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jazzmaster, ASE Certified Tech
Category: Buick
Satisfied Customers: 2951
Experience:  ase certified
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Buick LeSabre: I have a really spongy brake pedal after bleeding

Customer Question

I have a really spongy brake pedal after bleeding the brakes (twice) using the Phoenix brake bleeder tool. What shoulld I be looking at to fix it?
Submitted: 2 years ago.
Category: Buick
Expert:  jazzmaster replied 2 years ago.
, did this all of a sudden happen ?did you replace any brake parts to have to bleed the brake system ?did the master cylinder get empty at all ?
Customer: replied 2 years ago.
The brakes have been requiring more effort over the past couple of months. When I first got the car almost 3 years ago (with 26k on it, a 2003 model!), I noted how well such a big car braked. But that's not been the case lately. I leave a good bit of braking room. The fluid was quite dark, so I pulled a lot of it out, and pushed a lot of new fluid into the system, figuring to get air out and new fluid everywhere. I'm considering the possibility that the master cylinder is leaking into the brake booster now. I wish there were a good way to evaluate that without pulling the cylinder. I don't think the master cylinder was ever empty. I have replaced pads on all four wheels, but haven't opened the brake system prior to bleeding.At one point, the ABS light came on when my wife drove it, but it went out again. I think that's a separate issue, though.
Customer: replied 2 years ago.
The ABS light was involved with a C1224 code (RR wheel sensor). The sensor checked out (1100 ohms or so, and 400mv when turning the wheel), so likely a wire or connection issue between EBCM and sensor.But this seems unrelated to the spongy pedal.
Expert:  jazzmaster replied 2 years ago.
usually the brake pedal will feel hard as if there is no air booster action .
but you can remove the air fitting off the booster and insert something in it as a piece of wire(white color) and see if when you pull it out if it has brake fluid on it or is wet ..
you dont
't have to remove the master to really check to see if it is leaking from the rear seal .
I know the brake lines loved to rust there .
but just take off the nuts and pull it forward a little to see if it is wet there .
these also, have the sliders in the calipers or caliper brackets .
look for sliders that are frozen (common issue) and this will definitely cause the brake pedal to feel soft .
the issue with the abs could be a break in the wiring to the abs sensor .a quick check is to see if there is an bubble or high spot on the wiring insulation.
that usually indicates a break or corroded wire ..
Another thing you can do is raise the car off the ground and secure with jack stands .
push lightly on the brake pedal and see if all 4 tires can be rotated or spin the tire and touch the brake ..
Customer: replied 2 years ago.
Sliders? The caliper pins that the calipers ride on?
Expert:  jazzmaster replied 2 years ago.
yes and the caliper slides/bushings
Customer: replied 2 years ago.
Just a faint bit of brake fluid at the rear of the master cylinder when I pulled it off. Possibly runoff from filling the reservoir, or a pretty minor leak. Certainly not a lot of fluid.
Expert:  jazzmaster replied 2 years ago.
well, if the sliders and bushings are good and move and there should not be any moisture or wetness from the back of the master ,I would myself replace the master cylinder .
it is not worth a chance of getting into an accident or not having brakes and even if there is just a tiny bit of brake fluid on the back side of the master that will cause a spongy pedal ...jazzmaster ..
Expert:  jazzmaster replied 2 years ago.
hi, did this information help you ?if so please rate me positive as that is the only way I get credit and we can still continue to work on this please don/t rate me if you still need help ..thank you ..jazzmaster
Customer: replied 2 years ago.
I have had to step away from this for this week due to an out of town engagement. I will resume investigating it when I return on Sunday the 26th. I changed the master cylinder out after bench bleeding it, but things are still spongy. I'm going to try bleeding the calipers once again. Otherwise, I will need to investigate other possibilities.I apologize for the delay.
Expert:  jazzmaster replied 2 years ago.
ok, yeah, you most likely have air in the system from the master cylinder leaking ,What happens is it may not leak much but it still sucks in air ..make sure all the sliders and bushing work and are not binding up and I find sometimes just opening the bleeder at each caliper or wheel cylinder and let the brake fluid run a little at each-one at a time .also, bleed the wheels starting at the right rear /left rear /r-front and then left front ..
Expert:  jazzmaster replied 1 year ago.
If I helped you -Please rate me positive and we still can continue with this issue if needed .
this is the only way I get credit for helping .
please don/t rate if you are not satisfied yet ..thank you ..jazzmaster
Customer: replied 1 year ago.
I will be working this more today, finally. (Assuming the weather holds up.) I will try bleeding things again to see if it helps.
Expert:  jazzmaster replied 1 year ago.
ok, thank you