Problem - Q45 brakes on S14

[DaPCWiz]

before I start -

car: '96 S14
brakes: Q45 calipers / bracket and rotors
side: front

I just recently swapped out my old rotors (possibly slightly warped) for new rotors, and reused the same pads. Don't have shims on the pads.

Everything seemed fine with the old rotors (except for some steering vibration under braking... so I figured the rotors were a bit warped)

Put everything in, drive around - works awesome. Then it rains and of course you get bits of surface rust on the rotor. This surface rust comes right off as soon as you use the brakes - but I look at my driver's side rotor and all of it doesn't rub off, there is a ring of rust on the inside of the rotor, indicating that the pad isn't making full contact with the rotor.

I take things apart and upon closer examination, I notice the pad isn't sitting correctly, and looks like this:

http://www.dapcwiz.com/misc/brakes.jpg
rotor: gray
pads: green
caliper: red
look at the outer pad, pretty much sits exactly like that on my car...

Car drives and feels perfectly stable and normal under braking.
Also note: the rubber on the brackets is really worn, but I don't think that's what would cause this.

I tried swapping the inner and outer pad and it didn't help...

I'm thinking I need to get a new set of pads with shims? Before I order I need someone to tell me I'm right or wrong...

[projectRDM]

Shims aren't the problem. From your picture it appears the pad is crooked in the carrier, shimming it would just space it out further. One of the metal tangs on the clip is bent or something else to hold the pad back. Doublecheck it all again.

[burningsquirrels]

buy a camaro.

[gotta240]

I think he is referring to the little bit of rotor that doesnt get touched by the pad. Its about 5mm of metal that doesn't get used before the rotor goes outward for the hub. Is that correct?

If so, my brakes are the same way on both my 300zx and my j30. I don't think its an issue

[DaPCWiz]

buy a camaro.

lol G, domestics aren't the solution to everything, unless you are talking about beer :rl:

[DaPCWiz]

I think he is referring to the little bit of rotor that doesnt get touched by the pad. Its about 5mm of metal that doesn't get used before the rotor goes outward for the hub. Is that correct?

If so, my brakes are the same way on both my 300zx and my j30. I don't think its an issue

no, its a good amount more than that. at least 1/4 - 1/3 inch above the area that isn't touched by the pad...

[gotta240]

yes, 1/4 is close to 5mm.

[JohnD1079]

arnt all brakes like that?

[DaPCWiz]

yes, 1/4 is close to 5mm.

arnt all brakes like that?


nope nope... the passenger side rotor is fine, the area is maybe a few mm, normal. The driver's side its pretty big, and I can see the pad not making contact with the rotor, and the rotor now looks ugly and rusty.... ewwww, lol.

[gotta240]

ah. In that case, r240na's solution would be a good way to start. Pics please.

[mrmephistopheles]

that's also what happens when reusing old pads with new rotors
Better to put new pads on a set of turned rotors.

[onehundredoctane]

old thread I know, but I didn't feel like trashing zilvia with another Q brake problem on an S14, my problem is I'm not building brake pressure, I've bled each side multiple times, I can't even remember how many now. I've checked the slide pins, and they are greased and move easily, I pushed the pistons back in to ensure they were moving freely with a c-clamp and still I can't build brake pressure.

I'm thinking about taking the calipers back to the place I bought them from and asking to try another pair from another car.

But before I do that, does anyone have any advice? I would like to think I have all my bases covered so far, but I may be missing something.

[98s14inaz]

The rebuild kits for the q45 calipers are so cheap you might as well rebuild them. The external rubber seals and pins are very important to how the pads and everything else line up. I'd suggest rebuilding them and see if it changes anything.

[onehundredoctane]

rebuild kit is $50 and a 2 day wait at Autozone, and I can just go to the salvage yard and try the other set of calipers w/o having to tear any apart, my main concern is that these are frozen up, and the others may be as well. I'm not comfortable tearing calipers apart as I've never done it before.

[onehundredoctane]

tested another set of Q brakes before removing them from the donor car, installed them on my S14 last night, and the same problem persist. Either I have a hell of alot of air in my lines, or the stock S14 master cylinder doesn't move a large enough volume of brake fluid to the calipers, in which case I plan on bleeding the brakes many more times, if the problem continues then I plan on putting on a Z32 bmc I have here.

[DaPCWiz]

I run the stock BMC. no issues with that...

[onehundredoctane]

my calipers came from a 2001, I can't find any instance where anyone has used newer ones, atleast noone noted the year of their calipers that I've seen. lmk.

[98s14inaz]

tested another set of Q brakes before removing them from the donor car, installed them on my S14 last night, and the same problem persist. Either I have a hell of alot of air in my lines, or the stock S14 master cylinder doesn't move a large enough volume of brake fluid to the calipers, in which case I plan on bleeding the brakes many more times, if the problem continues then I plan on putting on a Z32 bmc I have here.

S14 BMC is just fine for those calipers. If two sets of calipers aren't working I bet your BMC is shot. I'm not some random guy telling you what to do either. I have this exact set up on my s14 and it works fine.

[onehundredoctane]

everyone flame me now, but the calipers weren't marked left and right, now you see where this is going, the calipers were on the wrong sides, changed that, and problem fixed. This isn't the first time I've done a brake swap either, that's what's funny. The brakes work fine now, small oversite on my part, and lets just say, this bitch stops! I don't even want to know how much faster it will stop with hawk pads and drilled rotors.

[JohnJohn86]

everyone flame me now, but the calipers weren't marked left and right, now you see where this is going, the calipers were on the wrong sides, changed that, and problem fixed. This isn't the first time I've done a brake swap either, that's what's funny. The brakes work fine now, small oversite on my part, and lets just say, this bitch stops! I don't even want to know how much faster it will stop with hawk pads and drilled rotors.

How can you tell? From the bleed screw?

[onehundredoctane]

the bleed screw has to be at a higher point than the brake hose on the caliper when it is bolted to the car. That way when you bleed the brakes, the air trapped in the line will float to the highest point in the caliper. Since my calipers were on the wrong sides initially, the higher of the 2 points was the brake hose, which was trapping massive amounts of air in the line, and not building pressure in the lines. It's just one small error, this isn't the first time I've ever done a brake upgrade, more like the 5th time, but in the rush of things small shit like that gets missed.