Brakes not releasing completely

[kis]

If the callipers are sticking then just take out each pin individually, clean, apply red rubber grease and reinstall.

Never greased myself but was considering until I stumbled across this:


source: http://www.bimmerfest.com/forums/showthread.php?t=398500

Whats the consensus? Grease? With synthetic only? No grease?

 

[Scooba_Steve]

I imagine this refers to usual greases that are not compatible with rubber. RRG won't do any harm - I'm usually one for sticking to what the book says but not in this case!

 

[Smartbear]

If the callipers are sticking then just take out each pin individually, clean, apply red rubber grease and reinstall.

Never greased myself but was considering until I stumbled across this:

do_not_grease_slide_pins.jpg
source: http://www.bimmerfest.com/forums/showthread.php?t=398500

Whats the consensus? Grease? With synthetic only? No grease?

I think that’s referring to the installation of the pins, the reason being that greased threads alter the tightness attained compared to a dry thread, even if using the same force (torque)
Once installed with dry threads I would definitely grease them to stop wear/dragging calipers
Rob

 

[kis]

I imagine this refers to usual greases that are not compatible with rubber. RRG won't do any harm - I'm usually one for sticking to what the book says but not in this case!

I think normal greases can go gooey with time and heat? I will take a look into red rubber. Is this a synthetic type grease?

 

[cj10jeeper]

Ok here's the update with pics and a couple of questions.
First off, with a slight push the car moved normally this morning. No signs the brakes were slightly on.
Could they have possible opened up overnight?
Would this be indicative that the pins need lubricating?

Removed all wheels and checked pads and discs.
All pads had a fair bit of meat on.

FRONT
I put new Front discs and pads on exactly 2 years ago.
Front discs easy to move by hand. Offside pads touch the disc ever so lightly, just enough to hear and feel it when turning the discs
by hand.

Should the pads completely clear the discs when the brakes are off?

REAR
I could turn both rear discs by hand but the pads are coming into contact with the discs and
I could hear and feel slight resistance when turning discs by hand but they are still pretty easy to turn.
The rear discs haven't been changed there's about a 1.5mm wear into the rear discs on both sides which can be seen in
the pics.

What are the rear disc thickness specs that show they need changing?

IMG_639s4.JPGIMG_6398.JPGIMG_6406.JPGIMG_6403.JPG

Regards lubricating the pins, is the pin with the arrow in the pic the pin to lubricate?IMG_6396.JPG

IMHO your chasing a problem you don’t have. By very nature disk pads are designed to rest on the disks. That’s how they work. There’s no mechanism for them to retract from the disk.
If you can turn disks by hand you have no problem
Just drive it and next time you stop, check the disks. If they are all warm then fine. If one is very hot compared to others then there is you’re problem. You would however smell it while driving more than a few miles

 

[DMC63]

Wow, lots more to consider..cj10jeeper, I've not had the problem happen again since but it was definitely a case that the car would be stopped by the brakes where it would normally roll freely to a standstill. I will keep a close eye on this situation and this thread which seems to be kicking up some very interesting brake related info.

 

[Smartbear]

Wow, lots more to consider..cj10jeeper, I've not had the problem happen again since but it was definitely a case that the car would be stopped by the brakes where it would normally roll freely to a standstill. I will keep a close eye on this situation and this thread which seems to be kicking up some very interesting brake related info.

Are you 100% sure it’s not the hill start assist you noticed? It can feel very unnatural on sloping ground :?
Rob

 

[Ducklakeview]

The caliper seals actually relax slightly when the hydraulic pressure is released. THIS is what gives the brakes "working" clearance. Old and tired seals do not perform as well and can sometimes not pull the pistons back enough.

Mike

 

[cj10jeeper]

The caliper seals actually relax slightly when the hydraulic pressure is released. THIS is what gives the brakes "working" clearance. Old and tired seals do not perform as well and can sometimes not pull the pistons back enough.

Mike

For sure Mike, but this is minute movement and on good condition calipers. If the brakes aren’t heating and they can all be rotated freely by hand (as op’s do) then they are working well enough. Alternative is refurb or replacing one or more that just becomes and expensive excercise for limited benefit.