I am an idiot -- Can anyone tell me what I just messed up?

[covert]

Aargh!

In my typical fix one thing, break two others modus operandi, I did a stupid thing today.

So I replaced my speedometer gear today because of my rear end change to 3.55 gears.  While it was up on the jack stands, I had the emergency brake on.

You probably see where I'm going.  After going out for a test ride, I suddenly realized there was smoke coming from the back of the car and a really funny smell.  That's right, I left the emergency break on about 8 miles.

I should mention that the brake light on the dash was never on.  And, with my new taller gears, I didn't even notice.  (the whole car handles differently, and in retrospect maybe there was a little more resistance to moving forward, but the engine and gears pushed through like it was nothing.)

So release the brake, and get on the highway -- hoping some fast driving and no brakes will help cool them off. 

When I get off the highway, my brake pedal is really soft.  If I pump it up, it firm and there, and the car stops, but I do have to pump them a little.

Plus, now (NOW! -- why wasn't it there before) my brake light is coming on.  I first press on the brake, and (while its soft) the light turns on.

I should mention too that the brake shoes on the back are brand spanking new.  Well, they were new.  They were replaced when the differential was swapped out (since they had everything apart anyway)

What am i going to have to fix now?  how did my emergency brake (which is cable operated) effect my power brakes?  Are my rear brakes pretty much screwed?

Argh!

[422STROKER]

They could be smoked!   Joking aside, I bet you boiled the fluid in the rear.  So at a minimum you should flush the fluid out.  Take a look at the pads while your back there.

Good luck, I have driven a couple miles before, not 8.LOL  But the brakes seemed ok after I did it.

Tom

[duodec]

You will need to pull the drums and take a look.  Its certainly possible that the wheel cylinders got hot enough to damage the cups/seals and are leaking; that would explain the soft pedal and warning light.

The only event of this I knew about before, the drums and shoes were toasted; the shoe lining had cooked and glazed, and the drums had heat-checked (scattered surface hardening due to the heat; effectively they were heat treated) and could not be turned to a smooth surface again.

If you see that type of damage it might be worth replacing the hardware too (springs), which may have been weakened.

Good luck with it...

[Bullitt-]

  There is a different switch that turns on the brake light to show the Emergency brake is on under the dash (yours must be bad or not connected)whereas the pressure switch on the brake lines indicates problems with the hydraulics.

[ViperMan]

I agree that wheel cylinders may be affected - the rubber boots won't take the heat well for 8 miles.  It is also possible that you simply cooked off enough shoe material that they need to be readjusted outwards to the proper clearance for firm pedal, but I agree with all in saying "tear it apart and check it out."  Then bleed and flush the brake fluid - not too tough to do with some help.  As far as the light being on, is this a newer vehicle?  Because I'm pretty sure older cars don't have a sensor for the fluid pressure in the brake system - the brake light only comes on with the e-brake, doesn't it?  I at least know that my car doesn't have a sensor for brake fluid - it's nowhere in the wiring diagram.  The switch at the parking brake pedal might just be out of adjustment.

Luckily, shoes, hardware and wheel cylinders are generally pretty cheap.  Good luck.

Jeff

[HP2]

Yes, old cars have a fluid sensor. It is in the distribution block that mounts down on the frame rail where the two front brake lines mount up.

[ViperMan]

Ah okay, I stand corrected.  Mine must either be working (which would shock me) or is shorted to ground giving a false signal...

Jeff

[MJS73]

You may have also boiled the brake fluid.

Mike

[gkring]

Ah okay, I stand corrected.  Mine must either be working (which would shock me) or is shorted to ground giving a false signal...

Jeff

not to get too far off topic
Newer cars have fluid level sensors in the master cylinder reservoir, which is what I think Jeff is thinking of.
You also have a light to tell you the parking brake is on.
usually the same light is used in older cars to tell you when there is a problem with the brakes.
That light is triggered by a sensor in the proportioning valve that sees any weird pressure changes, like the front or back brakes being too soft

[MEK-Dangerfield]

Just a guess, but I think the brake fluid may have turned to tar.    I would definitely start with flushing out the rear brake lines.



  Mike

[ViperMan]

not to get too far off topic
Newer cars have fluid level sensors in the master cylinder reservoir, which is what I think Jeff is thinking of.
You also have a light to tell you the parking brake is on.
usually the same light is used in older cars to tell you when there is a problem with the brakes.
That light is triggered by a sensor in the proportioning valve that sees any weird pressure changes, like the front or back brakes being too soft

Yeah - I was trained on the new stuff.    Sowwy...

Jeff

[covert]

Hi guys,

OK, I'm back -- I had to take a couple of days for both I and the brakes to cool off. 

After time to think about and for my blood pressure to lower, I've decided to have a sense of humor about it and I figure that its a good time to learn a bit about my brakes.  Its actually an area I've never worked on before.

Was any one else here ever a fan of Mitch Hedberg, the comedian?  He used to have a joke:  "They call it the emergency brake.  I call it the 'make the car smell funny lever'"

So I pulled the drums, and at least to my very untrained eyes, everything seems to look relatively OK.  I mean, the drums are what I would call smooth, the shoes too.  Definitely much more warn than what brakes with only 15 total miles should have on them, but still OK.  I'm going to try to find some websites tonight to see what I should be looking for.

I'm going to bleed / flush the brake fluid tomorrow, push out all of the old stuff, and pour in some new, and see how it goes.

There is one thing worrying me.  There's some kind of grease / fluid leaking from the ends of the axles.  This is not because of my incident with the emergency brake -- I had noticed spots on my garage floor before I ever left for my brake burning trip.  But when I took off the drums, this same fluid was all over inside. 

Did the guys not put something together right when my rearend was setup?  Is this just some kind of axle grease that is something I should expect after having my center section replaced. I attached a picture.

Oh -- and on the brake light question -- Its definitely used for both in this car.  It used to light when the emergency brake was on, and something must have happened to the switch, but yesterday it was on whenever I had not pumped up the brakes to have pressure.  So definitely used for both.  and its bright bright too.  Like, if it had been on when I took off, there's no way I wouldn't have seen it -- by far the brightest light on the dash.

Thanks guys,
Covert

[hooD]

I don't recall reading if you ever did a visual check of the brake fluid level in the master cylinder.   I'm curious to know what you found.

[422STROKER]

Sounds/Looks like your rear axle seals are no good.

Bring it back to them.
Tom

[covert]

Hi guys,

OK, I finally got around to fixing my axles and brakes. 

I decided I would do it all myself -- I didn't want to take it back to those guys to replace the seals.  Wasn't too bad.

BTW, the brake fluid was a very dark brown.  As usual, I did end up braking something else -- as I was trying to flush the brake fluid all around, one of the front brake bleeders broke off.  Oh well, at least it broke off at a point after the air was out, and its closed.  So when I do the front brakes, I'll fix them then.


One question though -- the back right axle had an "adjuster" on it -- it had a lock on one of the bolts, and you could spin it around.  I found references in my manuals I had that it should be there, but I couldn't find anything on what this thing was actually supposed to "adjust".  I think I put it back the way it was, but what is that thing there for?  is it a wheel alignment thing?  It didn't seem to make much of any difference in any position.

Back on the road -- for now....

Later,
Covert