brake system TOO sensitive

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The system is always pressurized. Pump stores energy in the accumulator when then bleeds pressure out consistent with pedal pressure. If the hydraulic pressure downstream of the master wasn't releasing then the truck would feel very heavy and sluggish. And the brakes would smell hot.

I almost wonder if you don't have a cracked brake pad. Grabby, non-linear brakes are a symptom of that. If the pad is in two pieces, the front can wedge under the rear and the wedging action itself increases braking force.
 
OregonLC said:
The system is always pressurized. Pump stores energy in the accumulator when then bleeds pressure out consistent with pedal pressure. If the hydraulic pressure downstream of the master wasn't releasing then the truck would feel very heavy and sluggish. And the brakes would smell hot.

I almost wonder if you don't have a cracked brake pad. Grabby, non-linear brakes are a symptom of that. If the pad is in two pieces, the front can wedge under the rear and the wedging action itself increases braking force.
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I took the front brake pads out to inspect them when I installed the OME shocks just after we got it and they seemed like new with no issues. They were blue so I asked Toyota what brand they installed since Toy pads have always been brown to my knowledge and they said the new Toyota pads are blue and the tech I was speaking with said he installed them in my wifes car himself.

I'll take it in to the dealer next week to have them look into the possibility of messed up caliper, master cylinder or pads. Lucky for me they did all this work while it was on their lot so its covered under the 1 year Toyota service warranty (if I can get them to admit something is wrong).

I'll keep you all posted.
 
The brakes on our 04 are also VERY sensitive compared to my 2000 and they have newer Lexus pads.
 
The problem was never resolved even after I had the master tech from Lexus visit the dealership and test the truck. Their reply was "it is normal" which was BS. At a later date I sold that one and bought a different one.
 
Today Toyota service checked out the calipers, and pad brackets and said its all OK (when they did the brakes on my LC 6 years ago they put the rear pad brackets in all screwy to the point one of them was rubbing on the rotor before I realized they were in wrong when I changed the rotors and pads myself 2 years ago). I'll take her rig out today and re-break-in the pads and rotors. If that doesn't calm the brakes down a little I guess I'll just make do until I change out the pads and rotors in a couple years.
 
There's something wrong here.
- The ABS triggers when one or more wheels lock up [stop turning when vehicle speed > 0 MPH. ]
- If the brakes are locking up and triggering the ABS under normal braking, something is wrong. As others have said, wheel lockup should only occur under very heavy braking and/or if one or more wheels are on ice/oil/other slippy surface.
- The pads and calipers might look fine [and may be fine] but if the braking system is acting as you describe there is definitely a problem that needs to be solved.

This is a safety issue. Keep on it until it is fixed. Please don't assume 'its just something to get used to'. Its not.
 
lexus had the same answer "everything is normal" but it wasnt. the truck used to engage abs even with the slightest touch more than normal on a dry road. it was not normal.
 
Dwon said:
Today Toyota service checked out the calipers, and pad brackets and said its all OK (when they did the brakes on my LC 6 years ago they put the rear pad brackets in all screwy to the point one of them was rubbing on the rotor before I realized they were in wrong when I changed the rotors and pads myself 2 years ago). I'll take her rig out today and re-break-in the pads and rotors. If that doesn't calm the brakes down a little I guess I'll just make do until I change out the pads and rotors in a couple years.
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Driving home from Toyota the brakes were a little better. Not quite normal, but not nearly as bad as before. Took it out and broke in the pads like they should have been done when first installed by Toyota before we bought it (50 mph - 5 mph hard braking without engaging ABS ten times, until the rotors glow blue). Now its a lot closer to my 01. I'd say its either something they accidently fixed like a sticky caliper or more likely properly breaking in the pads, or both.

My wife's 02 is a now only a little faster at braking, but not what I'd call out of the normal.

I knew I should have broke in the brake pads as soon as we brought the rig home from the lot in Aug.
 
Its probably something they fixed. Braking in rotors is a myth at best. If anything its going to warp your rotors as thesearent yigh end high heat rotors that can withstand the process.
 
lexs470 said:
Its probably something they fixed. Braking in rotors is a myth at best. If anything its going to warp your rotors as thesearent yigh end high heat rotors that can withstand the process.
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There's two very different views of "warped" rotors, what causes them, and what the "myth" actually is regarding them.

The old view says rotors "warp" or deform normally over time or heat, changing shape and distorting and rotors should be ground down with each pad replacement.

The other view (seems to be the most popular, i.e., only view I could find online) is what you find when you google "warped rotors myth." It says that car rotors don't actually "warp," the brake pads lay down pad material unevenly when hard braking if the rotors weren't properly coated with pad material to begin with, thus resulting in jidder. Grinding rotors is only required to grind off the old layer of pad material before putting on new pads, but only if you're using a different brand or composite of pad.

http://www.stoptech.com/technical-support/technical-white-papers/-warped-brake-disc-and-other-myths

http://www.examiner.com/article/there-s-no-such-thing-as-warped-brake-rotors

http://www.mossmotors.com/SiteGraphics/Pages/brake_discs.html

Having grown up constantly accepting jidder as a "warped" rotor and grinding down my rotors every time I replaced the pads, I assumed that was the right opinion. That is until I decided to try an experiment and "properly break-in" my pads and rotors last time I changed the pads, rotors, & bearings. 6 years and going with no jidder, I'd say I have to agree with the current view that proper pad "break-in" works.

Shops could explain that the jidder is caused by uneven pad material because they didn't properly breakin your pads when they installed them and just grind off the uneven material without actually cutting into the metal, but its easier for them to just slap on some pads and grind down into your rotor's metal, which means you'll keep needing to buy new rotors from them every pad replacement.

I can't say with any authority (other than personal experience) which is actually myth, "warped rotors" or "properly seating brake pads" but I know what works for me and I can't find any info online that says properly breaking in your pads will warp the rotors.
 
Dwon said:
Shops could explain that the jidder is caused by uneven pad material because they didn't properly breakin your pads when they installed them and just grind off the uneven material without actually cutting into the metal, but its easier for them to just slap on some pads and grind down into your rotor's metal, which means you'll keep needing to buy new rotors from them every pad replacement.
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Super interesting. I have somewhat of a jitter when I brake. I just put on new OEM pads, but decided to leave the rotors and machine them a bit later. My fiance's dad is a tech and he didn't really explain it like that to me, but he's old school so maybe he's of a different belief. Are you suggesting that I have him machine the rotors only slightly, and then do some seriously exaggerated braking immediately after? Would it be pointless without brand new pads at the same time? I think I could afford a new set lol :rolleyes:
 
I'd say read through these articles. Don't take my word for it.

http://www.stoptech.com/technical-su...nd-other-myths

http://www.examiner.com/article/ther...d-brake-rotors

http://www.mossmotors.com/SiteGraphi...ake_discs.html

New Rotor w/ Old Pad works
New Pad w/ Old Rotor won't work because the old rotor is imbedded with the pad material from the old pads. It will work if its the same pad manufacturer and material though.

But if your getting jitter, I'd say replace your rotors. You'll be done replacing them before a shop will be able to diagnose the "problem" causing your jitter.

Personally I'll never pay someone to grind my rotors down again. Raybestos rotors run between $20-40 on RockAuto.com so why spend that much on grinding down old rotors, I say just replace them when you replace your pads. While your at it you might as well repack/replace your bearings while you're in there. I know I can do a much better job installing my bearings, rotors and brake pads than the local Toyota dealership (personal experience fixing their mistakes). Once you do it yourself you'll never let anyone else do it because its so easy for someone else to do a half-assed job.

I was hesitant to use 3rd party rotor, but so far the Raybestos rotors were money very well spent (or not spent).

If it was me I'd keep the new pads and just swap out the rotors. I changed my bearings when I put on new pads/rotors 6 years ago and repacked the bearings last year when I put on new pads.
 
Thanks for the reply, Dwon. Also I appreciate the Raybestos recommendation and may go that route. Fortunately I'll be able to machine rotors for free if I choose that as well. I know the pads that were on the truck were also OEM, so I guess I"m good there but I do agree that new rotors would be the ticket. I was saving up for the Powerstops, but I haven't really justified the purchase yet. My old 4Runner used to shake real bad, this is barely noticeable in comparison. My passengers don't even notice, but I'm hyper vigilant for that type of thing.
 
Dwon said:
I'd say read through these articles. Don't take my word for it.

http://www.stoptech.com/technical-su...nd-other-myths

http://www.examiner.com/article/ther...d-brake-rotors

http://www.mossmotors.com/SiteGraphi...ake_discs.html

New Rotor w/ Old Pad works
New Pad w/ Old Rotor won't work because the old rotor is imbedded with the pad material from the old pads. It will work if its the same pad manufacturer and material though.

But if your getting jitter, I'd say replace your rotors. You'll be done replacing them before a shop will be able to diagnose the "problem" causing your jitter.

Personally I'll never pay someone to grind my rotors down again. Raybestos rotors run between $20-40 on RockAuto.com so why spend that much on grinding down old rotors, I say just replace them when you replace your pads. While your at it you might as well repack/replace your bearings while you're in there. I know I can do a much better job installing my bearings, rotors and brake pads than the local Toyota dealership (personal experience fixing their mistakes). Once you do it yourself you'll never let anyone else do it because its so easy for someone else to do a half-assed job.

I was hesitant to use 3rd party rotor, but so far the Raybestos rotors were money very well spent (or not spent).

If it was me I'd keep the new pads and just swap out the rotors. I changed my bearings when I put on new pads/rotors 6 years ago and repacked the bearings last year when I put on new pads.
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Agree, I now simply replace the rotors when needed. I went through a lot of times where the shop didnt cut the rotors correctly etc and it was too much going back to the shop to machine them properly. these days, i agree, the low price of rotors, make it a no brainer to simply put new ones in when needed.
 
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