brake adjustment on Miata

[headsup]

Help. I just repaced rear pads in my 1.6 '90 miata. Followed instructions from the web "back off 1/3 turn once pads touch rotor. Brakes are locking up way early. I must have done something wrong.

Hate to head off to Tremblant with a problem that can't be fixed trackside. Any suggestions?
Thanks

Brian Springmann

[WillM]

Hi Brian,

Are the fronts or the rears locking up early, or both?

Doesn't sound like the rear caliper adjustment would be to blame, but here is my fool-proof method:

Jack the car and get the car supported with both rear wheels off of the ground.

Take off the rear wheels.

Put the transmission in neutral, and release the parking brake (if you have one).

You should be able to grab the hub by the wheel studs, and rotate each one. There should be some friction. This might be a good time to calibrate your arm. I only use the "1/4 turn back-off" as a guide, and set the final position by feel.

Pull the 14mm cap off of the allen screw adjuster. Unwind the allen head until the rotor spins freely. Tighten the screw a bit, and try turning the rotor. Keep doing that until you can feel a slight drag of the brake pads, and it takes a little muscle to turn the rotor. Keep in mind that a 1/4 turn is A LOT of adjustment.

Also keep in mind that if you are installing new pads, there are likely high spots on the pads which will quickly get knocked down as the pad brakes in.

[headsup]

Thanks Will.

It is just the rear with new pads. I pretty much had done just what you described. After the first test drive, I backed it off a little more and I think it improved a bit. I'll try it again.

As you suggest, it may be high spots, which will get knocked down with some use.

Do you think it would be prudent to buy an extra set of rotors to have on hand? They looked fine, but I'm no expert.

Thanks again for the input. If there's any precautionary efforts such as the extra rotors, let me know. I'd rather have the insurance on hand when we're away.

[Mark Swinehart]

Buy a Nissan.

[breakaway500]

I didn't think Miata drivers used their brakes...

[Stynger]

"The rotors looked fine" I take it you replaced the pads with the same compounds you took off?

[paultg]

The first time I did this (and followed internet guidelines) I screwed it up as well.
I had changed pads & rotors, brakes lines, and all new fluid at the same time. Before starting or driving the car I finished up by bleeding the entire system, then adjusted rear caliper brake pad setting, putting the wheels on, and went for a drive. For some reason everything felt find before going for the drive, but once I started the car and drove the car, used the brakes, I quickly realized the adjustment was wrong (like the first time I stopped and a cloud of smoke blew forward from the back of the car!).

Now I make sure I start the car and pump up the system before adjusting the rear calipers (even if I do nothing with the fluids or lines).
I follow what Will described above in terms of adjustment, and I also find that the e-brake handle itself should click about 6-7 times when pulled up (if things are adjusted correctly). I only use that as a guide cause the cables could be stretched from age, etc.

[CP]

I set mine to 1.5 turns out with Hawk Blues. It takes about half a lap for them to self-adjust. Never had a problem with rear lockup or smoked rear pads in two seasons of racing. YMMV.

[paultg]

Did this again today and still messed it up. No pads dragging, but the opposite. I must have backed the allen screw out too much, the ebrake barley works now.
I'll have to try to adjust it again tomorrow.