How to guide to replace front Brake Pads and Rotors on a W123 - Page 2 - PeachParts Mercedes-Benz Forum

whunter · #16 11-04-2008, 12:11 PM

Quote:

Originally Posted by Brian Carlton

Take a look at the calipers where the pads ride. There are four machined pads on each caliper half that have a good surface finish. The backing plates contact these points and slide against them as they move toward the rotor.

One of the principal reasons for poor braking is the binding of the backing plates against these rusted and very poorly maintained surfaces.

The reason that the pads are difficult to install is the failure of the owner to clean these surfaces and grease them.

Oh, and.......have a great day.

That is not a slide, it is the brake pad guide = sloppy fitting box.
Vehicles in no salt/snow locations, generally do not need to clean this area = no corrosion.

Excess coating on cheap/sloppy aftermarket parts is a very common reason brake pads are difficult to install.

dannym · #17 11-04-2008, 12:15 PM

Quote:

Originally Posted by 79Mercy

whatever

I'm going to have to side with Brian on this one.
You did a great job with the tutorial & we appreciate your effort.....but

The factory shop manual gives specific measurements to make sure it's done right.
It's like the difference in checking timing stretch by lining up the cam marks or checking at 2mm valve lift. Will the other way work? Sure it will. Will the masurements be accurate? Who knows.

Using a dial indicator on the rotor isn't hard at all.

Also I don't care what car your working on brake components need to be cleaned & greased. A can of brake cleaner goes a long way.

Danny

Brian Carlton · #18 11-04-2008, 01:08 PM

Quote:

Originally Posted by whunter

That is not a slide, it is the brake pad guide = sloppy fitting box.
Vehicles in no salt/snow locations, generally do not need to clean this area = no corrosion.

Excess coating on cheap/sloppy aftermarket parts is a very common reason brake pads are difficult to install.

If the backing plates slide against it.........the term "slide" would be appropriate. If you want to call it a "brake pad guide", be my guest.

All vehicles need this area cleaned of rust and corrosion unless you've figured out a way of keeping water and dirt out of that area.

If you don't clean the slides, the pads typically won't install without force. If the pads are binding, you've got brake problems.

If you're ignoring this important maintenance requirement during a pad overhaul, you're making a critical mistake.

If you want to characterize Textar pads as a "cheap aftermarket pad" ........be my guest with that as well............

rrgrassi · #19 11-04-2008, 01:54 PM

This is a good write up for those who were thinking this job is near impossible.

tobybul · #20 11-04-2008, 02:56 PM

Lets see... 18,000+ posts vs 7800+ posts vs 3500+ post vs.......

..... hmmmmmm......

.... i guess since we're nitpicking.... how about the "how to" on pressing the calipers back.... thats a trick in itself..... vs 1500+ posts.....

Hi, Roy!! How ya doin'?

::matthew · #21 11-04-2008, 03:08 PM

Quote:

Originally Posted by tobybul

Lets see... 18,000+ posts vs 7800+ posts vs 3500+ post vs.......

..... hmmmmmm......

.... i guess since we're nitpicking.... how about the "how to" on pressing the calipers back.... thats a trick in itself..... vs 1500+ posts.....

I'm not sure how the number of posts someone has here relates to their knowledge level about specific repairs.

Brian Carlton · #22 11-04-2008, 03:13 PM

Quote:

Originally Posted by ::matthew

I'm not sure how the number of posts someone has here relates to their knowledge level about specific repairs.

Precisely true.

However, I pride myself in restricting my comments to those tasks for which I have personally completed and have specific knowledge.

This is one of them.

tobybul · #23 11-04-2008, 03:17 PM

Just lightening the mood folks.....

I was getting a little tense reading this thread. Probably should thank 79mercy for his efforts and desire to be of help. Many of us have played with various issues on our cars and am sure have some amount of expertise in one area or another.

Others can probably address repairs with theirs eyes closed since they are so good and have done so much of it..... and some of us learn something new everyday. Some have tried things that others don't even want to attempt.

But whats great about this forum is that everyone always tries to help

But I do recognize that those who have been around doing it longer must have more knowledge than me..... if that is wrong then I stand corrected

::matthew · #24 11-04-2008, 03:31 PM

Quote:

Originally Posted by tobybul

Just lightening the mood folks.....

it does read a bit like a Nikon forum.

I've seen the MB special tool for pressing those calipers back. Looks a bit like a duckbilled channel locks.

79Mercy · #25 11-04-2008, 04:17 PM

I used a old edger blade wrapped in a towel to push the pistions back.

I bet that wasn't in the FSM either, but it worked great.

redassag00 · #26 11-04-2008, 04:34 PM

Quote:

Originally Posted by Brian Carlton

If you want to characterize Textar pads as a "cheap aftermarket pad" ........be my guest with that as well............

Whats wrong with Textars?

I use them. Other than being a little dustier, I think they're a fine pad.

dmorrison · #27 11-05-2008, 02:42 AM

Brian is correct, in my opinion, about greasing the side , not slide, of the pad. See picture one for greasing the Bendix caliper pad.

Second, setting the bearing torque should really be done as per the manual. Or as I have shown in the post below for the rear bearing. Use the same technique for the front.

http://www.peachparts.com/Wikka/W123RearWheelBearings

The second picture shows the manuals method for setting the bearing torque.

Dave

whunter · #28 11-05-2008, 11:49 AM

Quote:

Originally Posted by tobybul

Lets see... 18,000+ posts vs 7800+ posts vs 3500+ post vs.......

..... hmmmmmm......

.... i guess since we're nitpicking.... how about the "how to" on pressing the calipers back.... thats a trick in itself..... vs 1500+ posts.....

Hi, Roy!! How ya doin'?

Going slowly nuts balancing work with getting ready for the Texas tech session.

I don't want to forget any parts or tools, the drive home is to long, twenty hours straight through driving each way.

whunter · #29 11-05-2008, 12:32 PM

Quote:

Originally Posted by Brian Carlton

If the backing plates slide against it.........the term "slide" would be appropriate.
If you want to call it a "brake pad guide", be my guest.

All vehicles need this area cleaned of rust and corrosion unless you've figured out a way of keeping water and dirt out of that area.

If you don't clean the slides, the pads typically won't install without force. If the pads are binding, you've got brake problems.

If you're ignoring this important maintenance requirement during a pad overhaul, you're making a critical mistake.

If you want to characterize Textar pads as a "cheap aftermarket pad" ........be my guest with that as well............

The brake pad guide does need to be cleaned/lubricated in most cases.

Note: Depending upon corrosion level cleaning can be ...
* Light = stiff wire brush
* Medium = light application of sandpaper
* Heavy = hammer, chisel, and files, the caliper is generally (damaged) not functioning correctly at this point = needs rebuild.

Here in Michigan the corrosion is frequently HEAVY = replace the calipers.

I did not name a brand because many members use the lowest cost pads from their preferred supplier.

Bill Wood · #30 11-05-2008, 02:18 PM

Thanks 79Mercy!

This DIY has been added to the Wiki HERE.

I also added a warning at the end that refers readers back to this thread so they can read the member comments here.

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