Brakes Slipping?

[bigbengalbubba]

I have a strange problem that I've never experienced before I thought I would ask if anyone has any ideas. I'll try to give as much information as I can. I have a 2003 silverado 1500hd. It has 4 wheel disc brakes. Recently it has developed a symptom I can only describe as this. Sometimes as you come to a stop and you are almost stopped it will feel as if the brakes just slip a little and are stopping no more. I have checked fluid level and pads are fine. Not even close to worn down. It's a little disturbing since I have a trip planned next week. I know if I take it to a mechanic they will drive it around the block once and not find a problem. Ever heard of something like this?

[merlin5577]

I guess you could call this normal. I have this problem every once in a while on my trucks when the brakes are hot. I will try to explain as best I can what is going on. As you are slowing down the transmission is downshifting to match the vehicles speed to the appropriate gear. When it down shifts, obviously the torque of the engine is multiplide because of the lower gear ratio. This torque multiplication sends a small and short "surge" of power to the drive wheels, pushing the vehicle forward. Normally, the brakes are able to compesate for the momentary "surge", but on older vehicles or vehicles with hot brakes, it can become more apparent. If your pads are in good shape like you say, I wouldnt worry, I dont believe there is anything wrong. Hope this helps.

[bigbengalbubba]

Thanks, I'll try to worry a little less about it. It does seem to do it more when hot. It seems weird that it just recently started though. Someone suggested cleaning the ABS sensors or one might be bad.

[bigbengalbubba]

This issue started happening more frequently so I took it to my mechanic. He said it's a BPMV (brake pressure modulator valve). Of course mine is the expensive one. $913.00. Yikes!!!

[asilverblazer]

What?! Is it the Electronic Brake Control Module? Were the brakes "pumping" or "pulsating" as if the abs was coming on? If not, I doubt that (EBCM) will fix it. Sometimes as the engine rpm's drop or raise it causes the vacuum to fluctuate, vacuum being the source of power brakes can affect how they feel.

[Shaners]

Thanks, I'll try to worry a little less about it. It does seem to do it more when hot. It seems weird that it just recently started though. Someone suggested cleaning the ABS sensors or one might be bad.

 

This seems to be a way too common problem! It only seems to happen at slow speeds. Do a quick search on here because it has been talked about a lot. Some people claim they lose almost all stopping power under 5 or 10 MPH.

[bigbengalbubba]

not the electronic control module. It's a hydraulic valve. I have no idea why it's so expensive.

[HDdave]

This happened tp my dads 03. Change or clean the abs sensors and you'll be good to go.

[bigbengalbubba]

Well after stressing a lot over the repair bill for this it occurred to me that I may have purchased an extended warranty. A search of my great file system prove I was right. Into the dealer it went. It was the BPMV and the left speed sensor and cleaning the right speed sensor. Warranty covered parts and labor to replace them.. It didn't cover cleaning the sensor or brake fluid. It did also cover 35 a day for a rental car. Not too bad considering the alternative.

[Zembonez]

Well after stressing a lot over the repair bill for this it occurred to me that I may have purchased an extended warranty. A search of my great file system prove I was right. Into the dealer it went. It was the BPMV and the left speed sensor and cleaning the right speed sensor. Warranty covered parts and labor to replace them.. It didn't cover cleaning the sensor or brake fluid. It did also cover 35 a day for a rental car. Not too bad considering the alternative.

Is it fixed? Like the others here, I suspect that one sensor they replaced was the ACTUAL problem. I've never seen several items go bad at once on these systems. They are over-engineered to begin with... It just is highly unlikely.

[minibike132]

Well after stressing a lot over the repair bill for this it occurred to me that I may have purchased an extended warranty. A search of my great file system prove I was right. Into the dealer it went. It was the BPMV and the left speed sensor and cleaning the right speed sensor. Warranty covered parts and labor to replace them.. It didn't cover cleaning the sensor or brake fluid. It did also cover 35 a day for a rental car. Not too bad considering the alternative.

Is it fixed? Like the others here, I suspect that one sensor they replaced was the ACTUAL problem. I've never seen several items go bad at once on these systems. They are over-engineered to begin with... It just is highly unlikely.

 

 

 

+1 this was a sensor problem and a sensor problem only. Gonna thread jack for a second. Glad to see you Jim I thought you'd be off the air and headed inland. Button em up that Ike is looking pretty big.

[matthuber1]

Thanks for following up

[bigbengalbubba]

It was diagnosed by 2 separate mechanics. The one at the dealer and a private mechanic that I trust. (before I discovered the warranty) Both said BPMV.

[Zembonez]

It was diagnosed by 2 separate mechanics. The one at the dealer and a private mechanic that I trust. (before I discovered the warranty) Both said BPMV.

Well... anything is of course possible. That would be highly unusual. Glad it got fixed.

[bigbengalbubba]

Is it possible that driving it with a bad speed sensor could damage the BPMV?