General Technical Questions and Answers last answered over 1 year ago.
You may also want to visit the Wiki(pedia) for a more structured index of T25 repair, maintenance, technical and ownership topics
first time I've smiled tonight! boot was removed cable looks good, i've smothered most things externally in vasolene to improve longevity with a small ammount on mating surfaces. bad? its out now any way shall I wipe it all off? didn't do this with first starter and had same symptoms.
Last edited by Hacksawbob on 11 Dec 2006, 23:37, edited 1 time in total.
You could try measuring the voltage drop down the main starter cable under load. When you say that the voltage across the starter was 12.6v i assume that it wasn't turning at the time.
First thing to do is measure the voltage across the battery terminals while cranking the starter. Then measure the voltage drop across the starter motor with it cranking. The difference is how much voltage is being dropped across the cable. An alternative way to do this if you've got some long leads for your multimeter is to connect one end to the positive terminal of the battery and the other end to the positive connection on the starter, then crank the starter. The reading on the multimeter is the voltage dropped on the cable.
Voltage dropped is proportional to current ( Ohms law V = I x R ) so a small resistance in the starter cable suddenly become a big voltage drop when the currents get high.
Another thing i've just thought of is how you're grounding the starter motor when you're testing out of the van. I assume you've got it bolted to the chassis somewhere.
If the cables ok then the only other thing i can think of is the main contactor in the solenoid is faulty or not being shut sufficiently by the solenoid.
Andy syncro-nutz wrote:Do you have a good earth via the box to chassis?
As Andy says - double check your earth lead, I had this when I swapped a gearbox and used the earth lead that was on it, swapped starters a few times, double checked all tightness of leads etc. Swapped the earth lead out for another one and hey presto...
I'll get a long lead from maplins today and see what I can find, any one want to take me on in a time trial for starter motor in? I think I've got it down to about 15 mins now
take a look at the picture on this page, this is how I am testing it out of the van, I need to know if this is not correct as I am basing the assumption that the starter may be knackered on it. testing completly unconnected to the van just with battry Jump leads and a smaller wire to act as ignition key (jump from spade to main positive bolt) http://wiki.80-90.co.uk/index.php/All_e ... t_starting
Not got my wallet today so no trip to Maplins, I have some Wire and croc clips I could use.
Oops. I didn't check out the wiki link before posting. That method of testing with jump leads and a croc clip should be fine. Are you sure the battery is ok? You could try measuring the voltage on the battery while cranking or trying the starter with another battery.
cheers dave, what is a bad drop? I have a working battery in the camper which I tried on the first starter with no effect, the starter motor will only whir if I test it uninstalled with a running motor. (14V)
You can't test a petrol starter like that for the same reason they don't like starting when the starter bush is worn.
The armature is supported on one end by the bearing in the starter, the other end of the shaft is supported by the bush in the bellhousing, trying to get it wor work unsupported like that isn't going to yeild good results and could damage an otherwise serviceable starter.
By doing what you are doing you are sticking the armature to the stator, they are electro magnets after all.
If you want to test it off the van then use a spare bell housing, but it's not really a good test anyway, you need to put the motor under strain and test the current it draws.
So, the new starter you took back probably started out okay, could have been damaged by the way you are testing it.
Oh, and whoever took that stuff from the Brick-Yard and put it next to that drawing telling people how to knacker their starters please split them up, put them at oppersite ends of the page or something, i don't want people to think i condone that test.
first starter motor wasn't tested like that and yeilded same results, what exactly occurs that is bad for the starter, whats a stator by the way, deleted testing pictures.
yes.
worn or missing bush (or trying to test out of bell housing) means the bit that should spin in the middle, the armature is touching the casing (stator) meaning extra friction. If it's left in extreme cases the windings can become damaged.
so from o-level under standings of motors, current flows through outer windings attracting inner magnets in a rotational kind of way, how much space is there between them? isn't th cental shaft held at the rear in a bush and then at the point where it leaves the motor, (I guess not otherwise there wouldn't be a need for the bellhousing bush).
boot was removed cable looks good, i've smothered most things externally in vasolene to improve longevity with a small ammount on mating 
surfaces. bad? its out now any way shall I wipe it all off? didn't do this with first starter and had same symptoms.