'87 300TD Left Rear Wheel Hot - PeachParts Mercedes-Benz Forum

BrierS · #1 06-26-2006, 06:18 AM

Brake pads were not moving in the caliper. If interested, read on for the rest . . .

I drive the above off and on but not during the winter (much). Last winter I parked it and never drove it. After about 300 miles this year, I started hearing a slight (nearly) scraping noise coming from the left rear. My first thought was rust on the rotor/pads especially since I rarely have to do any hard braking. Rather than do as I should have, I ignored it. Last week I hopped in, drove about two miles when one of my sons mentioned a strange burning smell. I stopped and found the left rear wheel was quite hot to the touch. Brought the car home and parked it. Yesterday, I jacked the left rear corner, wriggled the rear tire/wheel to see if there was any appreciable bearing play (dreaded that thought). None. Lowered it to remove the tire/wheel. Back up and placed two jack stands under the left rear, moved the floor jack to the right (chucks foreward and aft of both front tires) and jacked it up. Car in neutral, with my son turning the wheel I watched the left side. He told me it was turning extremely hard and I could hear the pads/rotor dragging. I found two things and corrected one. My fluid needs to be changed and that will be done very soon. The other is the pads, though in great shape, were rusted to the areas they should be sliding in. We removed the caliper, with dust masks on thoroughly cleaned the mating surfaces of the caliper, pads and also the pins that hold the pads. Synthetic caliper grease very lightly applied to the slide surfaces and then reassembled. Two driving/braking sessions later the wheel was consistantly as cool as the other three. Still a little rubbing noise yet I had not cleaned the rotor surfaces prior to putting the caliper back on. Power brake fluid bleeding is next (along with a lower ball joint replacement).

blueranger · #2 06-26-2006, 08:37 AM

thats called a sticking caliper and it usually occurs when the pads are worn down and the rotors are worn away as well....The caliper piston is usually operating at the end of its sleve. At a minimum I would replace the brake pad and rotor. This would move the caliper piston way back into its sleve.

Since you desire to change your fluid then I would spend the extra 20 bucks and rebuild the caliper.

#3 06-26-2006, 09:22 AM

Quote:

Originally Posted by blueranger

Since you desire to change your fluid then I would spend the extra 20 bucks and rebuild the caliper.

Do you have a source for rebuild kits for these calipers?

BrierS · #4 06-26-2006, 12:47 PM

Quote:

Originally Posted by blueranger

thats called a sticking caliper and it usually occurs when the pads are worn down and the rotors are worn away as well....The caliper piston is usually operating at the end of its sleve. At a minimum I would replace the brake pad and rotor. This would move the caliper piston way back into its sleve.

Since you desire to change your fluid then I would spend the extra 20 bucks and rebuild the caliper.

Your description is a malady I saw many times on customers' vehicles and even occassionally some of the used beaters I purchased.

Though I expected to find exactly what you mentioned, my particular situation was different. Pads are at least 90% in the living, rotor is well within limits, and after doing some standard maintenance, it works perfectly.

The reason I want to change the fluid is it has not been done in at least the past three years. Additionally, while I am building my own power bleeder I am going to tackle at least three of my vehicles. I figure it will fill a good vacation day.

Though I have rebuilt a fair number of calipers over the years, I have nearly as often replaced them. Saabs and BMWs for example. My 300TD was suffering from seasonal and infrequent driving though I expected worse. Not that I can this quickly rule out that the problem isn't as you suggest . . .

Thanks for the reply.
Best regards,
Steve

t walgamuth · #5 06-26-2006, 06:55 PM

i thought he was describing pads sticking on the sides of the opening. in this case i always take the new pads to my grinder and take some off the sides so they will move freely. a little grease on the edges wont hurt either.

tom w