Battery change - retaining bracket removal

[nicholas]

I'm looking to change 12v battery on our 2006 forfour - I measure it at around 8v so I think it needs replacing. Unfortunately I'm struggling to remove it from the car. From visual inspection I believe I need to remove a metal bracket at the base of the battery which looks like it's holding the battery down.

IMG_20200810_193528__01.jpg

Is that the correct way?

I was not practiced at removing rusted nuts, so while I got it to turn, it now doesn't travel along the threads. It looks like both the nut and the bolt rotate together. (I assumed the bolt was welded in place, but maybe not). I'd assume access from underneath to hold a bolt still isn't normally required to change the battery.

It's difficult to reach, so I want to check it really does need removing before I figure out how to do it!

[nicholas]

disconnected from the car, charged it back up to 12.6v and then reconnected to car; car didn't start though and voltage dropped to ~10v, so still looking in to how to remove it to replace

[pinger]

I was not practiced at removing rusted nuts, so while I got it to turn, it now doesn't travel along the threads. It looks like both the nut and the bolt rotate together. (I assumed the bolt was welded in place, but maybe not). I'd assume access from underneath to hold a bolt still isn't normally required to change the battery.

You are right in that the hold down plate you have encountered is restraining the battery and correct also in that most probably the (captive - yes, welded in place) nut has broken loose. The other possibility is that the threads have 'stripped' hence the bolt not winding its way out.

You should be able to tell by feel as the captive nut broken free will likely offer little resistance while a stripped thread may.
If you can get hold of the bolt head with vise grips and rotate ACW and pull at the same time, if its a stripped thread you might just get it to 'catch' and it unwind and come free.
If the captive nut is spinning you will need to find access to it to hold it. It will probably be a square nut but a 12 point socket should hold it but it may have a blob of weld on it just to annoy you some more.

It looks like it is going to be awkward to deal with and even once removed something will have to be done to replace the captive nut - broken free or stripped - but that will be easier once the battery is out of the way.

If you can access the nut in question then there's some hope. If not, maybe better to buy a new battery with 'free fitting included'.....

[reinaldo_is_spam]

Mole grips , maybe even a long nosed version of them , and find a way of clamping the threaded section below with them, then unscrew the nut.
The mole grips should turn until they get obstructed by the side of the battery, I.e. you won’t need to hold onto them if securely snapped onto the threaded bar.

[nicholas]

Great, thanks reinaldo_is_spam - gives me something to search for.

I've had it confirmed that this bracket does need removing - and also that the nut we have there at the moment isn't OEM!

[nicholas]

Thanks pinger - sorry I didn't see you reply sooner - smartz.co.uk seems to have broken CSS/style for me so the pages are all just text!

I've got a camera under now, and I see the bolt underneath seems to have a E12 torx head, and I can see that rotating when I rotate the nut and bolt at the top. The nut on top is a 13mm hex. With a lot of struggle due to the pipework and metalwork around, I have managed to get a socket set ratchet around both at the same time, but didn't manage to turn the nut while holding the torx still. Needs more torque than I can manage without longer tools.

Thank you for the help, I'll keep trying and probably bring in a mechanic to take apart some of the plastic pipework to be able to get better access to the bolt.

[pinger]

Thanks pinger - sorry I didn't see you reply sooner - smartz.co.uk seems to have broken CSS/style for me so the pages are all just text!

I've got a camera under now, and I see the bolt underneath seems to have a E12 torx head, and I can see that rotating when I rotate the nut and bolt at the top. The nut on top is a 13mm hex. With a lot of struggle due to the pipework and metalwork around, I have managed to get a socket set ratchet around both at the same time, but didn't manage to turn the nut while holding the torx still. Needs more torque than I can manage without longer tools.

Thank you for the help, I'll keep trying and probably bring in a mechanic to take apart some of the plastic pipework to be able to get better access to the bolt.

Sounds like someone has toiled with this previously - I'd expect a bolt topside and captive nut underside from the factory.
That you have gained access from below means this isn't the nightmare it could have been. Try turning back the way when it jams up and forwards again (rinse repeat) as that will sometimes work.

I had forum problem here re display. Clearing cookies sorted it IIRC.

[mikerj]

Thanks pinger - sorry I didn't see you reply sooner - smartz.co.uk seems to have broken CSS/style for me so the pages are all just text!

See the last couple of posts in this thread.