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-   -   Cooling fan motor repair (https://www.the75andztclub.co.uk/forum/showthread.php?t=315231)

chicochapman 12th September 2021 14:49

Cooling fan motor repair
 
I see on the Rave disc there is this dire warning :-


"Caution - fan assembly must be replaced if removed, do not fit original assembly"


Anybody know what the risk of putting back the old unit might be?
thanks,
Malc
PS this looks like quite a big job, just to get at the motor :eek:

vitesse 12th September 2021 18:49

I believe the statement refers to the fan blades rather than the motor. The plastic bayonet clips holding the blades to the motor spindle are said to get brittle with age, however Iíve re-used the fan blades on several occasions and never bought new blades.

Regards

chicochapman 13th September 2021 19:21

Thanks for the re-assurance. I'll just be careful.
Malc

chicochapman 14th September 2021 19:36

Now can you remember what size socket you used to "hold" the centre spindle nut with ?
I've got a 1/4" drive socket set that stops at 14mm which seems too small
but might have been thin enough and a 3/8" drive set where the wall is too thick. Looks like a 15mm size ?
thanks,
Malc

Arctic 14th September 2021 20:22

Quote:

Quote:

Originally Posted by chicochapman (Post 2899578)
Now can you remember what size socket you used to "hold" the centre spindle nut with ?
I've got a 1/4" drive socket set that stops at 14mm which seems too small
but might have been thin enough and a 3/8" drive set where the wall is too thick. Looks like a 15mm size ?
thanks,
Malc


Hi Malcolm.
To remove the fan blade you do indeed need a thin walled 15mm socket, which will hold the nut while you turn the blade clockwise.

If you are referring to repairing the fan motor with new brushes, then the fan as whole including the cowling needs to be removed from the car, takes about an hour.

Bumper off, slam panel off with lights attached, then remove the fan, if your car as gas then it's best to cut the cowling round the A/C joints so you do not have to disturb the A/C gas.

If the motor is ok and the brush board is ok you can add new brushes, then fit the fan back on the car.

https://youtu.be/v422cKkvFAk


https://youtu.be/ls1BJGxUoPo

vitesse 14th September 2021 20:52

Just a slight revision to the above, even though Arctic is vastly experienced. I suggest you don't cut the cowling or attempt to remove it, instead when everything is unbolted / free, raise and pivot the right hand side (as you face it) outwards. There's enough room to get your hand in between and undo the three torx bolts holding the fan motor. Done about 10 fan jobs this way and will be helping another owner next week.

Try and time the job so that you can drench the torx bolts, and ideally the two cowling waist bolts while you have lunch, they can be quite stubborn.

Good luck

ps. When he says takes about an hour, that means 2 and a half hours for us mortals

chicochapman 14th September 2021 22:25

Gentlemen - thank you very much for your guidance.
Without this forum I'd have no chance of keeping this car on the road.
thanks,
Malc

chicochapman 16th September 2021 19:15

........and finally
 
here it is
https://www.the75andztclub.co.uk/for...38aa09bed0.jpgand I think I can see what's caused the fan to stop working!

Even with all the help I've had it was still a difficult job due largely to the number of seized fasteners. Some of them I've resorted to grinding the heads off and because of this while I could see that Vitesses' technique of swing the shroud out to access the three set screws holding the motor would work, I went with Arctic's suggestion of butchering the shroud to clear the A/c pipework. Even then, I had to grind one fastener off. I think in the earlier part of its life, this car has spent some time at the sea-side.


For anyone like me, tackling this job for the first(and hopefully last) time, here are a couple of tips
At the bottom of the shroud(or cowl) are two small metal clips holding it onto the radiator(easy to miss)
In terms of taking the "lid" off the motor, Arctic makes it look easy but my mole grips were too clumsy for that so I used a flat faced punch to straighten up the small tangs and then holding the motor in one hand I tapped the three lugs in turn with a medium hammer and slowly the lid came off.
Of course, my only experience of replacing brushes was on my 1968 Midget so foolishly I was expecting expecting screw in lugs on the brushes but now I see its soldering time. Good job I've got a solder sucker.
So, just got to put it all back together now.
Malc

stocktake 16th September 2021 19:33

The first time it is without doubt daunting, there are a few of us on here that have done quite a few now and you still worry if the two torx on the front panel will come off ( there is a work around if they don't) and then if the three motor body torx will come out and then what is the state of the board in the motor and the rest and finally and hopefully the magnets aren't cracked.
Still when you plug it in (laid on the floor before you put it all back together I may add ;) ) it's a great feeling when it spins into action.

vitesse 16th September 2021 21:45

Quote:

Originally Posted by chicochapman (Post 2899847)
here it is
https://www.the75andztclub.co.uk/for...38aa09bed0.jpgand I think I can see what's caused the fan to stop working!

Even with all the help I've had it was still a difficult job due largely to the number of seized fasteners. Some of them I've resorted to grinding the heads off and because of this while I could see that Vitesses' technique of swing the shroud out to access the three set screws holding the motor would work, I went with Arctic's suggestion of butchering the shroud to clear the A/c pipework. Even then, I had to grind one fastener off. I think in the earlier part of its life, this car has spent some time at the sea-side.


For anyone like me, tackling this job for the first(and hopefully last) time, here are a couple of tips
At the bottom of the shroud(or cowl) are two small metal clips holding it onto the radiator(easy to miss)
In terms of taking the "lid" off the motor, Arctic makes it look easy but my mole grips were too clumsy for that so I used a flat faced punch to straighten up the small tangs and then holding the motor in one hand I tapped the three lugs in turn with a medium hammer and slowly the lid came off.
Of course, my only experience of replacing brushes was on my 1968 Midget so foolishly I was expecting expecting screw in lugs on the brushes but now I see its soldering time. Good job I've got a solder sucker.
So, just got to put it all back together now.
Malc

Can't really see how much is left on those brushes, most of the motors I've worked on have had a none existent brush or just a sliver, sometimes even worn so much that the spring has eaten into the commutator.

Doing another one on Tuesday at 10am, bloke faces a 3hr drive to get here but local garage rates are about £160 per hour, so we help each other if we can and I don't mind some quality garage time.

Good luck with the rest of the job

ps Forgot to ask how long it took, please don't say an hour as suggested by Arctic, as I never manage anywhere near his time.


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