My 2006 Tacoma brake upgrade (EDITED!!)

We have new master cylinders....I don't trust used hydraulic parts that have been sitting around with open ports exposed to who knows what....not a good idea. Boosters don't deal with fluids so much safer used.

Rebuilt boosters are also an option, but that adds about $250 and realistically...I don't think it's needed. These are not problematic units.

 

Since someone is probably gonna ask what's up with the female fittings...these are fittings designed to clip into a body bracket when used down at the caliper...That's why it has the flat and the groove in it. Instead of ordering new plain hex fittings, I just used what we had...functions fine.

 

I just did a 14" front disc with six piston caliper upgrade with a rear conversion to disc and still have pedal play even after two full bleeds including the ABS system, no leaks in the booster after tests it's oem do you recommend a upgrade to a larger booster and master cylinder? I'm running 35x12.50x 18's on 9" rims and need the stopping power while pulling my heavy cargo trailer, I am taking it for another diagnostic at a performance shop next week hoping they can resolve the issue any positive input would be appreciated and by the way you did did a great job on your upgrade congrats!

 

I'd definitely install a larger master cylinder and booster.

 

What 6 piston caliper and what rear caliper? What do you mean by "I still have pedal play"? Do you have a low but firm pedal? Do you have a soft pedal?

 

Front system; Wilwood's W/B 140-14578-D big brake kit with drilled and slotted 14" rotors 140-14578-D's, kit name;; "Wilwoods Forged Narrow Superlite 6R Big Brake Front Brake Kit".

Rear System: Pedders rear brake conversion kit PED-PBCK006 , Pedal travels approximately 3 1/2" then stops firm with low pedal booster tested no leaks, line test no leaks, master cylinder tested no leaks.

 

I was curious so I measured mine. With how I measured mine it rests at 4.25", pushing the pedal with my hand the pedal travels to 1.75", for a total of 2.5". I'm positive the pedal would go further if I pushed it with my foot instead of my hand.

Your truck went from a pair of 4 pistons calipers (total of 8 pistons) and a fairly small pair of wheel cylinders to I think 22 pistons and you're moving those 22 pistons with a master cylinder that's exactly the same size, moves the exact same amount of volume as it did before, and you're doing it with no extra assistance (bigger booster or dual diaphragm booster). Even if my piston count is incorrect the volume of brake fluid held in the stock braking system is significantly different than the volume that is held now.

The answer was/is extremely obvious to me, the system is going to require more fluid to be moved and extra assistance is never a bad thing.

 

Ignore piston count...it's meaninless.

Look at piston surface area. The Wilwood 6 pistons have .25 sq in. LESS surface area than the OEM 4 piston calipers. The front brakes are not contributing to a low pedal. The rear brakes may be, but I can't find any info as to what caliper they're using...If I had that information, I can do the math. You might pinch of the rear brake hoses (if rubber....don't pinch SS braided lines), start the engine, and see how the pedal feels.

I dislike rear disc conversions because it's damn near impossible to compare the hydraulic sizing/torque of a drum brake assembly and relate that to a disc brake assembly.

I imagine the rears are consuming a significant amount of fluid volume which is causing your low pedal. The solution would be either a smaller bore caliper in the back (less brake torque in the rear, but higher pedal) or a larger master cylinder (less relative brake torque in the front, and a harder pedal). Neither of which are good options.

The front setup seems correct. The rear is the problem here.

 

You're correct in that piston count isn't necessarily important but the piston diameter by itself doesn't give the entire picture either. It's about the volume inside the cylinders in the calipers with their pistons installed and how much fluid it takes to move those pistons.

Your idea on temporarily pinching the real line is a good idea.

 

Volume inside the bores makes no difference....if it did, your brake pedal would go to hell when the pads wore a bit. The seals only retract the pistons .010" or so when the pedal is released...multiply that number (0.010) by the surface area of the pistons (4.75") in this case and that's our fluid volume movement between apply and release of each caliper half. The OE calipers have a surface area of about 5.00 sq/inches per half, so the difference is more or less non-existent.

 

I disagree but it's difficult, at best, to argue with math. Pretty sure that means I'm incorrect. Lol.

 

This was definitely the trucks heaviest haul to date. 2006 V6 double cab, auto, PreRunner, 400-500 lbs in the toolbox and in the back seat's floorboard, plus 200ish lbs in the bed, plus a tandem axle utility trailer that had working brakes, plus several thousand pounds in the trailer. A total guess is 7,000 lbs in the trailer not including the trailer's weight. There was a lot of slamming of weight on and off my custom built hitch whenever the trailer's brakes kicked on or off and it would totally harshly move the truck. The truck itself never complained until I tried to tow the trailer up a really steep mountain so I left the trailer mid-way on the mountain, put more in the bed, emptied the bed, took more out of the trailer and put some in the bed a second time, emptied that, and then towed the trailer up the mountain.

I definitely would not have tried it without the 4Runner front brakes and the Tundra master cylinder and booster upgrade. It stopped extremely well and a lot better than I thought it would.






An all day job (11 hours).

 

I picked up the pedders rear disk conversion for my 07, what master cylinder is the go to?

 

Thanks, I can pinch the back brake lines to verify your input if they are rubber if not then I will check into what caliper Pedder's is using and get back to you. I also checked the vacuum and the gauge is reading at 23lbs if that makes a difference since I was told by Wilwood techs that the vacuum needs to be at a minimum of 20lbs. I just need to get this problem resolved!
Do you think that by going to Tundra's master cylinder with braided steel hose should fix this issue, I reviewed the link you had posted.

Here is the link to my Pedder's rear conversion parts
https://pedders.com/products/pbck006-brake-conversion-kit-rear-toyota-tacoma-2005-present

 

Sorry if missed this, but I run a shock hoop for my coilovers. How much longer Tundra is the unit? Not sure I can fit it with my shock hoop.

 

A shock hoop like an engine cross bar that connects the upper strut mounts? Like the Dirt Design one?

 

It's 11 3/4" long but requires more room than that to be installed.

Does your TRD Sport have traction control?

 

I does not, I will measure tonight and see if it will fit. Thanks DG

 

If anyone is planning on doing this conversion, I have an extra Tundra master cylinder up for grabs, shipping costs only.

(the eBay seller sent me a master cylinder instead of a brake booster, hence why I have the extra).