Rubbing brake pads

umcamara · Post by **umcamara** » September 26th, 2007, 3:09 pm

I've completely diasassembled my front calipers. Cleaned thoroughly and installed and greased new caliper pins & sleeves, and pad springs. Pistons are not seized, and calipers are able to float on pins. Pads are evenly worn on both sides of rotors.

Problem is when driving or when I spin the front wheels with car on jack stands, there's quite a noticeable rubbing noise, and the wheels do not spin freely (Car is in neutral of course). Not only is the rubbing noise annoying & embarrassing while driving, but I'm sure it's slightly hindering fuel economy and performance.

When I rebuilt the calipers I pushed the pistons in with a C-clamp, put the wheels back on, and spun the wheels. They spun perfect, no rubbing at all. But once I stepped on the brake pedal at least once (which pushed the piston out again), the rubbing came back. This is how I know that it's not the brake dust shields rubbing against the rotors (besides, I removed those).

I guess my question is, is this normal, does anyone else experience this same issue? Any ideas? I feel that I've covered every angle.

94mx3precidia · Post by **94mx3precidia** » September 26th, 2007, 6:40 pm

Are you sure that you have pushed the clips that go between the caliper and the break pads all the way in? ive heard stories and i personally have troubble with my clips rubbing against the rotor on my back end.

Tunes67 · Post by **Tunes67** » September 26th, 2007, 6:54 pm

Sounds like your the pad springs arent pushing the pads back away from the rotors completely after you release the brake pedal.. This is happening with both sides? Possible there is still some air in the brake lines preventing the calipers from returning to full open? Just a couple of ideas. Not an issue I have had with either of my MX-3's to date. So I would have to say "No" to your question of it being normal or not.

Tunes67

umcamara · Post by **umcamara** » September 26th, 2007, 7:14 pm

I think I know which clips you're talking about. There's two per rotor, they just kind of sit snug onto the calipers, and serve no purpose that I can see.

Tunes, I have also flushed brake fluid, and properly bled from RR, RL, FR, FL, two times. Also, the pad springs are just tiny little things, like paper clips, and I don't see how they could possibly open up the caliper, when it takes a heavy C-clamp to compress the pistons.

Anyway, thanks for the ideas.

Tunes67 · Post by **Tunes67** » September 26th, 2007, 7:28 pm

They dont really compress the piston back into the rotor.. the release of pressure usually sorta pulls the piston back in.. almost like a vacuum in the lines.. what the spring does is push the pads back away from the rotor complete. Assuming that the piston is going back in as it should.. there should be a small amount of space for the springs to push the pads back away from the rotor. Possible if the pads are after market pads and not specific OEM pads that they may be slightly thicker than OEM pads and require a bit of time to wear down enough for that to work properly. I'll see if I can find a pic of the spring I am talking about.. cause its a bit bigger than a paper clip too.

Tunes67

Tunes67 · Post by **Tunes67** » September 26th, 2007, 7:34 pm

Here we go.. man I love that http://www.napaonline.com has pics of their parts.. makes life so much freakin easier LOL

The spring I am talking about is the one in the upper left corner. It spans across the rotor to either side and snaps in place against the pads.. hope that makes sense.

Tunes67

umcamara · Post by **umcamara** » September 26th, 2007, 11:07 pm

Tunes67 wrote:The spring I am talking about is the one in the upper left corner. It spans across the rotor to either side and snaps in place against the pads.. hope that makes sense.

Tunes67

Yeah, I know the springs you're talking about. I've toyed with 2 ideas:

1) Yes, they are replacement pads, and VERY new. Previous owner who I bought the car from a few months ago had them installed, and then the car sat parked for 2 & a half years. They are very meaty. But still, if I compress the piston in all the way with a clamp, then insert brake pads, and replace wheel, no rubbing.

2) Maybe, even though I can compress the piston with a clamp, the pistons are still not sliding as easily as they should be. The piston walls were very clean and shiny, however, I don't know what the inside of the caliper cylinder is like. Maybe it's rusted or warped or something.

I'm not going to worry about it too much though. Over the winter, when I have time from school, I would very much like to do an engine swap. I know everybody's gonna think I'm nuts, but I want to swap in a KLZE. I know that nothing in life is certain, but my plan is to buy a written-off GS donor car, swap all the engine bay, suspension, steering, brake parts, etc, and have a go at installing the KLZE. Gonna be a lot of work, I know, but I hope to buy a winter beater to drive, and work on the MX3 for a few months a little at a time.

Why don't I just sell mine a buy a GS to start with? Don't know, I guess I've become emotionally attatched to the chasis that I have now.

I've spent countless months working on it, and have $3000 towards body work and paint lined up from my insurance company. It received a tiny bit of hail damage. Like one ding per body panel. For some reason they won't do paintless dent repair on this vehicle, and therefore have to repair and paint every panel that has a ding from hail.

That's my little story. Thanks for comin' along. Hope you had a good time.

Goland · Post by **Goland** » September 28th, 2007, 1:45 am

I had a very similar problem, it sounds exactly like what you're talking about... It was making a sort of grinding noise that was rotational with the wheel. Whenever I disassembled the wheel to take a look at it, try fiddling with something (very professional, I know) and put it back on, the noise would go away for a while but come back slowly as I drove and, of course, applied the brakes. Next time I'd go to take the wheel off, the lugs were looser than I remembered putting them on, the entire caliper was off-center (the edge of the brake rotor scraping the inside of the caliper was actually what made the noise).

If it's exactly the same problem as I had, you can check by testing the wheel for play. Push and pull on the top and bottom of the wheel, back and forth. I had a lot of give in mine, but the guy who owned it before me mis-diagnosed it as a bad lower ball joint (which I replaced, and is nice and shiny, but didn't fix the grind).

Long story (slightly) shortened, it turned out my wheel bearing was bad. I brought it to a local Mazda place and they replaced it with a stock piece for around $270. If you have the ability to do it yourself, you might want to check it out.

But yeah, that worked for me.

Also, the clip that Tunes spoke of doesn't do ANYTHING. My driver's side wheel was the one that was acting up, so I checked the passenger side wheel to see what the "control" setup looked like... It was actually missing that W-shaped clip! I thought, like you guys, that the clip was there to push the brake pads apart, but as it turned out it didn't even have enough spring force to do that anyway. Really, when you think about it, the wheel isn't gonna make that kind of noise just from having a brake pad loosely applied anyway. I mean, it doesn't grind when you put your brakes on, right?

umcamara · Post by **umcamara** » September 28th, 2007, 2:15 am

Goland wrote:Really, when you think about it, the wheel isn't gonna make that kind of noise just from having a brake pad loosely applied anyway. I mean, it doesn't grind when you put your brakes on, right?

Actually, now that I think about it, the noise is there when I apply the brakes as well. Common sense would say that it couldn't be the pads rubbing then.

Perhaps it is the rotors rubbing against the calipers. But for both sides to have the exact same uncommon problem? I don't know. Why after compressing the pistons, then bolting on and spinning the wheel would there be no rubbing. I could leave it like that for a year, and there'd be no rubbing. But as soon as I apply the brakes once, the rubbing's back.

Looking at the assembled calipers, there's only about a thousandth of an inch gap (next to nothing) between each pad, and it's respective side of the rotor. I mean, I'd have a hard time sliding a piece of loose-leaf between them.

Yoda · Post by **Yoda** » September 28th, 2007, 1:08 pm

Did you also change the pads and was the car purchased used? It could be a common problem norrmally found on some '91-'93 MX-3s if the answer is yes to both.

umcamara · Post by **umcamara** » September 28th, 2007, 1:40 pm

umcamara wrote:Yes, they are replacement pads, and VERY new. Previous owner who I bought the car from a few months ago had them installed, and then the car sat parked for 2 & a half years. They are very meaty. But still, if I compress the piston in all the way with a clamp, then insert brake pads, and replace wheel, no rubbing.

Tunes67 · Post by **Tunes67** » September 28th, 2007, 2:00 pm

Also, the clip that Tunes spoke of doesn't do ANYTHING. My driver's side wheel was the one that was acting up, so I checked the passenger side wheel to see what the "control" setup looked like... It was actually missing that W-shaped clip! I thought, like you guys, that the clip was there to push the brake pads apart, but as it turned out it didn't even have enough spring force to do that anyway.

If the spring isnt pushing the pads open.. you need to grease the slider pins and make sure the system is clean. They dont have a lot of pressure.. they arent designed to push the piston back into the caliper.. just keep the pads off the rotors.

Tunes67

Yoda · Post by **Yoda** » September 28th, 2007, 2:22 pm

umcamara wrote:
umcamara wrote:Yes, they are replacement pads, and VERY new. Previous owner who I bought the car from a few months ago had them installed, and then the car sat parked for 2 & a half years. They are very meaty. But still, if I compress the piston in all the way with a clamp, then insert brake pads, and replace wheel, no rubbing.

If that is the case, look at the casting numbers on the Calipers. Some of the MX-3 especially the RS and early GS can have the smaller 22V13 calipers. If the pads were replaces with the pads for the V14 calipers found on most of the '93+ MX-3 the edge of the pad backing plate closest to the rotor hub can rub the rotor hat under braking and sometimes when rotating the wheel by hand. If you service the calipers it will take a couple braking cycle to pull the caliper slightly in to the hub and the backing plate of the pad to rub the center hat. Some times you will find a newer MX-3 were somewhere in it history the calipers were changed and the smaller ones used instead. I have also seen cheap "Asian" made pads and rotors listed for the V14's were the backing plate is a little to long or a rotor were the diameter of the hat is over spec. and rubbing can occurs as well. Unfortunately we can hear the actual rubbing sound to identify it.