Well, yesterday was a fun day. I was going to work and almost had a wreck.

I left for work, and everything was normal. Driving down the twisty road I live on. Several sharp curves and the like.

I get into town, I'm behind another car, coming up to the intersection. The light turns red, the car infront of me stops, I go to stop and the brake pedal goes to the floor and the warning light comes on. I quickly pump the brake pedal and I have brakes, and stop. A little too close for comfort!

Light turns green and I turn towards work, the brake light went out, and I had good pedal feel. I have a mile to go.

As I'm turning onto the road works on my brake light comes on again. I have to stop at a railroad crossing. The brake pedal is very spongy, but I stop.

A few hundred feet and I'm at work. I stop the car barely and I popped the hood and get out. I smell brake fluid.

There is none in the master cylinder. I walk around the car and I see my right rear wheel is wet. Yep, brake fluid.

I do my AM route, get done and get back to the compound. I tell the dispatcher that I most likely won't be back that afternoon.

****I will skip the conversation and deal making, and get to the rest****

So I have a vehicle, I go home get jack, 2 jack stands and come back to the compound. I take the wheel off, and I can see the piston on the calipers is hyper extended, brake fluid is coming from the piston. Then I see it. Or should I say, I don't see it! The inside brake pad is missing!

I take the caliper off, and the piston is all mangled and a crack is in it.

I find a caliper about 35 miles away, and head there. I buy it, a new rotor and pads. Head back to work, install said items in 10 minutes and I'm back on the bus for my afternoon route.

I get done, and get back to the compound and spend 2 1/2 hours bleeding the brake system.

Now I have brakes.

Now mind you, the remaining pad, and pads on the left side were in very good shape. Back in October I had new tires put on and the guy putting on the wheels made a comment about them, on how good they looked.

I have no clue where the inside brake pad went, but there wasn't any evidence of any part of it was there.

Up until the stop light, my brakes felt normal. The only thing that I can think of, is last Wednesday backing up at work I heard a loud noise. I felt a little shake but that was it.

Back in November I started to have some noise back there, but when checked visually everything looked good. So, who knows what happened. I have a theory, but would like to hear what y'all think.

ARman

That’s strange. I could see a pad cracking and falling away. But not the metal backing. Maybe extreme heat from no pad and hard braking caused the metal to bend and come out? Was the rotor scored? I assume the caliper piston scored it but was there any indication it was scored by the metal of a brake pad?

Pad material separated from backing plate then plate was able to get extended enough to fall out of the caliper?
Pictures would be helpful if there are any.

quote:

Originally posted by frayedends:
That’s strange. I could see a pad cracking and falling away. But not the metal backing. Maybe extreme heat from no pad and hard braking caused the metal to bend and come out? Was the rotor scored? I assume the caliper piston scored it but was there any indication it was scored by the metal of a brake pad?

The rotor had a gouge in, the caliper piston was mangled. The was nothing that looked like heat/temperature damage on the rotor.

I have a theory on what I think happened. I just want to see what someone else comes up with.

I have been driving for almost 40 years, and been around cars, working on, and all even longer. I helped rebuild a Jeepster Overlander before I could drive. I have never seen (or not seen) anything like this before.

But you have mentioned something that is part of my theory.


ARman

quote:

Originally posted by 220-9er:
Pad material separated from backing plate then plate was able to get extended enough to fall out of the caliper?
Pictures would be helpful if there are any.

No pictures. I wish that I did!

But that is part of my working theory.

ARman

I always used to wonder when I was at stop lights “how in the hell did that (brake pad) get there?”

And how did the driver not know something was up

Don't have a clue why you lost a brake pad. Maybe it broke in half?

I lost brakes in my truck recently , pedal went to the floor in dense traffic. Had to have it towed home two hours away.

Turns out the brake line had rusted through, leaking fluid.

$600 towing-$200 repair bill.

Well my working theory is that the noise that started in the beginning of November was the pad has separated from the backing plate. When it was visibly inspected by the shop, and later on by myself it wasn't apparent that it separated.

Last Wednesday, the loud noise was the backing plate being bent and sometime between then and yesterday morning fell out.

In that time frame I drove home Wednesday night. To work and back Saturday, and then Monday morning when this happened.

All the while, the brake pedal felt the same as always, and the car stopped normally.

I will say that I have track/street pads on the front from Hawk, and the rear pads were Brembo high performance carbon-ceramic pads, so there is always some brake noise. I did not notice anything that was out of the norm.

Now, how it separated is anyone's guess. They are (were) Brembo pads.


ARman

I lost a brake pad like that about 20 years ago. The failure occurred while I was braking, and was accompanied by a loud "crunch". There was no doubt about when the pad departed the vehicle.

I got the one brake fixed and had the others checked. The mechanic wouldn't even speculate on the cause - just said he saw it from time to time on all types of vehicles, and couldn't find a pattern to it.

I've seen this happen. Usually older metalic pads that freeze to the rotor after a car wash or going through puddles.

Pad ejects when the car is moved, and pedal goes to the floor on next apply.

Not uncommon in Michigan.