Rear brake binding after caliper change

[SwaitsySG]

Rear brake binding after caliper change

Afternoon all. Think anyone could shed some light on this?
So more often than not, but not all the time the nearside rear brake seems to stick, causing the wheel to heat up and the pads to smell.

I'd initially changed the pads, cleaned the slider pins, filed the caliper carrier to clean it, and replaced the pad shims. I also added a thin smear of anti seize grease to the backs of the pads. No change. I've now changed the caliper, so that's brand new. Still no change.

I might add at this point there's no squeaks or squeals, no fault codes for the braking system, no issues at the pedal end, no dash warning lights and the EPB appears to be functioning as it should. There was also no issues during the mot test, which the car passed two weeks ago.

Any suggestions folks?

[Magnet]

Possible starting-to-break-up-inside flexible hose??

[SwaitsySG]

Not something I'd considered, but it's possible. How firm should the flexi-hoses be? 

[Magnet]

Thanks, - not sure I’m understanding the significance. Simply change it as a process of elimination. 
Kind regards,

Gareth. 

[SwaitsySG]

For the sake of opinion. Cheers.

[Magnet]

Still not sure of the significance, but…

[cliffcoggin]

I doubt you will feel a difference in firmness because the hoses are armoured. It is the rubber lining that perishes.

[Stevey Y]

4 hours ago, SwaitsySG said:

For the sake of opinion. Cheers.

Hi the brake hoses rot from the inside out as Cliff explained, when they rot the inside collapses not allowing the fluid to return, this then holds the piston on to the pad worth changing that first as the other possible cause is the ABS unit malfunctioning which is a whole different expense.

Steve.

[SwaitsySG]

Thanks lads. I don't believe it's the abs unit Stevey. Not when the hoses are a tenner a pop. I'll try them first. I was curious about whether being solid externally or not at least gave some sort of indication as to whether they were bad. It's an old car, and the brake pipes are going to be rusty where they meet the flexi hoses. So trying to remove them could be a world world of pain in itself. 

[Stevey Y]

4 minutes ago, SwaitsySG said:

Thanks lads. I don't believe it's the abs unit Stevey. Not when the hoses are a tenner a pop. I'll try them first. I was curious about whether being solid externally or not at least gave some sort of indication as to whether they were bad. It's an old car, and the brake pipes are going to be rusty where they meet the flexi hoses. So trying to remove them could be a world world of pain in itself. 

Hi they wont be that bad to remove if you give them a good wire brushing and soak them in Plus Gas fast release overnight also if you use the right size brake spanner with the cut out that allows you to get past the the solid pipe, like a ring spanner with a bit missing, the whole job is easier.

Steve.

[SwaitsySG]

Cheers Stevey. That's optimism i can live with, and I've plenty plusgas 🤣 I've a set of ring spanners but not any dedicated brake spanners, so maybe jump online the night and have a look for some 👍🏻

[SwaitsySG]

Well, that's gubbed. Whether it's the cause of the sticky brake or not is still not confirmed. But I'm not going to attempt to loosen it. 

So the plan now will be to cut that whole end off and replace it with a new piece of pipe.

[cliffcoggin]

It doesn't look good. Might as well change all four while you are at it.

[SwaitsySG]

Well Cliff, my two mot advisories were for this and the offside rear. So I'll replace the ends on both rear lines. I'm not going to touch the front. Fifteen year old car with 254k miles, I'm not doing any more to it than I need to.

[cliffcoggin]

Fingers crossed that the rusty brackets don't break off.

[SwaitsySG]

I think they'll be ok if I'm honest. They look worse than they are. If I can carefully persuade the flexi hose out, I'll give the lot a good clean and some rust converter. Then get the ol'Dinitrol on it, preserve it for a wee while longer. 

[Magnet]

Hello Chris,

By what I can see, the flexible hose end is unserviceable rusty and should be replaced.  Others?? 

Replacing parts of brake lines by piecing in is not a practice I would endorse. I really think this shouldn’t be a case of ‘ not doing any more than I need to…’ , but one where the job is carried out thoroughly, to best ensure your and other road users safety. 
Kind regards,

Gareth. 

[SwaitsySG]

Cheers Gareth, appreciate the concern. I have new Brembo hoses there. Beyond that, there needs to be a balance. Replacing the full line (correct me if I'm wrong for thinking the fuel tank needs to come out? I read that on here somewhere) pretty much means the vehicle is probably scrap. Which is a shame as its got plenty miles left in it. 

I'll give it some thought before making a decision on what to do. I made this very repair to an old Merc once, where I replaced the knackered end of the brake line with a new piece, double flared and joined with a union. It passed its mot without issue and never gave me any bother. 

[SwaitsySG]

Well, first off happy new year to everyone. Hope Christmas was good. 

For the sake of tidying up this thread with a conclusion, I've since gone ahead with the brake line repair. I cut the steel line just past the corroded end section, chamfered and reamed the end of the line, made it all neat and tidy, threaded on a union nut and flared the line. 

Corroded section of steel brake line has now been replaced with a new piece of cupronickel line with a flared union to the steel one. To the end of that I've replaced the old flexi hose with a new Brembo one. The bracket itself was solid, it has a quick tidy up but I may return to that and give it some better protection. Brakes re-bled to finish off.

So far no leaks at the union, no fluid loss from the reservoir and more importantly no hot wheel or smell of brake pads. It's early days so I won't say problem solved yet. A short motorway run to my nearest services will give me a better idea. But so far, so good. 

[cliffcoggin]

Thanks for the update Chris.