This just started doing this in my 03' MCS with 71,000 miles. And there is only one other post from 2007 which 2 people commented with no help. Unfortunately I have no info on brake history work before purchasing it in April 08 with 53,000 miles.

I drive in the rain all the time, so I know enough to pump the brakes when they are wet, but recently they dont work as well in the rain while driving on the highway. I almost have to stand on the brake pedal

The brake pedal doesn't seem to even go down all that much, even when I apply more pressure on the pedal, and there are no brakes at all for a scary long time....

The best way I can describe it is that it's very much like there is a brick under my brake pedal only allowing it to travel a short distance and thus have only partial braking.

I have NO other indicators of wearable parts. No pulsing, No noise or vibrations...should I pick up a set of rotors and pads before my next appointment at Inskip MINI ?

Any suggestions as to a fix would be most welcomed. As I said, there is only one other post from 3 years ago and limited input/info.

 

when was the last time you flushed the system?

 

Not sure of brake history AutoX, I purchased the MINI bone stock a year ago with just over 50K miles on it. Guy was a family man who owns/manages a bunch of muffler/oil/brake shops in area.

This problem virtually happened overnight.

I checked the brake fluid reservoir and all fuses - everything it is up to snuff and the fluid is clear like brand new.

Is there a vacuum pressure regulator on the brake assist drum on firewall that may be causing this issue ? It's stuck in the front of the drum with a rubber gromet. Because to me it seems like there is not enough pressure being applied from the calipers..

 

I'd start with a fluid flush and bleed with new fluid and see if that cures it. You have check the pad wear?

 

Thanks for the info.

I am not able to see the wear on inside pads unfortunately. But to me the disks look pristine, and have little wear and the outside pads are thick. This issue virtually happened overnight.

I get a sense that the brakes were done at some point before I purchased it last year as the PO had his own shops to do that sort of work.

 

If it was a fluid flush problem...........wouldn't I experience a problem with my brakes ALL the time and not just when it rains

As I said, it only happens when the bakes are wet, and they have been wet before but I always had braking power up until now.

How does flusing the system help in this case.

 

Could it be a vacuum booster problem? Mini calls it the brake servo unit I believe.

What does the pedal feel like when the car is off and has sat for a while? Is it firm as a rock which I assume would imply a vacuum leak? I would probably get someone to take a look at the brake system.

 

since it only happens when wet it hard to say what it is. Just because it was owned by someone in the biz doesn't mean it was taken care of. The "look" of rotors is also not a good way to tell much of anything.

The avg life of MINI brakes is 50K and the inside pads do wear faster then the outside. Also not the rear inside pads to come off and that can also mess with the pressure.

I'd pull the rear wheels and take a good look at the inside pads. If they are OK start looking at all the lines and then the master for leaks. The Master can leak behind the firewall so it's hard to see. Hope that helps you find the issue.

 

When car is off and has been parked for a while ( almost 8 hrs now ) Brakes seem normal. Each time I press the pedal thereafter it gradually gets harder to do so and I can hear an air sound.

 

Main reason for flushing and putting fresh fluid in is to make sure you haven't gotten a big air bubble in the system somewhere, like a caliper, etc and to check for leaks. Never experienced exactly your problem when it rains though. You really might want to have it checked out by a professional you trust.

 

Yeah see I would agree with the brake flush if it were not for the fact I only have issues when brakes are wet during drives in the rain.

I never felt anything like this before during wet weather, in ANY car, so I am at a loss as well. I feels like the brake pads have a sheen on them like glass and only becomes a problem when a layer of water is between the pad and the disk....I have no wear indicators lighting up, and absent other symptoms to point me in a direction, I guess an appointment with Inskip is in order.

Thanks for the input. I will post back what we find and the remedy.

 

First I hope you meant to say 'lightly apply the brakes to get the water off the rotors"...

I had an Audi that had an issue which sounds like this - the front shields were crazy small and seemed to do little to keep water off the rotors. First brake application was scary and felt like you were pressing against an immoveable force w/no braking action.

The cure for the Audi was larger brake rotors from the A8 - somehow they both resisted getting covered as bad and/or had enough more surface it didn't matter; the (article below) mentioned additional shield was not very effective. Before this change, it meant really planning ahead on braking whenever possible on the highway (yes I know how crazy that sounds); light application for a good few seconds to warm them/get the water off or whatever.. and then they would be fine.

Here's one link about the Audi. My MINI has never had that issue though.


http://www.motorbeat.com/complaint/339478/

Are the pads much more worn? What changed? When you figure it out, please post.

 

From my understanding that is normal operation.

 

Yes me too.

Here is a pic of RF pads thru caliper wear window taken this AM.

Does anything appear abnormal here ? Pads seem to have alot of meat on them still .....

 

Any idea of what the Brand/Compound of the pads are?

They may be one that is horrid when wet.

 

Nothing was changed by me mechanically with the car. Just all of sudden there is no initial braking power when driving in the rain.........

It always worked fine in the rain until recently........

I poste a photo of a view thru the caliper window.

Thanks

 

Hey, thanks for chiming in Nate, Happy Easter.

I truely wish I did, they were recently done IMO before buying the MINI last year in April, it had about 53,000 miles on the odometer.

But they always worked fine in the rain before, and after looking at the rotors and pads, I dont see alot of wear on those parts.

 

Here are some more pics, this time of the rear. Pads seem to have enough meat on them as well....

BUT, I noticed that the pads are not fully retracting from the disk ? Even after making sure the E-Brake is fully disengaged when I spin the rear disk by hand I hear and feel it rubbing against the inside pads.

A previous post I made, I described how it felt like the pads had a sheen on them and were not grabbing. Now I am wondering if the rear calipers are the issue. Maybe the inside piston is not fully retracting and needs to be removed, lubed and put back in ?

I have done this with Toyota's - Can this be done with a MINI ?









view looking down from top of RR Brake assembly.............

 

Rotors look to be glazed in the picture, but hard to tell. Might want to try taking some sandpaper to them clean them up a bit. Also the pad too, take off the top layer.

 

But wont they just reglaze themselves if the pads are not fully retracting?

 

actually don't use sandpaper as I've been told it can leave residue - the trick for clearing glaze my racer buddies use is racing compound brake pads on the street for a VERY short time... I was wondering though, the inner pads looked thin (I thought) and if the piston is out a lot perhaps it is partially or even completely frozen? If so that could mean way reduced braking force on that wheel..

 

I think your brake booster (servo unit) is faulty or there's a vacuum leak somewhere that's not allowing vacuum to build up in the servo unit. What is puzzling is why it happens only when driving in the rain. The servo unit can get wet as it's located under the cowl vent. I would have it checked.

 

My thoughts initially as well, but the front discs basically do more than 70% of the braking. And when this happens, I dont even feel 70% of braking power that should be there. Almost seems like it's a problem at all 4 corners...

 

Yeah I know......even after a thorough check, there doesn't seem to be any one thing we can put a finger on.

And yes, braking is fine when dry. Go figure.

So I am calling on Monday for an appointment. I was hoping to diagnose this before hand because If it ended up being wearable part(s) I just wanted the new one's on hand before going down and having it all taken apart. It seems that some OEM stuff can be a bit pricy especially when there are some kick **** aftermarket parts for a few bucks less.

When I figure this out I will post an update for all.

Thanks.

 

.