Star adjusting rear brakes.

[oilboy123]

How hard does the car need to stop fwd and backward to actuate the star adjusters?

This is in relation to renewing rear brakes on rear drum vehicles. I always do pretty hard stops both ways. But I don't know if I need to do hard stops for it to self adjust.

I have done brakes for many years but just want opinions, Preferably from experienced mechanics.

Thanks

 

[AcuraTech]

I'm not sure that they adjust themselves at all. This is why they occasionally need to be re-adjusted. I'm not a fan of drum brakes. The only thing they have going is that they don't get all rotten like rear discs often do.

 

[oilboy123]

They do because I installed the shoes on the loose side. When I did about 20 fwd and backward stops the pedal was a lot higher.

 

[mechtech2]

I like rear drums on a street car.
Not good with ABS, though - you need discs for that.
A lot of braking is done with the fronts. The rear drum brakes don't fully engage with normal driving.
That is why people recommend hard stops to actuate the mechanism - you get full travel.
It is the full movement that actuates the adjuster, or cam.
Much can be accomplished with the car sitting still, and pressing the brake pedal hard.
There is nothing rotating [wheel wise] that actuates the adjusters.

 

[alreadygone]

"There is nothing rotating [wheel wise] that actuates the adjusters. " Mechtech2

While true that nothing turns, there is slack-slop, extra travel, when shoes are out of adjustment. I was taught that this play,when excessive, combined with rearward movement would accutate self adjust system, causing it to turn the star wheel.

Some of the newer selfadjust systems (i.e. 90ish Chev PU) seem like setting the park brake would be required to accutate self adjust, as it's built into the park brake main rod instead of having a star wheel?

Bob

 

[cmhj]

I really depends on the car/setup. Back in the 70s I had a few occasions with delivery vehicles that did so much backing into delivery ports the rear brakes got so tight the drums overheated.

 

[oilboy123]

So 1 vote for hard braking needed to actuate?

 

[mechtech2]

Hard pressure on the pedal, for sure - pump it every few seconds.
Moving in reverse and hitting the brakes is the old Mantra, but I can't see the reason for it.

 

[andyd]

i'll hafta try the pedal pumping trick on the Grand Wag.

 

[alreadygone]

"Moving in reverse and hitting the brakes is the old Mantra, but I can't see the reason for it." mechtech2

I believe that the cable/rod part of self-adjuster is mounted to rear shoe, with vehicle in reverse shoes tend to pull(stretch) on that cable/rod, instead of pushing(compress) it. Any slack in shoes, letting them move slightly farther would cause adjuster pedal to ride up on star wheel enough to catch a new tooth and turn it slightly tighter. IMO

What I'v yet to fully understand is the self adjusters mounted to emergency brake cross rod. Seems when I'm installing this type brake there's no time for ponderment, but it'd almost have to activate when park brake is set,,,an act that most drivers never commit,,causing chronic low pedal on these vehicles. (Mostly refering to Chev PU's)

Bob

 

[oilboy123]

To throw another sprocket into the mix...... The parking brake is self adjusting as well on the Caravan.

 

[oilboy123]

To throw another sprocket into the mix...... The parking brake is self adjusting as well on the Caravan, at least the drum.

 

[tom slick]

Older toyotas adjusted the rear shoes by using the parking brake. When I say older I mean over 20 years old. I don't know if anyone else does this.

 

[dwendt44]

Four wheel disc brakes on GM cars adjust with the parking brake.
The last four I've had did anyway.

 

[alreadygone]

Originally Posted By: dwendt44
Four wheel disc brakes on GM cars adjust with the parking brake.
The last four I've had did anyway.


Untill they started putting parking brake shoes in the "hat" of disc brake rotors.

Bob

 

[mechtech2]

There may be some additional adjustment benefit with some systems [star wheels]when mashing the pedal in reverse.
With the newer cammed/wedge type, it doesn't matter.

 

[Squishy]

How does the adjuster work on a rear disc setup? I thought disc brakes were "self-adjusting" because there was no spring to force things back, and the piston only retracts enough to make slight pad contact with the disc.

Also, what kind of lubrication is ideal for the adjusters?

 

[dwendt44]

It's not the discs themselves that need ajusting, it's the parking brake that's involved.
The parking brake sometimes uses the inside puke as the brake, and it may wear more than the outside puke.
A ratching takeup, taken up by using the parking brake, keeps things in spec.
Those systems that use a 'shoe' type parking brake have a differing ajustment system that I'm not up on.

 

[tom slick]

what is an inside or outside "puke"?

 

[alreadygone]

Originally Posted By: tom slick
what is an inside or outside "puke"?


NOTHING I'd want near my brakes!!

Bob