This is a followup to an earlier posting on a low brake pedel on a '94 940T Sedan. This is my son's car, and we have been trying to resolve this problem for quite some time. The pedel travels quite a bit before it becomes firm. While applying braking power, the pedel feels mushier than it should before getting real firm. The brakes feel no where as firm as my old 740's and current V70 and XC70.

Here is what we have done over the last several months:

New (rebuilt) master cylinder
New (rebuilt) brake booster (to solve a cold weather problem)
New brake hoses on all 4 wheels
New (rebuilt) rear calipers (each had a frozen piston)
Front calipers checked and found be free with operational slide pins
Bled the brakes twice, there is no air coming out any of the calipers.

The system is not loosing any brake fluid, so there are no leaks.

None of the above actions have improved the problem.

What else is there that can cause a low pedel? Is it possible there is air hidden in the ABS modulator? It is the only place I can think of where air may still exist. Is there a way to check for air in the ABS, and get it out?

Any thoughts are greatly appreciated. This problem has got me stumped!

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Gary D

Thanks for the thoughts.

I have used both the pump the brakes method and a pressure bleeder. I like the pressure bleeder since I can do the job so much faster. I have found in the past it helpful to do a pressure bleed, then finish it off with some brake pumping. For my son's car, we have used both methods, and still have the low pedel. As for frozen brake parts, like I said, the rear calipers were replaced the other night. The front calipers are free and the slide pins are working just fine. While replacing the master cylinder, we did a bench bleed, and hooked up the brake lines with brake fluid dripping from the ports. So, no air should have gotten in. Then we repeated the bleed, and got no air at any of the calipers. Used about 1 1/2 quarts of brake fluid doing the bleed.

Any other thoughts?
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Gary D

Are you sure the hydraulic parts are correct? Mismatches between master and calipers can require more fluid, thus more pedal travel.

You simply cant bleed the brakes properly without a pressure bleeder, I have a motive one, I think it was about $40 from FCP. It turns a crappy job easy and allows you to do it single handed. My experience has been that a long pedal is almost always due to one frozen or binding slide pin on a front caliper, barring any air issues. The sliding part of the caliper then has to rack and the piston has to travel much further to push the pad to the rotor. Speaking of air, did you bleed the master cylinder? A little air there will certainly lengthen the pedal. As far as the ABS is concerned, I always bleed thoroughly then go find a wet patch of pavement or a gravel parking lot and lock 'em up 10 or 15 times to get the ABS hammering away clearing any air out that might be there. Then bleed again.

good luck

How did you bleed the brakes? Pressure bleed or just pump with the pedal?