1996 C220 Brake & Rotor Replacement Lessons Learned
 

Hello All,
First of all let me thank all those that posted previously about changing the brake pads and rotors...doing an extensive search enabled me to compile a lot of information and tips. Without them, I would have been left in the dark...since there deoasn't seem to be any 1996 C220 repair manuals written yet. With that said, I just finished changing the front rotors, pads, and wear sensors on my C220.
On the first one, I took my time to carefully check my work and what needed to be done. IT took me about 1-1/2 hours. The second one took me all of 30 minutes complete!
Here's what I've learned that might help others out.
-- Many posts stated to remove the bottom caliper bolt (with a 13mm socket & a 15mm open end wrench) and just loosen the top on to allow the caliper to swing up and out of the way. I found this too hard to since the tension on the brake line prevented me from swinging the caliper up as told. I found it MUCH easier to simply remove both bolts and remove the caliper all together. This enabled me to push the piston back in (with a C-Clamp) and place the new pads much easier. It also didn't put excessive strain on the brake line.
-- The pads I got were very thick so I had to push the caliper
piston back in all the way. Don't forget to place a rag around the brake resevior to catch overflowing fluid, and do one side at a time. I was lucky, it came REAL close but didn't flow over.
-- Several posts stated that a 19mm socket was needed to remove the caliper bracket bolts. MY car required a 18mm socket.
-- Also, a hammer or rubber mallet came in VERY handy to impact the socket wrench to get the TIGHT 18mm caliper bracket bolts loose. It also was needed to knock the left rotor loose from the wheel due to some grime and rust (which I cleaned off).
-- When loosening and tightening the 5mm allen screw that holds the rotor (brake disc), be careful since the wheel spins freely. You'll have to hold onto the wheel to apply "counter pressure".
-- I found it MUCH easier to work on the calipers and brackets by turning the steering wheel to the right for the right side and the left for the left side. This enabled me to easily see the work and tool positions were MUCH better to handle.
-- The wear sensors I got were skinnier than the stock ones so the retaining clips had a lot of play. I squeezed the clip to reform the shape so it was tighter to the sensor.
-- KUDOS to Mercedes for putting anti-sieze compound on all the bolts!! This REALLY helped me out. Put some back on when putting everything back together...or at least spray on liberal amounts of a rust inhibiting lubricant.
Here is a list of ALL the tools I needed to get the front brake pads and rotors replaced.
-- 2 jack stands
-- 1 wheel chock (2 is better though)
-- 1 C-Clamp (to push the calipers back in)
-- 1 18mm socket (for Caliper bracket bolts)
-- 1 13mm socket (for the caliper bolts)
-- 1 15mm open end wrench (for the "inside" nuts that the caliper
bolt tighten into)
-- 1 pliers (needle nose works best) to remove and push in the
wear sensors & reform the sensor clips if needed
-- 1 small-med tip flathead screwdriver (to remove the cap on the
car sides for the jack
-- 1 hammer or rubber mallet (be VERY careful using a hammer)
-- 1 5mm allen/hex head socket or wrench
-- work gloves
-- Brake cleaner spray ( I didn't have any but it DOES help to
keep everything clean)
:D

Just a suggestion: Never hit a socket wrench handle with a hammer. The wee little pawl in the wrench that flips it from right to left is not designed for that type of impact. You can easily sheer it. Plus there is a lot of bounce when you hit.

If a nut/bolt requires that kind of force either use a socket with a break over bar or a box end wrench with a cheater. If it is a bolt that is stuck, try hitting it sharply on the head with a hammer a few times. The shock will often loosen it.

Thanks Randy, very informitive. I'll be changing the pads on my 2000 C280 Sport sometime next week. I feel a whole lot better after reading your procedure. Thanks Jeff

I prefer to take some brake fluid out of the reservoir with a turkey baster (shop used only). Brake fluid will strip paint from evbrything it contacts if you let it overflow.

You didn't mention brake flush as I guess many people don't consider it while doing a pad change. I usually combine it with a pad change and not as a seperate job. My interval is whenever it's been at least two years since the last flush. This works for me because I go through pads often enough as I only own daily drivers.

hoses and calipers should be inspected and replaced as necessary. Although I doubt most would recommend it I rebuild my own calipers.

brake flush
 

According to the service records, the previous owner did flush the brake fluid not too long ago, hence why I didn't do it. I have read in other posts that for very humid environments, like the MS Gulf Coast where I'm at, a complete flush should take place once a year. I still have to do the rear pads and rotors...I just might consider a total flush then....better safe than sorry.
Also, on the above remark about banging on a socket wrench with a hammer....I do admit this was somewhat unorthodox and kinda like "Bubbah the backyard mechanic" but I couldn't get a cheater bar in the tight space and didn't have a impact wrench. I never thought about tapping the bolt head though...my bad.

Cracking open the bleeder when pushing the piston back in not only clears the dirty fluid out of the caliper rather than pushing it back into the Master /Res...it also makes the piston seat in with little force required...
A hose on the bleeder to a disposal can makes for a clean and easier job....
I never push the old fluid back up the lines....just doesn't make any sense and can actually cause Master problems..
If you try this sometime and see what winds up in the disposal container , you will know why...

Excellent post and information. I will be doing the front pads on our 95 C220 in the next week or two.

Any insight on who's break pads you used. I've done breaks several times on different cars and about 1 or every 3 sets ends up with a terrible squeek. Somtimes the squeek goes away after a few weeks, but other times it seems to be there for the life of the pads.

Any tricks of the trade to prevent or minimize the squeeking would be appreciated.

Chris

I use antiseize compound on all the rubbing surfaces (where the pad metal backing rubs along the caliper). Don't put too much on to avoid any getting on the working surface of the pad. I don't think it is a good idea to use ordinary grease as it will flow when the brakes heat up. There are other products (hi temp brake paste) that work like the antiseize compound.

I use the OEM brand of pad (I believe one of them is Pagid) which seem to be quieter although rather dusty.

Pads Used
 

When I ordered the parts off the Fast Lane site, I'm sure I ordered the semi-metallic pads. Can't remember the catalog number...when I get home, I'll check it out. I smeared the anti squeal compound as well where instructed, and so far I have ZERO noise from the pads and hardly any dust on the front rims. I haven't driven the car too far, so it could be that they haven't "worn in" yet. I very well may experience some squeal down the road, but I'll cross my fingers and hope they stay quiet.
The rotors I placed are the ATE Power Discs (with grooves that look kinda like a flower, or a spirograph drawing).