In my 1981 300D the right rear wheel is very hot after ruining 4 miles o less. I have changed the break pads and fluid. The wheel continue hot.

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Juan

have you checked if the parking brake shoes on that side are too tight?

I'd repack and inspect the wheel bearings as well.

Is the caliper dragging? A collapsed brake hose could cause that.

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1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200

repacking the rear wheel bearings is quite a job, before you attempt it i suggest you read up on the subject, i do agree with the brake hose theroy

Here is a simple trick for diagnosing brake hose restriction..

Jack that wheel and go push the brake pedal down very hard.. once

Now go try and hand turn the wheel... if it is locked or very hard to turn, loosen the bleeder . If it now turns easily, it is a bad hose .. if it still is hard to turn, you have a sticking caliper or dragging emergency brake.

Thank you
Juan

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Juan

If brake hoses are over 10 years old replace them. They are only $10 each why bother with them?

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1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200

Thank you for your advisement. Both rear calipers are leaking. The repair of caliper is an easy job for my mechanic. He stated that if the pistons were damage the problem would be very serious. I would appreciate if anybody can tell me how frequent the pistons are damage.

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Juan

Hot wheel? that's nothing. One day I stopped for petrol and found the back wheel had smoke pouring off it.

Took the wheel off and found that one piston was seized and the pads were down to the metal. Not only was it seized, but I found that one half of the caliper had been broken in the past and had been welded back together by a previous owner. Now why would anyone do that when a replacement caliper costs $75?

As for piston damage, the exposed areas get pretty cruddy and corrosion builds up if you don't check and clean them before you push the pistons back in to accommodate new pads. Once the piston surface starts to pit, it tears up the seals and fluid leaks past them. If your mechanic is replacing the seals and the piston surface is pitted, they'll probably start leaking again.

You can, if you're patient, remove the pistons, thoroughly clean and degrease the piston surface, fill the pits with epoxy and smooth with fine emery paper. but hey, these are your brakes we're talking about. if they are in poor condition, get them replaced. it could save your life one day.

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1987 300e manual 250,000 km (sold)

Thank you one time more. I got the caliper kits repair and the hoses. I will take the car to the mechanic. I hope the pistons be OK
Juan

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Juan

In my neck of the woods it would be a waste of money to pay a shop to rebuild a caliper.

Re built calipers are $80, brand new ones are $20 more. I wouldn't bother letting someone else rebuild them. If the pistons are pitted you could end up spending more money in the end.

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1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200

Just a follow-up. The piston of the left rear caliper was partially seized, but both of them were in perfect condition. I had forgotten to say that the brake signal was on. The caliper kit repair has been installed and the hoses replaced. The brake signal is off and the car break are working OK.
Thank you
Juan

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Juan

don't want to be picky but when you say the brake signal was on, do you mean the brake wear indicator lamp on the dash? it is my understanding that the brake wear indicators are only on the front wheels, at least they are on my 124.

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1987 300e manual 250,000 km (sold)

It was the dash lamp.

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Juan