Does anyone know how to disconnect the ABS?

The reason I ask is I've been having brake judder problems nearly ever since I've had the car, only at quite high speeds (about 70) and thought it was probably the front discs, so I changed them for Skyline's, if anything it's made it worse, so then I changed the tension rod bushes and at first thought that had cured the problem but it hasn’t. Just took my mechanic out and he suggested it might be the ABS, but wasn't sure how to disconnect it to eliminate that.

I don't think the ABS is causing it, but you can (temporarily) disconnect the ECU which is behind the driver seat behind the interior

 

Do you have stock or aftermarket wheels ?

I noticed some aftermarket wheels seem to make the brake judder a lot worse

 

Also it's VERY important that all wheelbolts have been tensioned the same (not too tight), since the bolts not only hold the wheels, but also the discs

 

-Eric

John

 

...I know it's a long shot, but what state are your pads in? When mine need replacing I get real good juddering. As soon as new (thicker) pads go in the juddering dissapears. Like you I replaced the disks and tie bars and only solved it with new pads...

 

good luck

 

Jack

I've got aftermarket wheels, but it juddered before they were fitted and the pads were changed when the skyline discs were fitted about 1K miles ago.

Cant be ABS - is it new calipers too or the original ones?

 

If you have sticking pistons in one caliper then one side of one disc heating more than the other with the energy of high speed braking will be enough to warp em a little and still not give any pulling.

 

Same can be temporarily solved by new pads because you force the pistons back in to the cylinders. Once the pad wears again and the piston reaches the point where it will stick you are back to the same problem. Solved by popping the pistons, a good clean up and new seals or new pistons if they have rust marks on them.

 

Big slightly out of balance wheels could also impact this.

nice one Willie - I hadn't thought of that. One more item on the to-do list.

 

cheerz

 

Jack

Different calipers as well and they were checked before they were fitted. My theory is if one wheel sensor is not working one wheel would lock the other would not and the steering would shake like a faulty disc. (just my theory though).

As mentioned above ABS ECU is behind drivers seat. You need to remove the back seat and the drivers side rear seat panel.

 

These are the ABS sensor wires if you need them. Be careful there are two brown wires in the ABS ECU.

if one sensor was faulty the abs warning light should come on.

You can hear when your ABS kicks in so its not that and ABS only comes on when you lock your wheels up.

It won't be the ABS - as Paul said it has diagnostic stuff built in.

 

Check ALL the bolts on the tension rods - I had my bushes replaced and a month or so later I got the wobble back.

 

Turned out to be the bolts had come loose (or where never tightened more likely) where the bar fixes to the suspension arm on the drivers side.

They were so loose that one came off with 2 turns of the finger and the other was nearly as bad!

 

Get them checked because if the bar comes off the wheel will collapse into the arch and you'll find it very difficult to steer with one wheel locked up and steering where it wants! :eek:

Another poss but I think its probably rare as Z bearings seem to be long lasting. That would be wear in a wheel bearing allowing the hub to run off true. This could give the same effect as warping of the disc. I worried mine had that as new Nissan stock discs were giving vibes within a year of fitting and even after tension bushes etc it was still there. Had the discs skimmed - still there. Gave up and new 3g discs fitted and re built the calipers - result great brakes and no vibes. Mines appoaching 130k now.

 

Can you check the trueness with a borrowed dial guage to measure disc runout when you spin the wheel. I used one to see how far out my discs were. Even took em off and put on on different stud holes on the ultra cleaned up hub to see the difference - there was one but not as much as the warp the guage clearly showed I had on just one disc.

Thanks for the advise, I am going off the idea it might be the ABS, not sure what to do next.

Do you want to try swapping wheels for a couple of months to see if that sorts the problem out ? :D . Sorry I got to stop going on about your wheels and get myself down to elites.

NOT the ABS as already said. Have you checked the top links??? Try and wobble the wheel top to bottom with it off the floor. Have you had your tracking checked??? As chris says check the tightness of the tie bar bolts - esp the one it pivots on. Also check this for excessive play.

 

Just a few ideas for now....

 

CheerZ,

 

Andy