New brake disks without replacing pads... - Will the world explode into a ball of fire?

Dale V · 22 Feb 2018 at 07:35

Id run the pads down a smooth surface of emery cloth to deglaze and straighten them out. You don't want to be putting old pads that have imperfections in them from following the surface of an old disc, as they'll most likely do the same to new discs.

Lopéz · 22 Feb 2018 at 10:34

Acme said:
Just looked up the job, turns out changing the discs on these is a piece of ****.

2 bolts and the caliper is free, 2 bolts and the carrier is free, then the disc falls off.

That's how you change the discs on pretty much anything with a single piece disc.

Gibbo · 22 Feb 2018 at 11:02

Lopéz said:
That's how you change the discs on pretty much anything with a single piece disc.

Yep, he is young so still learning.

Hawk Tuah · 22 Feb 2018 at 11:06

I'd just sand the pads down a bit if they've got plenty of compound left.

Although, realistically I'd change both together, just because for the hassle of getting them out, you may as well stick new ones back in. I guess it all depends on how long you intend to keep / run the car.

Akagi · 22 Feb 2018 at 12:35

Lopéz said:
That's how you change the discs on pretty much anything with a single piece disc.

Gibbo said:
Yep, he is young so still learning.

Not going to deny it.

I've never had to change a brake disk...

Hawk Tuah · 22 Feb 2018 at 13:37

Of course, it's easy in theory. However when the bolts are rounded off and rusted solid - it's a whole different matter.

Lopéz · 22 Feb 2018 at 13:55

I rounded out a hex socket caliper carrier bolt before. Not recommended. Sometimes those bolts are equally easy to cross thread when going back together too, because the caliper is slightly under compression when you put the bolts back in so you need to make sure they are absolutely straight.

Akagi · 22 Feb 2018 at 17:50

Im hoping it should be fine cos they all came off recently to do the wheel bearings.

Howard · 22 Feb 2018 at 21:52

Nothing is more annoying than removing a disc retaining screw if you don’t have an impact driver, and even if you do it’s sometimes awkward.

Phemo · 23 Feb 2018 at 00:40

Yeah retainer screws are a nightmare at times. I've had many disc retainer screws that have been a right **** to get out - no idea why people seem to do the damn things up so tight. When I did my discs last time one of them came out no problem at all, but the other one just rounded off. Managed to drill bits of it out and hammer a larger bit into the newly gouged mess

Sure makes things easier when cars have discs without retainer screws. Or when the screws have been done up normally by someone with a brain.

Diagro · 23 Feb 2018 at 01:44

Acme said:
Wasn't me.

I didn't know they were cheap ones tbh. The fact that one is warped prompted me to flit through the history, and found that they are "Evora" drilled & grooved discs.

A quick Google told me they are cheap eBay tat.

Absolutely nothing wrong with those discs.

They are simply OEM discs that have been reworked.

It's because they are drilled, weakens them.

I run those discs but non drilled versions. Have gone from 70mph down to 10mph very quickly a few times, no sign of any warpage.

Cookeh · 23 Feb 2018 at 07:08

Corollas dont use retaining screws, so one less thing to worry about.

bainbridge · 23 Feb 2018 at 07:37

My cars don't have retaining screws on the discs anymore.

Akagi · 23 Feb 2018 at 07:54

i either dont have any, or theyve been sbapped off in the past. either or

Howard · 23 Feb 2018 at 08:10

bainbridge said:
My cars don't have retaining screws on the discs anymore.

Yeah, funnily enough I've never felt the burning desire to put one back

Akagi · 23 Feb 2018 at 08:27

well when i had the front wheels off i couldnt feel anything moving around, and i still have a knocking noise which goes when the brakes are touched, so im going to look at the back later...

Entai · 23 Feb 2018 at 09:21

Very good article here showing why the common misconception about warped discs is a myth.

http://www.apecbraking.co.uk/Resour...ding-Brake-Judder-and-Preventative-Steps.aspx

Flack88 · 23 Feb 2018 at 09:40

Diagro said:
Absolutely nothing wrong with those discs.

They are simply OEM discs that have been reworked.

It's because they are drilled, weakens them.

I run those discs but non drilled versions. Have gone from 70mph down to 10mph very quickly a few times, no sign of any warpage.

This. Imo drilled disks are a waste of time if the disk is not drilled from factory. Grooved or c cut are more than adequate. I have heard of drilled disks cracking under hard use.

Dogbreath · 23 Feb 2018 at 12:39

Entai said:
Very good article here showing why the common misconception about warped discs is a myth.

http://www.apecbraking.co.uk/Resour...ding-Brake-Judder-and-Preventative-Steps.aspx

It doesn't say anything about warped disks being a myth, because they aren't. What is says is that vibration under braking is most often NOT caused by warped disks.

If reusing pads then I would also recommend you de-glaze and flatten the surface of the pads using emery paper on a flat surface.

Phemo · 23 Feb 2018 at 14:21

Yeah I had vibration under braking on my old car and I never did figure out what it was exactly - I always suspected discs but I was wrong.

My first set of front discs lasted at least 85k miles before I got the brake judder so I replaced the discs and pads and it went away...for 4 months/12k miles or so then it came back. It wasn't really noticeable at town speeds but on the motorway it was pretty bad so I changed discs and pads again and it went away again for a few months, after which I thought I'd try just taking the calipers off, pushing the pistons back in and popping it all back together again. That made it go away for a few months again so in my case it had to be caliper related but I never did get to the bottom of it.