Stuck battery terminal on an MX5 Mk2

Stuck battery terminal on an MX5 Mk2

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T40ORA

Original Poster:

5,177 posts

220 months

Friday 2nd March 2007
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Car's been covered outside for the last couple of months, and this morning I uncovered it and went to start it only to find zero battery charge.

I connected up a boost pack, which usually works, but there was then only barely enough juice to turn the engine over - but slowly (booster pack was fully charged). SO I reckon that the battery is knackered and tried to disconnect it.

Negative lead came off fine, but the positive connector won't budge. I've soaked it in WD40 and I'm waiting, but any other suggestions? I know it should have been put on with copper ease but I guess the dealership didn't do this when they changed the battery some years ago.

Cheers, Lee.

trickywoo

11,818 posts

231 months

Friday 2nd March 2007
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If it comes to it just cut the connector off and fit a new one.

If the terminal looks corroded you could try brushing it with a sodium bicarbonate solution.

I'd also use normal grease (not sure what effect the copper would have on electrodes).

t40ora

Original Poster:

5,177 posts

220 months

Friday 2nd March 2007
quotequote all
trickywoo said:
If it comes to it just cut the connector off and fit a new one.

If the terminal looks corroded you could try brushing it with a sodium bicarbonate solution.

I'd also use normal grease (not sure what effect the copper would have on electrodes).


Yeah, thought it might come to a bit of cutting but I'm always loath to do it. The terminal doesn't look in the least bit corroded so I'm quite surprised it won't budge.

I'll get my wire snips ready...

EDLT

15,421 posts

207 months

Friday 2nd March 2007
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If you've taken the bolt out try spreading the connector with a large screwdriver/chisel by forcing it into the gap.

t40ora

Original Poster:

5,177 posts

220 months

Friday 2nd March 2007
quotequote all
EDLT said:

If you've taken the bolt out try spreading the connector with a large screwdriver/chisel by forcing it into the gap.


Had a go at that but then it started pi55ing down so decided to leave it. Will give it a try.

M3 Mitch

538 posts

230 months

Thursday 8th March 2007
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You really should not have to cut it off - any good parts store will have a specific puller for battery terminals, they are not expensive. If you can get some Kroil penetrating oil, it is way better than WD-40.

I have never seen a battery terminal so stuck that spreading the ears where the bolt goes, and maybe a little judicious tapping and prying would not loosen. But the specific puller almost has to work.

That said, cutting the end off and putting on a replacement is not exactly an all-day job.

I like Wurth copper-based anti-seize paste on battery terminals, works very well.

In general, you can count on a dealer to never be arsed to apply anti-seize to a battery terminal, also to gorilla-torque it, just want to get rid of you and take your money as quickly as possible, in my experience..

GreenV8S

30,208 posts

285 months

Thursday 8th March 2007
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Is it an ordinary tapered round post? If so, just take the clamping bolt right out and then put a big flat bladed screwdriver in the gap, give it a tap if necessary to open the gap, then just pull it sideways as if you were trying to spin the clamp round the post.

t40ora

Original Poster:

5,177 posts

220 months

Thursday 8th March 2007
quotequote all
I got it off eventually. Couldn't use the blade of a screwdriver as one of the ears on the connector had a sort of flap going over the other one, so I couldn't get a screw driver in.

A combination of soaking in WD40 followed by, as suggested, judicial application of a hammer and a pair of mole grips finally did the job.

I was at it early this morning as my wife was bashing around the place moaning that it was such a lovely day it was a real shame that she couldn't use the 5 for work.....

Thanks for the help guys - and I didn't know that you could get a special tool for these circumstances.

BTW I've put grease liberally on the terminals, but would you suggest anything else?

mx-5 lazza

7,952 posts

220 months

Friday 9th March 2007
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t40ora said:
BTW I've put grease liberally on the terminals, but would you suggest anything else?

If you are using a proper MX-5 battery you shouldn't need to grease the terminals.
MX-5's use sealed gel batteries so the terminals shouldn't corrode. Just don't tighten the clamp any more than you need to, it doesn't need to be that tight.
The best battery to use is the Westco from MX-5 Parts. It's a fibreglass filled sealed gel battery so can be mail ordered and delivered to your door. It's higher rated than the standard battery but the same size (more or less) so fits with the stock battery clamp.

t40ora

Original Poster:

5,177 posts

220 months

Friday 9th March 2007
quotequote all
mx-5 lazza said:
t40ora said:
BTW I've put grease liberally on the terminals, but would you suggest anything else?

If you are using a proper MX-5 battery you shouldn't need to grease the terminals.
MX-5's use sealed gel batteries so the terminals shouldn't corrode. Just don't tighten the clamp any more than you need to, it doesn't need to be that tight.
The best battery to use is the Westco from MX-5 Parts. It's a fibreglass filled sealed gel battery so can be mail ordered and delivered to your door. It's higher rated than the standard battery but the same size (more or less) so fits with the stock battery clamp.


That's the one I've got. Not bloody cheap, eh? But cheaper than a standard one through a dealer. MX5 Parts have always been good on delivery too.

I'll check the terminals tomorrow to make sure that I've not over-tightened the connectors.