parking brake - PeachParts Mercedes-Benz Forum

oso · #1 07-16-2009, 10:46 AM

I am in the process of replacing lower control arm bushings and decided to use this opportunity to replace my parking brakes as well. From what I have read and from what I can see there is no doubt that it can be a PITA especially for someone doing it for the first time. Is there a "right" way of doing it? For example:in what order should I work the little springs?
Thanks for your help.

byronnash · #2 05-18-2010, 08:29 PM

I have my rear brakes all apart for new rotors, calipers and pads. I have the parking brake as well and I'm thinking about changing that now too. Are there any instructions online?

byronnash · #3 05-18-2010, 09:23 PM

I think I found one. You may send me a "Let me Google that for you" link.

http://www.dieselbenz.info/fix_parkingbrakes.htm

chomptown · #4 05-18-2010, 10:54 PM

He updated his site, so it is layed out a bit better:

http://www.dieselbenz.info/wiki/index.php?title=Replacing_Parking/Emergency_Brake

charmalu · #5 05-19-2010, 03:18 PM

This guy is a little vague in his discription of replacing them. I think one of his lines is, you can figure it out. he also says to place the caliper on a box or something. I use a black rubber bungee cord 10in long. hang it over the sway bar and place the hooks in the bolt holes that mount the caliper. just don`t have them hang by the brake hose.

the Haynes manuel has a fair write up and a couple pictures.

the FSM has the best descriptions and pictures.

make sure car is on level ground,
block front wheels front and rear.
loosen all rear wheel lug bolts, easier when wheels are on the ground
jack up rear and place on jack stands
release parking brake
remove rear wheels
remove calipers. 2 19mm bolts and hang with bungee or piece of wire
remove rotor, pull towards you.

looking at the brake shoes is a star adjuster and a return spring on the back side of the shoes at the top.
there is another larger spring at the bottom of the shoes
(MB refers these as the restoring springs)

1/2 way between top and bottom is a small spring that holds the shoes to the backing plate. through one of the lug bolt holes, a flat blade screwdriver pushed into the spring and turned 90deg will release the spring. one on each side.

the large spring on the bottom can be removed with a needle nose Vice Grip.

Pull both brake shoes apart until they can be removed over rear axle shaft flange.

Disconnect restoring spring from brake shoe and remove adjusting device. (star adjuster at top)
note direction they face, helps later when adjusting them. wash them to get out any old gunk etc... I used some anti seiz so they turn good later on.

insert adjusting device into both brake shoes in such a manner that the adjusting wheel is facing forward.

attach restoring spring to both brake shoes. Note; it should be on the back side of the shoes.

Pull brake shoes apart, introduce over rear axle shaft flange and attach to expanding lock.

Insert spring (with J hook) laterally into brake shoes.
Introduce installation tool through a theaded hole of rear axle shaft flange, (flat blade screwdriver) then compress spring slightly, turn 90 deg and attach to cover ring (backing plate) Make sure that spring is correctly attached.
Note; these are a PITA to get in.

Attach lower restoring spring ( I have a large flat blade screw driver that had the end broken off. ground shaft flat on the end. then ground the end back about 1 in to fit into the spring. cut a slot in the end to catch the spring so I can turn it.)

Install brake disc (rotor)

replace the Caliper

Adjust parking brake. This is done with a flat blace screwdriver through one of the lug bolt holes. line up the star adjuster and turn to tighten shoes to the inside of the brake drum. then back off a few clicks so they turn free.
should have about 2 or 4 clicks on the parking brake peddle to apply them.

might be easier to mount the wheels first, it would be easier to turn than trying to turn the rotor while adjusting.

Be sure to torque the lug bolts.

Hope this helps some.

Charlie

gastropodus · #6 06-28-2010, 01:55 AM

... a picture may be worth something here. I don't know about you, but it really helps me to know what the hidden parts look like when I'm doing something for the first time. Here are some pictures to give you some idea of what lies behind the brake shoes.

The photo labeled "Left Rear Brake Plate" shows the two slots that the retaining retaining springs are hooked through. The other photo shows one of the springs. Note the relationship of the hook, which goes through the brake shoe and backing plate, and the radial portion of the spring before it goes down the center: the hook is in the plane of that visible part of the spring. If you think of that radial bit of the spring as a pointer, and if you know the orientation of the slot, then it makes it a lot easier to line the hidden hook up with the slot. It took me half an hour (forty five minutes?) of random jabbing to get the springs off the first side of the car, but once I knew where the slots were, and how the springs were constructed, it took much less time to free the springs on the other side (say, ten minutes).

In order to take the photo showing both slots in the brake plate I had to tilt the camera a little, so it's not straight on. However, I put a green arrow in the photo to show you the top (12 o'clock) position of the brake plate. Note that the slot on the left is almost perfectly vertical. The slot on the right is canted toward the front of the car; if it was an hour hand on a clock I would say that it is pointing to about 10:45. Of course, don't forget the car is canted a little bit nose-down due to the jack stands, so this is 10:45 in that condition.

One other trick to mention, if you don't happen to have the nifty screwdriver blade with a notch ground into it: I found it helpful to use a regular pair of pliers to grip the body of the spring while jabbing with the screwdriver. This way I could control the twist of the spring better to line up with the notch. Also, if you grip the spring with the pliers such that the your pliers are three-quarters on the spring and one quarter outboard of the spring you create a little pocket that helps keep the screwdriver from slipping off the spring while you're pushing (and cursing).

Cheers,

Kurt

gastropodus · #7 07-14-2010, 02:33 AM

OK, so you wanna get those PITA retaining springs removed or installed in 30 seconds?! Then get yourself down to the hardware store and buy six inches of brass rod, 1/4" diameter. Put it in your vise, and carefully cut a 1/16" to 3/32" slot in the end of it (I used a bandsaw at work because it had a nice wide kerf, but a hacksaw would probably work, too). Now you can poke that tool through the lug bolt hole, engage the slot on the radial portion of the spring, push and turn... presto!

Kurt

Stretch · #8 07-14-2010, 04:05 AM

My retaining springs were all rusty so I'd already bought some replacements. In this situation I recommend to take no prisoners - cut the bloody things out with a bolt cutter.

Putting the new ones back in? (As also described above) Find an old flat blade screw driver and cut a notch in it. It works a treat.

Also before you assemble the parking brake make sure that the cables run smooth and that the geometrical spreader bit (the bit attached to the brake cable) moves smoothly in and out... also take the opportunity to (lightly) grease up the adjuster.

petes450se · #9 04-29-2011, 09:39 AM

Don't stress too much about getting the old retaining springs out. I just did mine with thanks to this post. I just got a flat blade screw driver that was just the right size to get through one of the threaded holes on the hub. I inserted as far into the spring as I could and twisted until they snapped right off. Only took about 3/4 turn to do this. This was a much easier project than I thought. I never worked with drum brakes because I have always owned a Mercedes. Now my parking brake works again.