03/SR5/V6/2WD- electronic vibration in brakes

ELECTRONIC VIBRATION IN BRAKE PEDAL:

ABS or Traction Control is vibrating my brake pedal every 3rd or 4th time I come to a stop (even at slow speed). It should only vibrate/initialize once during or soon after startup, not continually, right? I'm not referring to the typical pulsation/vibration caused by ABS during a hard stop.

The vibration is occuring regardless of speed as if a computer problem is causing the system to initialize repeatedly. No warning lights come on and I don't hear any buzzers but it's extremely irritating.

Is it supposed to do this? I need some feedback before I go to the dealer. Please help, thanks

I guess I'll reply to myself. New master cylinder fixed the problem.

I have just 750 miles on my 2003 V8 Sport....I have an intermittent occurence of a slight "snap" in my brakes when being depressed. Not a vibration.

Any ideas?

PS Congrats on the fix!

I think I know what your referring to but I can't tell what it is. I thought maybe I was being overly perceptive. Oddly enough, didn't notice it until the new master cylinder was put in.

At any rate, I plan on returning it on Tues because they need to re-bleed the brakes, as there's too much pedal travel now. Seemed good for the first couple of days so I wonder if there's a tiny leak.

Could be a leak or maybe the top to the reservior wasn't put on well or completely...maybe just bleeding again all will be well.

I'd be curious to see what they say about this snapping if you do ask. It seems to happen mostly when coming to a stop from a slower speed.

Good luck!

Taking it in tomorrow instead.

Still there but braking and pedal travel are normal after bleeding brakes. Don't know about the popping, mentioned it to dealer last visit but they said all was normal now. Have to wait for feedback from other owners.

one way to check if ABS is doing the trick is disconnect ABS so that your base brake systen is only used, the ABS will illum. if the pulsations or whatever still occurs, it had to do with your base brake ie; rotors/ drums, hydraulics-master, mechanical-booster. if your brake looses pressure when applied and no visible leak, master. if you push down and it feels like a rock under pedal booster. that 's the basic stuff, other stuff can get more tricky but main thing you check your BASE BRAKE
to see if it works properly first ....... good luck

My pedal has that same snap (04 4runner V6). Also, hill-assist does not seem to work properly. Think they may be related?

I don't think my brakes make the "snap" anymore. If they do, it's so faint, I don't notice it. Give it a while for break-in.

It seems to be getting worse in my case.
I brought it to the dealer and they tell me the brakes are fine.
Since then snap has started to happen more often. I can count on it happening every time I hit the brakes.
I'll give it a while longer but in LA stop and go traffic this gets very annoying.

Hello,

I have an extensive thread(s) on this at the Yotatech.com forum for Runners. If your "snap" is the same common problem, you will find that it is the slip joint portion of the drive-shaft and that the problem will eventually wear away. Do a search at the other site and you will find it.

Interesting but the "snap" I feel is there even when the engine is off and the key is in the "ON" position in the ignition.
From what I can tell it seems to be related to the brake booster canister.
The "snap" can be felt whenever the booster pump shuts off after re-energizing. It seems to be a valve or something.

Well I just brought my 4runner back from dealer.
Yesterday they had 3 mechanics looking at my brake booster cannister and determined that it was slapping up against the bracket whenever the pump started up. They brought out 4 brand new 4runners and compared them with mine. It seems that the bracket in my truck had a much looser fit then the other ones.
Long stiory short.. they replaced the entire brake booster assembly and it I don't feel the snap anymore (cross my fingers).
I'll let you know if the problem resurfaces over time.