Brake light switch

[SvenSomerset]

Hey folks,

Unfortunately, I think Sven, our 64 Amazon, has now suffered brake switch failure, but wanted to make sure with ya'll before contacting our electrics fella!

Fired him up this morning, to take some friends out for the day, and did the usual 'check all lights are working' routine, but although the rear lights came on okay, no brake lights. So I removed and rotated all the fuses in the box in the engine bay, in case of oxidisation, and checked that the 'second filament' in each rear light was intact, but still no brake lights.

Does that deffo mean that the brake switch needs replacing or upgrading? Our electrics dude, Julian over at Coombend Auto Electrical in Radstock, is really good and has a lot of experience with classics, notably Minis. I'm guessing that he's familiar with pressure-sensing switches failing! Could there be any other issue causing the rear lights to work but not the brake 'filaments' to light up?

Please advise, and 'happy' holidays!

[Derek UK]

To prove the switch just short the 2 wires together. If the lights come, on the switch is u/s.

[SvenSomerset]

Thanks Derek, I guess it must be the 'early' type – found the relevant part of the service documentation, is there a way to lubricate/clean the existing switch, so if it's just gunged up it'll start working again, or is it 'not working, full replacement' or upgrade to the 'pedal position' type?

So to find out whether it's deffo the switch, I should first put a piece of wire across where the two electrical wires are, and if the brake light come on, that's deffo the issue?

At this point, if it'd be possible for me to simply replace the existing switch, I'd rather do that, but does the brake system have to be bled, as per step 5 in the grab from the manual attached?

[Ron Kwas]

Sven;

Test for Brake Lights should be performed, with Ign Sw ON!

I always recommend full upgrade to a Pedal Position Sensing Switch, for all the advantages, but if you confirm Hydraulic Pressure Sensing Sw as nonworking (typical!), and insist on simply replacing it, Braking system must be opened for that, so will need to be bled.

See also: http://www.sw-em.com/safety_bulletin_1.htm

Good Hunting!

Edit: Answer to your specific question: If other Fuse 2 load (Reversing Lights, Horns) are working fine, then Fuse 2 is OK and failure is quite likely Br Lt Sw. Test as previously explained.

[SvenSomerset]

Thanks, Ron. We'll pop round to our storage garage tomorrow and perform the test to make sure it's the switch. This is really disappointing, as we won't have been able to use Sven over the holiday season. :-(

I guess I'll have to ring both our previously mentioned electrics fella and our trusted local mechanic, and see whether they can perform the switch upgrade, or simply replace the existing one.

Ron, do you have your RHD switch upgrade kit in stock, and if so, how much would airmail shipping to the UK be? Please advise...

[Ron Kwas]

Sven;

Don't let Hyd Brk Lt Sw failure keep you from taking that ride! In the interim, you could implement some "Field Expedient Engineering" ...short term only though, please! See: http://www.sw-em.com/hydraulic%20bra...nt_engineering

RHD kits are in stock. But it would be inappropriate to do business on this Forum. Please e-mail direct, through SW-EM site.

Cheers

[Derek UK]

Many people have swapped these switches over and not rebled afterwards. You do have to be very quick and have the new one in the same hand you use to take the old one out! Fluid should flow out rather than air getting in. I don't want to tempt you to have someone put the very lightest of touches on the brake pedal to make sure fluid does flow because the pedal will tend to go to the floor fairly quickly when you remove the switch. Coming off the pedal before the switch is tight will tend to suck in air. Also a bit messy so the risk is up to you. Don't forget to top up the MC afterwards.

[Ron Kwas]

Derek;

I too have quickly removed and replaced these switches, and found afterwards that Brakes did not get totally spongy...I expect in that case only a very minor bubble of air gets introduced, which is easily overcome while depressing pedal, so not even noticed...if you can do it and get away with it, fine, but it's a bit of a trick and so not the first recommendation...
...but having someone apply even only minor pressure on the pedal to assure no air enters is even trickier, because the moment that switch is removed, the system is open and even minor pressure in the system will force fluid out maybe uncontrollably...a "feather touch" is called for here!

Cheers

[SvenSomerset]

Thanks Derek and Ron – I popped into our local motor factors today and they have a switch, Intermotor 51600, which would seem to fit, can either of you confirm that? If it would fit, I'll have a bash at doing it myself, and pay £6 from the local place, rather than $13+ VAT and delivery from a Volvo specialist, and then £45+ VAT to get the garage to fit it!

[Ron Kwas]

Sven;

Yes that looks like it will fit...I just hope it is not one of the ones from the aftermarket with terrible reliability (see earlier in this thread)...but it likely is...doing it yourself inexpensively is worth a try...work fast!...question is: How long will it last?

Good Hunting!

[grahamwatson]

There will be a small hole at the threaded end of the new switch. Fill that with brake fluid before fitting - it will only take a drop! - to increase your chances of avoiding having to bleed the brakes afterwards.

[SvenSomerset]

Well, folks, a bit of good news! Went round to the garage today, went under the hood and just made sure the electric connections to the pedal switch were good and tight, and the brake lights now work again!

It's been pretty darn cold the past coupla days, so could the seeming failure of the switch, as it goes on brake fluid pressure, be connected to the low temperatures?

On another point, our local mech sorted the carbs out in the spring, as a serious amount of gunk had come down the line and fouled everything up. Sven now runs really well, but even in warmer weather, starting from cold with full choke, we've had trouble with the car puttering to a halt when my wife takes her foot off the gas pedal, coming out of the sidestreet where our rented garage is, and down to the main road junction. This was really pronounced today, when it was cold, and as you can imagine, stalling at a busy junction isn't fun! I think our mech must have set the idling/tickover when the engine was already warm, which would account for the petering out, as there's no problem after the engine warms up and it restarts first go after it stalls due to lack of revs. How easy is it to 'up' the idling speed? Tempted to just drive Sven back over and get him to sort it for free...

[old fart]

Stalling

Just leave the choke out a bit until you are properly on the move.If it's ok when warm I would leave it alone.

[SvenSomerset]

The problem is that, even with the choke out, if my wife takes her foot off the accelerator, the engine sputters out/stalls, which is why I think that the idling/tickover is too low. We sat there getting the engine warm, after starting with full choke, which is always easy enough, for a good five minutes. Then, leaving the choke out about half way, it still sputters out/stalls at the first junction. The roads are very busy here, so that isn't ideal!

[old fart]

Stalling

Check the adjustment of this screw. It should have a gap of about 1mm between the screw and the cam (that's what it is on my car, anyway). This increases the idle when the choke is pulled out.