OT: Brake sensor switch in master reservoir, how does it work?

Hello Folks,

Annoying: Li'l brake light randomly comes on in the dash of the Toyota. Has nothing to do with whether brakes are used or not, purely random. I've traced it down to the master brake cylinder sensor switch. No leaks, reservoir is at the usual full level. Looks like it can't easily (or maybe not at all) be swapped on its own and changing the whole brake cylinder is messy and not really necessary. How do these things work? What could make it close the contacts once in a while? Wanted to avoid emptying out the reservoir before I know ;-)

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Regards, Joerg

http://www.analogconsultants.com/
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Joerg
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Coming on at random is odd. Change out the switch. ...Jim Thompson

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| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
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Jim Thompson

If I knew how ... looks solidly embedded in the whitish plastic reservoir, which in turn looks permanently married to the main cyclinder :-(

Regards, Joerg

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Joerg

If there are not already air bubbles in the brake lines, changing out the master cylinder is trivial. Disconnect lines, remove two bolts. Reverse the procedure. ...Jim Thompson

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| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
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Jim Thompson

Looking from the outside or the inside?

Are you sure the light isn't also a wear indicator saying its time to replace the brake pads?

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Failure does not prove something is impossible, failure simply
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Nico Coesel

Pretty sad if that has to be thrown out just because of a wee switch. Oh well, maybe it has to be done.

Today is honey-do list day. Hate it. Fridge peed on the floor a couple days ago, line to ice maker leaked. Got new poly tubing, still leaks, turns out little white compression nut has a micro crack in its ferrule. Ferrule is built in (#@^&!!), thread is non-standard, just a smidgen off (^#@^#$*!!!). I bet they did that on purpose so you have to drive many miles to the Kenmore repair shop and beg them that they puleeeeze sell one to ordinary folk.

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Regards, Joerg

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Joerg

From the outside. Seems embedded.

Not on this car. When it's on and I unplug it there or tap on the reservoir it goes out.

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Regards, Joerg

http://www.analogconsultants.com/
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Joerg

I never use the poly tubing. I use the stainless braid clad stuff for everything that connects to water, from the washing machines to the taps themselves.

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krw

Jim Thompson wrote in news: snipped-for-privacy@4ax.com:

maybe the Toyota has a replaceable brake fluid reservoir like my Acura Integra had.

Check the proper service manual for your make,model,and year. It might even tell how to change the switch.

Who knows,you might be able to find an online version of the service manual,like I did for my Sentra.

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Jim Yanik
jyanik
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Jim Yanik

I meant: did you open the reservoir and looked inside? You probably did, but in case you didn't...

Maybe the brake fluid is dirty. When is the last time it got replaced (how old is the car)?

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Failure does not prove something is impossible, failure simply
indicates you are not using the right tools...
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Reply to
Nico Coesel

or maybe he should look a the E-brake switch..

May cars use the same light.

Reply to
Jamie

It is a level detector using a float. Cars with desk brakes are designed so that as the brake pads wear, the slave cylinders extend and use brake fluid to fill the space lowering the reservoir level. Unless some idiot mechanic is topping it off, the level will drop enough for the light to come on about the time you need your pads replaced.

Reply to
AZ Nomad

Well, it's on the non-pressure side of the valve and you don't have much choice. The soft stuff won't work. Did I already say that I hate compression joints?

Anyhow, since I am a packrat when it come to parts I found a fitting Kenmore valve nut in the garage. It's test running now :-)

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Regards, Joerg

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Joerg

Good idea, I'll look. But in auto part shops I could not find any spare parts for the main brake cylinder, only the whole thing. That in itself ain't a good sign because knowing how to get it out won't do me any good unless I can buy a new switch ;-)

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Regards, Joerg

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Joerg

Yep, but Toyota's fluid is dark, can't see.

Have to check, it's been a few years. The car doesn't get driven much, way less than 2k miles/year.

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Regards, Joerg

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Joerg

[...]

This one does, and I took that apart first. No dice, but at least I could give that area some TLC. All three of our dogs shed and so that needs to be done a lot anyhow.

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Regards, Joerg

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Joerg

that

it

need

That's what I thought at first but the pads look fine and the level is really close to the "max" line.

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Regards, Joerg

http://www.analogconsultants.com/
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Joerg

[snip]

You might want to look in Lowe's or Home Despot...

This past week I had to replace a dishwasher and discovered that the old "compression" fittings can be replaced with a like-threaded hose _but_ it has a neoprene (I think) insert that makes a tight fit. ...Jim Thompson

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| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
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Jim Thompson

Mr. Packrat (me ...) found a perfectly fitting valve nut in the garage. Of course the thin "modern" tubing needed an anti-crush piece inside. Had to be sanded down to fit into the valve outlet but I was amazed that ACE had those for 19 cents. Plus tax ...

T plus 1.5 hours and still no pee pee under the fridge. Things are lookin' up :-)

Got to snatch some coals out of the wood stove now, to grill steaks. It's my Weber "instant on" feature.

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Regards, Joerg

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Joerg

ta.

.

ily

rake

?

id

er :-(

The Home Depot guy (who seemed to be a very knowledgable, retired ex- plumber) said those poly lines were crap. Also, that if you didn't use copper, and had a flood, your home owners insurance wouldn't pay for it.

Our fridge (a Whirlpool) has this "press-fit" connection on the back. (Best way I can describe it.) And beyond that, it has poly tubing inside the fridge and before the electronic valve. I guess that poly is somewhat protected, being inside the fridge, but it could leak just as well as the other stuff. I guess insurance companies are always looking for a way off the hook.

As for the brake light on the dashboard, do what a friend of mine does: A little black tape over the light. Problem solved.!

-mpm

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mpm

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