Electrics: 164: temp sensor

[woodturner-fran]

Thanks again MalB.

all of that makes complete sense!

Yes I do think that the brakes are AOK. And that the sender is OK too - its just that the piston is offset just a small bit in the block and thats what has it lit all the time. I have a copy of the haynes manual - and in fact the drivers manual actually has the wiring diagram in there too!

Plunger in the brake balance switch is flat and flush with the nylon carrier, it should sit over the groove in the piston and not make contact unless the piston is displaced,

This is another thing I need to go back at again (the car is away at the moment getting a few rust spots sorted out). The sender looks like any other sender.. spade contact on top, threaded part, and then a nylon shaft that sticks out the bottom and has maybe 3 or 4 mm of movement in it. The end of this shaft is flat. The slightest push inwards and the circuit is made. When I look down into the block, I can see the groove and its very slightly offset to one side. Obviously when I screw down in the sender, the shaft is resting on the side of this groove and thats whats causing the circuit to light up. My brother (who in fairness is a mechanic) took one look at it and said that the block was the problem, not the switch!


So from what you are saying replacing the block is gonna be serious money? But then if its seized in the (almost) correct position it hardly matters only that if a brake line should burst I wouldn't have the protection that it offers?

At that rate I think I'll do one thing - check and see can I move the piston easily and if not, just leave the wire disconnected.

Thanks again for your help - its brilliant stuff and helps a lot.

Fran

[malb]

I'll pull the balance sensor switch on one of my 245's tommorrow and check it for you, I think there should be the threaded nylon housing with spade, a spring, and the probe. You didn't mention the spring, and I'm not sure how it fits into the system now as I haven't had one apart for years. Will come back tomorrow. My parts book shows them as a complete assembly, and all manuals describe them as non repairable. I think I know why, having tried once.

I think you should be safe with it disconnected, (or just remove the probe), provided that the brakes are fine now. If you split a hose, you will loose 1 rear side completely, and go to half strength on both fronts. You will still stop, you will have a fair idea that somethings not quite right, and you will need about 15% more space to stop in. If your not using the car competitively, you should cope.

How do I know, my new 245 blew a little seal in the front right caliper (between inner and outer castings) at 13 months/58,000km, 80m out from a blind T in a cutting at 150kph. Yes it did get around the corner, and yes the nice people at the dealer were slightly apologetic about it, but the warranty was defiintely expired, and no, they won't fix it as a gesture of goodwill.

Incidently the puff of vapourised brake fluid coming up from the front drivers side wheel arch told me long before the light did.

[Snowman]

Agree you'd be fine with one circuit for a while.

Split a braided hose on the front of my 140 at the start of a 130 mile road rally, managed to complete the event no problem, just planned a bit further ahead for the corners!

Not big, not clever but a good system!

[john h]

Another possibility for the temp reading, if you still have the original fan.

As the viscous fan clutch wears out, it is designed to slip less and hence cool the engine too much (as opposed to more slip which would let it overheat).

So it might be that the guage is correct but the engine is running too cool?

You could try putting the sender in a cup of boiling water for a few minutes to check it.

Let us know how you get on please... my 164 also seems to run cool!

John

[woodturner-fran]

JohnH:

I didn't actually try that, but of course it would be a way to see if it was the sender. I have a feeling that big old engines like this tended to run cooler than engines would now, however, in my case I know that this engine came close to boiling up (fan belt broke, long story but no harm done) and even at that the gauge didn't rise pass "C" into the green zone - it rose a bit off the bottom but not far enough. So basically I'm running without a temp gauge and if it boil up, I wouldn't know until its too late.

The other thing that I should have a look at is see if there is a build up of ****e around the sender in the head - that would stop it getting hot. Even though the coolant was clean when I drained it out there could be crud around the sender. Before you say it, I don't think its air!

VP autoparts have then sender and it works out at about €7.50. As they also have the door weatherstrips and few other bits that I need, I think I'll order one anyway. I don't really want to go pulling at the old one too much until I have a new one sitting beside me.

I'll keep you posted on how it works out.

Fran

[henning]

If your engine runs to cool your gauge will show very low. Check the thermostat first. Remove, put it together with a thermometor in a pot of water and heat it on your wifes stove. The thermostat should start opening on the imprinted temerature. It could even be that it does not close completly when cool..then get a new one. If it opens to early....get a new one.
To cool is not good, just as to hot.

[woodturner-fran]

Ok,

heres how this ended up:

I fitted a new sender but it made no difference. Its not the thermostat because the heater is working very well. So I went back to the clock. I took out the clocks (actually handy enough to do) and stripped down the cluster. Took out the actual clock and sprayed some contact cleaner in there. When it got a belt of the IPA in teh cleaner, the hand rose - what you'd expect from a thermocouple. So I cleaned any other connections I could find, refitted the clocks and hey presto! the clocks work AOK now.

So if anyone else stumbles across this thread, bear this in mind. I'd say the IPA dissolved some gunk that was stopping the thermocouple working, even though it was clean in there.

Fran

[Mike B]

Hi folks if you bleed the brakes on a 140/164 you must first remove the warning switch as you are able to snap the end of the nylon shaft when the piston centralises , then refit after checking that it has .
Regards
Mike B

[woodturner-fran]

Would anyone be able to take a photo of the bottom of the nylon shaft in the sensor?

Mike b's point above could well be the issue with mine, but I don't want to go and buy one only to discover that it wasn't that after all. Maybe if someone had one out at some stage you could take a quick pic for me??


TIA,

Fran

[Mike B]

Will remove switch and try to take pictures tomorrow.
Doing a bit of tlc to the bodywork at the moment , Knebworth in a couple of weeks.
I wont have time to finish but still take the Old Girl [and the car Whoops ]
Regards
Mike B