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Replacing An Alternator


shutterbugbob
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Hi

I was just wondering how hard it is to replace an alternator? Mine needs replacing but was going to get a second-hand one and have the garage fit it for me, but wondered if I would be able to do it. Is access to it from the top or bottom? I used to do most of my own repairs but that was when I had my cortina and engines where easily accessed, also because of work commitments it made it easier to drop the car off at the garage and let them do the work. Now however I like everyone else I am having to try and save money!!:-)

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Sorry but you have not given enough info for a decent reply. first off what car? is it petrol or diesel (sometimes very relevant)? and are you sure it needs replacing? The reason for the last comment is that I have a focus where the charge light came on at random but it is not actually an alternator problem! Simply an easy fix wiring one,.cost me me about 20 pence and half an hour to fix!

Phil

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check the charge from battery, started and put full load on. might be the socket (depending on alternator) what the pully spindle fit into, bearing my be fubared, was there any noise prior to the light coming on? same as above, they do have a electric problem which when everything is still working charging as it should you do get the batt light show up on display. from mine it has to be taken off from underneath....

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Hi sorry guys, knowing what car I had would help I suppose...Doh!!!

It's a 2002 Mondeo 2.0TDCi 115. My battery light started to come on about a week or so ago, after a couple of days of coming on it failed to start, battery was dead. So took the battery off and gave it a full 12 hour charge. I took it to my local garage, and he tested the battery and alternator battery was fine but there was no charge coming at all from the alternator. The battery lasted about 5/6 days before I needed to recharge it, only about 11 miles. Any other time of the year I would have just paid him to put a new one on, but with christmas thought it would be best to get a refurbed/second hand one....I've seen a couple on eBay from £20-£35

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If the 2.0tdci is the same as the 2.2tdci then access is from underneath/wheelarch area.

Its a bit of a pita as space is limited but easily done in a couple of hours. tbh, your best bet might be to have a look in a haynes manual (i cant remember exactly what was involved)

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If you found your warning light flashing on/off before complete failure it might still be worth a check on wiring before buying new alternator.

If its the same as the focus (and i suspect it is, Ford not known for making new if old will do!) From the alternator you have the main charging wires, the thick ones (rarely a problem) and a secondary loom carrying either 3 or 4 light weight wires (this is where I found the problem) trace the wiring loom along and you will find a plug (focus goes up beside radiator) at plug end gently pull on wires and one suddenly snaps! cut the same coloured wire at other side of plug and joint broken wire to this. Problem Fixed! Glad I was warned of this one as I hate spending money on new parts to find they are perfectly sound :angry:

Phil

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It's a fairly easy job - having been there, done that, got the fridge magnet, I could change an alternator in about 30 minutes.

It gets tricky because you'll have to remove the auxiliary drive belt from the alternator pulley, and to do that you need one of the magical, mystical "special tools" you keep hearing about. I have one, and it's basically a !Removed! long handle with a T shape on the other end with two studs on one side, that you put onto the tensioner, and pull it to release the belt tension allowing you to remove it.

I've heard that people have cobbled together their own tools for doing this. Personally I opted for a "right tool for the right job" approach, and got one for about a tenner off of eBay.

Also, be warned that, when releasing the belt you might find that it falls off some of the other pulleys as well, so make certain you know how the belt is routed before doing anything, in case you need some sort of reference for putting it back.

There is an idler pulley top-centre as you look at the side of the engine. I found that one to be the easiest to put on last, as you just have to give the tensioner tool a !Removed! good pull, and push the belt under the pulley (the back of the belt goes onto this pulley, not the ribbed side, so it's easier). When you're done, put a socket onto the crankshaft pulley and turn the engine manually (with the car in neutral), to make sure the belt is seated properly and the whole thing turns freely.

One more thing that may help - if you struggle for access it will help you to support the engine under the sump (I did it with a trolley jack with about 5 lumps of plywood on top), undo the o/s engine mount and drop the engine about five inches, taking EXTREME care not to damage the rubber boot, as it will hit the subframe. Bust that, and you've given yourself another job.

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Thanks guys for the replies, will check them wires I think just to be sure, as for fitting the alternator, I reckon I'll grab a Haynes manual first..... then probably decide to have someone else do it!!! I used to like it when they left things easy to identify and easier to get at without having to rip half the engine/car away to get to it!! LOL

I got a basic spanner and socket set. There's a guy around the corner who always seems to be working on cars so might see if he can do it if I bung him a few quid, no harm in asking I suppose!!

Thanks

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  • 3 years later...

Carefull with the Haynes Manual as the diagram is incorrect.

Remember that the smooth side of the belt goes underneath the jockey wheel [smooth pulley].

The haynes manual has it as going through the tensioner and over the jockey wheel,which is smooth and they Miss out the ribbed wheel on the tensioner.

over the ribbed,under the smooth

the smooth side of the belt always goes underneath the smooth pulleys and NOT over it and vice versa

Also a Big HELP is to put a piece of card between the tensioner tool and the car body  once you have located one of the holes this stops it slipping out and makes it easy to release the tension,plus you dont have too locate the tensioner tool in both holes [hex].

One hole will do then slide a piecice of card down

then pull,release the tension, and slide the belt under the jockey wheel,

Im taking it that the engine mount and has been taken off [4 bolts easy] and engine supported.

 Gives easy acsess

Much easier with an extra pair of hands!  

Edited by powwimpy
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Sorry if this seems a very delayed response/update but I have found another issue with the Ford charging system, it appears that the modern ford charging system runs through the ECU and if the ecu "thinks" alternator is overcharging it turns the charge off! Now I understand that this is a safety precaution (as the alternator can create suprisingly high voltages) but I have found (on my car at least) if the plug carrying the small wires has got water ingress, and consequent rust, this fault occurs, the obd reader shows the system as "overcharging" so it shuts the alternator down and does not charge at all. Unplugged the small loom (one plug) spray socket and plug with WD40, plug and unplug the loom a few times, another spray and plug back in! Problem has not reared its ugly head for several months now!!

Hope this saves people a few quid!!

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