Brake light switch removal

[sixdogs]

Can anyone suggest a way of holding the four way union whilst trying to remove the brake light switch. I have tried holding the bit underneath the switch with mole grips, but I cannot stop it turning. The new switch seems smaller and a bit different from the old one and its not clear to me in fact whether the bit I'm trying to grip under the switch is not part of the switch itself. I thought the job looked too easy to be true.

The problem with the Moggie is that although everything seems nice and easy to get at, you can never find a spanner to fit or put a socket on it. It's essentially a pliers, hammer and screwdriver car.

Thanks in anticipation of a solution, Clive.

[bigginger]

I usually use a pair of vice grips to hold the 4 way steady while I work on it, very much in the "pliers, hammer and screwdriver car" spirit. Probably not so easy with the front panel on though.

[MoggyTech]

Be carefull, it is all too easy to wreck the brake pipes if the 4 way twists.
There should be enough 'meat' below the switch to get a pair of narrow jawed mole grips onto the 4 way. I did this job last year, and as well as the brake pipes getting wrecked, a bleed nipple sheared on one of the Ford Calipers (Disc Brakes) and I ended up replacing both calipers. It cost £100 all in to replace a stupid switch. Some of the new switches don't last very long either. I believe there is a Land Rover switch that fits and is reliable.

Another option, is to fit an electrical Micro switch inside the chassis leg, that is operated by the brake pedal itself. You just leave the knackered hydraulic switch in situ, and use the old wiring run to the new switch.

In either case, good luck!

[bigginger]

My suggestion protects the brake pipe unions rather more than yours, but they have to be treated as disposable anyway, IME.
a

[sixdogs]

[quote="bigginger"]I usually use a pair of vice grips to hold the 4 way steady while I work on it,

What are vice grips, are they the same thing as Mole grips, or locking pliers? I have some lengths of fairly hefty angle iron. I was considering cutting two U-shaped notches in the end of a piece to suit two of the Tee branches on the 4 way union and welding a bar through the top of the angle. This still leaves room to get a socket on the switch. The problem is I'd need someone I could trust to hold the angle with the bar whilst I tried to undo the switch. Do you think this might work ? I did not want to remove the 4 way if possible to avoid having to bleed the brakes.

Regards Clive.

[kennatt]

I once fitted a micro switch to the brake pedal on an mbg(Same pressure system) as a temp measure for MOT My son has the car now 10 years on and still working off the micro switch.

[bigginger]

I usually use a pair of vice grips to hold the 4 way steady while I work on it,

What are vice grips, are they the same thing as Mole grips, or locking pliers?

Yup, generic name for Mole grips

[sixdogs]

I once fitted a micro switch to the brake pedal on an mbg(Same pressure system) as a temp measure for MOT My son has the car now 10 years on and still working off the micro switch.

Where did you fix the microswitch and what switch did you use ? It would have to be one which makes when the tension is released. There must be ones used on recent day cars which would do the job. Any ideas?

Clive

[eastona]

I like the idea of a microswitch, as my brakes need a good old stamp to make the brake lights work. (does that mean the current switch is a bit dicky??)

anyone got any piccies of the microwsitch?

Andrew

[sixdogs]

Yes, the microswitch is looking like a good option. You can at least hear them click (if the engine is not running. Perhaps it might be better to let sleeping dogs lie, regarding the 4 way and switch. It's so easy to open up a can of worms. Lets have more practical detail and the pictures if possible. One good picture is worth a thousand words.

[alex_holden]

Yup, generic name for Mole grips

[pedantic]Vise-Grip is a trademark of Irwin Industrial Tools.[/pedantic]

[d_harris]

and very good tools they make too imho

[bigginger]

Damn! That'll teach me to try to avoid trade marks (?) like Mole grip

[alainmoran]

Errr ... this may be a bit late, but ... why dont you just unscrew the two pipes coming out of the union, remove the bolt from underneath and then put the whole lot into a vice? (that's what I did)

One tip tho, use an open-ended spanner or pipe-grips .. cutting a slot into a ring spanner seems to weaken it enough so that unless the joint is fairly fresh (ie not ceased in) all you end up doing with the cut ring is carve off the corners of the pipe-end ... but that could be down to me using cheap spanners so hey, your mileage may vary ;D

PS: I never realised mole-grip was a trade name, I thought that's what they were called!

[bigginger]

There are 3 pipes connected to the union - and undoing them seems to wreck them all too often, which is what ( I thought) we were trying to avoid.

Anyhow, "Vise-Grip (R) is a Registered Trade Mark of Petersen Mfg., Co.,'s locking pliers."

and

"In the United Kingdom, there is a brand of locking pliers called Mole-Grips (TM).

written on one side

MOLE
Reg'd Trade Mark

and on the other-

Self-grip Wrench
Newport Mon.
Gt. Britain

On a recent trip to England I went searching for a pair of Mole-Grip locking-pliers, I discovered that Stanley of UK bought the Mole-Grip name."

From http://www.47d.net/~seven/vg/, on the very remote chance that anyone gives a hoot.

[alainmoran]

Ooop .. yes .. silly me .. i cant count!

[MoggyTech]

Anyone interested in the microswitch idea, it's very easy. All you need is a switch that will handle 2A at 250 volts (this is how most switches are rated). Most Micro switches come with three contacts. One is common and the 12V live is fitted to that terminal. The other two contacts, consist of 'Closed at rest' and 'open at rest'. You use the 'open at rest' contact for the rest of the cicuit. You need to mount the microswitch in the chassis rail, so that the brake pedal is pushing the microswitch contact arm back, when the pedal is not pressed down.

Maplin do suitable heavy duty microswitches with long lever arms which can be adjusted to suit.

Next time I have the carpet up, I'll post some pics.

The advantage of a mechanical switch, is it will operate the instant the brake pedal is pushed. The hydraulic switches seem to require moderate pressure before making the circuit.

You can if you wish, leave the hydraulic switch wired up as a backup, with the micro switch wired across it. That way you have a backup switch should one or the other fail.

[Stig]

I'd go for a slightly higher current rated switch:

2 x 21W bulb / 12V = 3.5A


mind you, the most feeble microswitch would probably last longer than the rubbish hydraulic switches I've had recently!

[bmcecosse]

AC switches often struggle with DC current - better use a switch that is rated for DC use.

[kennatt]

I used a micro switch that activates by being pushed I fitted it to the rear of the brake pedal by using araldite epoxy.on a short bit of steel strap and fitted the switch so that when you put your foot on the brake pedal your foot pressed the switch at the same time,I fitted it so the the switch was just poking past the side of the pedal.Ran the two wires up the pedal and conected them to the original wires at the pressure switch.A bit heath robinson but as said was originaly just to get it through mot. Will be sorted if it ever fails. But still ok after 10 years. Got the idea from my remembering that I once had a car(Vauxhall I think) that had a micro fitted as standard to the parcel shelf and activated on release when the brake was pressed. Can't remember where I got the positive pressure switch from, my son is an electrician so probably came from him.I suppose you could mount a release type inside the chassis leg by screwing something across the gap so that the switch was touching the base of the pedal under the cover.One thing for certain has to be worth a try