Attention All Puma Owners

[chook73]

During the immobiliser drama I had a couple of months ago I damaged one of the circuit breakers for the dual battery system so today I decided to swap it out and during the process I absent mindidly made a connection between the positive and the body, it lasted all of 1/10 of a second.

And yes I had stupidly left the ignition on...... :angel:

What resulted was the handbrake handle cable catching on fire! :eek: the fire was intense enough to burn through the handbrake cable :eek:

It seems that the wire for the handbake light on the dash had been previously caught in the handbrake mechanism and striped bare this must have made a connection during the short and the grease on the cable caught on fire (I assume).

Apart from now having no handbrake, a bad smell in the cab and taking 10 years off my life it all seems to be ok however it would be worth checking as if your driving along or were parked on a hill and for any reason something shorted out the result could be a lot worse than mine......

https://www.aulro.com/afvb/images/imported/2013/07/1055.jpg

https://www.aulro.com/afvb/images/imported/2013/07/1056.jpg

[LowRanger]

Just carry a brick to throw under the wheels instead of a handbrake.:D

Now to more important matters.....is your suspension fixed?

[chook73]

Just carry a brick to throw under the wheels instead of a handbrake.:D

Now to more important matters.....is your suspension fixed?

Brick would probably be more effective!

Nope the arms didn't turn up, all the bits are plasma cut ready to weld on but it seems the guy making the arms is in less of a rush than Brad :wasntme:

I head off this week for 3 weeks on a touring trip so will get the arms fitted when I get back.

[LowRanger]

Aren't you concerned that you will break things again,I thought the idea of the arms was to strengthen the rear end.Aren't you just as likely to do the same thing again while away,without doing the repairs.The truck needs to be kept in cotton wool until everything is completed in one go :wasntme:

[chook73]

Aren't you concerned that you will break things again,I thought the idea of the arms was to strengthen the rear end.Aren't you just as likely to do the same thing again while away,without doing the repairs.The truck needs to be kept in cotton wool until everything is completed in one go :wasntme:

It was fine after the coffs trip earlier in the year and that was all touring, with the A-Frame spaced up and everything else that has been done the only risk is if I go rock climbing i will possibly snap an output shaft....

[n plus one]

I head off this week for 3 weeks on a touring trip so will get the arms fitted when I get back.

Thread jack, but where you headed? I'm going out Flinders/Simpson/Corner country way (leaving in two weeks) - should I keep my eyes open for some portals to nick...err I mean eyeball :D

[chook73]

Thread jack, but where you headed? I'm going out Flinders/Simpson/Corner country way (leaving in two weeks) - should I keep my eyes open for some portals to nick...err I mean eyeball :D

If your coming up from the bottom I am going down from the top, I leave on Friday and head up the coast to spend three days with my parents in Iluka and then Brsibane, Noosa then head inland through to Dimantina Lakes down through Birdsville to Inaminka/Coongee Lakes then Farina, possibly lake Eyre and weave to Broken Hill.....

Sounds like we are going to cross paths!

[n plus one]

If your coming up from the bottom I am going down from the top, I leave on Friday and head up the coast to spend three days with my parents in Iluka and then Brsibane, Noosa then head inland through to Dimantina Lakes down through Birdsville to Inaminka/Coongee Lakes then Farina, possibly lake Eyre and weave to Broken Hill.....

Sounds like we are going to cross paths!

Yep, I'll be going 'uphill'. Cool - my Pumas the same as yours (just a little lower) - I'll keep my eyes open!

[yt110]

Chook73

PM sent,you may have another problem,ie the H/Brake cable acting as an earth cable

Jim.

[Iain_B]

Chook73

PM sent,you may have another problem,ie the H/Brake cable acting as an earth cable

Jim.

My first thought as well Jim - if you shorted out to the body Iain, the handbrake cable will do a great job of acting like an earth cable for a few seconds. I thought the handbrake light goes to earth when the handbrake is on - so worst that would happen is it would turn the light on it if shorts out.

I have made sure the body on the truck is properly earthed to the chassis - don't want all the little wires or cables being the primary earth if something happens to the main earth.

One known problem on older Jaguar V12 is that the earth strap corrodes, then the accelerator cable becomes the earth strap, and on some the accelerator cable runs under a fuel line :eek:

[chook73]

My first thought as well Jim - if you shorted out to the body Iain, the handbrake cable will do a great job of acting like an earth cable for a few seconds. I thought the handbrake light goes to earth when the handbrake is on - so worst that would happen is it would turn the light on it if shorts out.

I have made sure the body on the truck is properly earthed to the chassis - don't want all the little wires or cables being the primary earth if something happens to the main earth.

One known problem on older Jaguar V12 is that the earth strap corrodes, then the accelerator cable becomes the earth strap, and on some the accelerator cable runs under a fuel line :eek:

Yep after receiving Jim's pm I got to thinking he is right, as the contact was made with the seat box it probably found the handbrake cable as the shortest path to ground.

I dont think that the battery is directly ground to the body in the battery box. A job for the to do list this week!

[knodes85]

The exact same electrical fire engulfed the cabin of my Puma about a month ago, complete with snapped handbrake cable and reduction in number of remaining years to live.

Unfortunately mine happened after the battery broke free in the battery box during an excursion off road whilst touring one night. As a result I didn't realise it was shorting until the handbrake cable grommet was well alight.

Initially I thought the whole under-body had gone up and the flames were just lapping through the handbrake assembly rather than being the point of ignition. A lot of possessions were thrown out of the car at great pace for no reason! It was extremely relieving when I realised it was only the handbrake that was alight.

[manic]

I'm confused, why does a positive short to the seatbox go through the hand brake cable to ground when the seatbox is bolted to chassis mounts?

[chook73]

I'm confused, why does a positive short to the seatbox go through the hand brake cable to ground when the seatbox is bolted to chassis mounts?

I would think that the seatbox - handbrake cable - handbrake - engine - battery would be a conductively better path than body - chassis - engine - battery?

[manic]

If the negative terminal is ground to the chassis and the seatbox is bolted to the chassis I would NOT have guessed that the handbrake cable to the transfer box route is the least restrictive.

I would have guessed: Seatbox - mounting bolts - chassis.
Good job I'm not an electrician.

Anyway perhaps the best thing to do to prevent this kind of short is to line the battery box with rubber and have a rubber mat that sits on top of the batteries. That way even if something comes loose it would be hard for it to short out.

Of course you would still need to be careful removing the terminal connections with a spanner! Remember negative terminal first :p

[chook73]

If the negative terminal is ground to the chassis and the seatbox is bolted to the chassis I would NOT have guessed that the handbrake cable to the transfer box route is the least restrictive.

I would have guessed: Seatbox - mounting bolts - chassis.
Good job I'm not an electrician.

Anyway perhaps the best thing to do to prevent this kind of short is to line the battery box with rubber and have a rubber mat that sits on top of the batteries. That way even if something comes loose it would be hard for it to short out.

Of course you would still need to be careful removing the terminal connections with a spanner! Remember negative terminal first :p

Sorry yes I added the engine into the second route which it wouldnt be, but still it would take the path of least resistance and the distance between the point of the short and the handbrake cable was probably less than the distance between the short and the chassis bolt and back to the terminal?????

Im thinking out loud now so if there is someone with a qualified response :angel:

[yt110]

Im thinking out loud now so if there is someone with a qualified response :angel:[/QUOTE]

I too would like to hear from someone qualified about this.

Maybe as Chook73 said another lead from the body to the chassis to ensure a proper earth.

Jim.

[wrinklearthur]

I won't say one way or the other about my qualifications, other than there are people about without formal qualifications that do know something. :)

I would be looking at the all the existing earth points first, to see if any of those points need their point of contact cleaning of paint, rust and / or anything else that is resistive to current flow.
.

[yt110]

I won't say one way or the other about my qualifications, other than there are people about without formal qualifications that do know something. :)

I would be looking at the all the existing earth points first, to see if any of those points need their point of contact cleaning of paint, rust and / or anything else that is resistive to current flow.
.

Yes I agree,but is there a dedicated earth between the body and the chassis or just that its all bolted together so it should earth somewhere?

Jim.

[n plus one]

Yes I agree,but is there a dedicated earth between the body and the chassis or just that its all bolted together so it should earth somewhere?

Jim.

Whether there is or there isn't, it's looking pretty clear that the lowest resistance path to earth from the body is the handbrake cable - which is concerning to say the least (particularly as I shorted a battery the other week myself :eek:).

As a former electrical fitter/mechanic I'll be doing some serious investigation in this on the weekend.

[Leyland1980]

I had the same occur some years ago on my td5, something shorted resulting in a hand brake cable fire.

Might be worth adding a earth strap from seat/battery box to transfer case.

[Brid]

Just got my auto leccie doing some work here today, so I asked him about this problem and these are his comments.

1. The most common reason a "different" earth circuit is completed is when the battery earth lead is loose, dirty or other poor connection, rather than other poor earthing. So it's critical to make sure that the battery connections are good and secure.

2. He sees more problems with arcing & pitting of positive battery terminals and connections.

I know that after I had the battery out at one stage, my scan gauge showed lower voltage. I'd tightened the terminals, but one not tight enough. I'll pay particular attention to this in the future & check on the scan gauge regularly.

[chook73]

Ok I have just got back from KLR having fitted a new handbrake cable and we had a really good look at the earthing system. Frankly its less than impressive.

There is one earth cable from the negative battery to the chassis to the engine, this cable has a T joiner where it attaches to the chassis and if you unbolt it the chassis is painted. The body is painted and then attached to the painted chassis so not very conductive, no surprise that the current didn't want to travel down this path!

We have put some additional earthing straps in between the chassis and transfer case and when I am back we will also earth the body to the transfer case.

[RVR110]

LR may have addressed this starting with either MY12 oir MY13. In the front driver side wheel well my MY13 has an earth strap from the chassis to the footwell whilst my MY11 has an earth strap from the chassis that disappears up behind the guard... haven't checked any further though.
http://www.aulro.com/afvb/attachments/90-110-130-defender-county/63106d1373964687-attention-all-puma-owners-img_0510.jpg

http://www.aulro.com/afvb/attachments/90-110-130-defender-county/63137d1374041591-attention-all-puma-owners-img_0512.jpg

[Drover]

Looks like a couple of extra earth straps to be installed this weekend......

Better safe and a easy little job.

[manic]

Sounds like an earth strap from a nut on the back of the handbrake mounting bracket down to the chassis would be a good way to go.

[chook73]

Sounds like an earth strap from the nut on the back of the handbrake mounting bracket down to the chassis would be the way to go.

From what we looked at today I would suggest one from the back of the battery box to the transfer case, miss the handbrake all together. This will cover you off for what happened to me being the inadvertent touching of a wire or spanner against the battery box.

Then you need to earth the chassis to the transfer case (or engine) as the main earth is of course the engine, Brad was saying today that when they do their engine conversions they do at least 4 of these (2 each side) and scratch the paint off the chassis when they attach the stapes.

Of course you need to make sure that your earth from the battery to all of these is good otherwise your missing the key link.