HELP! - MK4 Supra nonturbo brake/ABS problem...

[3.8T]

Like the subject says. My girls 94 Supra non turbo has been giving her brake headaches for awhile now. Before her recent shop visit to get them to check it out, and from what she says, and from me test driving it....the abs light would come on and off randomly.....and when u would come to a normal stop at a light lets say, there would be crazy vibration in the brake pedal.....kinda like the ABS is functioning when it doesnt need to. **note-when the light would come on, the problem stopped....but once the light when out, it stared again.....

Now, she went to a shop (not my reference) to get it checked out, he replaced a part (friggin $300 part ONLY available from Japan) and he said it was fine after he drove it...of course she gets it back today, drives home and the problem is STILL there, vibration under normal braking.....BUT the ABS light is out. SO we are down to just having the brakes vibrating like a bitch when under normal braking conditions....I asked what part he replaced....of course she doesnt know...so I wil find this out 2morrow.

Any ideas??? Anything from master cylinder, to brake booster (if Supra has it), to ABS sensors....perhaps it just needs a brake bleeding, but i doubt this is the problem....and shoulda been done by the shop anyways....but wasnt.

Thoughts?

[cdnsupra]

My 2 mk3 supras both have abs, and i have had zero problems with them.

I can tell you that the abs is triggered if the sensor on the wheels sees the rotating motion of the wheel stop while the others wheels are still moving or the tranny is sending a speed signal greater than 5mph. on the brake rotors, there is a series of what looks like cooling fins, and the abs speed sonsor looks at these to check if the wheel is spining. you might wanna check that they are connected properly, allingend close enough to read the signal, and that everything looks reasonably clean and dirt free.

i have never worked on mk4 supras, but for the mk3, i would check the codes in the computer. we can check the abs/ecu/ and tranny computers just by itserting a paper clip in the right spot and turning on the ignition. The abs computer may be holding the secret already. The way to get the codes can be found in the toyota shop manual, or the cygnus online manual, but i don't have the url handy. when i find it, i will forward here and look it up as well for my own knowledge.

i remember that the mk4 started with 40channel abs, meaning it reads the rotation of all 4 wheels, then switched to a cheaper 2 or 3 sensor model. trucks, for example, usually only have rear abs, a 2 channel system. i would think your 94 would be the full 4 channel model.

good luck, hope that helps, and i hope to post other info as i find it.

[3.8T]

thanks man!

[ericblaze420]

i would check to see if the rotors are worn too thin, or if they are worn around the brake pad if she is using ceramic pads and didnt properly break them in.