Brake Light Shame....

[jre1983]

Morning gang, ok, so here's the problem, yesterday my brake lights were pointed out to me as not working on my way to college. checked connections...seem ok, get normal rear lights when the fronts are on, indicators fine, reverse fine...but no brakes.....checked contact on switch under the bonnet, seem to get good connection.....so what could this be????

HELP please.

[loon]

i hade the same problem with my amazon, after changing the switch all was fine:Banane32:

there was a lot of sluge inside the switch stoping mormal breaking preasure to make the contact

L:speechless-smiley-6N

[Steve121]

have you looked at the brake fillament in the bulbs? they are dual fillament so if the rear lights are on with the headlights, it doesnt mean that the brake lights will work

[48pop]

A new hydraulic switch or maybe one of these ?

http://www.sw-em.com/swemkits.htm#Brake%20Light%20Switch

[JIM C]

Sounds light the switch. You check the lights by disconnecting the switch.

[Derek UK]

Put a meter across the switch to check for continuity when the brake pedal is pressed. It should close with very little pressure but may need heavy foot, which isn't any good. Replace switch.

[jre1983]

thanks for the help guys....any idea where to get one from? any inter-marque/model tips? for example are rthey the same as another car? or just a general mechanical brake switch, from say the local motor factors?

thanks again.

Jimbo

[amazondean]

The brake switch is the same as many classics. It should be the same as the morris minor and the like. Ebay is usualy full of them. I presume it's a pre 1969 car as the switch is different on the later ones. They are known to be faulty even when new.

[Kauai1800]

similar trouble...

Aloha All,

Ironically I came on here for basically the same problem. I checked fuses and bulbs, and the rear lights come on with the fronts and decided it must be some type of switch issue.

Since I am a newbie, I am not familiar with the location of the brake switch under bonnet (on a 1964 1800S). Can you point me in the general right direction?

I have a service manual (Brooklands) but I could not find it in there.

Many thanks,
John

1800S Chassis No. 9217

ps I now see the link for the SWEM kit...anyone have one of these? Sounds like a pretty good upgrade...

[Andrew (UK)]

A new hydraulic switch or maybe one of these ?

http://www.sw-em.com/swemkits.htm#Br...Light%20Switch

That won't work for a RHD car. I went through this with Ron Kwas and have a design for a new bracket for a RHD car that I need to get back to Ron once I check it all out (18 months and counting so don't hold your breath).

Brake switch is in the middle of this photo, behind the red battery wire. This is from a RHD 1967 car, so your LHD 64 will be a bit different. It has four brake lines going to it and the two electrical connections coming out of the middle. The bit with the electrical connections unscrews from the bit that holds the brake lines and that can be replaced. I would expect any supplier of parts for classic Volvos to have them.

[Kauai1800]

Thanks so much Andrew!

Looks like you even took a picture just to show me.

The people on this forum are awesome....:)

[Ron Kwas]

Hydraulic brake light switches vs. mechanical

Forum;

The pressure sensing hydraulic switches are just not reliable...the actual electrical contact area closes under slow-speed, low closing force...a perfect recipe for non-function from an engineering design standpoint... it's a poor situation...the pressure comes up very slowly during normal braking, and thus puts the switch diaphram through a linear (flexible) region which closes the contact quite slowly, typically not breaking through the carbonized surface (which occured when the contact was last carrying current and opened), when it should ideally snap closed, breaking through this non-conducting layer...add to that aging and relaxation of the diaphram, and most of the switches quit...some quite soon after installation...add to that the unavoidable delay factor of having to make pressure in the system in order to show brake lights, and all manufacturers including Volvo in about '67, changed over to mechanical switches.

Regarding the "sludge" one poster found in the switch...I just can't believe this explanation...IMO, "sludge" is not likely what keeps the switch contacts from closing...in the first place, "sludge" would certainly transfer the pressure to the contact diaphram just as easily as clean fluid (I guess that means that just as a fluid is non-compressible, so is "sludge")...further, no "sludge" is capale of withstanding the high pressure which occurs in the system. I believe the failure mechanism is as described above.

...bottom line IMO is to just upgrade to a mechanical pedal position sensing switch, loose all of the disadvantages, and get all of the advantages: Reliably Brake Light operation the instant the pedal leaves its rest position. You don't even need to bleed the system!...

Andrew; Please get back to me with your design if you would...I have another interested party for the RHD version and I could use the detailed design...

Greetings from a foliage colorful New England!

[stuart131]

You might have already sorted this, but assuming your car is an Amazon, just get a new brake switch, the one thats on a bracket in front of the brake pedal. About £10 from Brookhouse and even an incompetent like me managed to fit this in 10 mins.
Brake lights were restored immediately.

[Ron Kwas]

Failure of Hydraulic Brake Light Switches

Forum;

For those interested in my detailed explanation of the chronic failure of these switches, I have just completed a new tech article, which I invite you to read: http://www.sw-em.com/hydraulic%20bra...es%20notes.htm

Cheers