Mechanical problems with removing Dynamo

[gtt1951]

Hello Folks,
I've tested my dynamo and found it not to be generating any voltage, so I've tried removing it.
This is where the mechanical problem has arisen.
I seem to vaguely remember (from when I last worked on a Moggy some 30 years ago) that at least
one of the three mounting bolts is actually a screw and needs to be unscrewed from the top front mounting.
Can anyone confirm this as I cannot remove the bolt in question and do not yet want to apply a big
hammer to drive it out (it will not turn, bolt head was already partly damaged - copious quantities of
WD40 applied).
A picture of the offending bolt can be seen in the first picture. The 2nd picture shows that there was no
third bolt (underneath - this hole is threaded) and that the adjusting bracket is just dangling (something
I did not expect to have to check for before buying the car - I removed the bracket nut and bolt).
There is not enough movement, at present, to create slack in the fan belt to remove it.
As I will be replacing the water pump, looks like I'll have to remove the two items together and drill out the bolt?
Can anyone please confirm whether this hole is threaded?
Thanks in anticipation, George.[frame][/frame]
Missing bolt below -
[frame][/frame]

[MarkyB]

Just take the fan belt off and slide the dynamo forwards.
You may have to loosen the other end of the adjuster bar to get the belt off.

[bmcecosse]

Just give that bolt (not screw) a thunp - run the nut down till it's flush with the thread end first. How do you KNOW the dynamo is not giving any volts?? The belt will just slip off - perhaps a gentle levering.....

[mike.perry]

If you cannot remove the bolts, slacken everthing off as much as possible then tap the dynamo downwards. Fit the starting handle and turn the engine over, at the same time levering the fan belt off the crankshaft pulley with a large screwdriver. Take care not to trap your fingers.
You should then be able to remove the mounting bolts

[gtt1951]

Thanks for the replies so far.
Dynamo not showing any output: I've performed Test 1 in the Lucas "Generator & Control Box" Tests booklet.
Result was Zero volts (this was after not getting any sensible readings when trying to adjust the Regulator, as
per the standard Workshop Manuals - Leyland/BMC, Autobooks, Haynes etc.) - so to get at the brushes I needed to
take the Dynamo off.
Removing fan belt: there is no movement on trying to swivel the Dynamo towards the engine, to get belt slack.
The bottom sliding adjuster is not connected to the Dynamo at all.
Bashing the bolt: this has now been tried and it does not show any movement. I can get a spanner, King-Dick wrench,
etc. on the bolt head, but it will not turn and the hex head is now beginning to round off.
This also means that I won't be able to slide the Dynamo forwards as the bolt doesn't move in the direction of the head.
(see pic below)
[frame][/frame]
If there are no threads in this hole, then I can only surmise that the mixed metals have reacted and the whole mess
has welded itself up - like the thermostat housing is prone to doing (mine has, as the remainder of the day's work
was to get the cylinder head off).
I'll try some Eezox in the morning - a powerful freeing agent used in gun care (smells very nice).

As a number of other people, across the forums, have already said - start with what looks to be a simple job and you
end up with a major battle on your hands ...
[The cylinder head removal was a piece of cake compared to the Dynamo problem - except a couple of studs came out with
the nuts].
Regards, George.

[MarkyB]

Someone has fitted a fan belt that is too short for the engine, you need to get it off first then you can use the dynamo as a lever on the top bolt.
You might have to take the pulley off the water pump to get enough slack.

[kennatt]

If you can't lever the belt off,just cut it with a hacksaw and fit a new one since it looks like it is too short a belt anyway

[bmcecosse]

Exactly - this is a very simple roadside job! The metals must indeed have reacted together - apply HEAT - lots of it. And cut the belt if it won't slip off. I'm not familiar with 'test 1' or whatever - but certainly a brush check would seem to be in order. Get the coil out of the way for a start! Then thump the dynamo inwards using a lump of timber and a wee heavy hammer. Does the dynamo have a band round the end of the main case covering the brush gear ? If so - loosen it and slip it round to get a first look at the brushes.

[gtt1951]

Thanks to MarkyB and Mike for suggesting taking hte belt off before proceeding further.
As you can see[frame][/frame]
The Dymano started moving forwards and is now completely off the car[frame][/frame]
The jammed bolt has now had some Eezox applied to see if this will help free it. Thanks also to BMCecosee
for suggesting heat. I did apply some, with a butane torch when in situ, but I was worried about too much heat.
I can now do this easier with the unit out.
Test 1 (from the Lucas book) says to disconnect both leads from the Dynamo, attach a voltmeter (I'm using
an Avo Mk8) to the D terminal (small one) and the other to a good earth - should see 2-4 volts - I had nothing
using the meter set to the 25V scale.
There is a band around the end of the Dynamo, carrying the coil - I'll remove this later.
I will post up a message after I've had a fiddle - but then the results may end up on the Electrical forum.
Problems don't stop there, as I resumed working on the de-coke and have now found that the Cylinder Block water
drain (no tap, just a screw plug) has very badly silted up. I'll swap this over to another forum - it never rains
but it pours (except not in this case).
Thanks to all that have replied in my hour of need,
George.

[mike.perry]

The band around the dynamo previously refered to is only applicable to the earlier C39 dynamo.
It is possible that a bolt with a slightly larger shank has been forced into the hole. Replace it with a 1/2 AF head nut and bolt.
I hope that you are using the correct size spanners, A/F or Whit where applicable, not metric

[gtt1951]

Mike,
I'm only using my old socket sets and spanners (from the late 60's and early 70's)
and they are SAE, Whitworth and AF - I do happen to have some metric spanners
(ring, open-ended and ratchet and a couple of small size metric socket sets) and
various adjustable open-ended ones as well.
Can't find my Mole Grips, however.
I put the Dynamo in my bench vice, applied LOADS of heat (butane flame), used an AF spanner
and a hammer and finally got the b**t**d out![frame][/frame]
I've now cleaned up the opening with a file - the bolt is now of no use at all - and I have also cleaned
up the other upper mount hole and recut the thread of the lower point (missing its bolt) with a 5/16 BSW
tap (I'm very glad that I saved so many taps and dies from my works when we were demolishing
all the old buildings on our campus type site).
I also salvaged a load of nuts, bolts, washers and lathe parts (not to mention a complete
Myford 7 lathe) - lucky me.
I'll have to source a suitable nut and bolt for the top forward mounting.
However, I cannot find my hub-puller to take the pulley wheel off - nearly there now, looks like a trip
down to the main Camberley Auto Factors (just down the road) for a replacement (if my daughter
comes round to give me a lift as I'm not allowed to drive yet because of my foot surgery).
I still haven't managed to open up the Dynamo, as the main bolts seem siezed as well (getting the pulley
off will give me access to the screw threads for the bolts and allow me to apply some freeing agent.
Regards, George.

[bmcecosse]

Don't touch the pulley!!!! Just take the rear cover off to get at the brushes....... Mark it all for reassembly, then undo the two through bolts and it all falls apart.

[mike.perry]

I'm not allowed to drive yet because of my foot surgery.

Removing the pulley is a lot of effort for little reward. There are no nuts to undo to open the dynamo, just spray some squirty in the direction of the long bolts, grip dynamo in vice and hit tops of long bolts with a hammer on a large screwdriver before gripping screwdriver handle or blade with a spanner and twisting. Remember to undo nuts on the terminals before removing back of dynamo

In your case I do not recommend kicking the hub caps

[bmcecosse]

No nuts! It's Lucar connectors.

[gtt1951]

Hi,
I haven't yet managed to get the bolts unscrewed - haven't hit them yet either.
If I need to do anything with the commutator, then I will need to remove the pulley.
According to an ESM parts catalogue from 2007 (it came with the car and loads of books),
the fan belt that was fitted (size 813mm) was meant for an 803 or 948cc engine. It was fitted to a 1098
replacement engine (I'll use the fan belt on my 803 engine - project).
The correct fan belt (according to the same parts catalogue) should have been an 825mm length - this
doesn't seem large enough as it will only give me an additional 12mm.
The Dynamo is a C40 model.

Looking in through the end of the Dynamo, I can see the brushes in contact with the commutator but
they look worn down. I'm waiting for my daughter to come back with my car (which she is borrowing whilst
I'm supposed to be resting my foot) so I can get at my jump cables/leads and try the Dynamo as a motor
(as suggested elsewhere in one of the Forums) - before resuming trying to get it apart.
Regards, George.

[bmcecosse]

No - you don't need to touch that pulley!! Leave it alone !! Yes - the motor test is the best one - but since you have gone this far you may as well fit new brushes now anyway. 825 is the standard belt. Get a spare too!

[gtt1951]

Did the motor test after seating the brushes with a pointy object.
Dynamo ran as a motor for a few moments, gaining speed and then a horrible squealing sound started up
(and I had been told the noise was most probably the water pump).
Looks like I will have to take the pulley off, after all, as I have now concluded the ball bearing race (at the front end)
has had it.
Have got the brush end off and Brushes are at 12.5mm book says to change at 7.1mm.
No sign of any burn spots, but turning the armature by hand, you can hear that there is something wrong
with the ball race.
If I can't source a ball race that fits, then I'll have to bite the bullet and get a replacement C40 Dynamo.
Vehicle Electrics Ltd have an eBay listing for a new C40 at £45.99 (outright sale - Buy it now, £9.50 P&P).
Either way, I'll have to remove the pulley - CAF didn't have a three (or two) legged puller, just a "universal one"
that won't do the job.

[bmcecosse]

Doesn't explain the lack of charging then -if the brushes have good length. The stupidly overtight fan belt has ruined the bearing. You'll need to try wedging it in a vice or similar - and then wallop the shaft. Have you got the nut off ?? Soak it all in Plus Gas - and apply some heat - lots of heat actually! I wouldn't waste money on another dynamo - certainly not a NEW one. Pick up an alternator from the scrappy!

[gtt1951]

BMC, thanks for sticking with me and my problems.
The charging problem may have been due to one of the brushes being very stiff in its guide.
I've bought a set of hub pullers, off fleabay, but will try your bashing suggestion tomorrow.
I got the pulley nut off a couple of days ago.
I've also identified a supplier of a "dynamo repair kit" - same fleabay source - the seller has a very wierd handle
of "LesboBird" !
I'll be trying the other problem (other forum, General - silted up water channels) solution tomorrow as well.
Thanks for your help, George.

[bmcecosse]

Usually the major problem is getting that nut off - the pulley is very fragile - I would just apply heat and very gentle levering - two tyre levers perhaps.