Earth points - options please

[steve.pritchard146]

Morning all,
Well after a few months of happy motoring it 'appears' my earthing woes have returned.
We were going to drive to reading last weekend (from Calne Wiltshire) got about 2 miles up the road, and the car hesitated and the gearbox warning light came on.
We limped back home and went out in my wifes mini...

After returning I removed and cleaned the three earth points at the front - one of which I had previously changed to a bolt. They all appeared to be fine, and on reassembly the car ran fine. I also noticed a "Halfords" strap running from the top of the engine to a suspension strut bolt (hadn't seen that before!! anyway I removed it and cleaned it all up.

I had to drive to Swansea Monday as my mum is ill in hospital in Wales and I've based myself out of her house for the week. All was fine until leaving the hospital yesterday evening pouring with rain, the car hesitated, the wipers stopped, satnav screen went on and off and the gearbox light came on - I limped up the road and pulled in just before which a red brake light came on and a continuous warning buzzer and message saying "cannot apply park brake, press foot brake")

In the layby the car would not restart - or do do much of anything. I sat there for 5 mins considering my options.... cursed, hit the steering wheel and it started and I drove cautiously the 20 miles to my mums house. There are no tools here at all - although Lidl is about a mile away and may have somethings of dubious quality

This sounds like it has to be electrical - I now that there are a lot of earth points, but can anyone give me a steer of what to try - I have a few more days of hospital visits before the 2 hour drive from Swansea to Calne - confidence in the vehicle is low at the moment..

Steve

[PaulGover]

Steve,

If the wipers were playing up, AFAIR the earthing tags for that bunch are on the bulkhead under the flap where the brake fluid reservoir sits.

Given the suddenness and severity of your symptoms, I'd suggest the earthing bolt has snapped, though you might be lucky and it's just come loose or corroded. DO NOT try to fix the issue by tightening the bolt beyond the recommended torque - the aluminium stud will shear. (I can't locate the torque, but I think it's something like 5 Nm, which is a job for a toque screwdriver or a ring spanner and spring balance, tape measure and calculator).

If it's snapped I think Jaguar drill a hole and fit a new stud from one side, so I suspect there's some sort of expanding fixing, but whatever, that will be pretty fraught. I hope someone else with experience will chime in to explain what you can do at home.

[steve.pritchard146]

Thanks Paul,
Just hit the local halfords and now have (yet another) socket and spanner set, wiring, earth tags, sticky tape (another) multimeter - will brave the elements shortly and investigate further

[steve.pritchard146]

Right then.... the sun came out so off I went

I decided to back over my previous work and one by one removed:
G1, G2,G3, G26 and G30 and in each case attempted to start the car and see what visual error cues I got.

It actually didn't take long before I was back at G2 and G3 (front RHS) which I had 'supposedly' repaired previously one of these, I think G3, when removed appeared to cause all of the symptoms I saw last night. Whilst I don't think I will be able to prove anything before a number of trips in the car, I used emery paper and cleaned all the paint off the alloy bulkhead in a decent area around the hole I previously drilled for the stainless bolt I mounted. On initial examination I maybe didn't do such a good job first time.

Also the bolt that I had mounted to the bulkhead seemed to have worked a little loose and maybe that coupled with not such a good contact area may account for the issue. I've now fitted a lock washer and refitted everything.

I have another hospital trip later so we shall see - although I don't expect to have any difficulties until its p***ing down with rain!

I will update if it solves the problem.

[Andy P]

Hi steve.pritchard146i,
Hope you have found the culprit.
Will keep my fingers crossed for you.
Good luck.
Andy

[steve.pritchard146]

So good news,
It was definitely one of the front earth points and me taking the time to clean and expose a decent amount of metal on both sides of the new bolt has made a difference as there is now no issue and I'm a good 400 miles on.

Of course I now have a stainless steel bolt running and earthing into Aluminium which raises the challenge of increased corrosion prospects.