Community Forums

BellaBo · 02-14-2008, 03:01 PM

Does anyone know if brake fluid boiling is always a result of a stuck caliper or over stressed bakes on downhills? If so, why isn't the brake fluid temperature monitored and indicated before the boiling point? Whatever that is?

This seems like it could be a good early indication of brake failure. Aircraft have brake temperature sensors and a flight safety item requirement on their checklists.

W/H could add this safety item for minimum cost and would save people a lot of money and maybe a life or two.

I'm considering developing a DIY system using thermistors and either warning lights or a temperature monitor panel. Anyone with some good ideas would be helpful.

BellaBo · 02-14-2008, 03:01 PM

Does anyone know if brake fluid boiling is always a result of a stuck caliper or over stressed bakes on downhills? If so, why isn't the brake fluid temperature monitored and indicated before the boiling point? Whatever that is?

This seems like it could be a good early indication of brake failure. Aircraft have brake temperature sensors and a flight safety item requirement on their checklists.

W/H could add this safety item for minimum cost and would save people a lot of money and maybe a life or two.

I'm considering developing a DIY system using thermistors and either warning lights or a temperature monitor panel. Anyone with some good ideas would be helpful.

DriVer · 02-14-2008, 05:53 PM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Streamerman:
Does anyone know if brake fluid boiling is always a result of a stuck caliper or over stressed bakes on downhills? If so, why isn't the brake fluid temperature monitored and indicated before the boiling point? Whatever that is? </div></BLOCKQUOTE>Steamerman, I wish I could answer that question with anything other than a system like that might cost a couple of grand and there isn't anyone that I know of that is wanting to spend that kind of money right now to include that as a stock component.

Now when OEM Engineering gets wind of this concept, who know what can develop in the back rooms of the skunk garage on the plains of Texas.

Oemtech · 02-14-2008, 06:24 PM

Thanks DriVer... and Kelley Johnson would be proud that the "Skunk Works" is a alive and kicking out here in Coupland, TX.

Right after I read this I went out to the shop and started digging around in some old electronics papers I had in a box. Low and behold I think found the mother load.

A 49 cent LM34 (F)/35(C) temp sensor, $1 9-volt battery, a $2.99 DVM from Harbor Freight and some wire and you got a temp sensor with display. .01 volts per degree .75volts = 75 degrees. Now add a sensor to each wheel, run the wire to a 4 position switch and the output to the meter and you can check each wheel.

Ralph · 02-14-2008, 06:44 PM

Oemy U the "MAN".

DriVer · 02-14-2008, 07:00 PM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by oemtech:
Now add a sensor to each wheel, run the wire to a 4 position switch and the output to the meter and you can check each wheel. </div></BLOCKQUOTE>Git'er Done!

Oemtech · 02-15-2008, 03:29 AM

It's on my project list.... I have lots of irons in the fire right now so it may be awhile.

BellaBo · 02-15-2008, 03:50 AM

Oemy...
That is exactly the device (LM34) I was thinking about using. Actually there are other uses too.
Ex: RIGHT FRONT WHEEL BRAKE
LEFT FRONT WHEEL BRAKE
RIGHT REAR WHEEL BRAKE
LEFT REAR WHEEL BRAKE
GENERATOR
REFRIGERATOR
FRONT ROOF AIR
REAR ROOF AIR
HOT WATER HEATER
REAR DIFFERENTIAL
TRANSMISSION
ENGINE COOLANT
BRAKE FLUID
POWER STEERING FLUID

While having the accurate temperature of these items is nice, several are only informational and serve no safety purpose. So one could say, a waste of time. Then again some people just enjoy the challenge of creating.

Kraft Crew · 02-15-2008, 04:10 AM

I found this brake temperature monitor awhile back, but never followed up on it. Seems rather expensive.
http://www.raylin.com/index.html

BellaBo · 02-15-2008, 04:38 AM

Kraft... Thanks for contributing
If I read the technical specs correctly it only monitors one brake pad. This system does seem expensive for what you get.

Our brakes need all wheels monitored in case of a stuck caliper. I also think our calipers can reach a temperature exceeding 250/F with normal braking.

Oemtech · 02-15-2008, 05:39 AM

There are a number of things to get resolved before this can be implemented.

1) max temp is in the 300 degree range for the metal version.
2) max cable length is about 30 ft
3) cost... the good ones are about $10 a pop
4) can be affected by surrounding temps.
6) they will work off 12 v.. this eliminates the battery. But, where do you tap in 12 volts switched/non-switched
7) R&D, testing etc

BellaBo · 02-15-2008, 10:59 AM

Oemy...
I was thinking for the brakes of maybe a thermocouple type of device because of the high temps. Haven't quite found the right one yet and not sure how to set up a circuit for them. I think the length can be overcome with equal wire lengths or an adjustable amplifier circuit. All of this of course starts adding cost.

I was also thinking about using an exhaust gas temp sensor for ambient air measured directly behind brake calipers.

Ideally, wireless remote sensors would be best but can't find high enough measuring temperature probes. But again, there goes the costs.

Back to the drawing board.

Oemtech · 02-15-2008, 01:32 PM

Considering that normal brake rotor temps are in the 250 to 350 degree range we will need something that can handle at least 500 degree.

Now, lets consider NASCAR.... Bright red rotors for 500 miles and they don't fry anything. Agreed they are running DOT 5 silicone fluid and probably have different calipers.

All this reminds me of 78 to 82 Corvettes (I owned an 82) that had a bad habit of getting air in the brake system. After may hours of testing and lots of reworked brakes it came down to the "BRAKE PUCKS". It seems that the rotors would pulse slightly (warped no doubt) and the pucks SUCKED air in around the seals. The solution was Stainless Steel brake pucks. There was an outfit in New York SSBC that would swap you 4 rebuild calipers with SS parts and take your old ones in. Expensive but it worked... no more failures.

BellaBo · 02-15-2008, 02:34 PM

I think a "K" type thermocouple would work. There are two problems I see so far.

1. The EGT Gauge is expensive. Cheapest digital I found was about $87. $57 on EBAY. Can be relabeled as "Brake Caliper Temp"

2. Not sure of the accuracy running Thermocouple wire 30ft+.

The "K" type TC is not that much so, say under maybe $200 you can have a decent 4-Caliper Thermo-coupled Digital temperature readout of your brake calipers. Now is that worth it to people to know if their brakes are overheating, fading and possibly failing? I don't know? If we didn't have to worry about this at all it would be better. But, sometimes one has to look out for one's self.

That said, is there a market for a $200 safety item like this? My guess is that most people would roll the dice and hope it never happens to them and/or depend on the ABS indicator or see smoke out the back end or push the pedal to the floor to no avail.

I'm reminded of a recent incident, where a fellow RV'er crested a hill to see traffic stopped, hit the brakes, they failed, he swerved, ran head-on to another car, killed the driver and at 57 years old is serving a term to life in prison for involuntary vehicular manslaughter.

On the other hand, W/H could probably design and build a system less expensive and include it in their safety features list. They could even just light a light that says "BRAKE OVER TEMP" and give their consumers a better piece of mind.

DriVer... Sorry don't think it would add thousands to the cost unless W/H wants to make a 300% profit on 1 little safety item that could be viewed by the NHTSA as a positive step.