Headlight vacuum system

[potleyu18]

Hi All,
Usual issue with these on my plus 2 they wont go down.

I replaced the vacuum pod around 6 years ago but not been used since then, last year replace the electric solenoid switch. This all works and can feel a low vacuum through the system and will pull the actuating lever in the pod down but takes only a low resistance to prevent it operating. i have checked for leaks on all connections and the spyder chassis cross member which holds the vacuum, none were found.

My question is how much vacuum should be felt from the inlet manifold output and through the system and is there any method of checking this. The alternative is to fit the Spyder replacement mechanism which is costly and not my first choice.

Steve

[john.p.clegg]

What you could do with is one of these...

http://www.ebay.co.uk/sch/i.html?_from= ... ge&_sop=15

and when/if you get one we can compare readings...

John

P.S. more vacuum at higher revs/lower throttle openings

[gus]

hook the pod right to the vacuum takeoff on the engine. No chassis or switch or solenoid

Is it stronger?

remove the check valve and replace with a barb fitting

Is it stronger?

If yes start adding things in to see where the restriction is

If no the pod is no good

[Grizzly]

Also worth doing the carb cleaner trick round the Carb-Engine Misab plate just to make sure you haven't got an Air leak to start with and then worth just having a look to make sure the Carb Butterfly is fully closing.

Out of interest, can you feel the headlight pod pulsing with the engine idling? If the One way valve goes it just won't build enough Vac to work correctly, what you can feel is the No1 piston on it's Inlet stroke pulling vac then it being lost back into the inlet when the Valve closes..


Bit more expensive but Mityvac's are great for this sort of thing http://www.ebay.co.uk/itm/Silverline-Mi ... SwXSJXPK9a

[cardno]

How about replacing the vacuum system with an electrical system. I have heard that an actuator from a Mazda can be used. Not sure which Mazda etc.
Can anyone help with details for an electrical system that is cheaper than the Spyder option?

[RichardHawkins]

Cardno,

I can't help much as I am in Lincolnshire. However the actuator that I used is from the early MX5 Mazda (the model with pop up lights). The circuit is basically that of a domestic two way light system i.e. where you can switch a light on or off from two positions, by using a changeover switch.

The actuator has a plug on it with 5 wires, which is initially intimidating. One wire is the earth usually black, but some are black and white. Another wire is green which was used on the Mazda to light an indicator lamp on the dash. Why you need an indicator lamp on the dash when there are two pods sticking up at the end of the bonnet I don't understand. Anyway this wire can be discounted. That leaves 3 wires, white and red that is connected to a permanent live supply, red which connects to one output of a changeover switch, and yellow which connects to the other output of a changeover switch. You need to put a supply to the common terminal of the changeover switch. When you operate the changeover switch the Mazda actuator will operate, when you operate the changeover switch again the Mazda actuator will return to its original position. Try this before you start to install in the car to see if you have it correct.

This is the basic operation. I used a changeover relay as do Mazda. I don't have the skills to publish a circuit diagram, but the arrangement can be wired so that the pods actuate as the lights are switched on.

Another fiddly problem is mounting the actuator in the correct place on the car so that the pods have the correct amount of movement, this also took quite awhile and a bit of trial and error. I am pleased with the result, but only you can decide if it is worth the effort.

Richard Hawkins

[potleyu18]

Thanks for all of the suggestions.
I did connect the pod to the output from the manifold and the amount of vacuum was the same so it would appear from Gus that the pod is not functioning to the required amount.

Happy to purchase the vacuum gauge but again no idea what the levels should be to operate the lights?

Looks like its either the Mazda electrical option but will look into the mityvacs option.

Thanks for your help and will update when decided whats my best option.

Steve

[jimj]

http://www.ebay.co.uk/itm/new-unused-19 ... 6016.l4276

[pereirac]

The T piece which connects the vacuum line to the front chassis member can split.. That's what happened to me. Also if you have a servo, check for leaks there. The diaphragm can also split internally and you can lose vacuum there as well . Brake fluid also 'vanishes' as it's sucked into the inlet manifold....

Carl

[Grizzly]

Have you checked the amount of Vac at the engine end? as i said a bad Carb-engine seal would be enough to prevent the headlights working correctly, as above a seized servo or perforated Servo diaphragm won't help either.

Easy way to check the pod is get a pipe, fit it to the pod and suck on it yourself, if you can't create a vacuum then it's got a hole in it..... if you can create a vacuum then seal the pipe with your tongue and if it holds then it's fine.

[Bud English]

If you decide to go the electric motor route, there's everything but a YouTube tutorial here that should help.

lotus-chassis-f36/modifying-headlamp-system-t30127.html?hilit=miata#p201050
and here:
elan-mods-f31/electric-headlamp-conversion-t33458.html?hilit=Miata

[holywood3645]

If it still up after 4 hours you're supposed to go to a doctor