New Brakes, Soft Pedal (long post)

Hey all, I purchased my 2002 Tundra Limited in April and she's been amazing. Only 134k and very clean for a mid-west truck. I did need to change the brakes and realized that one of my caliper pistons had seized. So I made the reasonable decision to upgrade everything. I went with the Powerstop Z36 package with calipers, pads, and rotors. Before I changed the brakes, the brake pedal was very firm. A small breath on the pedal was enough. After the brakes were swapped, the pedal was a bit more soft, but nothing alarming. When bleeding the brakes after the swap, the rear bleeder valves were completely seized. I decided to let the shop take care of the brake cylinders to get new rear lines, brake cylinder and such. When I picked the truck up, the pedal was so soft that braking would not start until 1 inch before the floor. If pumped, the pedal would firm up, but if released fully, would need to be pushed to 1 inch above the floor again. I returned the truck to the shop and made them aware of my concerns. They took it for another hour and a half. The tech flushed the system bled the lines again, bled the master cylinder, checked the front brakes, and check for leaks. Everything passed. He isolated the rear brakes and said the pedal was hard as a rock. He isolated the front and said that is when the brake pedal got soft. He said it wasn't abnormal to have a soft pedal and it was safe to drive as he tested it multiple times.

This seems a bit strange to me but I am not sure where to go from here. I got home and bled the system myself to check and all seemed good.

Any insight is helpful. Thanks so much.

 

Bigger calipers require more volume = more pedal travel.

 

I appreciate your response and understand that. I guess I was just surprised and the amount of pedal travel required. I have worked on cars with larger calipers and experienced further travel but this is my first truck build so if this amount of travel is normal in this case, I am glad to know that. Thanks again!

 

Rears are likely not adjusted properly. In these trucks, the rears are the key to brake feel. You need the rears to engage at the proper time for the fronts to get good pressure. Adjust the rear brakes on each side until you hear them slightly dragging. Check the LSPV to make sure it was also bled and it can also be adjusted to help with rear brake engagement. Lots of threads on here describing the process.

 

Awesome, thanks so much for the feedback and insight. Ill look into that.

 

It sounds like he only went up to the 13WL's. That's not enough increase to make his pedal go almost to the floor. That's the same kit a lot of people have used.

 

I would agree with adjusting the rear brakes. On vehicles with drum brakes that I’ve owned, the rear brake adjustment definitely made a huge difference. If you have a service manual for that truck, they often have an adjustment procedure, but adjusting them until they just start dragging is often a good place to start. Sometimes the procedure is something like: adjust the rear brakes until the tire locks up, then turn the adjuster screw back two turns. Either way, they always needed to be adjusted tighter than I would have thought.

The other item I would look in to is the ABS module. The ABS module sometimes needs to be cycled to completely bleed the system. You can sometimes do this with a quick stock on a gravel road to get the ABS to actuate. Or the shop can do it with the right scan tool. Air bubbles can hide in there.

 

Did your mechanic know to bleed the LSPV on the rear above the differential?

Also, as said above, rear brake adjustment is key for decent pedal on these trucks.

 

How well does your parking brake work? It is what adjusts your rear brakes. Check out the stickied post on this site about it.

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

 

I too have noticed longer than I'm really comfortable brake pedal travel on my 05 Tundra. I feel like the brakes could be better too. So if a larger disc isn't the answer, I imagine it probably needs new calipers, discs, pads, and new fluid.

 

Had the same thing happen with my 00 Trunda. I tried everything.. changer the master, lines, calibers... bleed everything that you could bleed. Adjusted back breaks and all pedal problem went away.