Brake problem

Here's what I have 2005 Tundra crew cab sr5 2x4 with the hydro assist brake system. The vsc, abs and brake light plus an annoying alarm are all on. I can tap the unit under the hood and sometimes the brake system will work correctly and sometimes it won't. Any clue to what the problem might be.

 

What does your brake fluid look like? Check the LSPV in the back under the bed and see how the hoses look?
There are a few different things that it could be. Can you post some pictures of the Master Cylinder and brake booster? Do you have any history on the truck? Has any work been done recently; either before or after this problem occurred?

 

I had replaced the rear brake about a week or 2 weeks before this problem started..

 

what did you replace? Both sides or just one?

 

And did you properly bleed the brakes after? AND bleed the LSPV?

You can't just open the bleeder and call it a day. You need positive pressure on the MC while you bleed. And bleed all four corners and LSPV in correct order.

 

Mine is missing too! How do I adjust this?

 

Yup. This gets my vote too. After replacing my brakes I had the brake light symptom too...but that was just while moving my truck to a better spot for bleeding.

 

You're what is missing?

 

LSVP

 

My truck must make automatic adjustments. I feel like the rear brakes are not keeping up and the front is taking on too much when braking. I will look into the drums and see if my shoes are worn.

 

Do you have an ABS capable scan tool? When that ABS light is on, it will spit out an error code very similar to a check engine light. Not all scan tools can read ABS codes.

If you do not have a scan tool, you can use a paper clip or jumper wire inside the OBD-II port above your gas pedal. You'll stick one end in connector #4 and the other in #13.



Once you have the connection made, switch the ignition on. The cruise control light should be blinking rapidly. After a few seconds, the ABS light will start flashing. Count these flashes, there will be two sets of them. (i.e. flash-flash-flash pause flash-flash-flash-flash = 34)

Here's a list of all the DTCs on the ABS system: https://www.toyotaguru.us/sequoia-2007-repair/dtc-chart-of-abs-system.html

If you got code 34 for instance, that would be your left rear wheel speed sensor.

It looks like you are missing the arm that connects to the LSPV and probably not the actual LSPV itself. The spare tire is hiding it so I can't tell for sure.

It probably broke off the bracket and someone shortened it all together. That arm is what opens and closes the valve and adjusts the braking bias. That's what you're probably feeling when you say this:

Crawl under your driver's rear. Do you still have a part that looks like what is circled in red, where the brake lines are connecting to?



Edit: there is the possibility the trucks with VSC don't have this same proportioning valve and it's handled through the master cylinder. If that's the case, there's nothing back there to adjust or bleed.

 

I don't know if you've seen this thread, but non-functional automatic adjusters are a common problem on our trucks.

Technically, its a broken or badly adjusted parking brake that is usually the problem. Read more here:

https://www.tundras.com/threads/rear-brake-adjustment-theory-and-practice.99575/

 

The questions from @shifty` would have been my next one. Let us know.