(96 Infiniti I30T) One brake seized, then the next after work - ?

[barcar37]

So my front left brake seized completely. I replaced it, and after driving this rear right caliper seized. Now on this car they are on the same circuit, what's up here? I'm almost done replacing the master cylinder - any idea what's going on?

(When I say I, I mean kinda helping a friend far more knowledgable than me.)

Thanks for any input!

[shorod]

By "seized" did it fail to release when you removed your foot from the brake pedal, or did it fail to apply the pads to the rotor? Your car is old enough that if the rubber brake hoses have never been replaced they could be deteriorated and acting as a 1-way valve. So instead of the caliper actually being the part that's failing, it's the brake hose. A collapsed brake hose will not necessarily be visible from looking at it.

If you have a caliper that appears seized and is difficult to compress, try opening the bleeder screw or removing the brake hose and see if it will easily compress with the fluid connection open. If so, the caliper is not what's seized. The issue is in the fluid delivery at that point.

This wouldn't necessarily explain why your issue seems to be going from one wheel to another other than you could have (at least) two hoses that are having issues and you previously only discovered the worst wheel. Does your 1996 I30 have 4 wheel ABS?

-Rod

[maxwedge]

Hmm wonder is the brake fluid was contaminated?

[barcar37]

By seized I mean that it would not release causing the rotor to become ungodly hot. Smoking hot actually.

Yeah, the car has ABS on all four wheels,.

After the caliper on the front left was replaced we bled the system. That's when my brother heard a noise on the right side, so I called in my friend. He realized it was the caliper actually seizing (not releasing), and in this car it's on the same circuit as the front left! We bled the system entirely again just to make sure it was done right the first time - no such luck.

We (he with me watching curiously) replaced the front CV joints and we'll have the master cylinder back in completely tonight (too damn hot in Texas to do this during the afternoon). I sure as hell hope this solves the problem, but I'm still curious as to what happened.

After the car would sit for a bit the calipers would release, and after driving around more they would seize again! But after the front left caliper was replaced, it changed to the back right! This is what I find crazy, and then after sitting it will unseize, only to seize again if driven.

Brake fluid was new and purchased from a major chain, it had been drained completely and bled twice, so I wouldn't think so, but I'm no mechanic.

[shorod]

The fact that after sitting it will release really causes me to doubt the issue is the caliper. That's pretty typical of a failed brake hose.

When bleeding the brakes was your friend using a vacuum pump or having someone press the brake pedal? If using a pump, was there a good flow of fluid or was it more of a trickle? Pressing the pedal would force enough fluid through to easily overcome a collapsed brake hose, but a hand vacuum pump might struggle.

Trying to compress the caliper with the bleeder open will pretty quickly identify if the issue is the caliper or the hydraulic system to the caliper and might prevent you from replacing expensive calipers that are not going to fix the issue.

-Rod

[barcar37]

It was bled by compressing the brakes, with clear tubing run into a bottle of fresh fluid. Large amounts did seem to move every time they were pressed.

He pretty much said he was certain that it never was the caliper, and my brother replaced it for no real reason, so the back right one isn't getting replaced. He told me it was the hydraulic system, probably the master cylinder specifically. I forget what test he did to check the brake lines, but he said they were fine. I suppose we'll find out tonight after the new master cylinder is in.

I was just bewildered why the front left would seize.... a new caliper is put in, and then the back right does, and the front left seems fine.

[barcar37]

I figured I'd update, just in case someone has the same problem. I guess he did check the hoses and I missed it because it was indeed the master cylinder. Thanks for everyone's input!