T100 Brake Booster Upgrade

Start with why the ABS light is coming on and work from there.

If you have a OBD-II scan tool that reads ABS codes, it might tell you the stored code that was causing the illumination. A good scan tool can also tell you the vehicle's speed, and each wheel's ABS sensor speed.

If you DON'T have an ABS capable scan tool, you can can use a bare wire, paperclip or something similar to get the ABS code. If you can stop and do this as soon as the ABS light illuminates that would be great.

You will need to connect two of the connectors inside of the OBD-II port above the gas pedal to get a code. #4 and #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 having issues.

 

Wow very interesting I don't have a abs capable obd reader, but I will try and get a hold of one so it can be easier.

 

Ok so I replaced the booster under warranty and still the same resistance. I also checked vacuum and I'm getting about 23 in which I believe it prefect. What I did notice is I not getting the little hiss by the brake pedal so maybe it was leaking a little vacuum but that wasn't the issue.

 

Any help would be appreciated, I have noticed that the truck is slowing down on its own. Like if there is light pressure applied to the brakes.

 

Wheels getting hot?

 

I would have to take a temp but don't see no smoking.

 

Also just to disengage from park to drive you have to push down very hard.

 

So I pulled over and passenger calibers is hotter then drivers side I spit and it Sizzles.

 

Since one side is hotter, i’d pull the calipers and work the pistons in and out, one may be stuck. If mine start to drag again, i might get some new calipers.

 

Even though they where fine before the new t100 booster and M/C? Could it be something else?

 

Theres a dealership tool that will cycle the abs pump on command. Maybe some gunk got dislodged from the lines during the swap?

are your caliper pins greased? Noticed some drag when i jacked my truck up, pulled the pads, greased the pins, worked the pistons, all is well.

 

Not for our trucks. Too old. Empty Lord confirmed before when myself and a few others asked.

 

Huh. Can it be hotwired?

 

How old are the calipers?

 

Not that old around 2 years they are I believe tbe 13WL

 

Sorry, I'm out of ideas.

 

Dirt or gravel road/lot and some heavy braking will do it.

I see NJ as his location. If they got some salt & water behind the dust seal on the calipers... could be time again.

 

So a little update still haven't figured it out. I inspected the calipers and they are not stuck. I took the pads off and cycled the pistons cleaned everything up and reinstalled them. Still have the same issue the pedal is super firm. Now I did notice that when I took the pads off and was cycling the pistons the pedal firmness was normal.

So not sure my theory is correct but is it possible that the new master and booster doesn't provide enough travel and that's the reason for the firm pedal?

 

So just went out for a drive and truck is slowing down on its own again and the passenger side caliper is hot. I'm guessing it getting stuck once It starts getting warm. Now I'm thinking in just upgrading to the GX470 caliper but not sure snice I already have issues with braking. What do you guys think

 

Did you ever count the blinks for the abs light?

 

Hasn't been on snice and no code comes up.

 

So I just got home from doing a 15 min drive and my rotors are 411⁰ and my calipers 211⁰ I would be driving and I would be slowing down like if I was pressing the brakes.

 

May have missed this in re-reading your posts but is the booster check valve the original or did a new one come with the new booster if an AC comes with one ?
I suppose what I am wondering is if your check valve is good or does an AC have a booster check valve ?

 

New booster New Check valve which I have checked.

 

Ok so not sure what clicked in my head but I took the M/C out to check the push rod length and guess what it was way to long. I adjusted it the most I could have boom the pedal is much softer. Know I'm going on a drive to see if the car doesn't stop on its own.

Moral if this story is check the push rod.

 

If you spread the front passenger pads, and start the truck with the front jacked up, do they start dragging by themselves? Or do you have to hit the brakes to start the dragging?

 

I think you are the first person that has paired the T100 booster/MC with the stock calipers. The T100 upgrade was intended to be paired with the larger 14WA calipers. Supposedly the larger bore MC would help push more fluid to the larger diameter caliper pistons.

I have the exact opposite problem as you. After doing the 14WA swap I've had a mushy pedal ever since. I've not done the T100 swap though.

 

Shit really I thought I had read guys swapping with the 13WL calipers.

 

Have you played around with your booster rod?

 

I have not. Seems like my issue is different since the pedal firms up after I up it once. I guess it's worth a shot. I would want to lengthen the rod so it's not traveling as far I assume?