Every couple of months or so when we are driving at low speeds in preparation for a stop, our van’s brake pedal will just drop to the floor and the “brake” light will come on. In the past if we stood on the brake, it would finally roll to a stop. This week, it would not stop at all. Fortunately we were in a drive-through and no one was in front of us. After sitting overnight, the brakes usually work again. The first time this happened, a year ago, we were living in North Carolina. We took the van to a GMC dealership there, and they could only find a small hole in one brake line, which they replaced. The second time it happened, they did about $400 worth of repairs to pads and rotors. When we were in the process of moving to Florida the following week, we had almost no brakes from Georgia to Florida. The dealership in Florida diagnosed it as a bad master cylinder, another $400. A few months later when it happened again, they thought it was the same, so they replaced it again, as well as the main brake line which they blew out while bleeding the system, both at no charge. This week they have found nothing wrong other than a worn battery cable, and they want $250 to replace that. We don’t dispute that the battery cable may be worn and we will pay to have it replaced, but we are not convinced that this is the problem. We asked them to check the speed sensors as this was an issue with other GMC vehicles, and they say they look fine. (We lived in Ohio prior to 2007 so salt/corrosion may be a factor.) At this point, we are terrified to drive this vehicle. We called the GMC Customer Service line, but they seem to be located in another country and can’t help us when the dealership isn’t getting any diagnostic codes.
As a follow-up question, if we cannot get this issue fixed with any certainty, can anyone recommend a replacement vehicle under $22,000 that gets reasonable gas mileage (21 combined would get us cash for our clunker), can tow a 1,500 lb. trailer, and can transport two adults (one over 6’) and a toddler in a car seat for long distances? The only ones we can come up with are the final year Chevy Colorado and GMC Sonoma Crew Cabs, but we don’t know if a GM product is a good use of our money anymore. The Ford Ranger does not have a full seat in the back. We are not opposed to buying a foreign car and we are open to any suggestions. Thanks in advance for your advice.
It seems you vehicles brakes are repairable, but for some reason it isn’t happening. I think a new vehicle is in order.
I think there are a bunch of vehicles that can pull 1,500 trailers, but you seem to be looking at pick ups. Your problem is the $22K criteria. I don’t know if a Ford F150 gets enough gas mileage for you to get the clunker benefits. I do think there are mid sized SUV’s that could do it. Ford Edge, Ford Escape, Chevy Traverse, Honda Pilot, Toyota Highlander, perhaps even Rav4’s and CRV’s can handle 1,500 lbs. To keep it under $22K you are going to have to look at used vehicles.
Honestly, this should not be that hard to fix. Brake systems are quite simple, the only variable is how the ABS system works. As long as you have fluid, and no air in the system, you can manually brake.
My guess is that something is causing a loss of vacuum, which would describe your initial problem (brakes work some but you have to push really hard to make them do so). That is easy to check with a gauge. It could be something as simple as a $2 check valve that is bad.
I would take it (or rather have it towed) to an independent shop that only does brakes. My bet is they will find something simple and inexpensive to correct the problem.
BTW, when they do find the real problem - please send the solution, with that bill to GM customer service. Their own “factory trained” people could not figure it out, but some general brake mechanics did - that might help you get a partial refund.
Thanks for the quick response. We would prefer to get the van fixed, because we do like it and it seems wasteful to junk a 6 year old vehicle with only 90K miles and no other issues.
We do not have a good history with vehicle purchases. We just replaced a Lexus sedan that was toast at 81,000 miles. We perform all of the scheduled maintenance and we are cautious drivers, so it is just our dumb luck. This is why our criteria for a replacement vehicle is (1) cheap and (2) under full factory warranty. We like SUV’s, but we were looking at small pick-ups because they met our cost criteria new.
Can a loss of vacuum be an intermittent issue? In other words, can we have two months of braking just fine, and then no brakes at all, and then brakes just fine again the next day?
Perhaps the advice from hallkbrdz below is worth taking. A good brake shop should be able to figure this out. You need confidence in the vehicle. Before you can regain that you need to find a brake shop that is competent and can find and fix your problem.
I would think it is an ABS issue, it has a lot of control over the braking system. Were talking big bucks here though.
Loss of vacuum would cause very hard brake, not going to the floor.
That is our thinking as well, that it is an electonic/control issue related to the ABS and/or the wheel speed. This was a problem with other GMC vehicles and there was a recall a while ago (but not for Safaris). However, the vehicles affected by the recall had the ABS kicking in and the ABS light coming on, and those are not happening in our case.
My feeling is that in order for the pedal to drop to the floor the brake fluid HAS to be going somewhere when the pedal is pushed.
Your symptoms are highly typical of a bad master cylinder, but since you’ve already had it replaced twice and I have to assume that the dealet tech knows enough to bench bleed the MC (?) the only thing I can suggest is a reputable independent owner-operated shop. This one is fixable, but it’ll tale someone hands-on to do it.
Paying a few hundred to an additional shop is unfair, but it will be a whole lot cheaper than trading the vehicle.
Post back and let us know how you make out. We do care.
Thanks everyone, we will be taking our van to a mechanic we found in the files on this website. We will let you know what we find out.
One far out idea that I have is that somehow the brake fluid is being heated and then boils. Brake fluid, in its liquid form, doesn’t compress, but in a gas form, it compresses very easily. Is it possible that an exhaust leak somehow heats the brake lines? Is a brake caliper sticking intermittently which would generate heat and possibly cause this problem?
My first thought was a master cylinder problem as I have had this happen. However, you have had this replaced. I go along with the recommendation of others in finding a good independent shop that knows brakes. I had a 1990 Ford Aerostar and had problems with the back brakes sticking on after a hard stop. The Aerostar I owned only had the antilock brakes on the rear wheels. The Ford deaer never did find the problem even after I took the technician for a ride, jammed on the brakes in front of the door to the service area and locked up the brakes for him. I finally went to an independent shop and they cleaned a valve on the antilock brake system–no more trouble.
Your Safari uses a belt driven pump to provide brake boost so vacuum loss is not one of the possibilites.
Some additional info: we picked up the van from the dealership yesterday (at no charge, since they could not find anything wrong with it) and noticed that while the regular brakes were working, the emergency/parking brake is not working at all.