soft pedal 2002 x5

[ReneL]

Have spongy pedal,front right and rear left brakes are weak(unpluged abs fuses
to diagnose on gravel front left,right rear can lock up)Thought it was bad master cylinder,no change , replaced bled extensively,Did not previously or now have fluid loss at any point.Could abs unit have had air without having opened system?Is it possible for fluid to bybass in abs unit,so that one circuit is less effective?Thoughts?
Rene

[Clavurion]

I would first bleed the brakes with diagnostics which activates pre-charge pump and valves while bleeding.

[jcp240z]

Second that. If you replaced the master air could have gotten into the ABS.
When I replaced my master it took a number of bleeds to get it right. Bleed, let it “settle” for a day or so, bleed again. Was a pain.

[ReneL]

Originally Posted by jcp240z

Second that. If you replaced the master air could have gotten into the ABS.
When I replaced my master it took a number of bleeds to get it right. Bleed, let it “settle” for a day or so, bleed again. Was a pain.

My plan is to bleed abs module more with Foxwell,I dont think i got air in system,iam pretty anal about that,I had same symptoms with old Master cylinder,system never lost fluid,but yeah bleed,bleed,bleed.

[andrewwynn]

How did you bleed? You need to run through both methods with the fox and use a pressure bleeder. The pump three brake method just won't work. Pedal soft = air and your clever test will help you figure out where.

[e39_touring]

An old trick I learned a long time ago is to tap on the caliper with a wrench while bleeding it. The castings can be porous, and little air bubbles like to stick to the rough sides of the caliper casting. Even when I think I've gotten all the air out, I find that tapping on the caliper dislodge a few more small bubbles.

[andrewwynn]

That's pretty smart

[Ajg72]

i had the same issue and it turned out to be a leaking brake line on the drivers side. It's a known issue with these cars. Once I fixed it, I had a hard time bleeding it. I did have to use a Foxwell to bleed the abs system then the normal procedure. Good luck with it

[aureliusmax]

If you don't have the tool to activate the abs motors, you can do this;
manually bleed all brakes in the correct order - use the approved procedure of one person pump the brakes, other one opens the valve with a hose attached going into a cylinder where the hose is submerged in liquid to prevent air bubbles going back up.
now here's the fun part, find a gravel road and do some brake skids and activate traction control for a good 10 minutes.
drive back to the shop, bleed your brakes again for the second time.

if you old brake fluid was particularly nasty, you may need to wait a week and repeat the procedure as the new fluid will be absorbing the leftover moisture and contaminants from the old junk.

i've done this procedure several times when working on cars that i didn't have a scantool for. in fact, it's the procedure described in the Chrysler/Dodge service manuals to manually bleed brakes without a scantool.

[andrewwynn]

Soap water and smooth cement even better than gravel but if you are going too maintain a car you should get a scanner like foxwell.


AUTOPHIX BMW Diagnostic Scanner Tool ,Enhanced BMW 7910 Multi-System OBD2 Scanner Auto Fault Code Reader with Battery Registration for All BMW After 1998 https://www.amazon.com/dp/B07RTJYLQ8...ing=UTF8&psc=1

This looks like a copy of foxwell but possibly with a much better display maybe better interface.

I'm thinking of buying to test it. I can return if not impressed.