I just found my MINI playing hide and seek in the bushes and rolled down our horseshoe driveway

I looked inside to check if I had forgotten to pull up he e-brake - nope, e-break was up close to 35-40 degrees, where I normally pull it up to. After testing it, I found that I have to muscle it up all the way to get any hold. I'm just glad that it was the bushes rather than oncoming traffic or another one of our cars in the driveway.

My 25k Service is coming up. Does anyone happen to know if e-brake is 'freshened' up a bit as a standard service?

(I usuall dont leave my car in gear because it would disable he remote start, which I tend to use during extreme hot/cold weather. I'm going to turn my wheel a bit and leave it in gear until this can be fixed..)

I do remember a few other members reporting movin' MINIS a few months back...

 

wow, that's pretty scary stuff. hope you didn't get too many scratches
on the bodypanels.

I do remember reading some college kids messing with a MINI while
they were drunk or something and the car ended up in the ditch
behind the owner's driveway...or something or another.

 

I believe that the parking brake is checked (tightened, if needed) at the 25K service. You should probably leave it in gear whenever it's on a slope and just pass on the remote start. Or maybe you could just throw down a wheel chock whenever you park.

 

[QUOTE=kenchan]wow, that's pretty scary stuff. hope you didn't get too many scratches
on the bodypanels.

[QUOTE]
They were some pretty thick evergreen bushes, but it looks like ZAINO saved the day!

 

did you leave the car in gear - reverse? first?

 

kcollins did you leave the car in gear - reverse? first?

[QUOTE=BriNYU] (I usuall dont leave my car in gear because it would disable he remote start, which I tend to use during extreme hot/cold weather. I'm going to turn my wheel a bit and leave it in gear until this can be fixed..)

QUOTE]

 

yet another reason why remote start is not such a good idea..

 

You really need to leave it in gear. Take it from somebody who's dealt with a runaway MINI.

Our Cooper rolled out of it's spot at the mall about 6 months and approximately 10k miles after we got it. Even worse, the mall had a barely perceptable slope yet it still rolled out of it's spot with the e-brake on....

I know remotely starting your car and then playing find the MINI sounds like fun... But really it's not.

 

Never trust the e-brake on an incline... Keep it in a 1st, reverse.. and turn the wheel towards the curb.... if possible

 

Thanks for the constructive comment Just wondering, what are the other reasons so I'm fully educumacated

Winters here are freezing and summer here can get toasty - I prefer the convenience of pre-heating or warming the cabin. :smile: (to each his/her own, I always say).

In any case, just wanted to relay the experience so others can get a heads up to check their E-Brake when they get a chance.

 

Good, sound advice. Thanks! :smile:

 

My e-brake has slowly been getting weaker... but the dealership said there wasn't anything they can do about it.

I hate service departments.

 

Someone on the forum once surmised a theory, which I will pass along to the group without claim to its validity...(yada x 3)

You engage your e-brake when you return from driving and the brake components are still hot. As they cool, they contract just enough to cause the grasp of the brake pads against the rotor to lose the ability to hold the 2500 lb. mass of vehicle on wheels against gravity pulling it down the slope...

Any expert opinions?

 

thats a very good explanation of whats probably going on here. it does make sense...worth trying ot make an experiment of it!

 

then the only thing to say is shi**y design. The cable acts like a spring itself, and may systems have springs in them as well. If there is some shrinkage, what would it be, a few mm? Really, what this comes down to is poor parking brake automatic ajustments. If the Mini dealer says that they can't ajust this out, tell them to read page 340-31 of the bently manual "PArking Brake, checking and adjusting" There's a nut that can be accessed from the passenger compartment that ajusts the slack out of the cable.

If you want to test if it need ajustment (acording to Bently), if
1) Brake lever pulls up more than 7 clicks
2) rear pads or rotors are replaced.
3) Parking brake cables or handles are replaced.

If the car is new, I'd guess that you either have a lot of pad wear or your cable has stretched a bit (both happen in new cars). Youwould get over 7 nothces in this case... To get to the ajustment nut, unclip and lift the parking brake boot. The nut should be obvious. If you do tighten it, do so until there is no drag with one click of the ****, and just a bit of drag with 2 clicks. Now, a full ajustment involved removing pad, seating the pistons, putting everything back together and doing some stuff to get all the auto ajuster crap to work right......
The only concern I have is that these should auto adjust. So if it's loose, the question is why didn't it get tightened by normal use?

Matt

 

...and it came from Greatbear, of course!

 

If I hadn't been drinking wine all night, I'd look up the thermal expansion coefficien of cast iron. The pads may have more of an effect, but they have a high temp gradient across them so the expansion effect is most near the surface that touches the disk. But it just doesn't add up. What this comes down to is either poor design, in that the automatic adjusters don't really work, or poor desing, in that the pad travel, and spring effect of what puts the brake on, isn't designed to allow for the thermal effect in the brake system itself. Still comes down to crappy design!

So for the heat and expansion deal to work, you'd have to have a LOT of thermal expanison effects. For normal driving, let's say they heat up 300 F. That would have to change the dimensions of the pads and rotors by about 10% OR MORE to have the dimensional effect add up to what is needed to keep the parking brake from working.....

I still come back to poor design, or lazy Mini staff.

Matt

 

I couldn't find the numbers for the pads, but I did for the rotors and Al calipers.

The thermal coefficient of iron is 6.7x10^-6 per deg C! Al is twice that at 13.

If the rotor heats 300C, and it's 22mm thick, then the change in thickness is just 0.044 mm! IF the caliper is iron, and it heats to half this amount, the difference is halved. IF the caliper is Al, and the temp is half the caliper temp, there is no net change in gap. I didn't find the number for the pads, and it looks to depend on the materials. Some semi-metallic pads are 20% iron, so I can't really see the coefficent being more that a factor of 10 higher (some of the additives are used specifically to temper thermal properties). IF you give 25 mm pad thickness (and for most cars its much less), you come up with only about 0.5 mm deflection. This is starting to be measureable, but it's still small.

Other things to think about. The parking brake cable will have a temp gradient in it, as it's attached to a hot caliper. As it cools. it will SHORTEN. True, the temp difference isn't as much, but it works over a much longer distance, increasing the effect on overall length.

It's gotta be bad adjusters in the car..... Either you got lucky, or it's systemic to the design. On old drum brakes, this ALWAYS got crudded up and failed......

While I was looking for information, I found some good stuff at http://www.thebrakeman.com/rotortech
there are other tech articles on brakes there as well. IF you take the time to find his hurricane brake rotors (steel laminates with lots of fins) they start at just under $900, but run 30%-40% cooler than iron!

Matt

 

What if you accidentally leave it in gear, and the weak parking brake is not working right. You hit the remote start and the car jumps forward (or backward) into another car, or a person. Or you cause damage to your drivetrain.

Convenience is fine and all, but the clutch/starter interlock is there for a reason, and that reason is not to inconvenience the driver. It's a safety system.

On topic. I feel like my parking brake is getting weak as well. I was thinking it was just me and that the rear brakes were wearing quicker than the front. I heard a few people had their rear brakes replaced before the fronts due to some kind of warranty issue.

 

Another piece of advice is to ALWAYS pull the handbrake as far as it goes if you don't want your MINI to go. :smile:

 

There has to be an issue with the auto adjusters getting shot or dirty and not working.... I'm just surprised we don't see more minis wandering around with no drivers!

Anyway, Mini saying that they can't help is just BS. It more accurate to say the person you asked didn't want to deal with it.

Matt

ps, and ditto to making sure the handel is all the way up.

 

Easier said then done.
I can't pull it up very high (which could be a bad thing) and when someone pulls it up high for me, then i can't get the brake back down. I'm too weak.

I keep my car in gear at all times when parked. I learned after playing hide and seek with my miata... I got out of the car, shut the door, and it rolled behind me about 7 car lengths down my driveway and stopped right before it hit a post. But i always keep my wheels straight ahead, and lock the steering wheel. I don't know WHY i always do it, but it's just became a habit.

 

My wife has the same issue - heck, she has a REALLY hard time getting the MCS into reverse!

Bri - check and let us know how many clicks it goes up in the 'normal' position.

Depending on the slope, I don't know that I'd trust the e-brake alone. You may share my opinion now!! Definitely curb the wheels if you can, or at least point them toward something soft!

 

No hills or slopes in Miami, but I still make it a habit to leave the car in 1st gear and E-brake applied. I have never liked the idea of leaving a car in neutral.

 

Cars with remote starters from factory always seem to be equipped with automatic transmissions.