Car is a W123 coupe, 230CE, 1981 model year.

Originally discovered this problem shortly after I got the car and did a teardown of all the wheels to check condition of brakes and suspension.

Passenger rear brakes would squeal at low speed. When I took it apart to investigate, I couldn't get the pads out of caliper. Removed caliper and found the pads were split, and half the friction material was stuck to the rotor. Well, that was obviously the source of the sound...

Replaced rotor and pads. Noticed that wheel was a bit harder to turn by hand that the opposite one. Then started to watch that wheel since split pads is sign of heat buildup. Noticed that that wheel hub was slightly warm after driving. Not hot, just warmer than the other 3. Even after 20 mile highway drive still wasn't too hot.

Drove like this a few months, I only go 3 miles a day most days.

Finally got around to replacing both rear calipers, assuming that one was sticking a bit. Also replaced the soft brake hoses to both rear calipers. Fluid came out pretty readily when i disconnected the hoses

After replacement, everything was about the same as before. So I backed off the parking brake on that side so that it doesn't even engage. Still the same.

This leads me to believe it is not related to the parking brake or the primary braking system.

What else would make the right rear wheel drag a little bit and to build up heat? Bearings? Something else?

Thanks in advance!

my vote is on the wheel bearings. however, i would expect some noise or sound along with the heat. have the bearings been changed to your knowledge? what is your mileage?

The trailing arm bearings are not serviceable units on the W123. You need to replace them if they are worn. There's a limit for the axial play in the FSM (sorry can't remember it - look it up on the startek site).

You might want to try a bit of self applied lubrication. It might help enough for problem identification purposes but won't provide any long term solution.

When checking these hubs, however, don't forget that one wheel on these open differentials will always spin more easily than the other. Also when comparing temperatures it is probably best to measure just in case there's a psychological effect creeping into the analysis!

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1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

Yes, measure. Since the primary function of a brake is to convert kinetic energy into heat, at this point we can't say you have a problem.

https://www.google.com/search?sclient=tablet-gws&site=&source=hp&q=infrared+thermometer

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Prost!

wonder is there a porportion valve

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1999 w140, quit voting to old, and to old to fight, a god damned veteran, deutschland deutschland uber alles uber alles in der welt

Nope not really - the master cylinder has different sized piston areas to apply a reduced effect to the rear wheels. There's just a single line and a T junction at the back wheels. Very simple system.

__________________
1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

Did you replace the flexi brake hose on both rear wheels? The problem is that the rubber inside the hose perish over time and as fluid travells down to the flexi to the caliper, the hose opening inside is restricting the hole in the hose , and the fluid is unable to return ,so a little pressure is on all the time .So the pads never clear the disc. This is also caused by the garage monkey useing hose clamps to cut of the fluid supply, to make caliper work easy , and to stop the fluid escape ..

Yes I did replace the rubber flexi hose on both sides.

Interesting to consider that one will be easier than the other on a diff like this.

I'll try to get a thermometer and test the temps. Where would be the most useful spot to compare? Remove the wheel center cap and aim in there?

I have been meaning to get back to this. I got an IR thermometer and have tested it under different conditions. Pretty consistently, the right wheel hub (the one that has more drag) runs about +20F hotter than the left.

Under normal driving, if I check right when I park, the left will measure around 80F and the right will measure around 100F.

The worst I have observed was on a hot day after a lot of sustained high speed driving, it was about 100F at left, 120F at right.

Is this a concern?

Thanks.

Looking like bearing replacment, or even remove them clean and re pack them with grease .Check oil while your doing it in the back axle ...

They are the bearing assemblies at the center of the rear wheels of your vehicle.