Swapped Discs/Rotors now having a grinding noise, as per title Options

[Tuga2112]

Hi All,

If this is not my first post, it will be the first in a few years, Recently bought my Second 6th Gen Celica, a GT4 to upgrade my SR

I have swapped all the discs on my ST205 recently, took it for MOT and i noticed it is making a noise on some (possibly all) of the wheels, i think the sound is from the pads rubbing on the discs, the wheels spin without any considerable resistance.

I have been wondering if i did something wrong when fitting the discs. so here is my procedure.

take everything out.
push pistons back in the callipers
very light amount of copper grease is added on the "ears" of the pads, (so they can slide easier in the callipers)
also added a tiny amount of copper grease on the little U shaped bushings where they contact the calliper (on the other side, the pads have grease)
fitted the new discs (note i am using the old pads because they still have plenty to give)
retrofit everything.

Now this is the same procedure i have used when fitting discs on my parents Saab as well (with a small deviation as saab brakes dont have bushings, although they have some odd shaped springs) and their car is making more noise than mine.

The callipers on my car have been refurbished as part of the job and they have new square cut seals so i dont think there is any problem with the retracting of the pistons.

Im assuming im missing something very obvious, but from the youtube videos i checked there's nothing missing.

any ideas ?

[richee3]

Did you check and grease the slide pins in the calipers? I'd bet that is your issue.

[Bitter]

But DO NOT use the same 'copper grease' on any parts in contact with rubber!!! Use only silicone greases on those parts or brake slide pin specific grease.

[Tuga2112]

Did you check and grease the slide pins in the calipers? I'd bet that is your issue.

Thanks for the tips guys,
I recall the rubber in the slider pins appeared in good condition, i did not check these further mainly because I dont know how to check to without taking them apart. Also I have no idea how to put them back in, are the sliders something straight forward to reassemble ?

Im not a complete novice around cars, maintaining my 25 year old lotus elan has given me quite a bit of practice, but with the GT4 I am a bit extra carefull, so any input is welcome.

But DO NOT use the same 'copper grease' on any parts in contact with rubber!!! Use only silicone greases on those parts or brake slide pin specific grease.

Thanks for that as well, fortunately I have learnt that lesson already without causing any damage to my other car in the past. Its always worth re-iterating that detail since taking stuff apart to swap rubber seals for an MOT failure is a hell of a pain