Fella's,
Is there any reason at all to use the parking brake when having an automatic gearbox? I mean, when the car is parked with the lever in 'P', the rear wheels are blocked anyway, so the car cannot move whatsoever, right?

What do you think?

__________________
2011 Prius

It's a good habit to engage the parkingbrake, especially when you're parked on an incline.
Ask any car owner who's car has ever slipped out of " park ", rolled down the incline & caused some major damage.
There is just a small pin/cog engaging a slot in the transmission when you're parked.
NOT something I would trust!

__________________
2007 C 230 Sport.

Us flatlanders rarely use the parking brake, though we should, just to keep the emergency brake properly exercised. Nobody in my town has ever talked about their car slipping out of park. In fact, my experience tells me it's more a problem than good practice.... a few times I left the parking brake on a shared car, only to find the next driver didn't realize it was on and drove the car for some distance with the parking brake engaged.

On the other hand, I've lived a while in San Francisco. Runaway cars are a constant problem and cause a lot of property damage. The law says that if a grade is over 3%, a parked car must have it's wheels curbed. This means that if the car is parked facing uphill or downhill, the wheels must be turned such that it'll immediately hit the curb in the unfortunate event that it would start moving. On the really steep hills, parking is perpendicular to the street.

__________________
95 E320 Cabriolet, 169K

Kestas

I wouldn't share the car with anybody that doesn't notice a big red light on the dash, indicating " parking brake on".
Not sure if it was Ford or Chrysler, but one of them had a huge problem with transmissions slipping out of park.

__________________
2007 C 230 Sport.

That was Ford back in the late 70's.... and the problem was real. I remember there were a lot of cars parked on incline at that time for test at the Transmission & Axle Division in Livonia - a plant that was four miles from home and my dad's workplace for 33 years. People who owned these models were put their cars in Park with the engine still running, then step out only to get run over when the car slipped into reverse.

I personally experienced one of our Fords (74 Torino) momentarily lurch backwards during shutoff when I took my foot off the brake... and it wasn't the normal rollback for parking pawl engagement.

My pet peeve was the media who wrote article after article of how terrible this problem was without mentioning HOW it was happening.... the nuts and bolts behind it; very frustrating for a technical person such as myself... until finally I found an obscure article where someone wrote and explained how slop (tolerance stackup) in the system allowed the column shifter to indicate Park (and, I believe the lever detent was engaged in Park, though I'm not sure about this and the lever detent may have been between Park and Reverse), yet the transmission engagement was sitting between Park and Reverse detents, allowing reverse to still function..... sloppy, sloppy, sloppy. The later transmissions were then designed with Drive and Reverse spaced considerably farther apart.

__________________
95 E320 Cabriolet, 169K

It's quite amusing to see cars standing on their bumpers

Another reason is that if for some reason the car moves while in P, it can be difficult to shift out of P. I assume even flatlanders have sloped driveways.

Sixto
95 S420
87 300SDL

And if you don't exersize that parking brake it will eventually rust in place.

My current practice is to engage the brake... wait for the car to stop (on a slope)... then put it into park as a backup.

Better for the emergency brake and better for the tranny.

__________________
-Marty

1986 300E 220,000 miles+ transmission impossible
(Now waiting under a bridge in order to become one)

Reading your M103 duty cycle:
http://www.peachparts.com/shopforum/showpost.php?p=831799&postcount=13
http://www.peachparts.com/shopforum/showpost.php?p=831807&postcount=14

I don't remember having used my hand brake in the last decade (or more).
The system must be rusted solid by now. I won't spend a dime on it to fix it.

I religiously use the parking brake, even if I'm just at the gas station. Ever think of the damage to be done to your transmission if somebody rear-ends you while you are parked?

Just one more point to ponder.
Some people refer to it as the " emergency brake ".
What if you experience total brake failure?
Your going to jam on a rusted emergency brake ?

__________________
2007 C 230 Sport.

Thanks guys,
Reason for my asking are these two things:
- I've experienced now twice how the using the parking brake causes the rotors to get 'wobbly', particularly when parking for a week or more in very cold weather;
- and what do you think can happen to the auto gearbox when parked in just 'P' (and no parking brake) if the car is hit front or behind, like e.g. in a carpark? I can imagine it could damage the gearbox?

Cheers!

__________________
2011 Prius

I only use the parking brake on incline, never on flat road.

Put me down for using the E brake every time I exit the car. It has gotten to be a habit and yes it does keep everything in that system in order. I like the response about what will you do when you really need it,and it's not in working order,,, good thought.

__________________
95 SL500 Smoke Silver, Parchment 64K
07 E350 4matic Station Wagon White 34K
02 E320 4Matic Silver/grey 80K
05 F150 Silver 44K

Tip: For rear drum brakes it's best to have the service brakes engaged while engaging the parking brake. Just engaging the parking brake will only have the tips of the shoes touching the drum. Doing it while the service brakes are applied will ensure full purchase of the shoe surface against the drums and do a better job of holding the car.


Yes, the difference in rotor corrosion can be felt even after a week outside in damp weather. If left longer, sometimes it gets so bad that it sticks, or won't get wiped off after a few miles, which requires trueing the rotors. This same phenomenon can happen to the clutch of a car that's been stored. I had that sat outside for three months. It was so bad that I had to repeatedly bump the starter (with the clutch in) many times until it broke loose. The clutch rusted fast to the flywheel, and I was afraid I'd never break that bond!

__________________
95 E320 Cabriolet, 169K

I was told growing up to always use the parking brake, so I always have. This puts any tension that weight may cause at the wheels, not on the transmission and/or the engine mounts. I use my brake by stopping the car, putting into park, applying the parking brake and then release the driving brake. I also slip my car into neutral if I am sitting at a stoplight or drive through for very long as this limits slippage. I have had several MB's and never had any transmission problems even with my 280 up to 450,000 miles. (that is using recommended maintenance too) I would rather have 4500 lbs sitting on easily replaced brake shoes than on a difficult to replace drive-line. The brakes are to stop and hold the car, the engine and transmission are to move it along. Happy Benzing!

__________________
Brian W. Heitman

www.MBCA.org/northtexas

Join MBCA!!!