Date: Sun, 4 Jul 2010 11:20:45 -0400
Reply-To: Raymond Paquette <raymondpaquette@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Raymond Paquette <raymondpaquette@GMAIL.COM>
Subject: Re: Pedal Pressure & Brake Lights
In-Reply-To: <AANLkTimEtKdvTvdm3Dq_YwsgNEdT4IdxFhP_OcxD4scY@mail.gmail.com>
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Two thoughts, both of which might be off:
1) If either switch turns on the lights, couldn't one have failed years
ago, and the other be failing now? Or would that have turned on the
warning light?
2) The rubber lines on my '64 swelled up inside to the point where my
brakes worked (or so I thought) but the rears would drag for a while,
and slowly release as the fluid slowly returned forward through the
narrowed lines. Kinda like plaque in your hardened arteries. Seems to me
that this would cause the lights to come on before braking started, but
it may be worth considering in any case. Or maybe the rubber lines have
improved since 1964
Raymond
neil n wrote:
> Thinking about it again, it seems to me that the push rod adjustment
> is there to provide a suitable amount of play between the MC piston
> and pushrod end so it's not pushing on piston when pedal at rest.
> Regardless, I see what you mean Mark et al.
>
> To all. For sure. I understood that the switches were pressure
> activated. Just didn't suspect them, as I couldn't see both of them
> failing (or becoming less efficient?) at the same time. But I guess
> that could be the case. I mean if one fails, the other should do the
> job of closing at the right point right? Or, as per Marks comment,
> maybe that's just how they operate.
>
> If replacing the switches doesn't work, adding a pedal actuated
> electrical switch seemed like a good idea to me too.
>
> But if Marks anecdotal observation is correct, how hard would it be to
> retro wire in some 2 contact switches? I likely have the parts.
>
> Looking at my air cooled Haynes I see how the switches work in terms
> of lighting up the brake lights, but am not overly clear about the 3rd
> connection to the Brake Warning Light. Is there something in the
> switch(s) that activates causing light to go on in the event of a
> hydraulic pressure loss? Haynes says if light stays on, (all else
> correct) then a fault lies in the hydraulics. I'll search that one.
> I'm sure it's in the archives.
>
> I'm guessing, but am just about certain that finger pressure alone
> would light up the brake lights. I would have to have a helper confirm
> this, but at night, keeping one eye on bumper or other reflective
> surface of vehicle behind me, if using a light foot, I can slow down,
> come to a stop, no brake lights on. What I don't want is to be warning
> people that I'm slowing down by harfing down on the pedal more than
> need be.
>
>
> Neil.
>
> On Sat, Jul 3, 2010 at 12:49 PM, mark drillock <mdrillock@cox.net> wrote:
>
>> It is internal hydraulic pressure that turns on the switch, not pedal
>> pressure. So whether that pressure comes from your foot or the booster makes
>> no difference.
>>
>> Anecdotal evidence makes me think the early 3 wire switch takes more
>> pressure than the 85+ 2 wire one. Don't really know.
>>
>>
>> Mark
>>
>>
>> neil n wrote:
>>
>>> Hi all.
>>>
>>> It's likely that my brakes engage before brake lights come on. (need a
>>> helper to confirm this)
>>>
>>>
>>>> From archives, 2 possible causes stuck out. Corrosion at bulbs, and
>>>>
>>> rear shoes out of adjustment. i.e. fronts engage but rears too far
>>> away so extra pressure is needed to actuate switch for rear hydraulic
>>> circuit. But if one switch engages, all brake lights come on right? In
>>> my case, brakes work fine, pedal height is good, and has stayed
>>> consistent over several thousand miles, so the rears are working
>>> right. I'll check for corrosion at bulbs but they are likely fine.
>>>
>>> I recall checking the push rod adjustment on the new booster I
>>> installed ~4 years ago. Would an improperly adjusted push rod (on
>>> booster) affect amount of pedal pressure needed to turn brake lights
>>> on?
>>>
>>> What else would could be at fault here? Design flaw?
>>>
>>> Both brake light switches were replaced at time of booster install.
>>> AFAIK, the switch wiring is fine (untouched by me)
>>>
>
>
>
> --
> Neil Nicholson '81 VanaJetta 2.0 "Jaco"
>
> http://tubaneil.googlepages.com/
>
> http://groups.google.com/group/vanagons-with-vw-inline-4-cylinder-gas-engines
>
>
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