Changing Battery

[pragmatix]

My mk4 is on its original battery , the time has come to change it, now according to the Haynes book of lies, it says you have to disconnect the the battery at the body earth, now on mine it's corroded I've been spraying with plus gas in an attempt to free it off but so far no luck,

The question is can you change the battery with out doing this I.e. Is there enough slack on the negative lead to get the battery disconnected at the battery terminal instead of at the body earth? Scared I'll shear of the body earth if I persist with the Haynes method.

[dezwez]

i done mine at the battery

[GMX]

I don't think I've ever disconnected a battery at the body earth. This is a new one on me.

I've always disconnected at the battery, like Derek

[MONDEO TXS 2.2]

I can think of no valid reason why Haynes say that the battery negative must be disconnected at the body earth point . . & in any case the old battery will need to be completely disconnected anyway.

As long as the established practice of disconnecting negative first & reconnecting negative last is followed.

I can't help with the slack issue as the negative lead connection / negative battery terminal on my MK 4.5 is hidden in a protective black plastic cover with a flip up hatch allowing access to the positive terminal only.

[pragmatix]

And that's why I asked cos it's the same on the mk4 seems a right faff to change it air box lid off remove rear cover and as far as I can see there is no room to move the battery to get at the negative terminal first if at all

[MONDEO TXS 2.2]

I agree, even if you do manage to disconnect at the body earth the old battery still has to come out - it may be worth persevering & get the battery cover off & expose the negative terminal & disconnect there

[iantt]

Get the airbox out the way, unclamp the battry, slide the battery out sufficiently to gain access to rear negative post and undo clamp, easy when you know how.

But you will need to either disconnect the earth at body or positive cable first, if you do disconnect pisitive first wrap a rag round the cable and terminal post so you doesnt make connection again by accid3nt

[pragmatix]

Ian, I'm aware of all that, I asked if there was sufficient slack to move the battery to a point where you can disconnect at the terminal as the body earth is seized solid

[iantt]

Undo the positive first then as the positive lead will stop you sliding battery out sufficiently.

[BOF]

The battery cover, or at least enough of it, comes off easily and from there it is easy to undo the negative at the battery. Can't remember if you need any special tools such as a stubby spanner but it really isn't difficult.

You should note that if the earth connection is corroded it is difficult to tell whether it is making a good connection; while the battery is out of the way you may want to have another go at freeing that up and lubricating it...carefully, of course.

If you really have to, you can disconnect the positive terminal first, but extra care is needed because if, eg, a spanner shorts between the positive terminal and the body, you'll be in a world of trouble.

[jeebowhite]

I changed mine easy enough, but I removed the battery box, as I was having major battery issues at one point.

All you need is a size ten and eight spanner. Take the plate off the front of the tray, release the positive, and then pull the battery forwards, remove the negative and off you go.

I would recommend moving the airbox also, as Ian suggested, as it does make getting the battery in and out much more simple (a lesson I hard learned!).

With regards the earth point, I personally replaced mine. I was having some earthing issues during my battery issues, so I cracked out the socket set, pulled it off and realised it was thread bare on the bolt, and the surface was dirty and not making a good connection. A lightly dampened cloth with WD40, a wire brush and five minutes later, I had a clean and keyed surface ready for the earth point to secure to, replaced the bolt (I had it patched up with a mudguard clamp at one point and it ran spot on lol) - and the car has been spot on ever since.

[pragmatix]

Yea, I've got the methodology, I read the book it was a quick question was there enough slack in the negative, the answer is yes if you slit the rear half of the battery box as the negative goes in through a hole in the side of it.

Jeebo, how did you replace the earth bolt is it a weld one on job?

[jeebowhite]

Was nice and simple fella. Just a socket and a bit of elbow grease.

I doused the thing in WD40, and just kept turning it, the nut is welded on the other side, but the bolt which clamps the earth is just an in / out bolt.

I got a replacement from ford for a few quid, and it was different! it was more like an engine cover mount stud on top, with bolt thread on the bottom. I thought it was wrong, but apparently not. Got a spanner, nipped it tight and persuaded it a little further, and havent looked back!

[pragmatix]

Ta, that's what my one looks like was a bit worried as to how it was fixed.