Rusty brake line

[audiophool]

Gotta love BMW and their neat routing for hoses and hard lines. Traps dirt and moisture then rusts out the steel line. This is the rear brake line on our lower mileage X5. And yes, the stain is brake fluid. Other side is rusty but still dry.

[Purplefade]

Just wait until you run in to the fun waiting for you under the front driver side floor... plastic cover traps debris against the brake lines and rust them out there something fierce!

If yours haven’t failed there yet, pull the cover and do what you can now to try and salvage them... or just replace them now so you don’t have that sinking feeling at 65 mph on the outer belt...

[cn90]

This is why I rinse the chassis with water (at the self-serve car wash $2/time)
in the winter whenever temp is above 2-3C.

In April, I wash the chassis with garden hose. Rust accelerates in the hot months of June July Aug.

Don't blame BMW. It is lack of maintenance by the owner.

[Purplefade]

Originally Posted by cn90

Don't blame BMW. It is lack of maintenance by the owner.

Oh come on.... I had a Ford F-150 that I ran in everything but good weather and the brake lines never failed on that beast... over 260,000 miles of sand, mud, snow and crap on that truck.

That said, I do agree that a good power wash is a good thing every now and then, but “hiding” the brake lines under that cover that really doesn’t let them air out was kind of a silly move... just saying...

[crystalworks]

Originally Posted by Purplefade

Oh come on.... I had a Ford F-150 that I ran in everything but good weather and the brake lines never failed on that beast... over 260,000 miles of sand, mud, snow and crap on that truck.

I have to agree with CN90. Judging from the OP's first pics... that car seldom gets an under carriage cleaning. Don't have to remove wheels or unclip the lines to get water on them, if done before dirt/grime has already built up that is. I was worried about my front lines under the cover after all the horror stories here, but they still look great at 120,000 miles. I clean the wheel wells regularly and the undercarriage at least a couple of times a year. We rarely see salted roads so I'm sure that helps but the few times we have I clean the undercarriage immediately.

My undercarriage is not quite as clean as CN90's... but not far behind it either. Even seldom cleanings a couple of times a year makes a big difference it seems.

^None of that is saying that it's the best design from BMW either. But it is not a horrible or unsafe one if everything is kept from getting caked in garbage.

Edit: This is part of my twice a year under carriage cleaning:

[cn90]

I will be an expensive mistake.

We wash salt from our concrete driveway in the Spring to minimize damage to the concrete.

Every car is different Volvo, BMW, Ford etc.

Salt is corrosive to many materials: steel, aluminum, concrete etc.

My 1998 528i chassis is now 22 years old and it looks pristine underneath...

[Purplefade]

Was honestly something that I never thought much about until it jumped up and bit me in the butt... and I bet I’ve owned 40+ cars (this is the only one I’ve ever had a brake line failure on I will add)

Now that I have them fixed I actually drilled out my cover so that I could flush that channel every once and again and keep an eye on them... now

I also sprayed them with a healthy dose of rust inhibitor!

[audiophool]

Oh, I'm well aware of the lines under the floor. I'm looking there as well. Will I find problems? I'll let all y'all know.



But calling this issue 'lack of maintenance' is just wrong. You'd have to pull the wheels, un-clip that cover, and wash out the dirt a couple of times per year. Had BMW simply used open clips to secure those lines (3 on the passenger, 2 on the driver side), dirt wouldn't accumulate to trap moisture. Just a bad design. And without removing the cover from the underfloor area, would rinsing it even get out the crud?


.

[cn90]

- We change engine oil, we replace spark plugs. Washing the car is routine maintenance.

- The TRICK for the big shield...

- In the DIY Fuel Filter I wrote a while ago, I showed the photo of a hole I drill in the big cover. This allows me to get a garden hose (no pressure washer!), and spray water up there a few times a year, especially in the Spring. TRUST me, this makes cleaning the brake lines a snap!!!

- Detail below how how to drill a hole large enough for the garden hose:

https://xoutpost.com/bmw-sav-forums/...-filter-4.html

[Overboost]

That is an extraordinarily clean undercarriage cn90.