Panel voltage stabiliser?

[Charles Farran]

Dave,

If i understand you, you said the tank cap held good pressure overnight. Once the coolant has gone cold, i think you should just be able to turn the cap against the spring & rubber grip. Isn't the coolant (when the engine is/has been running) supposed to to be able to syphon back from the tank in to the block? If you have a dodgy cap this may affect this; might this be the cause of your small coolant leak which you might not spot when driving etc. (I may have a total misunderstanding of how the cooling system works, but i thought it worth mentioning as we are all here to learn from others aren't we)?
I am also aware from the BBS forum that there are plenty of miss-fitting caps around due to poor manufacturing / divergence in dimensions of the cap spring length , circumference of rubber washer at base of spring which do not fit the neck of the expansion tank very well.

Cheers,
Charles

[Dave Wheatley]

Charles you wicked man. Finding me more problems to solve!! When you think about it you are correct - the pressure should push the coolant back from whence it came when it cools. My pressure cap is 15lb - not sure if this is correct.

So, any more thoughts on this?

Charles Farran wrote:
> Dave,
>
> If i understand you, you said the tank cap held good pressure overnight.
> Once the coolant has gone cold, i think you should just be able to turn the
> cap against the spring & rubber grip. Isn't the coolant (when the
> engine is/has been running) supposed to to be able to syphon back from the
> tank in to the block? If you have a dodgy cap this may affect this; might
> this be the cause of your small coolant leak which you might not spot when
> driving etc. (I may have a total misunderstanding of how the cooling system
> works, but i thought it worth mentioning as we are all here to learn from
> others aren't we)?
> I am also aware from the BBS forum that there are plenty of miss-fitting
> caps around due to poor manufacturing / divergence in dimensions of the cap
> spring length , circumference of rubber washer at base of spring which do
> not fit the neck of the expansion tank very well.
>
> Cheers,
> Charles

[Charles Farran]

Hi Dave,
The stated pressure on your cap is correct at 15lb . Whether it is fuctioning correctly at that pressure is another matter!
Cheers, Charles

[Vic Butler]

Charles, I agree with you about the poor quality of some of the radiator caps around.
Dave, many years ago some time last century shortly after I bought my B, I replaced the plastic plug in the thermostat housing with a brass one. I don't know if they are still available though.

[Charles Farran]

The brass ones are & sold ( i think by Moss,MGOC & DAavid Manners) as an alternative to the plastic plug which very easily gets butched on removal. The brass one is used with a cork gasket as opposed to a rubber o ring type seal . I bought & changed mine last year and it has been leak proof with no tell tail drips over the thermostat housing. I always carry a spare cork gasket in the boot never mind a plastic plug & rubber seal in the boot as tiny & weightless.
Cheers, Charles

[Dave Wheatley]

Vic Butler wrote:
> Charles, I agree with you about the poor quality of some of the radiator
> caps around.
> Dave, many years ago some time last century shortly after I bought my B, I
> replaced the plastic plug in the thermostat housing with a brass one. I
> don't know if they are still available though.

Mine has a brass plug Vic and Charles.

[Donie]

I realise that this long standing thread veered off into the area of temperature and pressure caps, but I'm definitely venturing back into the subject of voltage stabiliser.

My fuel and temperature guages (1978 MGB RB) don't work so I suspect the voltage stabiliser.

No longer being as nimble as I once was, I can't really dive head first into the driver's footwell upside down, to locate the stabiliser, so I resorted to using an endoscope to have a look.

I didn't yet locate the stabiliser, but a cursory glance revealed a lot of oxidisation on push-on connectors, due to the many years the car has lain comatose.

So it's possible, maybe probable, that 'dry joints' are the reason for my problem with the guages, although I have bought a new solid state stabiliser.

Even trying to remove the tacho, to give me access through the panel, is proving to be a problem, due to the oxidised condition of the threaded rods and knurled nuts on the rear of the tacho.

Has anyone been down this very path before, and can offer words of wisdom?

[Charles Farran]

Donie,
The original voltage stabilisers rarely breakdown. The location of mine (original) is adjacent to the wiper motor near the access grommet to the rear of the pedal box. (see attached photo).

Both the temp gauge & the fuel gauge (but not the oil pressure gauge) utilise the stabiliser which i believe smooths out a constant voltage of approx 10 Volts to stop the needles bouncing around. If both gauges stopped working at the same time i would initially simply remove the leads & the stabiliser, clean up the tabs & connectors & replace & see if the gauges start working again . You can briefly try by passing the stabiliser to see if the needles move , but only for a short while, otherwise i think you may damage the gauges. If the gauges stopped working at different times, then i would suspect poor contact issues elsewhere. (Poor + or - at the tank sender is a regular culprit (I had this issue , cleaned up the contacts at the tank end & my fuel gauge started working again). Simply holding the temp gauge wire to the block instead of being connected to the sender should see the temp gauge work, if it does , then you either have a dirty contact on the sender or the sender is faulty.
Much less hassle to access the stabiliser from underneath , rather than removing the rev counter!
Cheers
Charles

[Charles Farran]

Donie,
If you show my photo to a helpful youngster they may be able to dive under the dash for you!
Cheers
Charles

[Donie]

Charles,

How did you manage to take that photo

I might see if removing the steering wheel might help me, and with raising the car up high on axle stands, or I might even be able to work my hands in there,(without my head under the dash) with the wheel off.

As said earlier, it may well be bad oxidised conrtacts on the voltage stabliser.