[Eriksome]

My car has been minimally used, sitting mostly still for about 4 months, and has rusted as result. Does the rust look serious, or is it mostly surface rust?

[Wolf 335]

By the looks of it, at first braking the caliper will explode into pieces .

Is that a rebuilt caliper? Usually they strip the protective coating when they rebuild these.

Wire brush the rust spots and put some rust converter on them, and you're good to go.

[Eriksome]

Originally Posted by Wolf 335

By the looks of it, at first braking the caliper will explode into pieces .

Is that a rebuilt caliper? Usually they strip the protective coating when they rebuild these.

Wire brush the rust spots and put some rust converter on them, and you're good to go.

I've been driving it for a couple days now, brakes havent seemed to explode yet. They feel fine apart needing a brake fluid flush.

Im more concerned about the frame and/or suspension rust

[Ohio Enthusiast]

Yeah, that's more than just surface rust. The rust flakes and fissures don't look good. Wire brushing to remove loose parts will help reveal the extent of the rust and determine if it's a concern or not.

Originally Posted by Eriksome

Im more concerned about the frame and/or suspension rust

Then perhaps share some frame and suspension pictures?
From what little suspension parts are visible it doesn't look as bad as the brake calipers (with the control arm showing harmless surface rust and the strut a little more than that), but I would definitely do a more thorough inspection based on the state of the calipers.

[Efthreeoh]

Not serious. Cast iron. Surface rust.

[whyzee125]

From the little of the suspension and subframe I can see in the pics it looks like normal surface rust. These cars actually hold up really well against rust, the one exception in super salty climates being the rear subframe. Yours, from what I can see, doesn’t appear super rusty.

[eljay]

Post some pictures of the underside. We only see the brakes.
But it's doesn't seem like anything disastrous peaking from there.

[Eriksome]

Originally Posted by Ohio Enthusiast

Yeah, that's more than just surface rust. The rust flakes and fissures don't look good. Wire brushing to remove loose parts will help reveal the extent of the rust and determine if it's a concern or not.



Then perhaps share some frame and suspension pictures?
From what little suspension parts are visible it doesn't look as bad as the brake calipers (with the control arm showing harmless surface rust and the strut a little more than that), but I would definitely do a more thorough inspection based on the state of the calipers.

Here are some pictures of the underside of the car

[oVeRdOsE.]

you should focus on brake line fittings and subframe.

From the picture, it looks new comparing of what we have here.
Long winter + salt + calcium + uber humid summer = sht load of rust.

However, bmw is the most rust resistant cars I ever owned.

[TheMidnightNarwhal]

Nothing to worry about IMO. Caliper looks pretty rusted but I don't think it will affect the brakes.

[Efthreeoh]

My subframe is WAY worse than that. And has been for going on two years now.

[Wolf 335]

I wonder how much cost savings there was to go with hydroformed steel tubing instead of aluminun rear sub frame. It's a shame they did that.

[Tambohamilton]

Originally Posted by Wolf 335

I wonder how much cost savings there was to go with hydroformed steel tubing instead of aluminun rear sub frame. It's a shame they did that.

I'd love to have an aluminium rear subframe like the e6x, but it's also weight distribution I bet; if steel and aluminium were the same price, they'd choose the heavier one to better balance the weight of the engine.