Basic Brake question..

**ic3wall** · 05-06-2008 01:53 PM

Hi,

I did a brake job last week with a friend and we changed front pads/rotors. Everthing went smoothly.. A couple of days later, I noticed that when I brake hard on the highway, the car pulls slightly to the left .. So I thought I probably did something wrong on the right side since it is not braking as it should ...

This morning, I realized that the outter pads don't move when I push the brakes!! So the only thing that makes me stop I guess, are the pads on the cylinders side. By the way, the sliders looked fine..

What did I do wrong ??

(Apologize for my english)

**ct1.8t4me** · 05-06-2008 01:56 PM

The outer pads are fixed in place by the caliper carrier if I am not mistaken. The caliper actually slides on the pins.

You may be having a problem related to worn steering or suspension components or alignment/tire issues rather than the brake job. Something to think about.

**ic3wall** · 05-06-2008 02:01 PM

"worn steering or suspension components or alignment/tire issues" would prevent my outer pads from moving .. that does make sense to me !

I had no such problem before on the highway, so it has something to do with the brakes.

But I appreciate your input

**onemoremile** · 05-06-2008 02:06 PM

Did you bed in the new pads?

**ct1.8t4me** · 05-06-2008 02:10 PM

What I'm saying is that the outer pads don't move a whole lot. Look at this: http://www.audiworld.com/tech/wheel139.shtml. Here you can see that the outer pad sits in a little channel in the caliper carrier and is "pushed" inward by the clamping of the piston on the other side. The caliper is what does all the moving. The pad moves very little in relation to everything.

I could be way off base here, I'm just suggesting that your description of "the outer pad not moving" does not necessarily nail down a problem with your brakes - because they just don't move that much.

And there is something called a coincidence which would allow for two seemingly related events to occur simultaneously without any real correlation...

**Udo** · 05-06-2008 02:22 PM

Have you checked the other caliper to see if it is working as well? If the other one isn't working it would cause your car to pull to one side (the working side)

**djwimbo** · 05-06-2008 02:35 PM

The outer pad or even the inner pad isn't going to move that much at all.
The Lathe cut seal on the inside of the caliper, against the caliper piston(outer diameter) is designed to pull the piston back upon releasing pressure. The amount it's pulled back is anywhere from .015-.040 of an inch. Not much. Application of the brakes takes up this space and a very small amount more.
The pads and caliper are designed to make both pads move the same amount, making it seem even smaller.

There isn't a gap between the pad and the rotor is there?

When you had the calipers off of their carriers where did you hang them and by what? If you hung the calipers by the brake hoses then you need to replace the brake hoses and bleed the system of air. This is also an issue if you hang the calipers up on the spring and one falls off the spring and then swings by the brake hose.

I learned this one from personal experience. I replaced a caliper on my Camaro in H/S b/c the car pulled to the right during braking. I spent $45 on a reman caliper, then found out I could've fixed it w/ a $8 brake hose.
When the brake hoses stretch or deteriorate internally, they can become like a one way check valve or a restriction. Rule of thumb, if the rubber exterior of the hose is cracking or split, replace them. The rubber you see only protects the internals of the hose, but it's still a good idea to replace them.

Honestly though, the first thing I'd try to do is to bleed the system. This might point you in the right direction, and it's probably time for the old fluid to be changed anyways. It'll take less than 20mins w/ a buddy and it's a good practice to learn, if you don't already know how.

**ic3wall** · 05-06-2008 03:18 PM

Originally Posted by onemoremile

Did you bed in the new pads?

Yes

Originally Posted by Udo

Have you checked the other caliper to see if it is working as well? If the other one isn't working it would cause your car to pull to one side (the working side)

The left one seems to move a little bit. The right one does not move at all and the outer pad seems to be too far from the disc, something like 5mm away.

Originally Posted by djwimbo

Honestly though, the first thing I'd try to do is to bleed the system. This might point you in the right direction, and it's probably time for the old fluid to be changed anyways. It'll take less than 20mins w/ a buddy and it's a good practice to learn, if you don't already know how.

Maybe a really stupid question, but if I decide to bleed the system, can I bleed only the front brakes ?

And ct1.8t4me thx for the link!

**ShawFM** · 05-06-2008 08:30 PM

Originally Posted by ic3wall

Maybe a really stupid question, but if I decide to bleed the system, can I bleed only the front brakes ?

And ct1.8t4me thx for the link!

If I was going to the effort of bleediing the system, I would do the whole thing. To ensure there was no air anywhere in the system, not just in the front. New brake fluid will improve feel. Start with the right rear, then left rear, right front, and left front last. Bleed it until you see the clean fluid coming through.