Starter solenoid

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heinkeljb
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Starter solenoid

Post by heinkeljb »

Here's the problem:-

Turn the ignition side of things on.

Press the "start" button - and the dynastart turns over, BUT take your finger off the "start" button and engine is still turning over! After a little while (1 or possibly 2 seconds) the engine fires up.

Now I am assuming the solenoid is sticking in the "connected" position, presumably due to lack of lubrication internally or maybe the arm is "welding" the contacts bar in the connected position. After the engine is running, you can turn the ignition off and the engine stops so it is obviously not STUCK in the connected position permanently.

So, is it possible to dismantle the solenoid to clean it internally or is it better just to buy a new one?

John
Haflinger 703AP LWB 1973 - (Once owned by Lady Sutherland & Sons.) Now called "Lurch" !

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Markus
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Re: Starter solenoid

Post by Markus »

Hi John, On my model I could and im 99.9% sure its the original unit but it could be different for the later models like yours.

I can't remember if it has a gasket or an Oring sealing the unit.
could also be the push button.

hope this helps.

Markus
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heinkeljb
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Re: Starter solenoid

Post by heinkeljb »

Since it happened a couple of times, at the time I wrote the post above, it hasn't done it again. I will get round to taking the starter solenoid off the Haflinger and seeing if it will come apart.

If it will, then obviously I can clean and lubricate everything. :geek:

Trouble is finding enough time to do the that without having to put it down for a couple of weeks and thereby forgetting all the relevant things relating to how you took it apart etc. Done that too many times with some thing I have never taken apart before and then struggled to get it back together because I could remember which bit ought to go in first :oops:

John
Last edited by heinkeljb on Tue Nov 26, 2013 10:21 pm, edited 1 time in total.
Haflinger 703AP LWB 1973 - (Once owned by Lady Sutherland & Sons.) Now called "Lurch" !

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heinkeljb
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Re: Starter solenoid

Post by heinkeljb »

Well, it did the nasty on me a couple of days ago and stuck on long enough (with out the engine starting) to get me worried that the wiring was going to get so hot it would melt!

Managed to get the battery disconnected before anything too horrible happened. So Plane of action called for:-

1: Take starter solenoid off.
2: See if I can get a new one.
3: Failing that, repair old one if possible
4: FIT A BATTERY CUT OFF SWITCH BEFORE USING IT AGAIN!

Actually number 4 ought to be number ONE --- Just have to figure out the best place to put it where the live battery cable is not too long, it is easy and quick to get at. Probably on the side of the battery box as mine is a wooden home made affair.

John
Haflinger 703AP LWB 1973 - (Once owned by Lady Sutherland & Sons.) Now called "Lurch" !

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Julian B
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Re: Starter solenoid

Post by Julian B »

I have a battery isolator switch located on the rear vertical surface of the battery box, and it works well. I always switch it off when not in use to try to help preserve the battery etc.
Julian B
W Sussex, UK

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heinkeljb
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Re: Starter solenoid

Post by heinkeljb »

It turns out Haflinger Technik don't have any more Bosch starter solenoids and that they appear to have been discontinued!

That meant I have two choices, use some other starter solenoid or fix mine! As I have nothing to lose in attempting to repair mine, I thought I would have a go and write up the procedure if it worked.... As you will have guessed - it did work so Read on as I make a “How to” for stripping and refurbishing the Bosch Starter Solenoid.

To start with you obviously have to remove the solenoid from the engine bay - Don’t forget to disconnect the battery before you start working in the engine bay.
Remove solenoid from engine bay.jpg
Remove solenoid from engine bay.jpg (241.16 KiB) Viewed 1602 times
Undo the two big nuts on top of the solenoid and move the thick power cables out of the way.
Remove the two thinner red cables from the post nearest the back of the Haflinger. This post has the wire coming directly from the battery. So this would be live all the time when the battery is connected.
Remove the brown “trigger” wire from the spade connection tag. This is the wire from the starter button.
Remove the solenoid from the wall of the engine bay by undoing the two fasteners which hold it in place. Whoever thought of using machine screw with flat screw driver slots in them for this task certainly never had undo forty year old fasteners! If you can get the one nearest the rear of the vehicle removed, then you can “wiggle” the solenoid towards the back of the engine bay and it will come free from the second fastener as the bracket has slots rather than holes.

The top picture is of the bottom of the solenoid, showing the two screws you have to undo.
bottom and top of solenoid.jpg
bottom and top of solenoid.jpg (154.27 KiB) Viewed 1602 times
The bottom picture is of the top of the solenoid showing the two screws you have to undo.

You will need a HIGH power soldering iron for the next bit. I have an “instant” heat 100 watt which managed very well to heat and allow me to remove the solder on the spade terminal where the wire from the coil comes through the Bakerlite top. You can just make out the dark line on the right hand side of the solder (bottom of bottom picture).

So undo the bottom two screws and you can take off the bottom cover;

This is what you might find.
bottom ccover removed.jpg
bottom ccover removed.jpg (48.63 KiB) Viewed 1602 times
The plunger in the middle of the solenoid in the bottom part of the picture did move, but did not feel nice and smooth. I am quite sure that if I had continued to move it, it would probably have stuck at some point in its travel. So clean and lubricate. First use a thin oil – something like “PlusGas”, is good. Then slightly thicker oil / grease to make sure some lubrication stays down the shaft.

Now turn your attention to the top of the solenoid: You’ll probably see something like this:-
what you are likely to find.jpg
what you are likely to find.jpg (127.61 KiB) Viewed 1602 times
As you can see, the left hand side of the contact bar has had some serious Arcing which has eaten away a bit of the lower edge. Also you will notice the black soot / carbon deposits – you need to clean these parts up! Make them all shiny. I used a piece of wood with some fine wet and dry emery cloth on the end to clean up the contacts in the Bakerlite top as I didn’t want to undo the nuts on the other side and takeout the contacts (which you can do, just don’t lose the insulators). Then using a fine file I cleaned up the contact areas on the contact bar. This should be able to swivel all the way round and it has its own little spring so make sure it can move and that you put a bit of lubricant on it.
nice and shiny.jpg
nice and shiny.jpg (53.04 KiB) Viewed 1602 times
Put a ring of non-setting gasket sealant on top of the existing gasket as I doubt it will seal very well by itself any more.
Put the top Bakerlite bit back on making sure to get the wire from the coil to go back through the hole where the spade connector tag is. Put the two screws back in. Solder the wire back on to the tag.
top back on and wire resoldered.jpg
top back on and wire resoldered.jpg (74.1 KiB) Viewed 1602 times
I then put some grease on top of the two screws to keep the water out. I thought it would be easier to remove that if you ever need to get into it again then to fill it with the gasket sealant.
Then Turn it over and put a bit of grease into the bottom cap, put some more non-setting gasket sealant round the edge to keep the water out. Put the cap on and do up the two screws.
I put some of the sealant over the bottom screws as they are likely to get more water thrown at them and being proud of the surface easier to get the sealant off if you need to.
bottom cover on and screws sealed.jpg
bottom cover on and screws sealed.jpg (44.91 KiB) Viewed 1602 times
All that remains is to re-install the solenoid in the Haflinger. In the good tradition of the Haynes manuals: that is the reverse of the dismantling!

The only thing to say now, is that I hope you remembered to take photos / notes of where all the wires went on your one when you took it off!
If you didn’t, check if the following matches yours.
1: The thick wire which goes to the Dynastart goes on to the big post of the solenoid nearest the front of the vehicle.
2: The thick wire which comes from the Battery goes on to the big post of the solenoid nearest the rear of the vehicle.
3: The two thin red wires go on to the big post of the solenoid nearest the rear of the vehicle along with the thick wire.
4: The brown wire with the spade connector goes on the spade connector on the solenoid.

That’s all folks!

Hopefully you now have a normal functioning starter Solenoid after all that.

John
Haflinger 703AP LWB 1973 - (Once owned by Lady Sutherland & Sons.) Now called "Lurch" !

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heinkeljb
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Re: Starter solenoid

Post by heinkeljb »

It appears as a consequence of the sticking solenoid, the stater circuit stayed on too long and has accelerated the wear of the Dynastart brushes.

I am now having starting issues with the Dynastart struggling to turn the engine over (exactly like having a flat battery). When this first happened, I thought it was down to the cold weather having finally been too much for the battery. I have not idea how long that battery has been on Lurch. So I bought a new one and the staring problem disappeared.

Now, it is back! So new brushes on order. I will also be doing an oil change to SAE30 from the current SAE40 as that can't be helping, but I had planned on that for this weekend in any case. Up till now the weather has warm enough not consider the oil being too much like treacle.

Why did they put the brushes underneath, necessitating removal of the belts, the cowling and the Dynastart? If they were worried about water or dirt getting in if they were on top, surely some sort of seal / cover would keep it out?

Oh well, these things are sent to try us!

John
Haflinger 703AP LWB 1973 - (Once owned by Lady Sutherland & Sons.) Now called "Lurch" !

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