SAguirre

I have mentioned this a few times, but I never got around to looking for the manual of my 1991 300E to find the text. I finally got to it this evening and here it is. This has been printed on all MBs that my family and I have owned (including models owned in Germany). I also searched in the manual for the W211 and I don't see it there.

The technology of the parking brake on the W211 is at least 30 years old and has not changed a bit. I would speculate that MB is not recommending US owner to do this because of legal reasons, but this is very good advice!

As posted recently on a thread, the friction tracks on brakes (drum of disk) are susceptible to rust. They depend on the friction of the pad or shoe to clean the rust off. In the case of a MB parking brake (and also other car brands) the little drum brake can get wet and since it is not applied while the car is moving the friction track can become very rusted and impair the parking brake's performance. So if you need to use it on a hill to park or on a road SBC emergency it will not work optimally.

Also, the parking brake is NOT self adjusting and can be adjusted with a flat head screw driver and a car jack. But I digress; my 1998 190E 2.3-16 had a problem because this was not done. When I used the parking brake while rolling (to clean it) I heard a bit of scraping and I realized the there was so much rust on the friction track of the drum that the shoe's lining cracked. Then the shoe’s metal was scraping on the inside of the drum. BTW, this tends to only happen to the shoe that is on the top of the drum.

So, if you plan to keep your cars for a long time, I strongly recommend you do this. Also, if the parking brake pedal travels deeper and deeper before engaging you need to get it adjusted (or adjust it yourself).

When you try this procedure, make sure you don’t overdo it! It can overheat the little drum brake and it “could” warp your rear disk rotors or cause extra rust to accumulate on the outside of the rotor (really the outside part of the drum) and not look too good. Also, this will give you an idea of how weak the parking break is compared to the other brakes and is good overall practice.

When I am thinking about it, I will simply do this by keeping the break release lever pulled with my left hand as I modulate the pedal with my left foot. I recommend having the break release lever pulled at all times because there are some folks who are not too tactful with this kind of thing and will simply floor the parking break pedal, lock the rear wheels and wonder why the parking break pedal does not return up (all the mean time panicked). If you have the hand releasing the parking brake pedal, the instant you release pedal pressure the brake will release. This is probably not too important for the folks on this forum, but you never know.

Here is the scan of the page in the manual just in case you don't believe me.

Steve

CE750

Good tip, and makes sense..

I think, with the few times I've accidently driven off with it on, I've more than done my share of maintenance!

SAguirre

That might actually be why they took it off the W211's manual in the USA then! It has been a common problem for a lot of US drivers.

Steve


btw, I think that your Volvo has the same parking Brake design, so it should apply to that car too. I wonder if Volvo also mentions this?

CE750

I read the Volvo book cover to cover, and don't recall seeing it.. I'll bet its done when I take it to service and they do the "Adjustment" every 7500.

HELL ONA HARLEY

I've experimented with trying to stop my cars or trucks that I've owned just to see how the vehicle reacts to this percedure in an emergency stop. Its always good to know what your up against if this is your only means of stopping your vehicle.

SAguirre

I also do as you do. As far as parking brakes go, my Audi S6 has by far the best of any car I have owned. The parking brake is the rear disks brakes and it has 11.9' cross-drilled and vented rotors in the back. If you pull hard on the brake lever you will really stop quickly with no problems. On the other hand, if your brake failure is due to faulty rear brakes then you are in trouble.

As far as I know, MB, BMW, Porsche, Volvo and some Japanese cars like Acura (at least the MDX and an Isuzu I have owned) have this extra little drum brake in the rear rotor (which MB pioneered btw). This system is more redundant, but weaker in stopping power.

I too like to know what my choices are before getting into a situation where I have to discover them with no training. I always test how my cars stop with the parking brake and downshifting. I do wish however, that I could also test what the backup system on the W211 is like. I don't want to panic when my foot sinks all the way to the floor.

So far everyone who says they experienced SBC failure has not even thought of using the parking/emergency brake. I know that if you are caught by surprise you don't think of these things, but if you know it is there and you have practiced (even just a couple of times) and know how your car stops, you have a better chance of stopping on your own and not when you hit something else.

Along with testing how my car stops I take my cars out in the snow every fall and practice maneuvers wile over and under steering to get back in the hang of winter driving. This is for safety of course, but it is also tons of fun!

Steve

paulv

Steve,
Thanks for bringing out some good points about the parking brake. I plan on changes the brakes (pads & rotors) soon so I'll get a chance to inspect the rear rotor hat to see how much corrosion is there -- probably change the parking brake shows since I'll have everything apart anyways.

Regards,
paul...

SAguirre

I doubt that you will have to change the parking brake shoes, they last a long time (like 10 years ++ in damp climates). So inspecting them should be good enough.

Steve

paulv

Steve,
Good point -- by the way, my wife's SUV (non-MB) has the same rear brake setup and when I replaced the rotors and pads at 105K miles, the parking brake shoes still had a considerable amount of lining left over so I didn't change them.

Regards,
Paul...

JimPurdy

Yes, Volvo started using the drum brake for the emergency brake on the model 140 in 1968 and continued using the same components through 1993 on the 240 series. I don't know what they are using on the current models. I had several 140 and 240 series Volvos and had no issues with the emergency brake, even in Syracuse, NY where tons of salt is used every snowstorm.