Handbrake Warning Light 1998 1999 2000 2001 CG Accord Coupe

[BN Coupe]

If the lights come on again I'll let you know!

[Mazda Man]

On 07/03/2016 at 0:32 AM, hughezee said:

No need to say sorry buddy, customer of mine made a big boo boo today filling his engine with water so maybe I'm in a fly picking mood

Hannnnnnnngggggg on a minute.....filling his engine with water?? 

[jayhoath83]

I shall check my pad levels and fluid n see if my calipers are sticking but im thinking its a sensor fault as ive not done anything to my brakes but they work fine cheers for the advice guys 

[AhsyV6]

Guys, 

Since before replacing my rear discs and pads the handbrake and brake warning lights started coming on a few miles into my journey. I thought this might stop after the replacement of the discs and pads but it hasn't. 

I know there are a couple of posts on this topic with regards to there warning lights but nothing on the combo. 

I have checked the fluid level and it is at the correct level. 

Does anyone have any thoughts? 

Btw I haven't checked the handbook so excuse me if I'm being silly. Also my rear bulbs all work and operate as they should. 

Cheers 

[hughezee]

I am assuming you referring to combination of the brake light and brake light bulb failure warning, if this is the case I had a similar issue and since it was a twin filament bulb I assumed one had failed (very common) So my rear lights worked, but when pressing the brake pedal one lamp didn't get brighter so part of the bulb had failed replaced the bulb and 99.9% of the time this should solve it.

My situation wasn't so straightforward as a new bulb didn't work and I traced to the problem to oxidised crimp connection in the boot loom,  re-soldered it no problems since linked below.  The only reason I mention my conclusion was the fact I wasn't impressed with the Depo light bulb fitments and wire quality, of which I subsequently sold with project purple. However' after a month my suspicions turned out to be right after countless niggles with them, until Geoff asked for the stock units to be put back on, hopefully its just your bulb thought m8

 

[AhsyV6]

You're right in that the depos aren't the best in wiring and the actual holder isn't brilliant either. Every couple of months or have to push the bulb back in as it wouldn't clip in place. But this time the bulbs work with the brake pedal depressed along with the rear side lights. 

I've got spare bulbs so I might change them altogether. I'll let you know how it goes.

thanks again 

[hughezee]

That's very odd then if they are all visibly working, the feed to the bulb warning system could be a little oxidised or could have failed, unless I am thinking of the wrong warning indicator  post up a pic when you have a opportunity m8

[AhsyV6]

Just a quick update.....I changed the right bulb and it solved the issue. Very odd

[hughezee]

Thanks for the update m8

[welland99]

I've noticed over the last couple of months that my hand brake warning light is occasionally slow to extinguish on cold mornings when I leave the house.  It is very occasional and only on cold mornings.  It has not stayed on longer than a minute of two after pulling away. 

I imagine that it could be caused by a sticky switch on the handbrake,  but I don't know where the switch is.   Does anybody know?

[hughezee]

I would check the condition of your fluid and these cold temperatures will affect the viscosity of the fluid especially if it hasn't been changed in a while and its contaminated with water?

 

[Laird_Scooby]

I'm thinking exactly the same as Stu on this - the handbrake warning light also serves as a low fluid level warning light for the brake fluid. Besides the fact that cold weather makes it shrink in volume normally, if the fluid is contaminated with either water or worse still, air, that will also shrink in cold weather, effectively dropping the level of the fluid. As it warms up with heat from the engine bay, it expands again bringing the level up and putting the light out.

Must be very close to the borderline level to bring it on on cold mornings but low nonetheless. Worth checking as a starting point but check the condition of the fluid, anything other than clear coloured fluid (usually a sort of orangey yellow colour) and there's a good chance you'll need to change the fluid.

[Mazda Man]

I had this issue when we had the snow. Don’t get it when the weather is mild.  I think it’s due to the fluid viscosity and the cap on the reservoir making the light come on due to the fluid being thicker when cold as when the engine bay is warmed up, the light goes out. 

[hughezee]

My brake fluid is replaced every 2-3 years and was replaced before the cold snap no niggles, just saying

[Laird_Scooby]

20 minutes ago, hughezee said:

My brake fluid is replaced every 2-3 years

By that measure (and it's the right one too) mine is way overdue. Except on the Volvo as that had a full brake fluid flush just after i got it.

The other problem with running old fluid is it gets dirty and contaminated which can cause seals to fail in the master cylinder, ABS modulator and of course the wheel cylinders aka the calipers.

In my defence about running mine so late past when it should have been done, i do check it periodically and it's still clean, when it starts getting dirty it will shoot up the priority list! It's on there to be done though!

[Mazda Man]

Rest assured, when I do get my Legend EVERY fluid will be replaced, peace of mind and all that.  

[welland99]

It hasn't happened again since I posted?

[Laird_Scooby]

15 minutes ago, welland99 said:

It hasn't happened again since i started this thread. 

It's been warmer since - rumour has it that it's turning cold with a capital "F" this coming week so it might happen again.

[welland99]

3 minutes ago, Laird_Scooby said:

It's been warmer since - rumour has it that it's turning cold with a capital "F" this coming week so it might happen again.

Yes, I heard that too.  Though I can't work out why cold temperature would cause this.

[Laird_Scooby]

2 minutes ago, welland99 said:

Though I can't work out why cold temperature would cause this.

 

On 12/29/2017 at 2:21 PM, Laird_Scooby said:

cold weather makes it shrink in volume normally, if the fluid is contaminated with either water or worse still, air, that will also shrink in cold weather, effectively dropping the level of the fluid. As it warms up with heat from the engine bay, it expands again bringing the level up and putting the light out.

A more practical example is on cold days my heating oil gauge can show up to 120L less than is actually in there, on a particularly warm day it can show up to 120L more than is in there.

Granted there's 500L or thereabouts when it's most obvious and in the brake fluid reservoir there's probably 500ml at the most but the proportions are still the same. Simple expansion and contraction of fluids because of temperature difference.

[welland99]

1 minute ago, Laird_Scooby said:

 

A more practical example is on cold days my heating oil gauge can show up to 120L less than is actually in there, on a particularly warm day it can show up to 120L more than is in there.

Granted there's 500L or thereabouts when it's most obvious and in the brake fluid reservoir there's probably 500ml at the most but the proportions are still the same. Simple expansion and contraction of fluids because of temperature difference.

Ok, yes, i get the thermal expansion argument, but surely the coefficient of expansion of brake fluid is very small?  My level is about half way between min and max, so it's not very close to the limit.  

[Laird_Scooby]

The main bit of the point i was making is that if the brake fluid is contaminated with air, water etc it will alter the coefficient of expansion of the brake fluid. I don't know what the factor is on brake fluid but it will have changed as it's no longer new fluid.

Also if it's half way between minimum and maximum, there's a good chance it's at about the right level to bring the light on if the level drops because it shrinks in the cold. If memory serves correctly, the warning light comes on before it reaches the "MIN" mark as a warning the brakes might not be all they should until you're able to stop safely.

[PTR200S]

10 hours ago, welland99 said:

Ok, yes, i get the thermal expansion argument, but surely the coefficient of expansion of brake fluid is very small?  My level is about half way between min and max, so it's not very close to the limit.  

Interesting point this about the expansion, if you think about how much water expands as it freezes, burst pipes etc, then in theory the level of fluid should increase and therefore the light should not come on ?

However, before freezing it contracts, I presume, just like fuel as Dave points out with his heating oil..... Apparently it is best to fuel your car on really cold days too as you get more petrol/diesel for your bucks. So the presumption is this it what happens to the fluid/water in the brake system?

I would be looking to pump through new fluid soonest but also if your level is only half way up then for the time being fill it to the correct level, the fact its lower than max means fill it up not to wait to hit the low mark....

I would be looking at your brake pads too, if the level has dropped that far from max you may find the pads are on their last gasp 

 

[Laird_Scooby]

2 hours ago, PTR200S said:

in theory the level of fluid should increase and therefore the light should not come on ?

It would but the brake fluid acts as a sort of antifreeze simply because it's absorbed the water.

I've been searching online for some useful information to link to but there's very little in between anecdotal evidence and full-blown theses on the subject, one of which was done in Sweden but was more on the effect of temperature and how it effects the viscosity and efficiency of the braking system, all done with new fluid.

I found something from the aerospace industry along similar lines and although i've forgotten how to do the maths involved (in-depth Calculus) i could remember enough to work out they were basically saying that old fluid is much more compressible than new fluid. It does mention thermal coefficient of expansion and also points out between 0 and 4C, water has a negative expansion coefficient, in other words within that 4C range, it expands. However, factor in the antifreeze effect of the brake fluid the water is in and it could be argued (how successfully i'm not sure, i'm not a fluid thermo-dynamics engineer) that it remains positive and will shrink in volume with the brake fluid as temperature drops.

http://thermopedia.com/content/1191/

On the anecdotal front, this was quite interesting/amusing :

https://www.bikeforums.net/bicycle-mechanics/122678-expansion-disc-brake-fluid-sun.html

Getting back to the technical stuff, DOT4 brake fluid is an ether of glycol (in most cases) so while it's not ethylene-glycol (antifreeze!) in the true sense, i'm fairly sure the same coefficient of expansion could be used :

https://www.engineeringtoolbox.com/cubical-expansion-coefficients-d_1262.html

Look at that and it can be seen that it is about 2.5 times more than water so will contract or expand a lot more. Check the coolant level on a cold day and it's lower than a hot day and what is in the coolant?

[hughezee]

15 hours ago, welland99 said:

Though I can't work out why cold temperature would cause this.

Think Dave has gone above and beyond with his explanation, the bottom line is there appears to be a pattern with this light niggle and those who have replaced the fluid don't get it unless its handbrake related.