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Why is drum brake ( parking brake ) so primitive ?
I hate drum brake, I mean my parking brake is drum brake.
They look ugly, poor accuracy of mechanical placement and execution, they can move here and there and they uses springs* ( *a bi-etch to work with ) and even at zero setting, the brake pad still "kiss" the drum.
Is there a way to not have the brake pad drag/kiss the drum ?
WAS
Genuine MB parking brake kit
After lots of swearing, even when using special drum brake spring plier which is useless for the small U part of the hook MB is using............
These two special tool, useless :
1st tool
The hook of the tools is so thick, when I use it there is no more "U" space left of the spring to hook up to brake pad hook recess/catch.
Also the hook of the tool (1st tool ) will hit the brake pad before I can get the spring close enough to brake pad hook recess/catch LOL
I hope my description makes sense. I do not know how to describe better in English...sorry.
The setting at zero, still rubbing sound exist, so irritating. Image below is RIGHT side. Video is LEFT side
Video. I was running-in ( Bed-In) the parking brake pads. Parking brake is NOT ENGAGED at all.
Any tips for 100% silent no rubbing guys ?
Nothing is wrong with my parking brake, they just look ugly due to rust. So I replaced them.
It is also un-even wear on the parking brake pad. Too bad I did not machine my disc/rotor parking brake side of the rotor inner diameter ( me lazy ), as it is also not smooth due to previous parking brake pad.
Last edited by S-Prihadi; Nov 16, 2022 at 02:16 PM.
remove shoes and all the other parts and live without parking brake.
Or
adjust all they way in so shoes completely clear drum and just do not use it so they do not adjust back out into drum.
Tranny park pin will hold car and/or carry a wheel chock in trunk for behind a tire.
Even if you needed in emergency too small to give decent braking force or they can lock up rear tires and then you go spinning off into ditch.
I just do not trust parking brakes to do anything but fail and need repairs.
We just do not use parking brake here in the Deep south Gulf Of Mexico area of USA as it is really flat.
The brake shoe adjustment is already at "smallest" or minimum or most retracted as I pointed out.
Parking brake is a must have because if you rely too much on tranny parking pawl it is not good and at some high load it make that strong un-latching ( jerk-pop) sound upon release. https://mbworld.org/forums/e-class-w...vo-effect.html
My Bali villa's parking garage has some incline, so that is where I use parking brake first, let it bite and then I I engage tranny park.
Back in Jakarta home I do not use parking brake as house parking garage is flat
The emergency brake thingy, I would not use MB kind of leg operated parking brake, I like using the old fashion hand pull one, located middle of console where we can push
the lock button to make it lock-less and skid the car for fun , but I dont do that anymore, too old now.... LOL
I'm having this exact same rubbing issue, but only on one side after replacing shoes, disks and pads, did the rubbing settle down after some time ? Also did you notice an increase in temperature on the hub/ disk due to the internal friction when driving ?
No significant increase in temperature. The touching is very very light.
However, I now have to depress to maximum click distance on the parking brake to get good bite.
Perhaps some thousand KM later I will re-visit the adjustment. My car is hardly on the move the past many months
I use my thermal imager. This one, the PRO one : https://www.thermal.com/seekshot-series.html <<< best bang for the buck resolution. But no pixel temperature data after savings in card.
Better than my 2012 FLIR which was lower resolution but cost so much back then . This one has temperature data at each pixel when saved to a card.
I use an infrared handheld temp gun, but also just my hand on the hub part of the disk, it never gets scorching hot, but is hot to touch compared to the otherside.
They are on the rear axle, and yes seem very primative, especially for a Mercedes Benz
Pretty sure for that time period this was common practice for most vehicles. Even the top of line version of my truck (2014) which at the time cost almost twice as much as my E250 new has the same basic setup.
I have the same kind of parking brake on my 1922 Ford T.
Why change 100 years old design, when it does the job?
Now OP complains about shoes "kissing" the drum. The visual observation is not good here. If you really think they brakes might rub, get infra-red thermometer, take it on few miles drive on highway, stop it with minimal brake use and check the drum temperatures.
I have the same kind of parking brake on my 1922 Ford T.
Why change 100 years old design, when it does the job?
Now OP complains about shoes "kissing" the drum. The visual observation is not good here. If you really think they brakes might rub, get infra-red thermometer, take it on few miles drive on highway, stop it with minimal brake use and check the drum temperatures.
Primitive didn’t enter into the picture for Porsche, who has decided to use a drum-in-hat parking brake on the latest Cayenne platform which will be in production for years to come.
"will be in production for the years to come"
How many thousand times have I heard that?
You don't have to worry because it is happening today in front of everyone's eyes.
9Y0 Cayenne is expected to be in production until 2030, this would mean it is a 12 year platform. It could receive two facelifts, as the current Macan has received its second facelift.
Car companies are stretching out platform lifetimes to make up for pandemic losses and to milk the ICE platforms while they invest in new EV platforms.
Porsche makes more profit margin on volume production than any other brand. VAG is the largest car company in the world. These two facts mean that someone at VAG knows what they are doing and they know how to make money while doing it.
If that means using 100 year old drum-in-hat technology on their flagship luxury SUV, I guess that means they will do it. And they have, and are, doing it.
You don't have to worry because it is happening today in front of everyone's eyes.
9Y0 Cayenne is expected to be in production until 2030, this would mean it is a 12 year platform. It could receive two facelifts, as the current Macan has received its second facelift.
Car companies are stretching out platform lifetimes to make up for pandemic losses and to milk the ICE platforms while they invest in new EV platforms.
Porsche makes more profit margin on volume production than any other brand. VAG is the largest car company in the world. These two facts mean that someone at VAG knows what they are doing and they know how to make money while doing it.
If that means using 100 year old drum-in-hat technology on their flagship luxury SUV, I guess that means they will do it. And they have, and are, doing it.
Lots of "primitive" comments about the shoe brake used as the emergency or parking brake. For the parking brake it is good to remember that the brake needs to hold the car at all times no matter how long it is parked so this sets a certain limit for what kind of brake can be used. It eliminates using liquid actuated system as while the car is being parked the system could experience a leak that allows the brake to release and car to roll of. That would not be good if someone gets killed by it like in hilly San Francisco.
The parking brake needs to be mechanically actuated and if anybody has a better idea for it than what is currently used, I'm sure the car makers would go for it.
Another observation, the same type of brakes are still commonly used on trailers.
The only difference is that when parking brakes is cable-activated, the trailer brakes have a magnet, or hydraulic cylinder pushing the shoes.
I just installed brakes on my 3500lb trailer.
The "primitive" design will lock the wheels any time, unless I adjust the controller.
They make disk brakes for trailers as well, but I think less than 1% of manufacturers go this way.
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. Parking brake is NOT ENGAGED at all.
