Brakes staying on a bit after disc replacement

[Jodieboulton1987]

Hey all , I’ve just replaced all my discs as my MOT is coming up & I had an advisory last year that ‘Brake disc worn, pitted or scored, but not seriously weakened’ so even though I’ve only done 3k since last year I thought I best change them as it would like be a fail not an advisory this time . I did the pads last year for the MOT so they still have plenty of thickness left on them given that It hasn’t done much mileage.

So basically after fitting all the discs I took it around the block to test out the brakes. It was running fine, then when I braked at the roundabout I noticed I could hear slight grabbing. I drove about 30 seconds back home & there were wear rings on all the discs & they were warm considering I only broke once for the roundabout. It’s as if when when I depressed the brake the piston hasn’t retracted properly.

So jacked the one back wheel up, spun the wheel and was resistance. So took the wheel back off, removed the calliper to check the pads were located correctly and free of any debris that would cause the discs to mark. They were fine, took lid of brake fluid reservoir, wound the piston back In and re assembled. Spun the wheel , all good, lifted handbrake , whee didn’t turn , fine, released handbrake, spun the wheel all fine no resistance, pressed the brake pedal then tried to spin the wheel and it went about 2 spins and could hear it grabbing.

Does anyone know what could be causing this, there are wear rings on all the discs, which would be coincidental that all the pistons are playing up, when they were done before. Any help would be appreciated.I’ve uploaded some pics of the wear rings being caused on the discs& a few ‘during’ pics to see if anyone can see anything obvious that could be causing it. Also apologies if this has been discussed before. I did have a quick look but couldn’t find something the same.Thanks guys.

 

[JOG]

Older pads “bedding in” against new discs?

 

[Donk]

New discs will be thicker than the old and on top of that, did you fit new pads? Should’ve really. But the extra thickness will mean more of the calliper pins will be moved and also the pistons. Calliper slide pins corroded, not rusting and lubed? Same for the pistons? Those sticking could cause this.

 

[JOG]

New discs will be thicker than the old and on top of that, did you fit new pads? Should’ve really. But the extra thickness will mean more of the calliper pins will be moved and also the pistons. Calliper slide pins corroded, not rusting and lubed? Same for the pistons? Those sticking could cause this.

Yep, I always change the pads when doing the discs too rather than having "old" bed in with "new"

 

[Steved55]

From my experience it will almost certainly be the caliper pins sticking. Take them out , and either clean and lube or replace

 

[Mud Digger]

And reduced breaking as not much pad touches the disc when breaking only the high spots should at least reface the pads if they are fairly new

 

[Jodieboulton1987]

From my experience it will almost certainly be the caliper pins sticking. Take them out , and either clean and lube or replace

Thank you Steved55, so the calliper pins are those these little rubber boots or just the pin inside.

 

[Jodieboulton1987]

Older pads “bedding in” against new discs?

Quite possibly

 

[Deaky]

Thank you Steved55, so the calliper pins are those these little rubber boots or just the pin inside.

View attachment 148297

The pin inside.

 

[Jodieboulton1987]

Yep, I always change the pads when doing the discs too rather than having "old" bed in with "new"

Your right, I should have, well I should have changed the discs last year when doing the pads really but I didn’t realise they were in need of replacing, live & learn lol .

Yep, I always change the pads when doing the discs too rather than having "old" bed in with "new"

Your right, I should have, well I should have changed the discs last year when doing the pads really but I didn’t realise they were in need of replacing, live & learn

And reduced breaking as not much pad touches the disc when breaking only the high spots should at least reface the pads if they are fairly new

that makes sense, thank you
.

New discs will be thicker than the old and on top of that, did you fit new pads? Should’ve really. But the extra thickness will mean more of the calliper pins will be moved and also the pistons. Calliper slide pins corroded, not rusting and lubed? Same for the pistons? Those sticking could cause this.

Will try lubing the piston up & may replace the calliper pins and lube them too. Thank you

 

[Mud Digger]

Your right, I should have, well I should have changed the discs last year when doing the pads really but I didn’t realise they were in need of replacing, live & learn lol .


Your right, I should have, well I should have changed the discs last year when doing the pads really but I didn’t realise they were in need of replacing, live & learn

that makes sense, thank you
.


Will try lubing the piston up & may replace the calliper pins and lube them too. Thank you

Not to much lube / copper slip on the pistons or anywhere it could run onto the pads or disk
not sure how runny copper-slip spray is compared to copper grease if the pins are dry and rusty just rub down with emery cloth and lightly lube plus brake dust and grime will stick to any oil surfaces

you could paint your calipers while you got them in pieces lol

 

[JOG]

I did think it was an ideal opportunity to give them a lick of paint!!!

Not to much lube / copper slip on the pistons or anywhere it could run onto the pads or disk
not sure how runny copper-slip spray is compared to copper grease if the pins are dry and rusty just rub down with emery cloth and lightly lube plus brake dust and grime will stick to any oil surfaces

you could paint your calipers while you got them in pieces lol

 

[Mike23864]

Did you degrease/clean the new discs?

 

[Pete C]

If it was my van, I would just take it for a drive and do some heavy braking to get everything bedded in.

Pete

 

[DaveD]

If it was my van, I would just take it for a drive and do some heavy braking to get everything bedded in.

Pete

I'd just give it to Mrs D and tell her to drive normally, she gets through tyres and brakes like an F1 driver.

 

[JOG]

I'd just give it to Mrs D and tell her to drive normally, she gets through tyres and brakes like an F1 driver.

Cheaper than a gearbox!

 

[Gavinda]

Could be the piston seals, did the pistons retract OK when you wound them back in?

 

[Jodieboulton1987]

Not to much lube / copper slip on the pistons or anywhere it could run onto the pads or disk
not sure how runny copper-slip spray is compared to copper grease if the pins are dry and rusty just rub down with emery cloth and lightly lube plus brake dust and grime will stick to any oil surfaces

you could paint your calipers while you got them in pieces lol

Yea a lick of paint wouldn’t go miss . Managed to do it earlier on, I bought grease, Proslip grease, contained 3 different lubes, one for the pins, one for the clip (that the pad sits in) & one for the back of the pads. I removed cleaned & lubes the slider pins and brought the pistons out by gently applying the brake & lubes the piston before winding back in. It’s done the job. No grabbing at All. Thank you all for your help guys, just for the MoT now .

 

[Jodieboulton1987]

Could be the piston seals, did the pistons retract OK when you wound them back in?

Yes they went in ok but I neglected to lube them up. After lubing the piston, slider pins , back of the pad & the pad clip it’s all running as it should . Thanks for the reply

 

[Jodieboulton1987]

Did you degrease/clean the new discs?

I did not , update though, after lubing the piston, calliper pins, back of pad & pad clip it’s all working lovely now. Thanks for the reply