15 replies to this topic

[Will T]

Hi,

I just bought a 90 spec miata. I'm just getting into racing. I'm in the process of changing the rotors and pads and I ran into a problem. After I took off the rear caliper, I replaced new rotors and pads. When I try to compress the rear piston with the hex key in the back the caliper, the piston won't compress. I also tried to turn the piston itself but it did not compress. Any ideas?

Thanks,

Will

[Ron Alan]

If the adjuster is working properly...the piston should suck right in. If the adjuster has been disabled, just use a big clamp and press in the piston. If neither works my guess would be it is in the adjuster...something is broke or missing or you have the ebrake on?

I see your in Dublin...buy the car local? If you need anything or advice I'm in Pleasant Hill...shoot me a PM for a phone number...unless we have already talked and I don't remember..haha!

[davew]

Sounds like you need new caliper.

dave

[DCP]

I'm new to this too and did this this past weekend. The first one I did had no place into which to put an allen wrench so I assumed that the adjuster mechanism had been removed, but the piston would not push in. I called on friends for advice and discovered that the splined adjuster piece into which allen wrench goes can be removed. I found that the other side had an adjuster piece. I used it for both sides

[Will T]

If the adjuster is working properly...the piston should suck right in. If the adjuster has been disabled, just use a big clamp and press in the piston. If neither works my guess would be it is in the adjuster...something is broke or missing or you have the ebrake on?

I see your in Dublin...buy the car local? If you need anything or advice I'm in Pleasant Hill...shoot me a PM for a phone number...unless we have already talked and I don't remember..haha!

Hi Ron,

Thanks for the info. I did buy the car local, from a guy in Castro Valley. The ebrake is off, the adjuster is there but when I turn the adjuster the piston is stationary. When I'm turning the adjuster I sort of feel the gears are grinding. I'll try to clamp it in. If that doesn't work then I think a new caliper is needed.

Will

[Ron Alan]

PM sent. Dave is correct!

[davew]

If the adjuster mechanism is still in the piston, it will not push in. Unless something is broken in the piston. In eaither case replace the calipers.

FYI, save the little adjuster dealie. And the plugs for them. They take up very little room in the spare stuff box. And come in really handy when you loose one. I always save a few.

Dave

[Will T]

Thanks for all of your suggestions guys. I got the piston to retract last night by using a c-clamp to push the piston while turning the adjuster. I guess something isn't working properly inside but the combination of the c-clamp and the adjuster worked. I then worked on the driver side front and rear brakes and had no issues. The adjuster on the driver rear caliper worked properly and the piston retracted easily. Time to bed the pads today.

Thanks!

[davew]

Today is not the time to bed pads. Today is the time to get new calipers and install them. OBVIOUSLY the caliper is not working properly and needs to be replaced.

Please do not put yourself or your fellow drivers at risk by using a bad caliper.

Dave

[fishguyaz]

Today is not the time to bed pads. Today is the time to get new calipers and install them. OBVIOUSLY the caliper is not working properly and needs to be replaced.

Please do not put yourself or your fellow drivers at risk by using a bad caliper.

Dave

dave is 100% right.
funny how much time and $ people put into motors and HP so that they get a thrill when they press on the gas pedal.
ja real thrill is when you go to press on the other pedal and it doesnt work the way it should. when the gas pedal doesnt work, you slow down, when the brake pedal doesnt work, you do NOT slow down. think about it.

its a cheap and easy fix and one that needs to be done, so fix it before it fails. learn this now rather than after you wad your car, and/or someone elses, and end up fixing your brake system, along with all the other damage the failure cost.
your thinking is a false economy especially when a caliper is ~ $125.

only trying to help by passing on what i have learned the hard way a long time ago.

[davew]

Way back in my Pro Atlantic days, I had a driver tell me:

"You will never go fast if you don't trust your brakes".

That is a very true statement.

Dave

[wheel]

Be sure to have that C clamp in the car with you when that brake locks up at 100 mph and pitches you sideways.

[davew]

Look on youtube for Keith Mellens video of what happens when a brake caliper fails. Concussion, and a new car being built. Also tore up an innocent racers car.

I will note that this was not caused by what Keith did, it was a simple mechanical failure that turned into a $20k rebuild.

Dave

[Bench Racer]

Karma

[Will T]

Good point you guys! I ordered a new caliper from O'reilly Auto Parts. The cool thing is they charge $65 for the caliper but the core charge is $72. So they pay me $7 to get a new caliper...What a deal!

[Ron Alan]

Ahhh...I think its $65+$72 if you dont have a core! But I'm sure you new this and are just kidding You can get one that works from me for 1/2 this!