Caliper Replacement - Bleeding Air From ABS Control

[2002Silver4.6is]

Originally Posted by chubyball

Have done many brake jobs on most expensive cars suck as Lexus and Bmw. I know when bleeding the brake you need to have the engine on running because the ECU constantly get update information from your brake sensor and etc.... I think the master cylinder does not work right if your engine is off when you are bleeding the brake.

That is what my indy mechanic told me.

Do you think that just doing pads and not removing the brake lines is that different and does not require having the engine run while doing the bleeding??

So you guys think I need to bite the bullet and pat the $450??

[Eric Le Baron]

I still don't see why the engine should be running when bleeding the brakes.
What kind of information would the ECU need?
The car is standing still and the brakes are not used!
Or do you bleed the brakes without using a tool?

If the brakes would work relatively ok I wouldn't spend $450 and would wait a few months to see if they improve.
Maybe the air will be slowly absorbed by the brake fluid.
Would make an emergency stop and have the ABS kick in to see if that goes fine.

[2002Silver4.6is]

OK, had to pay the dealer for 3 hours of labor to hood the X up to their GT1 computer to cycle the air out of the ABS control.

Moral of the story... do not let air up into your brake lines!! If you are replacing the calipers make sure to clamp off the brake lines. For a normal rotor/pad replacement this should not be an issue.

My question is how would you go about clamping off a brake line? I would be afraid to put too much pressure on them for fear of damaging them.

[JCL]

I would use a pair of vice-grips, carefully. That is what I did when I did my last clutch delay valve. Just be careful. Alternative is to put one of the disposable plastic caps on the end of the line, they come on calipers, brake lines, etc.

Found this picture of a special tool for you on the web, lots of others available.

http://www.justoffbase.co.uk/Hydraul...9&category=115

[utahx5]

They make plastic brake line clamps they are cheap I do several brake jobs a day and always use them as far as air in the abs pump go out lay on the brakes and make the pump cycle I have done this many times after replacing master clynders and got air in the pump and have never had to use our scanner to cycle the pump sorry I didn't see you're post before you bit the stealer's golden bullet

[JBF]

I'm looking to buy a ~2005 X5 very soon and am a little concerned about the complexity of bleeding the brake system despite having done this on multiple cars in the past (including removal of the calliper on my 2006 Bosxter S).

I would be looking to check and most likely replace a section of the rear brake lines, if the issue flagged up here exists, that seems quite likely given that I've found quite a few references to the issue.

From what I can see there is no flexible hose in front of this component so clamping would not be possible. Even with the system under pressure whilst quickly swapping out this section I'm sure it would be possible for air to be drawn in to the lines.

Any suggestions or comments on replacing the part in question?

[JCL]

You can try capping the line, or using a pressure bleeder, but the risk remains that if you get air in the ABS controller, you will likely need a shop with appropriate tooling (GT1 or equivalent) to properly bleed the brakes. Not sure it is worth taking the risk of replacing brake lines yourself if you don't have the tooling. Why not just pay a shop to do it?

[JBF]

Because it should be a reasonably cheap and easy thing to do yourself rather than pay £60-150/hr for someone else to do it. Surprised there aren't any Chinese black boxes on eBay to cycle the ABS pumps.