ODD Brake setup

[ltljohn]

I had to put rear pads and rotors on my truck(04 Chevy 1500 4wd) today, and I found an interesting arrangement for the parking brake. The parking brake uses shoes inside the rotor while the brakes are regular disk brakes. Never seen anything like that before.

[4wheeldog]

It is fairly common with rear discs. Discs don't function well as praking brakes......They work well with rolling resistance, but don't hold a stationary lock well. Plus, they require too much pressure for mechanical actuation.......Hydraulic pressure is difficult to maintain when system is off.

[Joe Frickin' Friday]

It is fairly common with rear discs. Discs don't function well as praking brakes......They work well with rolling resistance, but don't hold a stationary lock well. Plus, they require too much pressure for mechanical actuation.......Hydraulic pressure is difficult to maintain when system is off.

 

FWIW my last car ('88 Acura Legend) and my current car ('03 Nissan Maxima) both had rear discs, and use a mechanical linkage to activate the rear calipers for parking brake action.

[Ken H.]

I've seen it on other brands too. Seems overly complex, but I guess it works.

[steveknapp]

It is fairly common with rear discs. Discs don't function well as praking brakes......They work well with rolling resistance, but don't hold a stationary lock well. Plus, they require too much pressure for mechanical actuation.......Hydraulic pressure is difficult to maintain when system is off.

 

FWIW my last car ('88 Acura Legend) and my current car ('03 Nissan Maxima) both had rear discs, and use a mechanical linkage to activate the rear calipers for parking brake action.

 

Mitch, maybe it has something to do with the load placed on the parking brake? Or in other words the GVWR of the vehicle.

[Ken H.]

It is fairly common with rear discs. Discs don't function well as praking brakes......They work well with rolling resistance, but don't hold a stationary lock well. Plus, they require too much pressure for mechanical actuation.......Hydraulic pressure is difficult to maintain when system is off.

FWIW my last car ('88 Acura Legend) and my current car ('03 Nissan Maxima) both had rear discs, and use a mechanical linkage to activate the rear calipers for parking brake action.

Mitch, maybe it has something to do with the load placed on the parking brake? Or in other words the GVWR of the vehicle.

Naw, the little Mitsubishi Eclipse has the same set up.

[ltljohn]

It is fairly common with rear discs. Discs remove body panels and the gas tdon't function well as praking brakes......They work well with rolling resistance, but don't hold a stationary lock well. Plus, they require too much pressure for mechanical actuation.......Hydraulic pressure is difficult to maintain when system is off.

 

 

 

FWIW my last car ('88 Acura Legend) and my current car ('03 Nissan Maxima) both had rear discs, and use a mechanical linkage to activate the rear calipers for parking brake action.

 

 

My 89 Olds had rear disks and a mechanical system to actuate the calipers for the parking brake, you actually had to pump the parking brake like a ratchet. It also made it a big pain in the a$$ to replace the pads. This was one of the easiest brake jobs I have ever done. I didn't even have to remove body panels or the gas tank.

[4wheeldog]

It is fairly common with rear discs. Discs don't function well as praking brakes......They work well with rolling resistance, but don't hold a stationary lock well. Plus, they require too much pressure for mechanical actuation.......Hydraulic pressure is difficult to maintain when system is off.

 

FWIW my last car ('88 Acura Legend) and my current car ('03 Nissan Maxima) both had rear discs, and use a mechanical linkage to activate the rear calipers for parking brake action.

 

Like I said, FAIRLY common, not universal. I am sure that the lighter the vehicle, the easier it is to work around the limitations.

To show how dated my initial information was, I can remember reading about this issue when rear discs were first put on Corvettes! (They did use the little drum set up, by the way.

[T__]

I had to put rear pads and rotors on my truck(04 Chevy 1500 4wd) today, and I found an interesting arrangement for the parking brake. The parking brake uses shoes inside the rotor while the brakes are regular disk brakes. Never seen anything like that before.

 

 

John, that is actually an evolution in braking system design.. The specifications require a separate way to apply the parking brake so the standard hydraulics can’t be used to apply the rear parking brake.. There lies the problem,, it is difficult to apply the rear disk brake pads on a truck with sufficient mechanical force to hold the rear wheels locked on a steep hill at GVW including a trailer.. It has been done in the past using a cable operated mechanical means to push the rear brake piston into the brake pads to hold the disk against rotation (still used in some auto applications).. That type of system is prone to corrosion where the mechanical (usually some type of coarse screw or cam) enters the caliper,, or prone to leaks where the actuating mechanism enters the caliper so is difficult to maintain over the life of the vehicle,, especially in salt usage areas.. It is also difficult to keep adjusted as the brake pads wear thin..

 

Using an internal expanding drum type brake (usually uses a single horseshoe type brake shoe inside the machined rotor hub) allows a very aggressive braking material,, allows a very firm apply mechanism,, allows complete release,, allows better caliper function of the main braking system (important on an ABS system).. It is actually a very light weight system as the brake shoe material is molded on a light weight spring type carrier so it needs no external return springs,, the brake rotor is already there so just needs it’s center casting machined as a braking surface & the apply parts are simple & small..

 

Twisty

[eddd]

I had to put rear pads and rotors on my truck(04 Chevy 1500 4wd) today, and I found an interesting arrangement for the parking brake. The parking brake uses shoes inside the rotor while the brakes are regular disk brakes. Never seen anything like that before.

 

 

John, that is actually an evolution in braking system design.. The specifications require a separate way to apply the parking brake so the standard hydraulics can’t be used to apply the rear parking brake.. There lies the problem,, it is difficult to apply the rear disk brake pads on a truck with sufficient mechanical force to hold the rear wheels locked on a steep hill at GVW including a trailer.. It has been done in the past using a cable operated mechanical means to push the rear brake piston into the brake pads to hold the disk against rotation (still used in some auto applications).. That type of system is prone to corrosion where the mechanical (usually some type of coarse screw or cam) enters the caliper,, or prone to leaks where the actuating mechanism enters the caliper so is difficult to maintain over the life of the vehicle,, especially in salt usage areas.. It is also difficult to keep adjusted as the brake pads wear thin..

 

Using an internal expanding drum type brake (usually uses a single horseshoe type brake shoe inside the machined rotor hub) allows a very aggressive braking material,, allows a very firm apply mechanism,, allows complete release,, allows better caliper function of the main braking system (important on an ABS system).. It is actually a very light weight system as the brake shoe material is molded on a light weight spring type carrier so it needs no external return springs,, the brake rotor is already there so just needs it’s center casting machined as a braking surface & the apply parts are simple & small..

 

Twisty

 

It might be an evolution, but it has it's problems. This is the system used on my 2002 Chevrolet 2500HD. The procedure to adjust these brakes is a pain. You need to remove the wheel, rotor, axle, and hub to get make any adjustment! If you try to get around the factory method for adjusting, the left one has an adjuster accessible when the rotor is mounted. The right side has no such access. What is worse, is the 3/4 ton and one ton trucks with this arrangement have rear axle seal problems (that is obvious from the number of failures, but GM won't admit any problem.) The seal failure is usually on the left side. (I've replace the left one 3 times.) When the seal fails, it drips gear lube all over the parking brakes.

 

If you are interested, here is a link to a post I made on how to replace the seal. It gives you a pretty good picture of the system.

 

If the areas of adjustiblity and seal failure were addressed it would be a good solution to the problem associated with parking brakes on vehicles equipped with rear discs. I don't know if the most recent models, but I know 2005's were still having the same issues.