199mm TBU Questions

[Arv]

The ABS is a whole separate issue, and I think it has to do with brake bleeding or just a plain bad ABS pump(maybe more common than we think past 150k).

OR the 4runner ABS was DESIGNED and CALIBRATED with the 4Runner caliper and changing to a Tundra caliper whether the 199 or 231 messes with the engineering and design. I'm no ABS expert but I'm assuming that the ABS pump is pumping at a designated amount/rate but now the volume of brake fluid in the caliper and size of pistons, pads, etc... have changed so it does not work as well or as designed. This is why I am also thinking that the ABS issue is more pronounced with the bigger 231 vs the 199 that are almost the same size as the stock calipers.

Its an anti-locking brake system, designed by Engineers with individual parts that work well together, sometimes we get lucky when when change something in an Engineered System and it works well or even better BUT I'm afraid it might not be the case for this brake upgrade wrt the ABS.

 

[gamefreakgc]

OR the 4runner ABS was DESIGNED and CALIBRATED with the 4Runner caliper and changing to a Tundra caliper whether the 199 or 231 messes with the engineering and design. I'm no ABS expert but I'm assuming that the ABS pump is pumping at a designated amount/rate but now the volume of brake fluid in the caliper and size of pistons, pads, etc... have changed so it does not work as well or as designed. This is why I am also thinking that the ABS issue is more pronounced with the bigger 231 vs the 199 that are almost the same size as the stock calipers.

Its an anti-locking brake system, designed by Engineers with individual parts that work well together, sometimes we get lucky when when change something in an Engineered System and it works well or even better BUT I'm afraid it might not be the case for this brake upgrade wrt the ABS.

All I'm saying is that on stock calipers with good pads with plenty of life, I would skid into the intersection on a regular basis in the rain because the ABS would kick on when I was in complete control of the vehicle. Put on bigger brakes and it doesn't happen anymore.

 

[Arv]

All I'm saying is that on stock calipers with good pads with plenty of life, I would skid into the intersection on a regular basis in the rain because the ABS would kick on when I was in complete control of the vehicle. Put on bigger brakes and it doesn't happen anymore.

Well I guess you're one of the exceptions, good for you. Like I said sometimes we get lucky when when change something in an engineered system and it works well or even better. In you case it paid off.

I had a few ABS incidents in the snow but its more like ice under a thin layer of snow so I think any ABS would have activated then. I never had any ABS incidents in the rain as I drive more careful (I think I do, lol) when its wet but ABS always kicked in for me in dry conditions even when the rig was new when I would be slowing down to take a turn (not really even turning that much yet) and I hit a bump or pot hole, maybe even a crack lol! I did come in pretty hot most of those times but as i recall some were pretty slow speeds.

 

[gamefreakgc]

Well I guess you're one of the exceptions, good for you. Like I said sometimes we get lucky when when change something in an engineered system and it works well or even better. In you case it paid off.

I had a few ABS incidents in the snow but its more like ice under a thin layer of snow so I think any ABS would have activated then. I never had any ABS incidents in the rain as I drive more careful (I think I do, lol) when its wet but ABS always kicked in for me in dry conditions even when the rig was new when I would be slowing down to take a turn (not really even turning that much yet) and I hit a bump or pot hole, maybe even a crack lol! I did come in pretty hot most of those times but as i recall some were pretty slow speeds.

I still get the ABS kick-in too over speed bumps. Usually because I didn't see it and the wheels literally come off the ground lol.

 

[Dieselchessy]

I think(??) that the issue with the ABS is that it pulses all the wheels when one slips. So your stopping fine, one wheel sensor detects a lockup, and the ABS then pulses all 4 wheels reducing braking power.

For me the TBU upgrade helps with the ABS. The way it helps is by avoiding warped rotors. When my stock rotors would warp then braking wasn't smooth and I'd lock up wheels much more often. With the TBU rotors don't warp and applying smooth consistent braking to avoid lock-ups is much easier.

I live up in the hills above town, so my daily drive involves several miles of down hill with switch backs and stop signs right at the bottom of hills. The OEM size 4 runner brakes never survived long.

I've never owned newer than a 99 so don't have intimate knowledge of the newer ABS.

I don't try and outsmart Engineers. I just understand that they have to consider many factors in their designs and sometimes I have a much narrower focus and usage. Sometimes changing things like suspension and such doesn't improve the overall design but for a small focus area of use. And almost always there is tradeoff and compromise when making changes.

 

[T4R2014]

OR the 4runner ABS was DESIGNED and CALIBRATED with the 4Runner caliper and changing to a Tundra caliper whether the 199 or 231 messes with the engineering and design. I'm no ABS expert but I'm assuming that the ABS pump is pumping at a designated amount/rate but now the volume of brake fluid in the caliper and size of pistons, pads, etc... have changed so it does not work as well or as designed. This is why I am also thinking that the ABS issue is more pronounced with the bigger 231 vs the 199 that are almost the same size as the stock calipers.

Its an anti-locking brake system, designed by Engineers with individual parts that work well together, sometimes we get lucky when when change something in an Engineered System and it works well or even better BUT I'm afraid it might not be the case for this brake upgrade wrt the ABS.

Oh, I definitely agree on the calibration. I don't think brakes are so simple. I wonder how 231's affect VSC performance in 01-02s. Even the rear wheel cylinders differ depending on what factory brake option you have. That being said these ABS systems can exhibit funky behavior even on factory calipers. Tundra brakes didn't help. Almost sounds like the pump starts working more slowly over time.

 

[T4R2014]

I think(??) that the issue with the ABS is that it pulses all the wheels when one slips. So your stopping fine, one wheel sensor detects a lockup, and the ABS then pulses all 4 wheels reducing braking power.

For me the TBU upgrade helps with the ABS. The way it helps is by avoiding warped rotors. When my stock rotors would warp then braking wasn't smooth and I'd lock up wheels much more often. With the TBU rotors don't warp and applying smooth consistent braking to avoid lock-ups is much easier.

I live up in the hills above town, so my daily drive involves several miles of down hill with switch backs and stop signs right at the bottom of hills. The OEM size 4 runner brakes never survived long.

I've never owned newer than a 99 so don't have intimate knowledge of the newer ABS.

I don't try and outsmart Engineers. I just understand that they have to consider many factors in their designs and sometimes I have a much narrower focus and usage. Sometimes changing things like suspension and such doesn't improve the overall design but for a small focus area of use. And almost always there is tradeoff and compromise when making changes.

Your explanation makes it sound like Toyota sold these off dealer lots and handed keys to automotive journalists with rotors completely warped. I have a feeling if they problem was as bad as it seems on T4R.org(home of the "LBJ failures are caused by anything but lift kits" crowd), then there would've been an SSC sent to your mail which got you upgraded calipers. Toyota did this for early Tundras.

 

[Dieselchessy]

Your explanation makes it sound like Toyota sold these off dealer lots and handed keys to automotive journalists with rotors completely warped. I have a feeling if they problem was as bad as it seems on T4R.org(home of the "LBJ failures are caused by anything but lift kits" crowd), then there would've been an SSC sent to your mail which got you upgraded calipers. Toyota did this for early Tundras.

I realize your on a big anti-TBU kick and take every opportunity to profess your distain.
I can agree to disagree.

 

[T4R2014]

I realize your on a big anti-TBU kick and take every opportunity to profess your distain.
I can agree to disagree.

I mean come on, let's try to reason with this mod. It's like every other mod bandwagon. Haven't really heard any numerical proof of this mod performing better than stock. Even the claim that the 199mm caliper displaces the same amount of fluid as stock is pretty much unbased as far as I've seen. Two 199mm setups using ceramic and semi-metallic pads yet I couldn't get a better result than simply staying stock and ensuring the rears were in proper adjustment. Perhaps it prevents warping for avg 10,000 miles more than stock. But then is it really worth the cost of upgrading all the calipers? Might as well spend the cash on better quality rotors. Second gen 4Runners use a very similar rear setup but you rarely hear warpage issues. Similar with the newest Taco as well. I'm just looking for the cause.

OH btw, I'll keep people updated on the 199mm with EBC setup once installed.

 

[T4R2014]

[MENTION=549924]Devbot[/MENTION] What did you go with. I'm about 1000 miles into the EBC Greenstuff 6000 with EBC blanks. Their rotors nicer than Brembo's. The Greenstuff 6000 pads have a decent bite, and definitely better than Powerstop ceramics.Only downside is the dust is insane. I still recommend PBR heavy duty brake pads for their bite and low dust.

 

[Devbot]

Never did make the jump, couldn't make a decision at the time and had other things that needed attention first.
I would have to get new wheels before I do the mod as my OEM sport calipers rub on my wheels and needed some grinding to make work, so anything larger would just get worse. I could get spacers, but I'm very happy with how my wheels are spaced as is and not too keen on going much wider.