Q45 S13 problem.

[Dolby109]

So, I have finally gotten around to swapping the Q45 front brakes onto my S13, but I have run into a bit of a snag.

The right caliper has this extra bolt hole in the back of it, but I don't have a bolt to go in it. I checked and it does go through to the caliper chamber (where brake fluid goes).

So is it safe to just get a short bolt and plug this hole up?
What exactly is it there for?
I do have a bolt that fits, but its slightly too long...so can I just run to home depot?

[Chaluska]

take a picture.... there "shouldnt" be an extra bolt going into the fluid pathway... there is one bolt in the center for brake fluid...

http://s3.amazonaws.com/fcp-product-photography-us/public/assets/products/79136/product/open-uri20120713-31620-ii8yd0.?1342173549

on this picture, if you see the rear of the left caliper, it has the center bolt for fluid, and the bleeder screw on top... are you talking about the bleeder screw maybe?

[Dolby109]

No not the bleeder...on the R caliper there is a second bolt hole with its own double finger to hold a line in place as if to hold a second line.
I blew into it and air came out the main brake line hole.

Both brakes came off the same Q45 car.
For now I just plugged it up with a short bolt/washer. I'll try to get a pic.

[Dolby109]

Ok, so now it got weird.

I got the car together (no pics cause my wife was out with the camera Saturday) and it drove great. I put 50+ miles on it Saturday and it was braking great.

I went out to drive it today (3 days later) and the brake pedal just goes to the floor. I almost rolled out into the street. The master cyl reservoir looked empty (I had topped it off during and after bleeding the brakes).

I know all the lines and bleeders and that extra bolt were tight before I put the car back on the ground, and if they weren't the brake feel would have felt spongy.

I'll jack it back up when I get home from work to see if I can find anything, but do any of you have an initial idea?

[zooopreme]

Are you referring to this extra hole?

http://img198.imageshack.us/img198/9900/img2413d.jpg

I don't know what that hole is for but it's not an extra brake line hole. I'm sure it has a function but on a S13, it serves no purpose and there's no need to plug it up either. It doesn't leak out brake fluid.

And as for your brake problems, if you had switched the BMC, bench bleed that. And if the problem persists, there may still be air in your brake lines. So keep on bleeding. I have Q45's on my car for more than a year now and there have been 0 problems with them.

[Dolby109]

I didn't change the master cyl, and the brakes were bled.
What doesn't make sense is that they worked fine Saturday with out any sponginess or fade, and then all of the fluid was just gone this morning.

I'm sure it has leaked out somewhere...so when I get home I can figure out where...I just don't want to have to bleed all 4 brakes.

[zooopreme]

A lot of members on this forum will tell you the exact same thing as I've said to you, that hole does nothing and these work no problem.

With what you said, the only things that I can point out are loose/bad bleeder valve/screw? Bad/leaking piston seals?

That hole does leak any kind of fluid out (at least for me, it doesn't) and plugging it up isn't necessary.

[Dolby109]

So it looks like the right caliper is blown (there is brake fluid leaking down on the back side of the rotor).
These calipers are surprisingly hard to find, luckily Adavance Auto had one single Q45 Right caliper in their national warehouse and I got a good deal on it.