Brakes failed on a 1999 996...

I am new to Rennlist and I was hoping someone could offer some assistance. I have major brake issues...got in my 1999 yesterday morning to go to work and the brakes did not respond in the normal fashion. The brake pedal (when pressed), only activated the brakes for the first 3/4 inch of travel. The pedal then got hard as a rock and any increase in pressure did not increase the braking ability of the car. If I release the pressure and apply the brakes again, it still only responds for the first 3/4 inch of travel. I checked the fluid level and the level is fine, plenty of pad left, car does not pull when brakes are applied while driving and...the hand brake obviously still works. Any ideas? Any recommendations? I did also check to see if there was anything blocking the pedal travel and it does not appear to be the case. I was thinking maybe a seal failed inside the master cylinder...just not sure how to trouble shoot that on my own. After a long (slow) test drive the check engine light came on but I don't know if this is related to the braking system at this time. I am trying to track down an OBD-II code reader right now...no luck yet. Thank you in advance for your assistance, Keith __________________ 1999 996 1972 Karmann Ghia Cabrio 2004 Volvo XC 70 (Wife's car) 2005 Saab 9-3 (Sold) 1989 Mercedes Benz 560SL

Brake booster failed or a vacuum leak up to it.

Thank you! I will start there. Would the check engine light have anything to do with it? I assume not since it came on an hour or so after the problem surfaced. I just wish the temps would get out of the teens so it was easier to work outside... Thanks again! Keith

Yes, if you have a vacuum leak you will get a check engine light.

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That's good to know.

I heard brake boosters are common to fail due to water puddling around them. Just a thought.

If the booster cylinder has failed (the most likely cause) you should be able to hear it.

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I have a reader you can use but I wont be in the city again until Monday, meanwhile, I'll be in the Burbs.

Thank you very much! I am heading out to pick one up now. I just wish I could find one that would also allow me to clear the service light on my wife's Volvo... Will it be a one time noise? Or a constant noise? Thanks for the advice! Keith

have you worked on the car recently? one time i made a bonehead move and the spring that sits on the brake pads got wedged between a pad backplane and the caliper. it was basically holding the pads open on one caliper. the symptom was as you describe.

I had the 90K service done within the last two weeks but it ran fine for 100 or so miles since then. I would think the problem would have surfaced right a way. Does anyone know if the booster would be impacted by cold temps? Would it fail at once or go intermittent and then fail? I also just read my codes and this is what I came up with: P 1124 Throttle Position Sensor Out of Self Test Range P 1126 Throttle Position (Narrow Range) Sensor Circuit Malfunction Looks like I have a bit more work ahead of myself. Thanks for the help. Keith

850 (1993-1995) There are two diagnostic units(it says A and B on the cover) located adjacent to washer reservoir under the hood. 1. Turn on the ignition and open the module A and insert the flylead into socket 7. 2. Press the button on the diagnostic unit 4 times, briefly but firmly. Then the LED illuminates and stays illuminated, and the system is ready to accept manual code input. A code number for resetting the service reminder light is 1-5-1. 3. To do this, press the test button once and release it. And LED illuminates again. 4. Then press 5 times and wait for the LED to illuminate. 5. Press the button once and LED should flashes several times in succession and the reminder should have been reset. 6. Switch off the ignition and replace the flylead in its holder and close the cover. 850 (1996-1997) and S70 and V70 (1998) You need an OBDII tool that resets Volvo service light codes. See this service light reset forum thread for more. They run about $100 to 200 -- or -- take it in to the dealer or independent Volvo mechanic and have them do it. Call to see if they charge for this first. Note: I've read reports of people having success with having the local Shucks/Pep Boys/Checker auto parts store do it. S70 and V70 and C70 and XC70 1. Press and hold odometer reset button. 2. Turn ignition switch to Run. 3. After SRL flashes, release odometer reset button. 4. Confirm by turning your Volvo off, then on again. S80 1. Turn ignition switch to position I. 2. Press and hold "day counter reset button". 3. Turn ignition to position II. 4. Continue holding day counter for about 10 seconds. 5. While SRL flashes, release day counter button. 6. Should hear "beep-beep" to confirm command accepted. S40 and V40 (1999+) 1. Hold down the odometer button 2. Turn the ignition so all the lights come on 3. Keep holding the odometer down for 30 secs or until the service light starts flashing 4. Release the odometer button while service light flashing 5. Turn off and on again to check

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The noise will be constant. I had a slight leak on my booster cylinder on one of my SUVs and it was annoying low level hissing noise that was there all the time. It was particularly noticeable when the car was idling.

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Makes sense, the engine has the highest vacuum against the booster.

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Yeah, exactly. The dealer explained the issue to me (as I thought it was something that they did, but the noise just happened to coincide with a service visit) and although my booster only had a slight leak that never caused any issue what they told me was that when the booster failed the noise would get louder and the brake pedal would require a lot more force to push, due to lack of assistance from the booster cylinder. Those guys (a Mercury dealership in MA) were the best dealers I've ever visited - they were open and honest, told me when something needed fixing, but more importantly they told me when something didn't need fixing. I wish I could find someone like them here in PA.

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Although a bit far for me (and probably for you as well) I recommend Dougherty's in West Chester PA. Stefan

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I've heard nothing but good things about them.

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Are you trying to tell us that Holberts doesn't do that for you?

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I wish! Hmmm.... if only I could have trust and honest in my dealer again.

I bet that you have a leak in the brake booster hose. The hose runs behind the air intake on the rear lid and tends to rub on the intake piece. The intake piece that I am talking about is the square black plastic piece that connects to the rear lid. I recently had the 2 codes that you listed and the brake booster hose was the problem.

Thank you everyone for the input...but the plot thickens. So, I was short on time this weekend and only got to spend a few minutes with the car. I read and cleared the codes, inspected the booster and lines/hoses that everyone mentioned. Didn't see anything totally out of the norm so I fired it up and the the check engine light did not register the codes once cleared. I pressed the brake pedal and the brakes were back to normal. One thing to note, the temperatures were in the 40s. Could the warm temps be masking the vacuum leak? I assume that the hoses become more flexible when warm and could that possibly be enough to prevent the vacuum leak from occurring? I must add I spent 4 years in Stuttgart when I was younger and I do recall some very cold days...do I now own a warm weather only car? My best guess is that the booster is still functioning and I have a vacuum leak. Thoughts? Thanks, Keith

What temperatures did you say that you had? The hoses will stiffen as the temperatures get lower, so it's a good thought, but typically the hoses should be good to at least -20 to - 30C before they start to crack and lose their seals. MN gets colder than that without any issues. I'm glad to hear the problem went away today - that's a good problem to have.. well, at least for those of us that don't drive in cold weather.

The temps were in the teens...nothing like MN. I am going to inspect the booster a bit more closely over the weekend. It's not that I have to drive in the cold weather...it is the 996 or a station wagon. Heck, I'd rather be in the 996 with no brakes!!!!! Thanks for the information! Keith