Questions and Answers

Chevy Astro Van BPMV Assembly Q. 1995 Chevy Astro Van, 52,000 miles. That's right, 10 years old and 52,000 miles. Has ABS Brakes, Original owner. First time: Brakes felt spongy, and had a lot of movement but stopped fine, only happened once and did not happen again for months. I do not remember if the ABS came into use at all just before this or not.

Second time: While running on a very bumpy area approaching a stop sign, I applied brakes and ABS kicked in. Stopped fine, no other symptoms. At the very next intersection when I applied the brakes they were spongy and traveled quite a bit before I felt I had brakes. It stopped fine, but I was very concerned that I wasn't going to stop in time. (Good thing that I have a habit of stopping with leaving at least a car length between me and the next car.) I had brakes but it scared me.

The next time I needed to use the brakes, they felt normal. My husband checked them out and found everything seemed normal. Couldn't get them to do anything wrong. He checked: brake fluid, power steering fluid, shoes and discs were fine. No leaks, lines seemed fine and the brakes worked fine. Then within two weeks later number three.

Third time: Husband driving-Towing trailer, entering camp ground, big dip and ABS brakes kicked in again, brake went spongy again, peddle traveled as before, was able to stop okay very concerned though. Since this episode, the brakes have not returned to normal. First chance into the shop it went.

Van is in the shop now, at a Chevy dealer (4 days now), they replaced the Master Cylinder. Did not help. They talked about contaminated fluid, or air in line. They said they bled the brakes. They were going to do it again. When I asked if they replaced the fluids they really didn't answer me.

They said that the symptoms are intermittent, HE said that he can get it to act up. They are talking about replacing the Brake Pressure Module Valve (BPMV) next. Said it was a $1200.00 part. They are trying everything they could think of before doing that, they say.

They said the Chevy rep was in the shop today, and they asked him about it being 10 years old with only 50,000 miles if they could help me out (I understood it as help with the cost), and he told them it's 10 years old.

They then told me that the head mechanic was going to take a look at it now.

I can't find the BPMV part that they are talking about in my manual, or so far on the internet.

Did I even need a new master cylinder at all. Both my husband and I are wondering if they are just trying on parts until they get it to work.

Since the Master Cylinder didn't fix the problem, should I have to pay for it?

I asked the service guy, when or if they plugged it into the computer did it give them any answers, He really didn't answer me there either.

I drive this van 99% of the time, the front disc brakes were replaced once at 20,000 miles. A piece of fishing line had wrapped around an area and caused one wheel disc to wear a lot, never noticed any pulling at all. (6 years ago). The rear shoes are original with, at least 50% wear left. I start and stop gently. (Yes I'm a grandma).

Any ideas? Appreciate your input.

Thanks, LB

A. It sounds as if the dealer is trying to help you out here. Most try to do everything they can think of before calling you to tell you the part they want to replace is $1200.00! If all your troubles begin when the ABS kicks on, then we can only assume there is a problem within the BPMV which is short for Brake Proportioner Modulator Valve. Basically it's the hydraulic part with all the valves in it that do the pumping of the brakes when you are in an anti-lock event.

There could be air in system but if there has been no work done on it, I doubt it. Any time someone complains of a loss of pedal with brakes, we want to replace the master cylinder because it's where the base braking begins and over time, seals can fail causing the problem. It's usually the cheapest part to replace as well.

As you can see, nobody wants to put this BPMV on and have you say it did not fix the problem. There is also a EBCM involved on this system. It is the brain of the unit. As a GM tech, I can tell you that it sounds like you are in good hands with your dealer. Give them a chance to fix it. I'm sure if they do put the BPMV in and trouble is still there, they will go to bat for you and possibly get it covered under warranty.