Emergency Break Not Holding Truck?

[EVOL ARDNUT]

My emergency break bottoms out and when I am on incline the truck moves an inch or so after application.

Is that normal?

IS there an adjustment to emergency break to 'bite" harder and not bottom out?

I am in Houston where it is flat, but my driveway has considerable incline.

[MEvang]

You must first check your rear brake shoes, make sure they are in good condition. If OK clean and adjust the rear brake shoes, make sure you have a minimum clearance but no drag. You will probably find at this point that the parking works fine. If it is still low, there is a slack adjustment in the main cable, but only adjust this after there rear brake adjustment has been done. Adjusting this first can cause serious damage.
Mike

[MEvang]

Darn, I'm sorry I looked back at your post and see you have a 2007 Tundra. I left my first post up as it would pertain to any Tundra with Drum brakes.
But the theory here is still the same. You have a small set of brake shoes in side the rotor hub. If you pull the rear wheel there is likely an adjustment access hole in the center of the hub. If not it's on the back. You will want to adjust up these shoes the same way, minimum clearance with no drag. Then adjust the slack adjuster if needed.
The thing to always remember when adjusting any park brake is adjust at the wheels first then adjust out slack if needed.
Mike

[gsxrsquid]

I don't know about later trucks but the 2000 is adjusted by pressing and releasing the parking brake pedal. I had not adjusted mine so long I hadn't been using rear brakes at all. Just press and release parking brake pedal until there are between 6 and 9 clicks when you press it all the way. I think you will find regular breaking improves a lot as well now that rear shows are actually hitting the drums.

[MEvang]

Pressing and releasing the part brake pedal on rear drum Tundra's 2000-2006 models will adjust up the rear brake shoes to some extent. Keep in mine here this is just a dally maintenance thing. If you haven't done this for a long time you'll need to manually adjust the shoes to get a good pedal.
I use my PB everyday and still do a manual brake adjusts about twice a year to keep a good pedal hieght.
Mike

[EVOL ARDNUT]

Dealership Adjusted It And Still Moves 2 Inches When Applied On Incline...2007 Tundra.

Should I Take It Back Because They Were Apprehensive In Doing It?

Break Still Bottoms Out And Does Not Hold Truck.

[DevinSixtySeven]

I'm not familiar with the 2nd-gen ebrake, but it sounds similar to mine...as the pad wears there's an adjusting bolt that has to be set, then backed off, to keep consistent pressure.

How steep is your driveway? Do you have larger tires than stock?

[EVOL ARDNUT]

stock tires-yes

Incline, its not on a mountain but need E.B. OTHERWISE ANY VEHICLE WILL MOVE.

[MEvang]

I have to add here that with the American popularity of automatic transmissions "Parking brakes" are far less important then they used to be. Therefore many will not longer hold a vehicles on a incline without assistance of the transmission in park.
Small "drum in rotor" style park brake don't have the power that a drum or disc activated system had.

"The Evolution of the Emergency Brake"
Parking brake were once called "Emergency brakes" and were a left over of the mechanical brake systems. Up till the late 1930's most cars still used a mechanical brake system. You would actually pull cables that activated the brakes to stop the car. Many felt uneasy with the new "hydraulic brakes and did not trust them, so the mechanical emergence brake system, that could actually stop the car were left as a back up. This was not over kill, up till 1967 a single master cylinder was used. Any leak in the system could mean a total lose of brakes. The mechanical emergency brake was your only hope of stopping.
By the early 1980's split diagonal system appeared and hydraulic systems had become extremely safe. It was down right difficult to loose all your braking at one time. By the mid '60's Automatic transmissions all had park gears (some early units did not) and the emergency brake had been transformed to a parking brake.
By the '80's parking brake were only used by drives when a standard transmission was used. Most drivers of automatic vehicles got out of the habit of using their parking brake altogether.
Now days they are not parking brakes at al but "parking assist brakes". Many vehicle models do not even have a standard transmission option in the US. Parking assist brakes are no longer designed to stop a vehicle or even hold it without the transmission in park.
The next generation of parking assist brake are now showing up in luxury models. They are electrically operated and do not depend on the driver to operate. You don't have to release them either. Don't be surprised that the "parking assist brake one day disappears all together. Technology tends to make these out dated accessories vanish. And this is just the first step to eliminate it.
Mike

[DevinSixtySeven]

Great post mike!

Could you explain the split diagonal system?

Two more questions...

Is it urban legend that a vehicle must (by law) have a second, mechanically actuated emergency brake?

Also is it urban legend that a vehicle can break the transmission out of "park" on a steep hill?

[MEvang]

Good questions, the first one I can answer. Split diagonal braking systems are used manly on front wheel drive cars or can be used on any vehicle that has low rear braking capabilities. Most fwd vehicle have very small rear brakes that only contribute about 20% or less to the braking. On a dual master cylinder system if you split the braking up front and rear and the front brakes are lost, you simply can't stop the car safely on the rear brakes alone. So they in turn split the system diagonally right front, left rear on one side and left front, right rear on the other. This way you always have one front and one rear brake to stop on if hydraulic pressure is lost on one side.
The other question I am not sure of. I take it this is no longer true since they are alowing electrical park brakes systems to be used.
The last on I don't quite understand. Do mean by break out of park, that a vehicle could slip out of the transmissions park gear?
Mike