I recently started having a lsight stick from the front brembos. I started investigating when i was told my brake light was sticking on. Anyway after this is looked at the disc and pads and noticed one side of the pad on drivers side was far more worn than the other. I cleaned the caliper up and re greased and all pistons move freely (with my hands pushing them in) i rebuilt and seemed to work but this has not fixed my brake pedal as i noticed that it doesnt return all the way to the top, hence why my brake light is sticking on

Any ideas

 

Car make/model?

If caliper pistons are clean and smooth, must be a master cylinder issue?

I doubt the switch is on the pedal, most are located in the pressurised portion of the brakes somewhere on the master cylinder. This gives a WAY more accurate brake light response, since the physical position of the pedal may or may not relate to braking force being applied.

 

I suppose what I said totally depends on how old the car is, I just realised its a Focus RS!!

EDIT: A little research now has shown you probably do have the brake light switch on the pedal, and not a pressure sensing type. This makes looking at the master cylinder worth while, I think.....

 

yes it is a focus rs. The pedal on my ST170 shoots up after pressing wereas this one sometimes needs flicking up with the foot to full disengage the brakes.

Switch is on the brakes and can feel its not quite pushing the barrel of the switch in.

 

Pretty sure you need to check the master cylinder. Could be something else silly, but really can't think of anything inbetween.

The issue with the one pad, on one side wearing more than the other, definitely sounds like the sticky piston (which you've sorted, and noticed it was sticky when you looked at it, yeah?) If this piston is DEFINITELY no longer sticky, and no others are, then I suppose it has to be the master cylinder and this single caliper is simply an additional issue caused by a lazy cylinder return.

Hope you get somewhere with this, annoying problem for even simple driving.

 

I'll update any progress

 

have you checked that the brakefluid level is spot on?aaand that the level sensor is not sticking..?

 

Ok still got this problem. Its not the switch and it doesnt seem to be the servo as the brake actually work spot on and hold pressure very well. Its just the pedal isn't returning quite to the top an I need to flick my foot under it to take lights off.

I've only changed the brake pads so far and bled the brakes twice.

 

sounds like the gap between pedal and switch is too much could be switch adjustment or the bar between pedal and mastercylinder

 

So a full inspection and reinstating of the brakes has them working perfectly?

Although adjustment of the switch/pedal may sort the light issue; if the pedal has changed position over time, and doesn't return to where it used to, then there seems to be an initial fault, and the light/switch issue is just a symptom of this.

You have to bear in mind, simply because the brakes work well, doesn't necessarily mean you don't have a return issue.

 

Yeah well something is obviously slightly out. My ST pedal (170) hits the roof no probs when i release from the pedal. This one is like 2-3mm from its highest point and although its touching its not pressing it enough hence the light.

Just dunno what to look at next

 

Well, in all honesty, fuck it; if the brakes DEFINITELY aren't dragging, and show ZERO problems upon a very close strip-down inspection, then simply make adjustments those few mm to allow the light to work as it should.

If you do this, keep one seriously sharp eye on the braking system afterwards.

How many miles on that peddle assembly/car?

 

think around 70k on car but 30k on engine


its pissing me off now. its like its just not returning properly. im not 100% they not dragging but its drivable with no probs apart from light

 

I was hoping it was a little higher than that, in order to blame/look at pedal assembly for excessive wear.

You gotta be 100% to do the switch adjustment. This is brakes after all, am I am certain there is a return problem somewhere.

What a bitch. No local 2nd pair of eyes for a second view?

 

Are you certain there isn't some dirt, or a burr/damage or ANYTHING on the pistons?

 

In fact, scratch this.

Jack it up... check it right out for dragging. Take it for a spin, do some medium braking, jack up check again. A RIGHT check.

If all clear, adjust the switch.

If the light stays off when you lift the pedal with your foot, then it should be cool. You're possibly dealing with pedal assembly wear issue, or similar.

 

Cheers for all the pointers. I'm gonna get my step dad have a look when he's free. Ill point out all these things and post back when sorted hopefully

 

NP.

Nice.

 

clamp the flexi hoses on all four corners this will eliminate the calipers being at fault if it still occurs with them clamped

 

how you mean?