BMW.

The labor or love huh. :roll:

So if the rust isn’t coming from the rubber seals where could it be coming from?

I have a theory that it’s the rubber trim pieces around the windows that trap water underneath and then cause it to rust.

If I’m right I’d rather just get rid of the rubber trim and prevent these issues in the future.

How much is a new hatch from bmw? I’d have thought it would be quite a bit. You could always go for a carbon one instead and forget about rust forever! I doubt it would be as straightforward to fit and align as an original part though.

As for the seal, you’re probably right that water gets trapped but I think it would look pretty unfinished without one. Given the car is nearing 20 years old, a decent repair should last for a long time.

 

[Meds]

My theory is the rubber seal the very top, at both sides of the tailgate.
I reckon water gets in from there.

But it could seap in from the bird bath, too.
I've had water sitting in there for days with no visible reduction, so mine's water tight, it seems.

Where is the rust? Along the bottom edge down the sides, or along the rear, or is it coming through the inside skin in the middle?
Check your drain holes are open, you may have a boot lid full of water!.

You can easily get the inside plastics out and then you'll then have access to look through some holes. A bore scope helps.

 

[mmm-five]

My rust was on the underside of the LHS of the hatch.

It looks like water/condensation sits between the lower body panel and the hatch and just sits there eating into the hatch.

I got it repaired once under warranty, and when it happened in the same place a few years later, they said they’d investigate and get back to me. They didn’t for 3 months, so I chased them up for them to tell me that it was due to a change in ownership of the franchise and I’d have to start again.

I decided to go to another dealer, but they couldn’t initiate the claim because it was still active on the other dealer’s system. The other dealer no longer existed, and the franchise who took it over had no access to their warranty systems.

Gave up and got it done myself.

 

[Meds]

My rust was on the underside of the LHS of the hatch.

It looks like water/condensation sits between the lower body panel and the hatch and just sits there eating into the hatch.

I got it repaired once under warranty, and when it happened in the same place a few years later, they said they’d investigate and get back to me. They didn’t for 3 months, so I chased them up for them to tell me that it was due to a change in ownership of the franchise and I’d have to start again.

I decided to go to another dealer, but they couldn’t initiate the claim because it was still active on the other dealer’s system. The other dealer no longer existed, and the franchise who took it over had no access to their warranty systems.

Gave up and got it done myself.

What a PITA.. !
When you got it sorted, what did you do to fix. ?
Repair and fix the cause of the ingress, or full replacement?

 

[mmm-five]

What a PITA.. !
When you got it sorted, what did you do to fix. ?
Repair and fix the cause of the ingress, or full replacement?

Just keep checking it out, and am prepared for the regular rub-down, anti-rust treatment, and area respray.

When we last looked, it was surface rust, and wasn't coming through from behind the panel, so must be sitting slightly too close to the base panel and maybe getting a bit of running which exposes some bare metal.

I suggested putting some matting between the two surfaces, but was told that would probably just hold the moisture for a longer period.

Maybe I'll just have to drive with the hatch up now and then

 

[Meds]

Are you able to wind out the stoppers that contrl how much the boot lid closes?
Maybe they're wound fully in, causing the lid to sit too low.