brakes & rotors

[black roadster]

On the grease, get some high temp grease at an autoparts store. The grinding is likely due to the slider pins needing grease. Also likely why your rotors went so quickly.

[rudedog]

OK, I finally got the rear caliper to swing up after prying.
It is tight.
I have polished the lower pin and found the outer pads to be great and the inner pads are gone completely.
But how the heck do you get the top pin apart to clean and lube it?
It is very tight.
TIA.

[rudedog]

OK, after soaking in BP the caliper finally came off.
With the busing that is supposed to be in the caliper still frozen to the pin in the bracket.
That was the only brake pad with any wear but the inside of the left rear was metal to metal and that disc scored.
I went ahead and replaced all rotors and pads anyway but the left rear.
What do I do? Buy a rebuilt caliper and a brake bracket?
Any way you've seen to repair this?
BTW, I have a nice set of three very good brake pads and three good rotors if anybody is in a fix.
Last of all, when I removed the front pads the "M" clips fell out and I don't find anywhere that these are addressed. I pulled directions off Miata.net and nothing.
I have Keith's book and was looking at it two weeks ago and now cannot find it. Bummer.
Are the front brakes all right without the "M" clips?
I have not reinstalled the wheels yet just in case.

[rudedog]

Apparently one of my rotors was cahnged in a past life.
Anyway I took the bracket to work and this morning it was repaired, a lathe ran over the pin, polished, and I'll re-install this afternoon.
But, I still have those pesky "M" springs and missing one "V" spring in the rear.
What to do about those?

[sammm]

But, I still have those pesky "M" springs and missing one "V" spring in the rear.
What to do about those?

You can order the brake hardware alone from Trussvile (or such).

[MadMerv]

The 'M' springs mount just on top of the stamped sheet metal insert between the caliper and the pad tabs, with the middle of the 'M' facing the same direction as the tongue on that piece. The ends of the 'M' go into the holes on the top of the pads. A caveat: I once got a set of pads(non-OEM) that didn't have the holes, so maybe that is why you can't figure where they go.

You can run without these (and the rear) tensioners, but you might get some rattles and the pads might wear a bit quicker than without them, as they are deisgned to minimize the pad pressure on the rotor when the brakes are not applied.

The frozen pin problem on the rear has been around since day one(1989) and the result is just as you described: Inside pad down to metal and outside just fine. It's almost always the right rear. My first Miata had the problem at only 30K miles, and showed some rust, indicating moisture getting past the rubber boot. I have a 93 in the barn that has one frozen now. You can buy new pins from Mazda.

[rudedog]

Maybe I need to clarify which springs I'm talking about so I don't go crazy

Rear brakes:
On the rear there is one "M" spring on each side. Thin wire type spring. One of thoise is missing and the other is weak. When I removed the one the spring just stayed pushed together. Very old and weak I guess. I don't see it is doing anything as is and the other is AWOL. I understand I can run without these. Correct? I have had a rattling at the rear I could not find. Maybe that is it? But do they push apart or pull the pads together. I cannot tell since there is no pressure from the one I have.

Front brakes:
On the front I repaced the 2 per side "V" springs that went into holes in the top of the pads and they pushed the pads apart. Again, thin wire type springs. But, another "M" shaped piece with a small arm fell out that I did not see where it came from. And yes, on the second one I was trying to spot it but it fell from somewhere before I saw it''s original location. The piece is like a eighth inch wide and a heaver clip type thing that has a "M" shape with a short straight part sticking out with a small bend at the end like a clip. I don't see how this could go in a hole anywhere. It looks like it clips over something but I cannot find anywhere that's the same width as the clip? Can I run without these? I have both at home and would like to raise the caliper while it's on jack stands and insert it if I knew where it went.

BTW, I called Trussville and they showed a hardware package for the brakes at $3.87 but was not in stock. In addition they showed no interest in ordering it as he just told me the shipping would be more than the part and I felt like he wanted me to hang up. So much for that. I also wnated or hoped the rubber seals would be in there because once I let the BP Blaster hit them they came apart real quick.

I will say that the $15.58 rotors look outstanding but the proof is in the pudding.

I found Keith's book and looked at it, the Chilton manual, and the Miata net directions and I cannot find anything about this clip spring piece. Strange.
Thanks, and I should have gotten MME help from someone who has done this.

[channelmaniac]

Yes, you will hear a rattling sound when going over bumps without those installed... If you lightly press the brake when you go over bumps and you notice that the sound is gone then that is the problem.

I had that on my 92 blue.

RJ

[MadMerv]

Sorry, I must have been half asleep when I wrote that! What can I say, I've got "OLD TIMERS"! The springs PUSH the pads apart. You're right, the "V" or "U" ones are the ones that fit in the holes. The "M" springs set in a little groove near the top of the caliper (wish I had a picture as it is hard to describe). Yes, you can run without them.

[rudedog]

Thanks, and yes there was a rattle somewhere out back and when I lightly pressed the brake it went away.

[rudedog]

OK, I'm to the point of giving up on my 92.
My brakes sound like something is scrapping when I drive the car. Like metal to metal.
I have replaced all pads and installed new rotors. I do not have the rear "M" springs installed as they were AWOL.
I repulled the rear wheels and looked everything over and even pried the shields a little further away.
I went to the extreme of running the car through the gears while on four jack stands and nothing. All seemed well.
I spun the tires by hand and nothing.
I am no expert but I have done brakes many times before and never anything like this. I'm afraid to drive it anywhere to have it looked at.
After the wheels were re-torqued I lowered the car and as soon as I started to back out of the garage there was that grinding sound so I parked it again.
I'm desperate. Any ideas out there or anybody close to The Colony who has done these who can take a look. Sorry for the trouble but I need to get this out of the way so I can get that roll bar ordered.
TIA.

[POS Racing]

I don't see any mention of adjusting the rear brakes with an Allen wrench, did you adjust the rears out to get the new pads in, then adjust them to just where they are touching the rotor??

[rudedog]

Yea, sorry about that. I had it posted earlier in this string but forgot it.
Yes, the allen insert/screw was backed out, pads and rotors installed, screwed in until it touched and stopped the rotor, and then I backed it off 1/2turn instead of the 1/3 suggested after the initial scrapping noise.
What am I missing?
I know I stood the new rotors up beside the old ones and they were a match but I'm near removing everything and doing it again.
BTW, this noise was my initial sympton that lead me to replace everything.

[POS Racing]

Another thing could be you have excessive grease on the slider pin, can you push the caliper all the way in until it bottoms out??? I loaded my old '92 up with grease and the grease actually pushed the caliper out, but I noticed it pretty quick since I couldn't quite adjust the rear brakes.

I'm sure you have read this write up a few times.

[rudedog]

I did put a lot of grease on the pins.
I will try and remove some tomorrow as I get up at 5 so it's off to bed now.
Would it sound like metal scrapping with new OEM pads?

[POS Racing]

Would it sound like metal scrapping with new OEM pads?

Noises are a tough thing to diagnose on a Forum. You may hear the pads rubbing the rotor.

Ya sure ya don't have one of the slider clips coming in contact with anything do ya?? (See figure 4)

[sammm]

If the M springs are MIA wouldn't that cause the pads to drag on the rotors?

[MadMerv]

Sounds like you're doing everything right. New pads should not do that. Someone who is close needs to look at them. I would take it out and jump on the brakes rather aggresively, but not lock them up, and see if it goes away. You obviously had a frozen caliper the first time, so it shouldn't be the same sound. Are you sure it's coming from the rears? Was there any rust on the rotors from the rain (Yes, some of us got some last weekend!)? That would do it, but it would go away quickly. Maybe it's a wheel bearing you're hearing, but you should feel that by slowly rotating the hub. If it didn't do it running on jack stands, I would think it is in the front. Wish I could be of more help.

[rudedog]

Thanks to all so far.
I also spun the fronts and nothing.
I can tell it is from the rear and it sounds like metal to metal. That's the reason I thought it was the inside pad that was all the way worn down making the noise when I took it apart.
But I have exactly the same sound now.
I pulled and rocked on the rear wheels and did not feel any loose play which would indicate a wheel bearing.
What gets me is why only when it is on the ground. I did not move any suspension bits so I don't see how all of a suddem I have interference.
I hate to do it but I think a shop will be in my future this afternoon. I need the car badly right now to work on the Vette.

[POS Racing]

But I have exactly the same sound now.

Can you describe the sound with a bit more detail?? Is it like loud metal grinding, or the sound of brake pads lightly touching the rotors??

I'd put a couple miles on it and see what you got, but that's just me.