bigairjunkie

Hey Guys, I need some help with my 2000 4runner. Over the past week when I engage in drive the brakes pulse really hard 4-6 times while im just rolling, then let off giving me no issues while driving. Hoping someone has seen this issue before. let me know!

Texas_Ace

What do you mean by pulsing? Like the ABS engaging or the brake rotors are warped pulse? If the rotors are warped you should feel it in the steering wheel.

bigairjunkie

Its not the rotors. I would say it feels like the ABS, and only right when I engage drive for a few seconds

Texas_Ace

Doesn't make sense, sure it is the brakes? If you are not touching the brake pedal then the only thing that could be causing this is the ABS but even that generally only stops pressure to the brakes, it doesn't make it. At least on older/simpler cars like this.

It would seem more likely that it is the transmission or possibly an engine tuning issue. Could be the engine hiccuping/misfiring which I guess could feel like the brakes since you would loose power for a second.

bigairjunkie

Thanks TA, that may be the issue. The truck actually wont roll when i put it in drive until i press the gas, then it grabs violently 3-5 times before letting go. I can feel it mainly in the front but a little in the back as well. I would love to be able to diagnose it and try to fix it myself as much as possible. I can tell there is something holding the truck when its in drive but before i give it gas (feels like the brakes?)

Texas_Ace

Have you tried putting it in Low instead of drive? What about reverse?

It might be a stuck brake rotor although kinda odd for it to grab a few times. Usually they are either locked or act like driving with the Emergency brake.

It could also be the parking brake not fully disengaging although odd and rare. Also odd that it goes away, it should pretty much keep doing it.

Could be an engine problem, does it do the same thing no matter how you press the gas pedal? Aka, little gas or a lot of gas?

bigairjunkie

Everything's fine in reverse, but it also grabs in both low gears. It seems to only occur with little gas. It's really odd and only happening about 70% of the time.

Texas_Ace

Could try jacking up the rear axle (put it in 2wd first obviously). Then try it and see what happens. Might shed some light on it. Have someone listen to see where the sound is coming from.

bigairjunkie

Ok i'll play around with it during the day, try and narow it down. Thanks for the help!

TheDurk

This may be odd and rare in Texas, but up here in the salt belt the bell cranks on the backsides of the drums (where the cables attach) are prone to corrode up and stick. (I don't see where the op is from). It is common for them to stay engaged at startup and then release after you have driven a short distance. So I suggest you check and lube your bellcrank pivots. Worth ruling out.

Also try parking overnight with the e-brake disengaged. If the problem does not appear, then you have your smoking gun.

Texas_Ace

You got it mixed up, see the line above the one you bolded for the emergency brake. I basically said the same thing and yes it is also rare in Texas but happens.

The parking brake is the transmission brake inside the transmission. It is basically a steel band with some notches in it. Should it not fully disengage it is possible that those notches could cause what he is feeling although pretty unlikely.

TheDurk

Oh, slush box thing. I have never owned one of those, but the correct term for an e-brake is in fact parking brake. See 4Runner FSM below:

http://tacoma.site40.net/4Runner_96-...br/pbl/ovi.pdf

So forgive me my confusion.

[They refer to the other as 'transmission parking lock', which is a more accurate description. As you state, it is not a brake at all.]

But, aside from terminology, we are on the same page, I think. He should check his bellcranks--especially if he ever sees salt.

bigairjunkie

Thanks Durk, Ill try the bell cranks as i'm living in Kelowna BC and we are getting snow up here. If anything we can rule that out.