Can someone describe the 199mm TBU pedal feel on a 96-00?

[tystaco]

Here is my situation:

I did the 231mm TBU on my 2000 limited. I am pleased with the results, much more braking power, BUT it requires you to push the pedal much further before you feel engagement. I understand that this is due to the factory brake booster needing to move more fluid due to the larger pad. I had read in the write up that if you bed the brakes twice you will see that go away...but it didn't. Now this wouldn't be a problem, but the 2000 has become my wife's ride since she loved it so much, and I bought a 1999 limited last weekend.

I have 2 options:

1. Swap the 231mm TBU to my 1999 and put the old 99 calipers on her 2000 with new pads and rotors.

2. Order the 199mm TBU and place that on her 2000 and move the 231's to my 99. I prefer this option, but I need to know if I am going to be facing the same pedal travel that my wife doesn't like.

 

[NBBAZ]

https://youtu.be/z3fFHB5PYGA

Check this video out. (hope the link works).

This is one issue holding me back from doing the tundra brake upgrade. I dont want to have a longer pedal travel to deal with. I wonder if this could fix it or if anyone has tried this.

 

[fblainen11]

I honestly didn't fee much of a difference in brake travel distance. I did 231s on three 3rd gens.

If I were you I'd do a thorough brake bleed and see if that helps.

 

[tystaco]

I honestly didn't fee much of a difference in brake travel distance. I did 231s on three 3rd gens.

If I were you I'd do a thorough brake bleed and see if that helps.

I have bled it, and know what air compression in brake lines feels like. As soon as you reach the pad, it is firm and you stop on a dime, no fading.

 

[19963.4lsr5]

Are your rear brakes adjusted properly? If you jack up rear and spin wheels you should hear shoe contact with the brake drums. That will cause excess pedal travel. I did the tundra brakes and after adjusting the shoes out and readjusting the ebrake clearance I have what seems to be the same pedal feel.

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[JRZEE2000TR4LTD]

Are your rear brakes adjusted properly? If you jack up rear and spin wheels you should hear shoe contact with the brake drums. That will cause excess pedal travel. I did the tundra brakes and after adjusting the shoes out and readjusting the ebrake clearance I have what seems to be the same pedal feel.

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^^This.

Brake pedal travel should be no different.

 

[Kyngfish]

How long have you driven

I recently rebuilt the calipers in my Carrera, and for the first 20-50 miles the pedal travel was much longer than before. Where usually I'd only have to press around 1/4th to 1/3rd to the floor to feel the brakes bite, It was suddenly more like 1/2 - BUT the brakes were not squishy - they were firm once it caught.

The reason was that the pistons in the new seals were retracting too far back. The piston seal essentially rolls a little as the piston pushes outward, and it's almost like a rubber band pulling it back in. On a new or newly rebuilt caliper, the piston is usually flush with the caliper instead of resting closer to the pad. After a reasonable amount of time, the piston situated itself in the cylinder better and the pistons rested closer to the pads.

Not saying you shouldn't be concerned, and the brake system in my 911 doesn't have ABS, so I'm not sure what complexity that adds, but the "deeper" pedal, with the lack of fade sounds a heck of a lot like the pistons having a farther distance to travel. Cheers.

 

[19963.4lsr5]

^^This.



Brake pedal travel should be no different.

I've noticed in my years that improperly adjusted rear brake shoes is usually the cause of excessive pedal travel. Not using the ebrake to keep the auto adjusters tight to me is main reason.

But saying that the ebrake bell cranks need set properly so they have enough travel to operate the auto adjuster arm too.....


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[tystaco]

I will look into adjusting the rears. There must be a good link around here. I guess I am just surprised that putting new calipers on would suddenly change the rear brakes adjustment...seems too coincidental, but I have to rule it out. The pedal was firm before right away, now it is firm but has to travel 2" further to be firm.

Can anyone compare the 199's feel??

 

[JRZEE2000TR4LTD]

I will look into adjusting the rears. There must be a good link around here. I guess I am just surprised that putting new calipers on would suddenly change the rear brakes adjustment...seems too coincidental, but I have to rule it out. The pedal was firm before right away, now it is firm but has to travel 2" further to be firm.

Can anyone compare the 199's feel??

I have 199s. Feel the same as the stock calipers when comparing pedal travel. I've driven a truck with 231s which I didn't even know had 231s. Same kind of pedal travel.

Did you clamp or stop up the brake line when you swapped?

 

[tystaco]

Did you clamp or stop up the brake line when you swapped?

Clamped and vacuum capped.

 

[JRZEE2000TR4LTD]

Clamped and vacuum capped.

Ok, how far does your ebrake come up when you pull it?

 

[19963.4lsr5]

When I did mine I replaced the lines too and got everything setup and had the bleeder open on the new caliper. Then let it drip while connecting the new caliper and line. It wasn't too messy. I just pulled the old caliper to the side and mounted the new larger one with the new lines in it. Then done the messy part last. The air always had a place to go with the bleeder open. You may not like hearing this but you may still have air in system.

Don't pump up brakes before you open the bleeder. It just makes two or three large bubbles into a million little bubbles that go all over the place.

If you don't have a pressure bleeder then ........have a helper open the bleeder-depress brake pedal to the floor-tighten bleeder-release brake pedal. That way the air always has a place to go. Sometimes it takes a second bleeding later to get the rest of the air out.

I like my pressure bleeder. It makes it a 1 person operation.


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[tystaco]

I will rebleed to cover the base. Are you to go all the way to the floor? Some write ups talk about that wrecking the seals on the MC.

 

[19963.4lsr5]

I will rebleed to cover the base. Are you to go all the way to the floor? Some write ups talk about that wrecking the seals on the MC.

To me if going all the way to the floor wrecks the seals then the MC should be rebuilt or replaced. The FSM for my truck specified the above procedure. Going to the floor and holding it there till the bleeder is closed. Anything less can risk sucking air back in the system.

Unless you have the person close bleeder while your pushing pedal and stoping before pressure is built up. Which I never tried.


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[tystaco]

To me if going all the way to the floor wrecks the seals then the MC should be rebuilt or replaced. The FSM for my truck specified the above procedure. Going to the floor and holding it there till the bleeder is closed. Anything less can risk sucking air back in the system.

Unless you have the person close bleeder while your pushing pedal and stoping before pressure is built up. Which I never tried.


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I can't say I disagree with your logic. Write ups just tell you to place a block of wood behind the pedal to prevent the last inch or two...person puts the pedal to the block, close the bleeder, repeat.

 

[19963.4lsr5]

I can't say I disagree with your logic. Write ups just tell you to place a block of wood behind the pedal to prevent the last inch or two...person puts the pedal to the block, close the bleeder, repeat.

I can't argue with that either. Give it a shot.

Every few years when doing a oil change I'll open the bleeders and gravity bleed the system till I see clean fluid come out. I've seen people with nasty brake fluid that was 15 years old. I think that is the main reason for MC failure. Not keeping the fluid relatively clean. (Same with power steering fluid)

Edit: I never worried about the MC seals.


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[tystaco]

Bled them again yesterday...didn't see any air come out. Might have made a SLIGHT difference in that you feel a little engagement sooner, but the real grab doesn't come until further into the pedal.

My wife says she is used to it now...so really, bullet dodged. I am going to order the 199's for my second runner and compare the two.

 

[19963.4lsr5]

If you jack up the rear axle and spin a rear wheel do you hear slight brake shoe rubbing? Or do the wheels free spin with no noise? If they free spin with no noise adjust the rear auto adjusters. Excess pedal travel a lot of times is improperly adjusted rear brake shoes on vehicles that have them.


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[NegroTundra]

I literally just finished with the 199mm install this morning. The first test drive, brakes wouldnt bite till the pedal was much deeper than before. Bled brakes a second time, and voila, just like she was before. I found it interesting though that during the second bleed I did not see single bubble of air come out. I have a different issue now though, fluid is leaking out of the bleeder valve threads. Probably start a new thread about that one if I can't get it resolved.

And BTW, given all the rear brake adjustment comments, my rear brakes are perfectly adjusted, so perhaps that helped my luck.