Nickamsweet

Basically when the car is cold the brakes don't vibrate much but once they are slightly more warm they start to have a vibrating issue only when the brake pedal is applied. It's as if the pedal is being put on then put off again even though the brake pedal pressure I have applied remains constant... Also if I have just used the brakes a bit harsher then it can vibrate for a while (same kind of thing as a wheel unbalance vibration) as if something is sticking/pulsing...

I have taken apart the rears so far to lubricate and clean up everything so it works smoothly and plan to do the same to the front systems tomorrow to see if it helps at all...

Would it be a seized caliper issue? ABS module/sensor problems? The condition of the pads are within specs and the discs themselves seem to be within the correct limits too... or could it be 'warpage'??


Thanks for any help,

Nick

ronnuke

Sounds like warped rotors to me.

SpitfireS

Get the brakes to do what you describe, go home and raise the rear.
Rotate the wheels by hand.



This is my MY'00 rear caliper.
It needed a rebuild (seals only)

Nickamsweet

Would the seals being damaged cause fluid loss from the reservoir?? Did you have similar problems with your car then or not??

4forall

it also could just be uneven buildup. depending on your driving style and stopping habbits. you can sometimes deposit more pad material onto one spot on the rotors.

this would explain the pulsation as well as the intermitten issue.

after you lube everything and visually check all the brakes i would recommend doing a few hard ~65 to ~15 slow downs. do not come to a complete stop. this is the same process used to bed in new brake pads and rotors.

what this does is allow the pads to make several hard force revolutions completely around the rotor. thus cleaning off the high spots of deposit.

if the problem still persists then i would look into getting your rotors turned or replaced.

this is all of course dependant on if your seals are bad like SpitfireS has pointed out.

Nickamsweet

Cheers for all the help.... just finishing off the fronts now then will do the 65-15 slow down a couple of times and see if that helps, if not then I may put it to a garage to see if they can source the issue easier... Could simply be rotor replacement but don't wanna spend the money to find out it's not the issue

Will get back to you in a couple of hours

Nickamsweet

Just completed the fronts and they have significantly improved!! However it still seems like there is some sticking of the pad and after the harsh braking the right front wheel seems a lot hotter than the right wheel. Think it could be due to slight piston seizing as at low speeds (7mph) and the brake pedal is released the car seems to brake at certain rotation on the disc... and un-naturally slows to a stop...

Would it be a seized piston or built up deposits on the brake disc itself causing this braking? Is the best way to check irregular thickness using a dial gauge?

4forall

or a pair of electronic calipers would do the trick.

it could be a weak seal in one of the pistons thats not allowing to acctuate at the correct speed/distance of travel.

another thing to consider beyond rotor warping is wheel bearing. if you have one thats bad its causing the hub to slightly wobble and that would create the situation you explained with the low speed braking with the pedal released.

I kno it feels like diagnostic hell but with over 100k miles things just start to go. My DD is a 93 civic Si with 200k on the clock, it gets frustrating trying to find all the little wobbles/creaks/problems lol.

Nickamsweet

^^ haha I know what you mean... mine is 70k with 7k on the engine (oil starve) so spending more money on her is always a PITA... just hoping that it will be a relatively cheap fix (below £150) so I can get on with ordering my shiny new BuddyClub N+ coilovers

Nickamsweet

Just refrained from using the brakes for the past 2 miles with the use of engine braking and finally the handbrake on my drive and all the wheels minus front left (passenger side (JAP SPEC) ) are cold... it seems that the front is definitely holding on somehow so will strip down the caliper tomorrow and investigate into possible seizing/restrictive movement and see how that helps...