E320 rear brake disc hot and esp/run flat warning on

[jshodgson]

In this instance 'hanging up' means jamming. With a sliding caliper the area where the ends of the pad sit collect grime and can corrode a bit - both of which can prevent the pad from moving and cause it to hang up.

Thanks for clarifying.
I took off the carrier off and cleared out all of the crud. Cleaned them off, cleaned the caliper before I fitted the new pads.

 

[jshodgson]

The pad wasn’t the easy fix I’d hoped for.

Changed the caliper today. The flexi pipes definitely need doing soon (perished although brake fluid was flowing freely through them).

Will take it out over the weekend and test the heat and MPG problems I was getting.

Took some pictures of the old caliper. To my untrained eye it looks ok. Small tear/Nick in the gasket I noticed and the piston is a little chewed up where the pad has been going in with its clip I guess (or someone forcing the piston back in on a previous pad change). Tell me what you think.

 

[Bellow]

The pad wasn’t the easy fix I’d hoped for.

Changed the caliper today. The flexi pipes definitely need doing soon (perished although brake fluid was flowing freely through them).

That could be your problem right there. Flexis can collapse internally and let the fluid through to the caliper but trap it there on releasing the pedal. Any doubts with flexis - replace them

Will take it out over the weekend and test the heat and MPG problems I was getting.

Took some pictures of the old caliper. To my untrained eye it looks ok. Small tear/Nick in the gasket I noticed and the piston is a little chewed up where the pad has been going in with its clip I guess (or someone forcing the piston back in on a previous pad change). Tell me what you think.

Not seeing anything untoward - generally, if the piston is free, the brake is serviceable. Not saying there isn't anything amiss but I'd prioritise the flexis.
(NB - I am in little doubt that many flexis have ended up collapsed internally due to the practice of clamping them to quell fluid flow when a caliper is removed. A practice I will not tolerate).

 

[jshodgson]

Quick update, the caliper I changed looks to have worked. The same journey I did last week saw the brake disc reach 110-120 degrees and today it was a cool 40. Checked the other wheels and the other rear was a bit hot so thinking I may change that caliper as well.

The mew flexi brake pipes get fitted in two weeks so was tempted to see if that would make a difference first what do you think? Based on the drivers side improving so much with a calipler change I am tempted just to do that first.

MPG has improved from 30 to 33 too. Should be 35-36 so suggests that there is still some drag on the brake.

 

[Bellow]

The mew flexi brake pipes get fitted in two weeks so was tempted to see if that would make a difference first what do you think? Based on the drivers side improving so much with a calipler change I am tempted just to do that first.

Or, of it isn't dragging too badly, wait until the flexis arrive and do both together and save a bleeding operation.
New calipers seem to be effecting a cure (all good) but new flexis is good practice here.

 

[W1ghty]

Quick update, the caliper I changed looks to have worked. The same journey I did last week saw the brake disc reach 110-120 degrees and today it was a cool 40. Checked the other wheels and the other rear was a bit hot so thinking I may change that caliper as well.

The mew flexi brake pipes get fitted in two weeks so was tempted to see if that would make a difference first what do you think? Based on the drivers side improving so much with a calipler change I am tempted just to do that first.

MPG has improved from 30 to 33 too. Should be 35-36 so suggests that there is still some drag on the brake.

So , do we think it was probably the caliper piston w211 fault (because they are a plastic/resin thingy ) ?
I might have to check mine at some point .

 

[Jobsworth]

So , do we think it was probably the caliper piston w211 fault (because they are a plastic/resin thingy ) ?
I might have to check mine at some point .

Yep. Like I said, I’ve seen it hundreds of times

 

[jshodgson]

I measured the piston on the one I replaced with calipers and it was exactly the same size all the way down the piston but not sure if the whole thing was swollen a bit? It was definitely a bugger to get back in once I had taken it out. Much harder than I thought (I had to use a vice to get it back in!).

 

[jshodgson]

Resolved.

I had the ESP warning light on and an ABS warning. This was fixed by changing the brake light switch (£10 part and 15 minutes to replace it)

I had hot brake discs and low MPG. The rear brake discs were hitting 110-120 degrees after a long run and the MPG was about 15-20% lower than normal. This was fixed by replacing both of the rear brake calipers. The discs now read 30-40 degrees on the same journey and the MPG is back to normal.

Still to do are the rear flexi brake pipes. They are perishing and will be replaced next week.

Thanks everyone for all of your advice and feedback.

 

[W1ghty]

Resolved.

I had the ESP warning light on and an ABS warning. This was fixed by changing the brake light switch (£10 part and 15 minutes to replace it)

I had hot brake discs and low MPG. The rear brake discs were hitting 110-120 degrees after a long run and the MPG was about 15-20% lower than normal. This was fixed by replacing both of the rear brake calipers. The discs now read 30-40 degrees on the same journey and the MPG is back to normal.

Still to do are the rear flexi brake pipes. They are perishing and will be replaced next week.

Thanks everyone for all of your advice and feedback.

Motivated by your saga’s I’ve just ordered some new rear pistons/seal kit and 4x flexible brake hoses ready for the next spring .

 

[HITECH]

Motivated by your saga’s I’ve just ordered some new rear pistons/seal kit and 4x flexible brake hoses ready for the next spring .

These brake piston seal kits are extremely un-reliabe. What might seem a quick cheaper fix will result in them leaking very quickly. Just my own personal experience with them. Ide replace the calipers instead of having to do a job twice and them failing very soon with a xmas tee lights dashboard and a brake pedal that travels to the floor with no braking at the wheels .

 

[W1ghty]

These brake piston seal kits are extremely un-reliabe. What might seem a quick cheaper fix will result in them leaking very quickly. Just my own personal experience with them. Ide replace the calipers instead of having to do a job twice and them failing very soon with a xmas tee lights dashboard and a brake pedal that travels to the floor with no braking at the wheels .

Thanks buddy , I used a kit from brakes international to do all 8 calipers on both cars a few years ago . Not had any issues with them , I just didn’t know about the E class rear piston problems (they are a plastic) when I did them last time .
I‘m trying to keep the costs down , otherwise as you say I would get new brake callipers

 

[HITECH]

Thanks buddy , I used a kit from brakes international to do all 8 calipers on both cars a few years ago . Not had any issues with them , I just didn’t know about the E class rear piston problems (they are a plastic) when I did them last time .
I‘m trying to keep the costs down , otherwise as you say I would get new brake callipers

Thats great no probs for years. Hopefuly it stays that way for you.