Another "help me diagnose my problem" thread - Brakes sticking/binding, but only ever so slightly

Howard

Howard

Howard

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Well it's not so much of a problem, more a minor irritation.

When I come to a stop after driving, i.e. at lights, junctions, etc., I can feel the car pull itself to a complete stop, but only ever so slightly, and it's only when the car is pretty much stopped anyway, if that makes sense. It doesn't seem to affect fuel economy and when I jack the car up, none of the wheels appear to be binding any significant amount, i.e. more than the usual very slight pad to disk rubbing noise. I've tried doing this with someone in the car pressing the pedal as well just in case it's a slow-to-return piston somewhere but as soon as the brakes are released, the wheels turn freely.

I've replaced the nearside front and offside rear calipers in recent times (mk3 Mondeo, famed for its crappy rear calipers), and this weekend gone just replaced the nearside rear caliper. The only remaining caliper is the front offside, and I've cleaned it all up in recent times anyway.

The only one that hasn't had attention recently is the first caliper I replaced, the offside rear - I did this one about a year ago. Perhaps I need to take it all apart on this corner and just clean up the carriers and make sure the pads slide freely.

Other than this, can anyone suggest anything else?! I don't see what else it can be. None of the wheel bearings appear to be failing, and the brake fluid has been thoroughly bled to all corners the last time a caliper was changed, so unless something large is stuck in the pipes acting like a one-way valve...

I hope this all makes sense. Thanks!
 
Wouldn't concern me tbh, ate the pads quite new? Might go away as they wear slightly.

Could try giving them a good stamp a few times too and see if that improves it
 
It only concerns me because other cars I drive don't do it at all :p

The front pads are 6,000 miles old, the rears are about 19,000 old, so not exactly new-new. The rear ones are crappy Pagid ones though ;)

I've tried that, believe me!

There's a loud brake squeal (you know that quite loud, irritating "medium pitch" squeal) coming from one of them which has developed in recent times too, and I'm sure in the summer I heard a very, very slight squeal when driving along indicating some form of contact. This could have just been regular pad contact exacerbated by dust or something, though. It would stop if you wiggled the steering wheel, i.e. as the load shifts the calipers/pads.

Crappy things.
 
Job 1 - replace the only remaining caliper you haven't done. For the sake of a caliper which is probably only £50 on ECP plus fitting would could solve your problem
 
I was going to do this because as you said, they're not expensive, but after having that wheel up in the air and getting someone to stomp on the brakes and then let go, it doesn't feel like it's binding. I'm tempted to replace it, but I'm 80% sure it'd be in vain :p


Gaygle said:
Can you describe the symptoms again as I don't really understand what you mean?
Click to expand...

OK so you're coming to a stop at some lights or whatever. You brake down to like 0.5mph and let off the brakes a bit because you don't like to be jolted to a stop unnecessarily. Maybe you feather the brakes a bit to stop completely, and as you let off when the car is pretty much stopped, the car jolts itself to a stop slightly, indicative of a very slightly sticky caliper. Other cars, such as my mum's or my dad's, don't do this, and they'll creep forward a bit more ever so slowly.

It's tricky to explain without actually demonstrating it, but does that make sense?

It doesn't ALWAYS do it, but most of the time it does. It's not enough to hold it on inclines or cause the wheels to get hot or smokey or anything, or indeed have any noticeable adverse effects, but it's enough to feel "not right" to my overly anal mind.
 
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Anything to do with the master cylinder?

The only thing i can think of also is to check the brake lines.
 
The most important thing is to make sure all the pads move freely in the carriers. This is always a trait of your boggo standard single piston caliper which i presume the mondeo uses?
 
Have you had the brakes apart to check the sliders are free?

Another common issue is that no one clears up the carriers when pads are changed so the build up of brake dust then prevents things moving freely, or at all.
 
I'm going to double-check at the weekend that everything's moving as freely as it should. I seem to remember the Pagid rear pads do sit quite tightly in the carriers so perhaps one of them is the culprit - when I changed the nearside rear caliper the other week, I did ensure the pad moved freely but I haven't checked the other one for a while. Will report back!
 
Matt82 said:
Have you had the brakes apart to check the sliders are free?

Another common issue is that no one clears up the carriers when pads are changed so the build up of brake dust then prevents things moving freely, or at all.
Click to expand...

This +1

When cleaning and lubricating the sliding pins one needs to use proper brake grease. Do not use ordinary grease (On many designs there are rubber components on the sliders to provide slight friction and therefore vibration damping. Ordinary grease can make these swell and jam)
 
Orionaut said:
This +1

When cleaning and lubricating the sliding pins one needs to use proper brake grease. Do not use ordinary grease (On many designs there are rubber components on the sliders to provide slight friction and therefore vibration damping. Ordinary grease can make these swell and jam)
Click to expand...

Would copper grease suffice here?
 
I've been told to never use copper grease on brakes as when it gets hot it tends to thin out and fly off (over pads and discs), but then again I've been using it on my cars and bikes for years
 
i was told copper grease on sliders was bad because it allegedly abrasive and only meant for anti seize

I just use normal grease and have always been fine.
 
I have always just used a bit of moly grease on the sliders, or the grease that comes with new calipers which looks the same anyway. And a thin ish layer of copper grease on the back of the pads.
 
Try driving along a perfectly straight quiet road, take your hands off the wheel but just enough so your not actually touching the wheel, and your ready to grab it at any second. When your doing this start to brake lightly but apply more and more pressure, the car should remain in a perfectly straight line and you shouldn't have to touch the wheel at all. If the car pulls to one side that'd suggest that the brakes are dragging on that side of the car.
How does the Handbrake work on the mk3 Mondeo? Is it mounted to the caliper, and have you tried to free all of that off?

When you say "I've tried doing this with someone in the car pressing the pedal as well just in case it's a slow-to-return piston somewhere but as soon as the brakes are released, the wheels turn freely."
Do the wheels spin freely, as in you give them a good spin and are completely free for like 3-4 or more seconds, if they only spin for 2 seconds or so then that'd suggest their not totally free and it might be worth checking for play in the wheel bearings etc. have you also taken the pads out and check to see if they ahve worn evenly, as they should tell you if there's any uneven wear on any corner of the car...

Hope you get it sorted out mate, keep us updated :)
 
It doesn't pull when braking, and both rear calipers which are operated by the handbrake are new. :)

Will keep you updated. At the moment I'm suspecting either one or both of the rear pads being not free enough, or the last remaining unchanged front offside caliper.
 
Best thing is to check all the pads for even wear, then you will find the culprit.

Are the pads all the same size too? I recently did a BMW 1 series, and they have sensors on one side, so the pad is actually bigger and will only fit on the inside of the disk and not the outside.

But like I say, pulling the pads out will sharp tell you which one is causing it. You may just need to seat them better, wire brush down the calipers a bit more in case they are catching. And all should be well
 
Ok if both of the rear calipers are new, are all of the rear pads free and not binding against the caliper themselves. I find that sometimes the pads are a very tight fit to get into the calipers and sometimes a gentle file around the outside parameter means they slot into the caliper perfectly without binding.
 
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