Low (20) lb. brake switch

[butch27]

Where can I buy a true "low pressure" hydraulic brake switch besides Ron Francis.  It's not just the cost BUT the shipping is $15. for a part that will fit in an envelope.  I.have looked at some here and they don't have the pressure amount marked. AND some are saying "low pressure but have the standard part number from Borg-Warner.  Rip-Offs???

[Charlie Chops 1940]

Back when the RF part was introduced and for awhile after that the low pressure switch was a problem part that didn't seem to live up to expectations, I tried a couple different ones on a couple cars and went back to a mechanical/electric switch and never looked back.

The lever type works great for through the floor pedals and the push button type for hanging pedals, either normal on or normal  off are pretty bullet prooof. The push button unit in my '40 Chevy has 100,000+ on it.

Charlie

[threefive]

try one from a vw.

[wayne petty]

i worry PERSONALLY WORRY that such a LOW pressure brake light switch would have a steel diaphragm that is so thin that if you get into a Panic stop position.. that the diaphragm will distort and leak under the emergency braking pressure...

this is MY PERSONAL opinion...

the 50 to 90 pound normal switches are what is currently available..

there is ONE option that i have NOT checked out yet..

on mid 90s ford vans and probably pickups.. there is a cruise control disconnect switch that is mounted on the top end of the brake master cylinder.. yes.. these were the ones that were recalled for shorting out and causing fires as they were powered without a fuse.. but a rather large fusible link..  so ford replaced them and installed a short harness with a fuse to protect the circuit..   it has a 3/16 inverted flair thread.. 3/8-24..  only serious issue.. its REVERSED..

normally closed.. OPENS on rise in pressure.. so it would need to run a RELAY..  to reverse the electrical operation.

http://contentinfo.autozone.com/znetcs/product-info/en/US/wl2/F4044/image/4/

az wells part number F4044...

http://www.wellsve.com/custom_searches/pdf/sales_drawings/F4044B.PDF

this is JUST an idea...

[butch27]

Good info on all points guys.  Thanks

[zzebby]

Three five mentioned one from a VW.  Can you elaborate ? What VW ?

[wayne petty]

lets look at the AZ / wellsve  

RB401 with 2 terminals..

http://www.wellsve.com/custom_searches/pdf/sales_drawings/RB401.PDF

1MM (.0393) PITCH
3/4" TAPER/ FT. THD.

SWITCH CIRCUIT NORMALLY OPEN.
CIRCUIT CLOSES AT 60 TO 120 PSI.

from 00 up nissans  
Duralast/Stoplight Switch Part Number: JA4413
this needs a nissan pigtail but its got a steel round end plunger.. not cheep at 40 bucks..



there are 336 brake light and brake pedal position sensors on the autozone site...

there are a few smaller diameter threaded mechanical switches that might be adapted..

JA411  which fits mid 80s nissans..
ja406
ja407 looks nice also..
js416 also looks nice
Rb406
hmm.. there is a 356 porsche brake light switch. but its threaded 1/8 -28..  and i don't see a pressure spec.. but it has SCREW terminals...
http://www.wellsve.com/custom_searches/pdf/sales_drawings/SW8047.PDF



RB402.. with 3 terminals..

http://www.wellsve.com/custom_searches/pdf/sales_drawings/RB402-1.pdf



as you can see... its got a 10MM x 1.0 pitch  thread..
edit from wayne.. this is more than likely a 10x1.0 taper..  it could be a straight thread... it will be easier to use if its a straight thread as a metric to sae adaptor can be used..   you will have to EXAMINE the piece in person.. the only one i have is on my corvair powered volkswagen van.. yes .with a powerglide transaxle..  and hooker corvair headers..

on the three terminal version its a double switch..
S.P.D.T. SWITCH OPERATING PRESSURE
N.O. CLOSES FROM 60-120 PSI
N.C. OPENS FROM 8-35 PSI


one might really want to look at the mechanical switches from AZ or wells... DR446  or
Duralast/Stoplight Switch
Part Number: DR458T


take a look through the az stop light switch section...

http://www.autozone.com/autozone/parts/Stoplight-Switch/_/N-9cias?pageNumber=1

[enjenjo]

I've yet to find an underfloor pedal that I could not use one of these on. http://www.autozone.com/autozone/parts/Duralast-Stoplight-Switch/_/N-9cias?itemIdentifier=927&_requestid=2184702

The original application is a 50s Chevy, and it comes in both a left hand and right hand version.

On the VW pressure switch, the original application was Bug and Ghia, late 60s.