Replaced CV Boots / "Check Brake Fluid"

[tbailey1712]

About 600 miles ago I had my CV boots replaced by a local BMW repair shop. While driving home today I noticed my 2004 4.4 X5's brake performance was seriously degrading. It was taking more pedal than usual to stop and it would slowly drop to the floor when at a full stop.

As I was just pulling into my drive, the CHECK BRAKE FLUID message came on along with the BRAKE red lamp. Is there any possible relation here to the CV boot work? What would cause my X5 to suddenly lose brake fluid?

Thanks in advance

[chasz17]

First, do NOT drive the vehicle at all; have it towed back to the shop.

What might have happened when changing the boots is that the flexible brake hose was supporting the brake caliper and failed because of the added stress. There are other reasons, but I'd guess that this is probably the reason.

Again, please have the vehicle towed back to the shop for a proper diagnosis.

[killcrap]

the brake lines have most likely rusted out. remove the left panel under neath the vehicle and inspect the brake lines going to the rear, it is a very common problem on the E53

[tbailey1712]

Follow-up on this issue. Turns out that the brake lines had completely corroded on the left side of the vehicle and burst.

Because of the low mileage nature of my X5, the hypothesis is that over the past few winters, the heavily salted slush from Chicago's roads covered the lines underneath and over time corroded the steel lines. The covering over the lines does not allow sufficient drainage, thus water pools easily. One of the first questions I was asked was if the car was ever involved in a flood.

I was curious as to why this was never noticed and the mechanic indicated that the lines are very challenging to get to and thus aren't inspected.

I recently heard from the same shop and they have begun inspecting all X5's that come in for this issue and have definitely found a pattern. It seems to me that BMW has created a serious problem here.

[patrickkc]

This happened to me too few months ago. Freaky experience..