boxsey911

I'll check that earth Rob but I did both of the others you mention last weekend. I've got spare relays for the ABS pump, so I can try swapping those. I also read in Adrian's book that a bad wheel bearing can upset the ABS. That would fit with the problem only occurring when I drive off but the bearings seem OK when I do the usual tugging at the wheels off the ground routine. Maybe there is only slight play in one and when it warms up the ABS problem goes away temporarily?

ras62

I think you have covered most of the bases tbh Steve, perhaps it is time to check connections on the clock and central informer and the earth behind the dash. If all else fails we can swap over the ABS unit with the one on my car, a cheaper check than getting Camco to check it.
I hadn't heard about the bearing affecting the ABS, not sure why that would be the case, perhaps someone on here can explain?

boxsey911

I know what you're saying about the clock because it's well known for spurious effects. What do you reckon about pulling the clock and driving without it to see if that affects the ABS warning? I'm sure I did this once before when I was looking for another electrical issue and don't remember it having a detrimental effect to any other warnings. Without the clock if the problem goes away I would know it's the clock. If I still get the warning without the clock I'm still at square one (could still be the clock amongst other things).

ras62

Im not 100% sure you would get a warning if you remove the clock even if there was a fault. If you haven't done the clock connections then its probably worth doing regardless.

boxsey911

I don't have the necessary skills to solder the clock...I'll only ***** it up!

ras62

Im sure if you can master the black art of Mass Spectrometry then a simple soldering iron isn't going to present to much of a problem

http://p-car.com/diy/clockrepair/

robt964

>I hadn't heard about the bearing affecting the ABS, not sure why that would be the case, perhaps someone on here can explain?

The only way I can see is that play in the bearing will effect the clearance between the sensor and toothed wheel. The bearing would have to be proper rogered tho and very noticeable I'd think.

boxsey911

Yes that's pretty much what Adrian's book says about the effect of a bearing on the speed sensors but I'm not getting any grumbling noises from the wheels indicating that one is shot.

At the moment I think I might just pull the ABS bulb and be done with it....either that or push the thing into the canal.

FeralComprehension

Have you read the codes?

sundog

In my case the sensor was damaged on the wheel that the bearing went out on. It was on track, so more motion in the wheel than normal driving. So it happened either during the bearing failure, or during the replacement at the shop. I don't know what the clearance between the sensor and the teeth is.

alexjc4

Lol canal.... pull bulb .... canal .... pull bulb - the classic dilemma

You'll figure it out eventually Steve, these things are always the last thing you try.

boxsey911

I've nothing to read codes so it will have to go to a shop to have that done. However, Adrian's book clearly states that a Hammer is of little use in checking the ABS and that the Bosch ABS tester is the only thing that can diagnose a fault.

Update 4:

The car has so far avoided the canal. I drove the car with the clock pulled from the dash and the ABS light and warning buzzer still came on which didn't tell me much. I then went ahead and re-soldered the clock and put it back in. The good news is that the spoiler light is now working again - on with the ignition and goes out as I move off. Unfortunately the ABS light and warning buzzer then comes on after a few more seconds of moving. I then swapped the battery for a fully charged one. Battery was 12.65 V with no load and then 13.85 V with the engine idling. I also swapped the two relays on the ABS pump for spares I have. None of this had any effect so the search continues (I have a few more ideas for things to look at next weekend).

freedman

Steve, apologies for offerering up the obvious, or if youve already mentioned it and I missed it earlier, but your brake fluid is 100% full, isnt it?

Was what used to make my ABS warning light and warnig buzzer come on all the time

boxsey911

No problem mentioning the obvious mate. Yes it's full but will be doing a bleed this weekend to ensure there's no air lock in the pump - adrians book metions a stuck return pump can fire the warning when moving off. I'm wondering if there could be air in there when the pump was removed during the fitting of the new floor?

darth

To check the ABS sensors, connect an analog (i.e. not a digital meter) AC voltmeter to the 2 wires at the wheel speed sensor connector. Very thin "wire wrap" (i.e. a very thin wire used in electronic circuit board prototyping) or equivalent, will contact the 2 pins, while still allowing the plug to be connected. An analog meter is required as it produces a needle sweep similar to a tachometer, making it easier to observe the relative amplitude. Select a voltage setting which produces a maximum or full scale swing of the meter needle. The AC voltage generated is directly proportional to wheel speed and any reading which differs greatly from the others, is suspect. The same AC voltage readings should be observed at the input to the ABS unit (i.e. but is more difficult making the meter connections to the smaller pins) for each wheel and is most important. The measurements at the wheels can be skipped or performed only if the desired results are not observed at the ABS unit.