So, I picked up rebuilt calipers the other day, and this morning went out and started installing them. Did the left front, no problem. Opened up the box of the right front, and immediately noticed that the new one was missing what looks like a heat shield against the pistons. Opened the other boxes for the rears, and both of them were missing the heat shield. Haven't pulled the rears off yet, so I don't know if the original ones have them or not. The new one for the left front DID have the heat shield.

How critical is this part? My parts house is in the city 80 miles away, so I can't just zip down there and grab another caliper. And the heat shields on the old ones are all rusted up and won't come out.

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1976 Mercedes 240D, unknown mileage
1977 Mercedes 240D, 225k
1992 Dodge/Cummins 4WD, 284k
1990 Subaru Legacy wagon, 330k
1991 Subaru Legacy wagon, 225k

Definitely not critical. Plenty of vehicles never had them. Neither did your rear calipers.


You could procure a caliper overhaul kit and install the included heat shields yourself.

Problems like this is why I overhaul my own calipers.

May I venture a guess that you bought Cardone calipers?

Check that you got a matched set of calipers. I think one style doesn't use heat shields (Teves? ATE?) and the other one does (Bendix?).

It's okay to replace one set of one style with a set of the other style, but not okay to mix them on the same axle; i.e. bendix + bendix OR ATE + ATE = good, bendix + ATE = bad.

Ditto for the rears.

The FSM actually permits different make calipers on the same axle if the bore size is the same. Such a configuration, however, might make logistics unnecessarily complicated.

Since we're picking nits, no it doesn't actually permit it. That would be the second sentence below.

It stipulates both the same diameter and the same manufacturer. I presume this is because there are two different diameter Teves for the rear, 38 and 42 mm, so simply specifying "same manufacturer" would be insufficient in that case. The logistics for the front would appear to be simple, since they're all 60 mm.

However, since pad movement is dependent upon the volume of fluid moved, it's important to have the same cavity size on the left and right - which is most easily attained by using the same manufacturer. Bore diameter is important since force is dependent on area. With equal diameter bores but mismatched cavity sizes, the force on the left and right would be equal, but one caliper would engage the disc before the other, resulting in uneven braking.

<> Mixing calipers from pre-79 cars with newer cars/calipers MAY also produce a situation where a set of pads won't fit both calipers on the same axle since M-B changed the design and went to a thicker pad. This is not necessarily relevant for the OP, but is additional info since the discussion includes having a matched set of calipers on the same axle.

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OK, I looked at the box and they are Cardone. They came from the same foreign parts house that I have been going to for over 20 years, but I have noticed similar problems on all kinds of rebuilt brake parts that I've gotten from a variety of different sources. Missing bits of hardware seems to be a common problem. They are a matched set, though, both ATE. The rears are also ATEs, but the ones on my car are Bendix. Still, they look pretty much the same. I haven't removed the rears yet.

I did manage to carefully remove the best looking heat shields from one of the used calipers and install them on the new one that was missing one. Even if it wasn't going to cause my car to crash or anything like that, asymmetry like that really bugs me. I would think about one side having a heat shield and the other side not having one, every time I hit the brakes for the next year or so!

Thanks for the replies, moving on to the rear axle now...

__________________
1976 Mercedes 240D, unknown mileage
1977 Mercedes 240D, 225k
1992 Dodge/Cummins 4WD, 284k
1990 Subaru Legacy wagon, 330k
1991 Subaru Legacy wagon, 225k