question Ferret brake switch

[MiketheBike]

tried to start the Ferret today and the batteries were flat, found out the brake lights are stuck on.

 

I do not think its the pressure sender, but it may be what I think is a relay on the right side of the speedometer?

With the brake pedal not operated, the brake lights are one, as I travel through the stroke they go off and then back on again, when I release the pedal they stay on. Also sometimes you can hear the relay chattering/buzzing.

 

I managed to keep flicking the brake pedal until the lights stay off, then when I short the pressure switch terminals, the brake lights come on and stay on.

 

Do you think my logic is correct (I could just measure across the pressure switch terminals, but that would be far too easy.

 

Next question....

 

does that relay just get held in by two screws, and is it a case of just taking out and replacing, without taking the entire control panel out?

 

Mick

[sirhc]

Mick,

 

I replaced my relay with one from the Durite catalogue. Just un screw it and plug another in. I will try and get the number for you today.

 

Chris

[MiketheBike]

thanks Chris,

 

I am right, its this silver relay on the right?

 

[sirhc]

Yep that's correct Mick.

 

I replaced it with this:

 

http://www.thetoolboxshop.com/0-727-24-durite-24v-20a-mini-make-and-break-relay-2273-p.asp

 

Looks different, does the same job.

 

Chris

Edited September 18, 2010 by sirhc

[Topdog]

I had the same trouble with mine but it was fluid running past the seal and activating the pressure switch without pushing the brake pedal. If the relay doesnt work, then go back to the master cylinder and check that thoroughly for leaks. Another symptom of it is a really hard pedal pressure.

Dave

[griff66]

i had a similar prob and it was master cylinder rusted internaly causing piston to not fully retract which in turn kept slight pressure in system causing brake lights to stay on , sometimes coming on a hour or so after parking up.cured by honing internal bore and fitting new seals.

[Richard Farrant]

i had a similar prob and it was master cylinder rusted internaly causing piston to not fully retract which in turn kept slight pressure in system causing brake lights to stay on , sometimes coming on a hour or so after parking up.cured by honing internal bore and fitting new seals.

 

 

That was quite a common problem in service, definitely not an electrical fault normally. I have known them come on over night in the Workshops, with a Patrolman reporting "someone left a vehicle's lights on" when we got to work in the morning. Another theory was overfilling the reservoir and possibility of a blocked breather hole in the cap, a slight pressure rise will put the lights on while standing.

[griff66]

yes a was quite shocked to see how much rust was inside the cylinder since over hauling has been perfect.

[MiketheBike]

You got me thinking, and thought my prognosis may be wrong.

 

With eveything connected and an ohmeter across the sender, I could see a short, and midway through the stroke it went to open circuit, then back to short with the pedal depressed. So I thought the sender was at fault.

 

When I disconnected the leads from the sender, it works as I would suspect, so I assume the relay is at fault...it almost sounds like the relay is holding itself on.

 

I have left it disconnected for now and will order up that relay.

 

If I leave the light switch to the "N" position, would that help with problems like this running down the batteries (I really must fit a battery cut-off switch..I bought one just after I got the ferret and have been too lazy to work out where to mount it!!!)

[griff66]

mike there is not a light switch position apart from off ,which will still allow brake lights to come on that u can use to stop batt drain , N, is not wired ,C will put the convoy light on best to disconect batts.

[MiketheBike]

Hi Griff,

 

I was thinking more of leaving the ferret standing rather than driving. In the "off" position, the brake light obviously still comes on when the relay if operated, but in the "N" position, the relay does not operate...thought it may be a better place to have the switch in case of issues like this?

 

Mick

[griff66]

hi mike N is as far as i know not wired at all from memory when my ferret was having similar problems no matter where i left switch if there was pressure in system brake lights would be on . once i had charged up batteries i left them dissconrcted till master cylinder was overhauled . i tried a new brake stitch as well at first but that was not at fault master cylinder comes off pretty easy. paul.

[MiketheBike]

Thanks Paul,

 

master cylinder comes off pretty easy.

 

mmm...sounds like one of my famous "5 minute jobs"

Looking at the rust on the unions on the master cylinder, I want to leave that for the winter nights! I need to take the master cylinder out at some point to replace the blow off valve on the right hand bevel box anyway.

 

I ordered up one of those relays that Chris recommended, someone is selling the exact same model for £4.99 on ebay, so may be a cheap check before delving into the master cylinder.

[MiketheBike]

I know Andy posted a link to a lockheed master cylinder on ebay early this year, but that item is no longer there...is this the same model as ferret:

http://cgi.ebay.co.uk/Lockheed-Master-Cylinder-1-1-2-Austin-Dodge-BMC-/310230103437?pt=UK_CarsParts_Vehicles_CommercialVehicleParts_SM&hash=item483b27b58d

 

Obviuosly hasn't got the filler tube, but guess that would be just screwed on the top?

[griff66]

one thing when refiting master cyl get pipe union started before bolting up master cyl can be a bit of a pig to get union started and you dont want to cross thread it!

[Richard Farrant]

hi mike N is as far as i know not wired at all from memory when my ferret was having similar problems no matter where i left switch if there was pressure in system brake lights would be on .

 

Paul and Mike,

 

If you switch to convoy when parked up out of use, it will isolate brake lights, or at least should do unless someone has wired it differently. Only thing is, remove the convoy light bulb, which is not really needed and if this help stop a discharged battery, well so be it.

[MiketheBike]

ok, if you want a problem diagnosed...don't ask me....

 

should've listened to Griff...it seems to be the pressure switch after all.

I will give bannisters or Margus Glenn a call to see if they have them.

 

I assume its impossible to change without draining the master cylinder?

 

Mick

[griff66]

mike if it is px switch and not master cyl u can just unscrew the switch depending on new switch contacts u might have to crimp on new terminals my orig was held on with screws new one had spade connectors no need to drain anything i lost hardly any fluid , still reckon it might be your master cyl sticking though!

[MiketheBike]

oh I see...you mean the master cylinder itself rather than the pressure switch?

 

is this the correct master cylinder? :

 

http://cgi.ebay.co.uk/Lockheed-Maste...item483b27b58d

Edited October 8, 2010 by MiketheBike

[griff66]

yes mike if you give bannisters a ring do it now might not be ther after 4 ! the listing u give has expired see if bannisters have a over haul kit for master cyl

Edited October 8, 2010 by griff66

[MiketheBike]

thanks Paul,

I think the overhaul kit may the answer, or the one that i son ebay (1.5inch Lockheed master cylinder), as you say, it looks the same, and it the same as the one that Andy posted up here yonks ago.

 

If I am doing that, I may as well replace the pressure switch...is it a standard fitting? There are some on ebay at the mmoent with "standard taper thread" and others with "BSP thread" or "3/8 x 24 UNF".

As the body of the pressure switch stands out a bit from the master cylinder, does that mean its a taper thread?

 

Cheers

 

Mick

[sirhc]

Mick,

 

I took the pressure switch down to my friendly commercial vehicle brake specialist, they had a new direct replacement. I suggest you find a similar supplier near you.

 

Chris

[MiketheBike]

Thanks Chris...good idea.

 

Mick

[MiketheBike]

I contacted a dealer who has master cylinders listed on ebay, they think the ferret is 1 1/4", but I think the ferret ones are 1 1/2" (and checking Andy Ferretkit's posting a whiles back, he suggested its an 1 1/2)

 

There is a guy selling these:

http://cgi.ebay.co.uk/Lockheed-Master-Cylinder-1-1-2-Austin-Dodge-BMC-/310230103437?pt=UK_CarsParts_Vehicles_CommercialVehicleParts_SM&hash=item483b27b58d

 

does anyone know if they would do the job?

 

Mick

[griff66]

mike if your ferret can be off the road for a week or so take off your master cyl and measure the i.d