Braking during a hard rain

[Kira]

No big deal here, just a first time observation.

'Twas a rainy drive south on the Interstate yesterday. Lots of rain, spray, splashing, fog, condensation....everything wet.
I'd touch the brakes when necessary and feel nothing. Leaning on 'em a bit caused a minor, somehow exaggerated vibration and finally a predictably even braking effect.

The first time was near alarming. I could see a mechanically disinclined person panicing.
How "well lubed" the brake hardware STAYED at less-than-strong pressures was surprising.

The few times I tested it for real involved peddle pressure far in excess of "surprised stopping" and 10 car lengths were needed to BEGIN stopping the car.
Anybody ever experience that?

Just for giggles, I'm going to inspect my 15,000 mile old front and 46,000 mile old rear brakes.

ps Today (dry day) the brakes feel just fine. No hint of pulsing / vibration.

 

[Rand]

probably just water soaked.
If you drive in heavy rain and dont touch the brakes for awhile.
takes a second or 2 to dry up and work better.

Also what brake pads were installed?

 

[Kira]

I have no idea what brand hardware was used.
Being the car was serviced at a Volvo dealership, I'd ASSUME they used Volvo parts.

The vehicle is a 2007 V70 NA...my pride and joy...my third V70.
Hunted so long I bought at a dealership.

 

[The motor guy]

Happens on my truck too. Totally normal.

 

[PimTac]

Very common. Drive through a deep puddle or standing water and touch your brakes to evaporate the water off by heat. If it’s the first rain in a long time then add road oil to the mix

 

[Wolf359]

Next time I'm driving in the rain, I'll have to check. Mine has a brake drying feature, it applies the brakes slightly to keep the rotors dry when the wipers are in use. A quick search shows that Mercedes, BMW, Audi, VW, and Cadillac are some of the manufacturers that have it.

 

[Vern_in_IL]

Originally Posted By: Wolf359
Next time I'm driving in the rain, I'll have to check. Mine has a brake drying feature, it applies the brakes slightly to keep the rotors dry when the wipers are in use. A quick search shows that Mercedes, BMW, Audi, VW, and Cadillac are some of the manufacturers that have it.


Wow, did not know this, thanks!

 

[Kira]

I think I heard of such "brake drying" feature before.

I suppose the feature has its place. I hope it doesn't eat brakes

 

[PimTac]

Originally Posted By: Wolf359
Next time I'm driving in the rain, I'll have to check. Mine has a brake drying feature, it applies the brakes slightly to keep the rotors dry when the wipers are in use. A quick search shows that Mercedes, BMW, Audi, VW, and Cadillac are some of the manufacturers that have it.



I like the old saying, “Trust but Verify.”

 

[Wolf359]

Originally Posted By: Kira
I think I heard of such "brake drying" feature before.

I suppose the feature has its place. I hope it doesn't eat brakes


It's mentioned in this brochure.

http://www.auto-brochures.com/makes/Mercedes_Benz/E-Class/Mercedes Benz_US E-Class_2008.pdf

Doesn't seem to eat them. I did the brakes about a year ago after having it for 2 years. It still had over half the pad left. It had new pads when I got it. I just got sick and tired of the brake dust and I put in Akebono pads instead. No dust now.

 

[KrisZ]

I have experienced this as well in heavy rain, totally normal. Yes it can feel scary at first because the delay makes it feel like you have no brakes.

 

[Linctex]

Originally Posted By: Wolf359

I just got sick and tired of the brake dust ... No dust now.


You now have ceramic brake pads.
Yes, dust is gone - - but I HATE HATE HATE how "low friction" they are.

Ceramic brake pads last forever, but can be really hard on rotors.

Carbon Metallic brake pads have been my favorites.
I'm not a fan of the new ceramic brake pads at all.

 

[bbhero]

Great answer by Rand.

I drove through rather deep water in Mathews county. Above the top of tire... Was going 50 mph and heading towards a rather sharp curve. Thank goodness I stated to brake early.... Took awhile for the brakes to get to working. I managed to get slowed down in time. Barely. Learned a good lesson that afternoon.

 

[bbhero]

Wolf359 is big, big money. Only cool cats with cash can have a feature that on their vehicles

Just messing with you Wolf. Hope you've had a good day today.

 

[MCompact]

Originally Posted By: Kira
I think I heard of such "brake drying" feature before.

I suppose the feature has its place. I hope it doesn't eat brakes


My 2 Series has brake drying; I'm currently at 39k miles- including three HPDE days and one night at the local drag strip. Still on the original pads and based on the Condition Based Service calculation I probably won't need new pads for at least another 10k miles.

 

[eyeofthetiger]

Originally Posted By: Linctex
Originally Posted By: Wolf359

I just got sick and tired of the brake dust ... No dust now.


You now have ceramic brake pads.
Yes, dust is gone - - but I HATE HATE HATE how "low friction" they are.

Ceramic brake pads last forever, but can be really hard on rotors.

Carbon Metallic brake pads have been my favorites.
I'm not a fan of the new ceramic brake pads at all.


+1

I usually opt for semi-metallic pads over ceramics. The better performance is worth a little dust and noise. I don't mind washing my car once in a while, either.

 

[Chris142]

You ever driven a car with 4 wheel drums in the rain?

 

[SHOZ]

Originally Posted By: Chris142
You ever driven a car with 4 wheel drums in the rain?
With vacuum wipers? Only good when slowing down.

 

[DoubleWasp]

Originally Posted By: Chris142
You ever driven a car with 4 wheel drums in the rain?


I would say that this should be illegal, but it practically is today.

Yes, I've done it, and yes, it sucks. It is a fun game though:

"Which wheel will start braking first? Try and guess! I think you'll be surprised!"

I will say that cross drilling or slotting in the brake rotors goes a long way toward preventing water related reductions in braking, if not eliminating them entirely.

 

[HangFire]

Interesting. With my current fleet, what I notice about wet braking on all my vehicles, is the brakes are MORE grabby. Sometimes annoyingly so.

I thought drying brakes went away with the advent of disc brakes. Back when I rocked 4 wheel drums I used to pre-dry brakes on a regular basis with my left foot on the brake pedal, not slowing down. Perhaps Kira could use that technique.

I'm wondering if what Kira describes is some combination of Ceramic pads and maybe a beveled pad edge and/or missing splash guard, that allows a film of water to build up. If I was in that situation, I would look into exactly what brake pads were being used, and maybe refinishing the discs.

And never assume the dealer uses OEM parts. Usually, yes. Out of stock at the moment? Whatever they can get fastest.