My elderly mother is driving a 2012 Volkswagen Passat. I drove the car recently, in the rain, and when I went to stop at a red light, the brakes slipped–didn’t catch–and the car almost went into the intersection. She says this has happened to her multiple times, and that she has had tires and brakes replaced to no effect. Brakes work fine in dry conditions. Traction control indicator light flashes briefly during these brake failures and then goes off. I’ve heard that other Passats have had braking issues like this. What is the diagnosis? Thanks to all who try to help
Ask the shop to do a detailed visual check on the brake components on all four wheels. If nothing found, and the master cylinder tests ok, next step is to check for any OBDII and/or ABS fault codes.
There are no warning lights on the dashboard, and the tires are in good condition, the correct size, and inflated to the correct pressure, right?
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The tires are almost brand new/correct size and inflated properly. Dealership mechanics told my mother that brakes were great last time she went for an oil change. Could it be faulty rotors or ABS control module?
I would have to say it is the tires if everything o the brakes checks out OK one set of tires on my wife’s car [ I don’t remember the brand but they came from Walmart ] started getting squirrlley on wet roads within a year.
Tires are new from the dealership. Definitely not the tires. But thanks!
This may indicate that the wrong type of tires have been installed. Some tires are made of harder rubber than others to make them last longer in hot conditions. The traction control light is indicating that the wheels are being stopped and preventing them from locking up. If you find you have the proper type of tires, I’d have to say you have an ABS issue. Usually the ABS system will throw a fault code for this but maybe not in this instance.
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That’s because the brakes are locking up.
It is the tires, they’re skidding because the brakes are locking up, the brakes are locking up because of the type of tire you have.
You need a different type of tire, an all weather or all season tire, not a low rolling resistance tire.
Or the tires are over inflated.
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It sounds like the ABS is activating on wet pavement. It’s either activating correctly due to a loss of traction (that is why others are saying it may be the tires), or it’s activating incorrectly due to some ABS fault. It seems like if there were a fault with the ABS, it would occur on dry pavement also. But, I have seen ABS activate in low traction conditions when it really shouldn’t activate and reveal other problems with the braking system.
I would recommend having another shop look at it. Hopefully a shop that will be willing to drive it on a rainy day.
+1
It’s still not clear to me exactly what the OP means by the brakes “not catching”.
If he is expecting the tires to screech when the car is braked on wet pavement, that won’t happen with properly-functioning ABS.
Does the OP mean that the brakes don’t work at all when it is raining, or that they are less effective?
Or, does he mean that the pedal feels funny (shaking/pulsating)?
Or, is he expecting to hear a screech from the tires when braking on a wet surface, and the absence of that noise is causing him to think that there is a problem?
This could be a tire problem (even if the tires are fairly new and were bought at the dealership), or it could be a genuine brake problem or ABS problem, or it could just be the ABS working as it was designed to do.
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@Mountaindweller When you stated that the tires are properly inflated, did you mean the pressure noted on the sidewall of the tire or the inflation pressure noted on the left door pillar?
The placard on the left door pillar is the proper pressure. I have had service personnel inflate tires to the maximum pressure noted on the sidewall of the tire, and have experienced similar problems. Buy a tire gauge and check the tire pressure and make certain it is the pressure specified by the placard on the door pillar.
This may not be the problem, but for $10, a tire gauge is a very useful tool.
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New from the dealership tires does not mean much. Dealerships usually sell a variety of tires. These tires may have poor wet traction.
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I agree with @Purebred. A couple of months ago, I needed to replace the tires on my Toyota Sienna. The Toyota dealer had a buy three and get the fourth tire free. I bypassed the offer. I do business with an independent tire shop that had been in business for at least 40 years. The independent shop also does alignments and brake work. Since I know from experience that I will.get a quality tire, and in my case, Michelin, I don’t go price shopping.
I did have a brake problem that the technician at my independent dealer was able to solve. I had a Ford Aerostar with antilock brakes on only the rear wheels. If I had to brake hard, the rear brakes would lock up. If the van sat for a couple hours, the brakes would release. I took it to the Ford dealership twice and the problem wasn’t solved. One time the rear brake linings were replaced and that didn’t solve the problem. The second time, I took the technician for a ride around the lot. I drove up to the door to the service department and slammed on the brakes. The rear wheels locked up. I got out of the van and said to the technician “Now it’s your problem”. The brake lines were replaced and it still didn’t solve the problem. I then took the Aerostar to my independent tire shop. I took the technician for a ride and slammed on the brakes, locking the rear wheels. That technician immediately said, “You have a sticking valve in the antilock brake system”. He cleaned the valve and I had no more problems with the brakes.
My suggestion to the OP is to find an independent shop that specializes in tires and brakes.
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Thanks to everybody for the comments. And let me say again, it is not the tires. Don’t want to keep going on about the tires. Looking for some ideas about what might cause the brakes to suddenly not work in wet conditions. Feels like the calipers aren’t holding the pads and the brakes are failing, then 2 minutes later they work again. Do I need slotted rotors, different brake pads, Abs control module to get checked? Anybody else with a Passat or who’s worked on Passats know about this problem? It’s all over the complaint boards for Passats but can’t find a good answer for the cause.
Late 60’s, early 70’s, some brake designs were indeed adversely affected by wet roads. I’m not exactly sure what caused it, but that problem has been solved a long time. My guess, your problem is caused by a malfunction in the ABS system. The first step is to make sure the wheel speed function is working correctly on all four wheels. And ask your shop if it is possible to temporarily disable the ABS system as a test.
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You could try frequent brake checks in case the friction is drying off the water causing slippage as a temporary solution.
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I will get the abs checked for sure. Thank you!
Good idea! That is a good temp solution
did this start happening since the last set of brake pads were put on? if so it could just be the brake pads them self.
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