New Brakes Binding - Options

[Lewis's Friend]

Hi all, a quick question for the collective intelligence...

I have just fitted new brakes to my MX5. The calipers/carriers have just been refurbished by BiggRed, and I have fitted new EBC Ultimax Discs with Greestuff pads front and back.

Now my problem is that even with the pistons wound/pushed back as far as they will go, the calipers with the pads fitted barely made it over the discs. This has had the effect of binding up the brakes to varying degrees. The backs are a little tight, but the wheels can be rotated by hand with a bit of effort. The fronts require quite a bit more force to turn the wheels.

How much of a problem is this? Once the car is in a fit state to move, can I just run it around the block a few times, and in a flurry of brake dust will they just bed themselves in and everything be fine? Or could this lead to excessive heat, and warping of discs etc?

I'm not quite sure what I could do differently in any case really, but I don't want to ruin brand new brake parts...!

Any thoughts welcome.

[GreenV8S]

I would stamp the brakes good and hard to make sure the pads and pistons are seated against each other fully, and then take it for a slow 100 yard drive and see whether it freed up. Any noticeable drag will burn the brakes up very quickly in normal driving, but given that it did fit together OK I assume you have the correct parts in which case the problem should go away very quickly. If the brakes keep dragging I'd double-check the rotor thickness against the originals, make sure the calipers slide freely and check for any paint/anti-squeal shims on the back of the pads that could be removed to get a fraction more clearance.

[HustleRussell]

I've seen your thread OP

Your discs (Black Diamond or similar?) have a protective coating on them, upon first application of the brakes that coating will disappear in a cloud of dust and your pads can then begin to bed in. Until that coating is gone your brakes are going to feel draggy when you turn the wheels by hand.

P.S. I fitted black diamond discs and pads to my first car. It was actually the first job I ever DIY'd. Full of pride and enthusiasm to test my new brakes I set off down the hill from my driveway to try them out. Once I'd reached a suitable speed I applied my brakes, expecting to be met with the proverbial brick wall. Instead, two clouds of black dust were emitted from the front wheels and there was in fact very little retardation

Edited by HustleRussell on Wednesday 28th February 12:52

[one eyed mick]

Dis you back the rear caliper / hand brake adjustment off!

[Lewis's Friend]

Cheers for the feedback all.

I have no brake fluid in it at all yet, so probably a good shout to get the brakes bled, allow it all to seat etc and see how they are after a quick spin. My concern was mainly around the offside front, which is really tight! But as you say, it may well free up after pumping the brakes/getting the protective coating off.

The handbrake has been adjusted right back, don't worry! The offside I was able to set as per the handbook (adjust in until the wheel won't turn, then back off a 1/3 of a turn), but the near side was a bit tight even wound fully back.

As said though, probably best to recheck after bleeding the brakes and testing etc.

[HustleRussell]

P.S. Those drilled and grooved discs are basically 100% gimmick especially when coupled with road orientated pads.

[Martin350]

Are the pads too tight in the calipers?

There have been times I've had to file at least some paint off of areas on the pad backing plate where they are simply too tight to move freely in the caliper.

[Lewis's Friend]

Martin350 said:

Are the pads too tight in the calipers?

There have been times I've had to file at least some paint off of areas on the pad backing plate where they are simply too tight to move freely in the caliper.

I've had this issue before too, but to be fair, on these they slide nice and cleanly. It may just be newly painted calipers, with new coated discs and brand new pads have just given it that little bit too much thickness.

[Lewis's Friend]

HustleRussell said:

P.S. Those drilled and grooved discs are basically 100% gimmick especially when coupled with road orientated pads.

They came as part of a package from MX5Parts, which was the main reason I went for them...!

[Dave Brand]

If everything else fails, just lay a sheet of abrasive paper on a flat surface & take a light skim off the pads. After doing that it's probably a good idea to give the pad faces a brisk wirebrushing to ensure that they haven't picked up any grit, which could damage the discs.

[GreenV8S]

Lewis's Friend said:

They came as part of a package from MX5Parts, which was the main reason I went for them...!

Unless you're paying thousands for steel or ceramic rotors, your discs will be cast iron.

Drilling cast iron discs is a bad idea from a performance point of view. If your pads are getting hot enough to need degassing then the holes will accelerate thermal fatigue cracking of the rotor. If they aren't, then the holes are giving no performance benefit and just increasing pad wear, dust and noise.