An account of one cheap quick 3 Amigos cure
I imagine it might be good to have info on D2 ABS cures collated here so I’d just like to add an account of repairing the Three Amigos in my 1999 D2 with no new parts or mods with a couple of hour’s work (I may be lucky but I’m guessing from what I’ve read on Aulro and other forums that many times the dealer claims a new part is necessary or the mechanic shrugs, the real problem may be a ‘noisy’ brake pad or greasy wheel sensor. This thread as well as a few other aulro threads and other forums, a nanocom and the surprisingly useful Haynes D2 workshop manual have been excellent help.
From purchase about 6 weeks ago I had el Trio Amigos in the 1999 D2 Td5 I just bought for my wife. After one hour’s work and clearing the fault codes two weeks ago the Amigos abruptly disappeared and have stayed gone for a week’s town driving on the Gold Coast, the 1100km trip to Canberra (from where I write now) with some dirt track action around campsites and roughshod kerb mounting urban driving in Canberra city. When I bought the truck I immediately I paid my $400 and bought the Nanocom direct from Blackbox. It told me about one repeated fault, intermittent signal from the front left hand wheel sensor. I used the ohmmeter (resistance tester) on a $24 Dick Smith multitester and found I had adequate resistance on the LH wheel sensor (was it 1150 ohms, I can’t remember the number now but it was equal to other wheel sensors). I could have connected an AC volt meter to the LH sensor and spun the wheel but took Pedro’s idea (thanks Pedro, I owe you a few already) and tested the whole chain of elements: Chocked two of the other wheels, lifted the (RH) wheel in question so that it could spin freely, placed an object on top that wheel (or marked the top with chalk) so I could later verify that it turned, got in the car, started it with foot on brake, put it in drive and watched the speedo and tachometer. Tachometer sat on 850rpm and the speedo sat on 0km/h! That shouldn’t happen in drive! I went out and checked the wheel and it had been spinning as the object placed on top had been tossed a foot away. That means the wheel sensor didn’t know the wheel had been spinning (Gracias Pedro). The interesting thing for me (before now an owner of traditional non-awd cars) is that the truck did not try to smash the back wall out of the garage and just span the raised wheel. Cool. I tested another wheel (should have tested all wheels but perfectionism is one of my faults I am trying to quell and decided not to) and found that at idle 850rpm the wheel span around 37km/h (after about 1 sec delay).
I chocked it, jacked it and put it on a stand and hydraulic jack, pulled off the wheel in question (was impressed by the one locking nut with an indent that needs the clever kit from the tool bag to undo) and had a looksee. I was immediately impressed by the simplicity, practicality and accessibility of the whole arrangement compared with the D1. Unlike the D1, to remove the rotor you do not have to remove the hub and each caliper has a clever harness allowing removal of the caliper body by simply undoing the brake caliper pins (two lightly torqued 12mm bolts) and using a piece of wire to hang it off the front suspension spring. As I needed to remove the rotor, to get at the wheel sensor I then tackled the two brake caliper bolts (19mm 12 point) torqued to 176 newton metres. I don’t know my physics but 176NM felt like bench pressing 172kg. Air impact driver couldn’t touch it. I used a 2’ long ½” drive breaker bar with another 1’ extension from and 2’ iron tube. You won’t get it without significant leverage, but it was easy with 3’ of leverage . The caliper harness comes off, then you undo the #3/#4 ? screw from the brake rotor. I used penetrative oil and the rotor came off with 20 seconds firm pulling and wiggling (unlike the fbhammer beating required for the D1 rotor). I checked the rotor and at 24mm it was near new for a D2. I checked the brake pads and at 10mm they were well within spec. So I was guessing the problem was either in the sensor or the brake pads ‘rattling’ on application and interfering with the wheel sensor output signal.
I took the brake pads to the bench grinder and gave them a tiny bevel on the bottom end which I thought might reduce brake squeal (it may or may not have had any bearing on the positive result). These pads had plenty left on them but only had very thin (1-2mm) and uneven painted on anti-squeal backing so I painted the back of them where they would contact the pistons/caliper with anti-squeal goop and let them dry for 15 minutes.
To address the sensor, I wiped down around it and then allen keyed it out. I found the sensor had plenty of white grease, but had a big gloop of grease on the trigger wheel end. I wiped the end clean and reduced grease all over it, leaving just enough grease to stop it seizing in the hole and the o-ring from perishing (reason being I had plenty other greases but couldn’t for the Google of me ascertain which grease might cause magnetic interference). I noticed a piece of dirt in the hole over the wheel, it may have fallen in when I removed the sensor or it may not; I got it out with tweezers. Some accounts of ABS issues recommend seating the sensor as deep as possible (until it just touches the sensor so I wiped out the hole for the sensor and used a sharpened chopstick to scrape the light film of grease and crud out of the seat for the o-ring to ensure the sensor sat as deep as possible. Wiped the o-ring and gave it a very very thin lick of the grease that was gooping up the sensor hole, fitted it to the sensor and put the sensor back in the hole. Put a blob of Loctite on the sensor allen key screw to be sure and tightened it to designated torque. I used brake cleaner to take any c^&p off the rotor and replaced the screw to hold it in place. Put the caliper mount back on and torqued it to 170nm (or was it 175nm) which was impossible with just the big torque wrench so I jacked up the wheel a little higher (about an inch above the stand) and stuffed a hardwood 4x2 under the end of the torque wrench, then slowly let the hydraulic jack down until I heard the torque wrench click. Sewed up everything else. Checked chocks then started the Disco and put it in drive and the speedo read 37km/h at idle 850rpm. Woohoo! So now the wheel sensor was reading wheel speed. Rock’n’roll.
The cause/s of the bad signal from the wheel sensor may have been:
- the grease on the end of the sensor (it may be magnetic grease?)
- the piece of dirt on the trigger wheel
- that the sensor was too shallow (though it didn’t seem too different)
- vibration from the brake pads (lack of anti-squeal goop or perhaps my beveling of the pads helped?)
Whatever it was is fixed for now. I fault with the nanocom and have a warning light free dash. Vamonos trio amigos. I’ve cleared faults before and the same one (left front sensor) kept coming back but this time the change in wheel sensor is tangible (thank you again to Pedro’s suggested speedo check method).
Cheers,
Rich
