Failed Brakes, 2003 Suburban

reimanc

Does anyone know of a problem with the 2003 Suburban braking system?
My Suburban has about 4K miles and yesterday with no warning, I had no brakes.
The car was towed to the dealership but I'm really afraid to drive it again.
Am I panicking too soon?

desi501

If it was a permanenty failure it could be a loss of fluid somewhere or a Master cyl failure. If it was a temporary failure and the brakes came back and assuming nothing was overheated, I would start looking at the ABS system.

fkozil

The ABS system is independent of the actual braking system. Just two computers and several sensors decide when and how long to pulsate/cycle the brakes for the ABS to be effective.

The mechanics of the braking system should not be effected by an ABS failure.

No braking on a new vehicle usually is a failure of the master cylinder.

desi501

Are you saying the ABS is not part of the hydraulic system and can't cause a pedal failure? Better read that again.
Just how does it release a fluid applied brake.

fkozil

Calipers, pistons, rotors, master cylinders and high-pressure lines cause brake failures.

The ABS system is comprised of computers and sensors which operate these parts that help prohibit a wheel or wheels from locking up. Limiting wheel lock allows the driver to have better control of the vehicle.

An ABS failure does not mean that the braking system is rendered obsolete. Only the ABS control of the system is down, not the actual braking system.

If the braking system fails, it is most likely caused by a mechanical failure and not an ABS failure.

reimanc

Thanks all,
The dealership said that a tiny amount of brake fluid leaked each time I stepped on the brake pedal...not enough to notice but over time the last six months the vehicle lost all the fluid.
That said, I told him I thought the computer should have given me some sort of warning before this...he agreed and said there had to be something defective in the ABS system as well.
I don't know enough about this but he said there is a back up system that would have stopped the car.
Does anyone know what he's taking about?

I will post the part but it was expensive...over $1,000.
Thanks

desi501

Thanks for the education on ABS but let me tell you a little. Although you have the theory right about what ABS is expected to do, you don't have it all. Yes, there is an electrical portion of an ABS system that does what you refer to but there is also a hydraulic component in that system also. It is in series with the hydraulic system and is managed electrically. How do you think the ABS module actually releases pressure to the brakes? It creates a fluid bypass situation and returns unused fluid to the reservoir. This unit can not only be bypassing but also capture air that can be very difficult to bleed. Some of the later models can bleed this unit electronically with solenoids by using a scanner but believe me, IT CAN CAUSE A PEDAL FAILURE!

fkozil

Like all hydraulic systems, the system is sealed. How do you introduce air into a sealed system?

The only way is to unseal the system - a mechanical failure!

Perhaps factual knowledge prevails over ignorance?

No. If you believe you are correct then so be it.

I am not going to debate this topic with you any longer.

Besides, what do I know? It's not like I work on these vehicles on a daily basis - right?

desi501

I can name a half dozen times I've changed an ABS dump valve to repair a bypassing pedal and I've seen internal leakage in GM ABS units also so don't say it can't happen.

Mr_Shiftright

I wonder if this car was sucking brake fluid through the power brake booster?

Seems to me you'd have a messy floor with a master cylinder that lost every bit of fluid.

desi501

He stated they did find a leak but he never told us much else about the problem like "did he ever check the fluild level". I guess he's all set now.

zueslewis

consumers have gotten past the "owner responsibility" level of doing maintenance and checking fluid levels.

The situations people continue to place their families in will never cease to amaze me. It takes less than 5 minutes to check all the fluids in my vehicle....I'll gladly invest that 5 minutes once or twice a week to make sure my family is safe.

I can hear the reponse - it shouldn't have lost fluid in the first 6,000 miles...that's right, it SHOULDN'T HAVE, but break-in periods are the MOST critical times to keep a watchful eye on your vehicle's vital fluids.

Thank God no one was hurt, and maybe the owner will be smarter next time.

Mr_Shiftright

Well this is the down side of having a warning light for everything. What happens when the warning light fails? Is there a warning light for the warning light?

zueslewis

we have too many "victims" these days and not enough folks who don't realize that it's their responsibility, not the manufacturer's, to check their fluid levels and other safety/reliability-related things.

swschrad

you don't have to know how to Parkerize a crankshaft to drive, but you should be able to check your car's vital fluids and tire pressures. I still think there should be a page for dummies that folds out of the manual that on an 8-1/2 by 11 sheet shows in pictographs how to check oil, coolant, and tires at a minimum.

zueslewis

first thing I taught my kid - he checks his oil every day. I told him that was overkill, but he loves driving, and loves that obsessive maintenance idea.

Nothing wrong with that.

desi501

Being in this business I find the same people doing it all the time. My favorite is the guy (or women) brings in the fried heads that you could cook steak on and says I saw the temp gauge (or light) BUT "I had to keep going, I had an important appointment" or " It was only a couple more miles to get home" These are the people that blame the car all the time. "This piece of junk cost me a fortune" Now WHY??