Hello guys, it's me again: The dude with a million questions...

So, in my quest to fix some easy stuff on the car for a little while (don't want to do any more big(ish) projects for a month or so) I figured brake pads would be a good idea. Mine are pretty worn down, and they are starting to squeal under light braking.
Anyway, looking at brake pads, I don't know what to get. I'm looking at this page:
1984 Mercedes-Benz 300D Base Sedan - Brake Pads & Rotors - Page 1

Some pads don't specify a brand of caliper, some specify use with ATE brand calipers only, and some specify use with BENDIX only.

How can I know what my car has, or can I just order those pads that don't specify a brand? I would assume those would work in either caliper?

Also, any extra stuff to get? Should I get the retainer pins and springs? Of course I'll get some brake grease.

I've only ever done brake-pads on more modern cars which have the brake calipers that can swing away from the caliper bracket. I think these older calipers are pretty much one piece, but allow you to get to the brake pads through a slot in the outside of the caliper, right?

Also, I figured that this would be a good opportunity to refresh the brake fluid. I figure I can start with the rear-right brake, and after changing the pads have my wife press the brake halfway down a bunch of times while I open the nipple to bleed the brakes. I have a little bleeder kit to catch the brake fluid. If I have her do that while topping of the reservoir a few times, most of the old stuff should be gone, right? I can then move to rear-left, right-front, and lastly right-left, and they all should be bled and with new fluid. Anything wrong if I were to do it that way? I'll put a thick block of wood underneath the brake pedal, so she can't just ram it all the way down to the floor...

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"The MB W123 is so bulletproof, you can drive them forever. Which is a good thing as it takes that long to get anywhere."
Betsie: 1984 W123 300D (hobby, 280k miles)
Myrla: 2001 Mazda Protege 2.0 ES 5spd (daily driver, 130k miles)
The Turd: 2007 Toyota Camry (wife's car, 118k miles)

You will need a large C clamp to push the pistons back; use the old brake pads to catch both pistons at the same time. Be sure to loosen the cap on the master cylinder. You will need some of the blue no squeak spray to coat the back of the new brake pads; let it dry for about 10 minutes then put the shims on the back of the new brake pads. If the 300D has the little wire in the brake pad which causes your dash light to illuminate when the brake pads get thin, you can reuse the wires. Just pull the rubber plug with the wire out carefully and remember to stick it in the little hole in the new brake pad - the SD has these; not sure about the D.

The no-rattle springs are reused; they will not come in the brake pad box. Seems like I lost one once and made a replacement with a coat hanger. I think the Bendix has the coat hanger type springs and the ATE has flat metal springs - or it could be the reverse.

Look at your calipers and you will see ATE or Bendix on the caliper. The only difference is that the slim brake pads will fit into both ATE and Bendix but the fat ones fit only one - cannot remember which though. You can always order the thinner ones; just ask for the dimension or thickness of the new pad.

There is nothing else that you need as far as parts.

@tyl604
Thanks! I have a C-clamp from previous brake jobs I did. I will have to siphon off some brake fluid before I can push the pistons back, as the previous owner for some unknown reason decided to top off the brake-fluid, even though the pads are way worn... I guess some folks think brake fluid should always be at the full level?
I don't think my brake sensors are currently hooked up. The light on my dash only illuminates when I turn the ignition, but turns off when I start the car and my pads are certainly worn...

I'm just gonna go ahead and order the thinner ones then. I looked at the calipers a while ago, but couldn't see a brand name on it. I might not have looked hard enough, I was more concerned with inspecting the brake pads then checking the brand name on the caliper.

Thanks for the info!

__________________
"The MB W123 is so bulletproof, you can drive them forever. Which is a good thing as it takes that long to get anywhere."
Betsie: 1984 W123 300D (hobby, 280k miles)
Myrla: 2001 Mazda Protege 2.0 ES 5spd (daily driver, 130k miles)
The Turd: 2007 Toyota Camry (wife's car, 118k miles)

Need to do front brakes on my 84 soon....was wondering the same thing about which pads.

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14 E250 Bluetec "Sinclair", Palladium Silver on Black, 153k miles
06 E320 CDI "Rutherford", Black on Tan, 171k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver, 142k mi, wastegate conversion

19 Honda CR-V EX 61k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife

If it turns out that you need a new caliper, I believe vstech has a bunch that he has rebuilt. I would trust him to do a good job.

The anti-rattle spring that looks like coat hanger is in fact Bendix; I just looked.

I would hope I don't need new brake calipers. As far as I can tell they are fine. They aren't seeping/sweating brake fluid and they don't stick at all. Matter of fact, I manually push my car forward until the bumper almost hits the end of my garage when I drive it in every day. I leave the gar in neutral and can push it forward with a finger...

__________________
"The MB W123 is so bulletproof, you can drive them forever. Which is a good thing as it takes that long to get anywhere."
Betsie: 1984 W123 300D (hobby, 280k miles)
Myrla: 2001 Mazda Protege 2.0 ES 5spd (daily driver, 130k miles)
The Turd: 2007 Toyota Camry (wife's car, 118k miles)

Remove one pad, push the piston back, install the new pad. Then remove the other pad and install the new one.

Doing one at a time will enable the other piston to not push out of the caliper when you push the piston back.

__________________
83 SD

84 CD

I highly recommend switching to the Akebono ceramic pads, FAR less brake dust and the performance is as good as if not better than the OE pads. Pricey, but better and worth it.

Your car should have the wear sensor wires in the front pads, recommend you order a set to install with your new pads.

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Respectfully,
/s/
M. Dillon
'87 124.193 (300TD) "White Whale", ~392k miles, 3.5l IP fitted
'95 124.131 (E300) "Sapphire", 380k miles
'73 Balboa 20 "Sanctification"
Charleston SC

I use a big screwdriver to pry the pads back....much quicker than a c clamp. I start with a medium size screwdriver then after prying it a bit take the big daddy and pry them the rest of the way. Usually I drive the small driver in with a hammer.

__________________
[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

@Maxbumpo
Thanks for the recommendation. I will probably ignore your good advise though... The W123 is a summer run-around thing. If I drive 5k a year in it, that would be much. It'll probably be closer to three. So I should be fine with just normal brake pads. Besides, I have to run everything by my boss-lady, and she already hates the car with a passion. If I start slapping "high performance parts" on a vehicle that never goes over 55mph, she's not going to be a happy camper...

Thanks for the good advise and tips, folks! I'll just go ahead and order the thinner pads so I know they fit and start changing this stuff out in the next two-three weeks.

__________________
"The MB W123 is so bulletproof, you can drive them forever. Which is a good thing as it takes that long to get anywhere."
Betsie: 1984 W123 300D (hobby, 280k miles)
Myrla: 2001 Mazda Protege 2.0 ES 5spd (daily driver, 130k miles)
The Turd: 2007 Toyota Camry (wife's car, 118k miles)

The caliper needs to come off. Even if you have to unscrew a hard line.

You must have the rotors resurfaced. This is non-optional, despite what anyone says. And measured for min thickness as well.

Mine as well repack the bearings. Way cheaper and safer than waiting for them to go and ruin the hub, have the tire fall off, etc.

And replace all rubber brake lines every 5 years.

You can see the performance of your calipers by brake pad wear. If they are wearing evenly (both sides on one wheel), you are fine. If not, they offer a rebuilt kit. Or just get new ones.

Thats a proper brake job.

Why does the caliper need to come off when replacing brake pads? I've never had rotors resurfaced after I replaced pads. I install new rotors if the old ones are warped. The ones on the Mercedes aren't warped though. I'll measure their thickness, not sure what the minimum thickness on them is? If they are above minimum thickness I'm not planning on replacing the rotors yet.

__________________
"The MB W123 is so bulletproof, you can drive them forever. Which is a good thing as it takes that long to get anywhere."
Betsie: 1984 W123 300D (hobby, 280k miles)
Myrla: 2001 Mazda Protege 2.0 ES 5spd (daily driver, 130k miles)
The Turd: 2007 Toyota Camry (wife's car, 118k miles)

You need to resurface them so the pad has a fresh flat surface to bond do. Although to your eye they don't look warped, on a lathe you would notice uneven spots. Its $10 each or so at most auto stores, money well spent.

As well, an opportunity to grease the bearings.

Im curious, how do you determine them to be warped?

And the caliper has to come off to get the rotor off.

The min thickness may be stamped on them, but I doubt it, as min thickness is different for ate and bendix calipers. Its in your fsm, or the place that resurfaces them will know for sure.

What will happen, and I have seen it, is the rotor goes past min and when the pad wears lower the piston in the caliper will actually come out. You will loose all brake pressure. As well, if too thin it can heat up and crack. Once again, no brakes, or the wheel locks up and does all sorts of damage.

Do all that, and you will never have to buy rotors or bearings.

Same with cleaning up the bores and pistons in the calipers and new seals. Once I own a car I never have to replace them, as they never are allowed to get to bad.

You can determine if a rotor is warped, when you hit the brakes...f your steering wheel starts shaking or if you get the sensation that your brakes are pulsing, it's definitely time for some new rotors.

I might go ahead and put some new rotors on there as well, but I was hoping to keep the spending money for this month a little on the low side. This W123 is turning into a money-pit... I'll find the minimum thickness for the rotors somewhere and will measure the rotors.

EDIT:
Found the information on this forum. Here's the information from Stretch:

.

Found in this topic.

__________________
"The MB W123 is so bulletproof, you can drive them forever. Which is a good thing as it takes that long to get anywhere."
Betsie: 1984 W123 300D (hobby, 280k miles)
Myrla: 2001 Mazda Protege 2.0 ES 5spd (daily driver, 130k miles)
The Turd: 2007 Toyota Camry (wife's car, 118k miles)

Ohhhh.

Thats exactly why you need to cut your rotors every time. The pad can't ever seat properly and thats what is causing that shaking.

If they aren't too thin they can be resurfaced and new pads put on.

A proper brake job will never shake. Unless you let your teenager take it out. The rotors are replaced when they are too thin to resurface.

If you don't resurface them, yes they eventually will shake.

I get about 250k miles out of a set of rotors, for reference. I would assume you have been replacing them much sooner without need.

And I would check the mercedes manual. Haynes is kind of universal and might only cover one. As well, different years could be different.

But I believe its bendix calipers that allow you to go thinner on the rotors.

I haven't seen stretch around much but hopefully he will jump in.

Edit: You can test warpage with a dial indicator, but I never worry about it. An experienced guy on the lathe can measure them, check minimum, and run his finger across and tell you if he can cut them above minimum. If he is wrong, and they end up too thin, he wont charge you.

I hope that makes sense. The shaking isn't from being warped, its from the pads not having a flat surface to bond to.