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Improving the MK1 NA 1 .8 Mk 2/2.5 Alternator hinge bolt

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Improving the MK1 NA 1 .8 Mk 2/2.5 Alternator hinge bolt

Postby Mazda Mender » Mon Jul 09, 2018 10:10 am

The hinge bolt on the MK1 NA 1.8 alternator and on all models and versions of NB/NBFL Mk2/2.5 there after is a pain at service time...basically the bolt is fed from the back to the front and the outside leg of the alternator is threaded, which is open to the elements, the alloy of the alternator body ends up fusing to the thread of the metal hinge bolt. Resulting in a solid fused bolt. It is not easy to be undone by the bolt head at the back and with limited space becomes a major hassle at service time to swap the Aux belt.

This guide will show you a fix for this and you will never have a seized hinge bolt again...

So wheel chock the back wheels and jack up the front on both sides and support the Roadster on axle stands on flat solid ground..

First off you "WILL" need to remove the under tray by way of the 10 mm bolts ,nuts,and self tappers, you will also need to remove the front most arch guards/liners. A Phillips screw driver is required for removing the plastic trim clips which is a twist and centre pops out then remove and 6 x 8 mm head self tappers underneath to the nose cone bumper .

Once the under tray/front arch liners are removed you will need....

1 x OE jack and brace....
1 x block of wood...
1 x 14 mm ring spanner..
1 x 14 mm 1/2 socket....
1 x 1/2 extension piece...
1 x 1/2 Ratchet....
1 x 12 mm ring spanner
1 x large screw driver or pry bar...
1 x drill...
1 x 10 mm drill bit...
1 x can of freeing up spray oil/penetrating oil...
1 x MK1 NA 1.6cc alternator hinge bolt and nut... http://www.autolinkmx5.com/alternator-m ... 1563-p.asp
2 x wheel chocks
2 x axle stands

Very first thing is spray the hinge bolt,thread etc, a good proper soaking with your penetrating oil

So we need to remove the 'Inlet support bracket' by way of 3 x 14 mm bolts, 2 at the top and 1 at the bottom. As the hinge bolt goes from the back to the front and cannot be removed with this in place, once this conversion is done there will be no need to remove this support...

So starting from the bottom crack the 14 mm first and remove, and then to the top 2...

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Now we can move onto the alternator.....Crack the 12 mm bolt that bolts down the adjuster block....

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Now wind out the 12 mm adjuster/tensioner bolt off to full as we will need to un hook the Aux belt...

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Once wound out we now need to crack and remove the 14 mm bracket bolt that locks it in place to the water pump...

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At this point the health and safety blah de blah comes in.......We highly recommend that you disconnect the battery at this point because of the electric current to this unit while we are man handling it so it does not short out to ground and give you a nasty jolt...

You can now if wished.... remove the bracket, block etc.... but there is no real need to...
So now the main event......getting that bolt cracked and out, spray it all again with freeing up oil/penetrating oil

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Get your 14 mm spanner and attach the ring half onto the hinge bolt head...

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Get your block of wood ,jack and brace....

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Put the block of wood on the jack and jack up to the spanner, ( we are using a OE jack in this guide as most Roadsters should have one in the boot?) once you take the slack up start to jack the spanner to crack the bolt, it will go and make a lovely noise while doing so keep spraying with the penetrating spray as you go..

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Once you have un seized it you should be able to get a ratchet spanner or socket on it to remove the hinge bolt....

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Pry the alternator free from the engine block with a large screw driver or pry bar and get it to rest so we can now drill out the thread....

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Now get your drill and 10 mm bit and drill out the thread....

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Old Mk1 NA 1.8 and all others up to 2005 at the top and the new MK1 NA 1.6cc alternator hinge bolt and nut at the bottom....

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Replacement 1.6 cc Mk1 NA alternator hinge bolt was supplied by Autolink MX5 for this walk through how to guide link below...

http://www.autolinkmx5.com/alternator-m ... 1563-p.asp

And check it fits with the new 1.6cc Mk 1 NA alternator hinge bolt...

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Once drilled out get your grease of choice ( Copper slip ) and apply it the hinge bolt shaft and the legs to the alternator ,then offer the alternator back into position with the new 1.6cc MK 1 NA hinge bolt fed from the front to the back and add the nut onto the rear of the bolt just finger tight at this moment...

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Now it is just a case of re fitting as you took apart...14 mm bolt for the adjuster bracket that secures to the water pump, re hook the Aux belt on take up the tension with the 12 mm adjuster/tensioner , lock the tension up bolt to the block up with a 12 mm... then put your 14 mm ring half of the spanner on the 1.6 MK 1 NA alternator hinge bolt nut and tighten up with a 14 mm socket and ratchet at the front ...

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Re add the inlet support bracket with the 14 mm socket and ratchet, switch on the electrics, re add your under tray and front arch liners ,get her back down on the floor and remove chocks...

Job done, no more seized alternator hinge bolt at service time ,,,ever. :handgestures-thumbup: :dance:

As is the norm ...any questions please feel free to ask, it's what we are here for.
The Disclaimer:-
This post is a natural product made from recycled electrons. The slight variations in spelling and grammar enhance its individual character and beauty and in no way are to be considered flaws or defects, the articles/answers/comments are provided for information purposes and they are not intended to substitute informed professional advice, I or mazdamenders.net cannot personally be hold responsible for any damage occurred from following this procedure or any injuries from it. Proceed at your own risk.

Mk 1 Eunos 93 black V.S II 1.8 ,
Mk 2 .1/4 Roadster 99 black & gold V.S 1.8 being rebuilt,
Mk 1 Eunos 90 1.6 (claimed by daughter)
MK 2.1/4 Blue V.S Roadster 1.8 99 ...being rebuilt
Mk 1 Eunos 95 blue G-ltd 1.8...being refurbed
http://www.mx5oc.co.uk/ http://www.mx5nutz.com/forum/ http://miata.net/ http://www.autolinkuk.co.uk/

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