1987 300td wagon - rear brake question - PeachParts Mercedes-Benz Forum

Chewable · #1 02-02-2014, 07:05 AM

I drove my wagon a bit on Friday and I think that there is something going on with the rear brakes. The car would shimmy at freeway speeds. Also the brakes started getting soft.
I pulled the rear wheels and the pads still had a lot of life (which I had seen before).

With the car in neutral the rear wheels barely turned - something is locking up.

I removed the calipers and things spun finally, but the rotors just pulled right off. There was no T30 torx screw.

I think that the rotors were fluttering and that heated the fluid and probably ruined the calipers and rotors.

Do new rotors come with the T30 torx screw?
What happens if you do not use the torx screw? (Are these typical symptoms)
What else should I check for? (Wheel bearing......)
I'll post some pictures later today.

vstech · #2 02-02-2014, 07:09 AM

I know the emergency brake repair kit comes with new screws, I don't know if the rotor does. how were your Parking brake shoes?

can you describe the shimmy? with the wheel on the car, the allen bolt does nothing. only way it would be a problem is if the rotor was not aligned properly when the wheel was installed, and or the lugs were loose...

Chewable · #3 02-02-2014, 07:16 AM

What would happen is that at freeway speeds I would hear a vibration in the rear. The car drove fine but I could feel the vibration and the noise sounded wrong.
Also the rear brakes felt too hot for a short 5 mile trip.
I post photos of the wheels and the parts I've pulled.

vstech · #4 02-02-2014, 07:39 AM

I'd look at wheel balance/tire condition first. if the pads are even, and equally worn, and the calipers show no signs of dragging, the allen screw does NOTHING. there are a LOT of parts back there that will cause vibration at speed... check the spindle bushing at the bottom of the hub, check the play in the rear bearing, check each and every link in the assembly, check the axles, check the flex disc... etc....
take pics, we'll help ya figure it out.

vstech · #5 02-02-2014, 07:41 AM

after rereading your first post, I'd pull the brake hoses, and change them. at all 4 wheels, and flush out the fluid.

Chewable · #6 02-03-2014, 12:20 AM

Photos -

Well I did a crappy job of checking the Passenger side caliper when I switched the tires......
When I bought this car it had almost brand new tires on it and my gas Wagon had the rims you see in these photos (the tires were pretty worn). I switched them over and checked the pads quickly when I did. I must have overlooked the passenger side because you can see that it was just metal. I have only driven the car about 50 miles since owning it so I am pretty sure that it was bad when I got it.

The drivers side looks good, so I think I may be able to keep that caliper for a bit and that I just need to replace the hose on that one and I am pretty sure I need a full replacement on the Passenger side.....

rscurtis · #7 02-03-2014, 10:09 AM

You should replace them in pairs. Besides, the dust shields on the second caliper are starting to go.

Chewable · #8 02-04-2014, 12:10 AM

I went to get new calipers today.

They said when I got them that the casing numbers should match.

I pulled the Drivers side old caliper and I have a photo of it next to the new caliper.

The number on my old case says - 6
On the new caliper it says - 75P

The new ones are rebuilt by Centric and the part numbers are:
141.35523
141.35524

When I look online those numebrs seem to be the correct part numbers for a 1987 300TD.

Could I have had the wrong calipers before?
Am I wrong to assume that the case numbers should match?

vstech · #9 02-04-2014, 07:37 AM

the new caliper is a generic sedan caliper... your wagon needs the larger piston. if you change just one you will have uneven braking. you need to change them in pairs.
if it were me, I'd get a rebuild kit for YOUR caliper, and rebuild it. notice the HUGE difference in piston size... that could be photographically misrepresented though... measure the piston size.

Chewable · #10 02-04-2014, 08:50 AM

I am doing both.

The photo is misleading they look exactly the same size. The new caliper is further back making it look smaller.

I'll double check them though and measure the pistons.

Chewable · #11 02-04-2014, 09:27 AM

Not 100% sure of the accuracy of this chart, but it shows the same calipers for sedans and wagons:

http://www.w124performance.com/images/W124_brakes/124_brakes.pdf

Chewable · #12 02-04-2014, 11:56 AM

The new calipers that I got appear to be the exact same size. I have not used a micrometer, but when held up together the piston housings are exactly the same.

vstech · #13 02-04-2014, 05:52 PM

there are several different size calipers between the wagons and the sedans, and other year sedans. I KNOW the 93 rear calipers are a different size from the 87 wagon brakes, and the 95 wagon is a different size as well. I do not know for sure if the 87 sedan has the same size pads or not.

Chewable · #14 02-04-2014, 05:57 PM

I took my pulled caliper and the new one to Olympic Brake Supply to look everything over today. Everything online points to the ones that they gave me being the correct ones for my car. They look exactly like the sample I brought in. My best guess is that there must have been a different casting number used at some point.

I should be picking up the new rotors today - I have a pulled one in my car to compare it with at the parts store.

Hopefully I'll have it back together tonight and maybe bled. I may not be able to bleed the system until tomorrow.

Chewable · #15 02-04-2014, 06:11 PM

By the way again this forum has totally come to my rescue. I really appreciate the help. There is no way I could afford to own one of these without this resource. I would be stuck in my old Honda Accord wagon (which I swore by for years, but now I can't imagine life without a W124).