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Old 10th June 2009, 22:06   #1
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Default Brake Fluid Replacement - IMPORTANT

Folks,

Most of us tend to get our brakes serviced whenever we experience
  • poor performance
  • minor drop in fluid reservoir level
What often gets done is just rectification of the faulty brake part,but we ignore the brake fluid.

What follows will highlight the importance of brake fluid and the need to replace it periodically.

In my 51/2 year old Versa, I suddenly noticed the brake warning alarm come on last week-checked the brake fluid reservoir and saw it at the minimum mark.Seeing enough fluid below the min mark in the reservoir,drove back, slowly though.

After travelling ten kms,saw that the fluid level was constant.But I noticed some stains on the rear right tyre which suggested a leak from the brake cylinder.I know by experience that brake cylinders don't just fail all of a sudden,but anyway got the wheel opened .The leak was bad.

On opening the cylinder,a NISSIN,MADE IN JAPAN,was shocked to see a deep cut caused by one of the pistons.Also noticed minor corrosion on one portion of one piston,suggesting moisture pick up in the brake fluid.There could have also been some sediment which caused the gash.

Changed both brake cylinders(Left and right rear wheels),and as a precaution,had the old brake fluid in the lines displaced with new brake fluid.All it cost me was Rs.80 for approx 500ml DOT3 Brake Fluid.

Three guys will be needed - one to pump the brake,one to bleed the fluid out and one to top up brake fluid in the reservoir.
  1. Just use a syringe and remove brake fluid in the reservoir(leave a wee bit lest you end up with problems in the master cylinder
  2. Get the mechanic to open the bleed on the left front wheel brake system.
  3. Keep pumping the brake to displace old brake fluid in the line(the guy watching the reservoir must ensure that the level is always max by topping up with new brake fluid).Once old brake fluid is displaced,keep the brake pressed and ask the Mechanic to tighten the bleed
  4. Repeat steps 2,3,4 for the other wheels
  5. Once done,top up to raise the reservoir level to MAX
Renewing brake fluid every 15 k kms is absolutely important as I have learnt it the hard way.For all that you know,this could perhaps help brake cylinders last a lifetime.

MORAL OF THE STORY: It is cheaper to renew brake fluid periodically than to replace brake cylinders.

Please chip in with your experiences.
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Old 10th June 2009, 22:56   #2
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Quote:
Originally Posted by vigsom View Post
Folks,

Most of us tend to get our brakes serviced whenever we experience
  • poor performance
  • minor drop in fluid reservoir level
What often gets done is just rectification of the faulty brake part,but we ignore the brake fluid.


MORAL OF THE STORY: It is cheaper to renew brake fluid periodically than to replace brake cylinders.

Please chip in with your experiences.
Good post. It's also cheaper to replace brake fluid than be involved in an accident. The driver may not live to regret it. Sounds morbid but it's true. Car mfrs suggest replacing the brake fluid every 2-3 years. On the other hand, almost ALL owners never bother about the fluid till they learn the hard way.

Rule of the thumb my fellow TBHPians - Dont compromise on any aspect of the vehicle that affects safety of yourself, passengers and others on the road. Critical items are tyres/wheels, the braking system, wipers, lights and the windshield.

Rgds,

Last edited by R2D2 : 10th June 2009 at 22:58.
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Old 11th June 2009, 07:28   #3
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Vigsom , nice explained. Can you please tell me if this method needs to be followed each time while replacing brake fluid ? How do I replace the fluid otherwise? Is there any valve to empty the container (I think not). So is syringe the only option? And is it necessary to empty the lines each time as well?
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Old 11th June 2009, 10:13   #4
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Two points to note:

1. Brake fluid is hygroscopic. So you must replace it periodically. Otherwise with moisture in the fluid, in heavy braking the water will become steam - bingo loss of braking, as this is equivalent to air in the brakes.

2. I have actually seen the brake fluid in the wheel cylinders polymerizing to form a gel. The chap had not changed the fluid for five years, So as @Takumi-san states it is necessary to bleed out the old oil from the lines as well.
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Old 11th June 2009, 10:27   #5
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An informative post and a good read!

Its shocking to hear that people actually don't bother replacing the brake fluid in their vehicles.
MUL recommends a change every 2 years or 20,000 kms which ever is earlier, so I suppose sticking to this will work for their cars.
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Old 11th June 2009, 11:00   #6
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Unhappy Advice Please!

My 2004 Santro Xing (1,45,000 on the ODO) has recently started having some minor brake issues. The brakes seem to lack the bite and feel a little spongy. Took it to Capital Hyundai (Sec 63, Noida) for a check-up.

The service advisor tells me that the brakes are okay, but on my insistence, he has it checked up by a mechanic. The mechanic dude tells me that the brake fluid seems to be the problem. It probably has something mixed (??) in it. I am guessing moisture build-up or (as sgiitk put it) "brake fluid in the wheel cylinders polymerizing to form a gel". The fluid (rather thick) in the reservoir seems to have some very small bubbles towards the top.

Now, the problem is that the mechanic tells me that the brake oil cannot be changed now, since all the rubber parts that are in the brake pump/vacuum cylinders would expand and get destroyed while bleeding, and would require complete replacement of the pump. He suggests using the brakes till they are usable, and then go in for the procedure.

Should I go with the advice? Can the pump/vacuum cylinder parts get destroyed on changing the oil, while bleeding. My car is regularly serviced, and I have no reason to believe that the brake oil has not been replaced at regular intervals.

Would appreciate any inputs on the situation!
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Old 11th June 2009, 11:10   #7
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I think I am going to get this done next time. Does this require any special equipment? I usually go the DIY way with a mechanic friend.

@ashukla - that sounds ridiculous, they wouldnt design it like this. Check with another garage.
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Old 11th June 2009, 11:26   #8
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Quote:
Originally Posted by ashukla View Post
My 2004 Santro Xing (1,45,000 on the ODO) .....


Now, the problem is that the mechanic tells me that the brake oil cannot be changed now, since all the rubber parts that are in the brake pump/vacuum cylinders would expand and get destroyed while bleeding, and would require complete replacement of the pump. He suggests using the brakes till they are usable, and then go in for the procedure.
First time I heard about the brake parts swelling. Brake fluid is designed not to interact with the rubber. If necessary go to an independent with about 1/2 litre of Brake Oil (DOT3 or DOT4). Hes hosuld not take more than half an hour for the job.

Quote:
Originally Posted by Takumi-san View Post
I think I am going to get this done next time. Does this require any special equipment? I usually go the DIY way with a mechanic friend.
Now how is it done. It needs two people without special tools.

1. Empty out most of the fluid from the master reservoir. Top up with fresh fluid.

2. One person goes (No.1) under the vehicle (on stands and not jack for safety). Puts a small length of tube (PVC) on the 'nipple' The other end is immersed in a container with brake fluid (you can use the old fluid here).

3. The second person (No.2) inside the vehicle pushes on the pedal. No. 1 loosens the nipple with a spanner. The fluid will come out into the receptacle. No.2 keeps the pressure on while No.1 tightens the nipple. Repeat a few times (3-4 typically) until fresh fluid comes out.

Do not release the pedal until the nipple is tightened otherwise air/old fluid will back up!

I suggest you top up the reservoir after every wheel is done. There should always be fluid in the reservoir.

Repeat for all the four wheels. Start with the rear wheels and then move to the front.

You could buy a small PVC tube with a no return valve to simplify the job. Also, there are devices to pressurize the reservoir. However, I find these superfluous.
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Old 11th June 2009, 11:39   #9
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Quote:
Originally Posted by ashukla View Post
The mechanic dude tells me that the brake fluid seems to be the problem. It probably has something mixed (??) in it. I am guessing moisture build-up or (as sgiitk put it) "brake fluid in the wheel cylinders polymerizing to form a gel". The fluid (rather thick) in the reservoir seems to have some very small bubbles towards the top.

Now, the problem is that the mechanic tells me that the brake oil cannot be changed now, since all the rubber parts that are in the brake pump/vacuum cylinders would expand and get destroyed while bleeding, and would require complete replacement of the pump. He suggests using the brakes till they are usable, and then go in for the procedure.
Rubber parts will not swell with new brake fluid, unless you are replacing the old fluid with another type, e.g your old fluid was red and you replace with white fluid. If it's the same brand and type, have no fear.

Go to another mechanic. The present fellow probably does not want to go through the painstaking process of replacing fluid, and may cut corners while doing so. Dump him!
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Old 11th June 2009, 12:19   #10
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Quote:
Originally Posted by filcord View Post
Rubber parts will not swell with new brake fluid, unless you are replacing the old fluid with another type, e.g your old fluid was red and you replace with white fluid. If it's the same brand and type, have no fear.
Brake fluid loves moisture...eventhough the brake circuit is a closed system, moisture/other contamination is not ruled out over prolonged period. This contamination makes the rubber parts on the brake circuit to disintegrate. Hence, if a master cylinder is working fine now it is no assurance that once you try to service the system it will continue to do so.

Additionally, please remember that brake fluid (dot3 or dot 4) is highly corrosive to paintwork and plastic. So, if you plan to DIY please be very carefull while handling it lest you damage your car.
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Old 11th June 2009, 12:28   #11
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I have a feeling that the prime cause of damage to rubber is Mineral Oil (contamination with normal lubes). As for Red/White it is just the matter of dye in the fluid. I have changed many times from one to another. Also, remember the hydraulic clutch uses the same stuff. Just stick to DOT3 or DOT4 which you are using. Most cars are DOT3.

@ashukla: Do not tell me that with 145,000km you have never overhauled the brake system. If so do so pronto! The life you save may be your own!!!
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Old 11th June 2009, 12:34   #12
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Question: Will replacing the brake fluid improve braking. Brakes on my zen are not responding as they used to. I changed the brake pads to little effect. So do I need to replace the brake oil ?
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Old 11th June 2009, 12:41   #13
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I tried bleeding the brake on my ThunderBird.

Quote:
Originally Posted by bblost View Post
This Sunday, I found myself with a bottle full of DOT3 oil and some time.
The DOT3 was bought a couple of week’s back, but that day my mechanic's shed was closed.
I had been looking at the dot3 and thinking how to go about refilling my bikes disc oil.

I opened the main container and topped up the oil.
The brake was working fine.

The devil crept up my ear and kept reminding me that old oil is looking old.
Decided to bleed the brakes.

Opened the nipple cover and set up the spanner for the valve.
press brakes three times
HOLD
open and close the valve.
Repeat the above.

complete loss of pressure in the brakes.
spent more than 4 hours trying to get the air out.
The valve was spitting out oil as expected but still no pressure.

finally went to the mechanic, Monday morning.
took him half an hour to fix it.

what I was missing
the hydraulic pump, needs to be opened up.
springs et all removed, flooded with oil and closed.
voila the brakes work fine now.

What I learnt.
riding a bike without brakes is more fun.cheers:
OT:
@BeamerBoy:
That property is called Hygroscopic.
Hygroscopic - Definition from the Merriam-Webster Online Dictionary
Quote:
Main Entry:
hy·gro·scop·ic

Function:
adjective
Etymology:
hygroscope, an instrument showing changes in humidity + 1-ic; from the use of such materials in the hygroscope
Date:
1790
1 : readily taking up and retaining moisture
2 : taken up and retained under some conditions of humidity and temperature
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Old 11th June 2009, 12:46   #14
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Quote:
Originally Posted by filcord View Post
The present fellow probably does not want to go through the painstaking process of replacing fluid, and may cut corners while doing so. Dump him!
^ This is the exact feeling I got. It felt these guys were hellbent on convincing me that the car is as okay as it can be, given that the car had been serviced by them just a couple of days back

Quote:
Originally Posted by BeamerBoy View Post
This contamination makes the rubber parts on the brake circuit to disintegrate. Hence, if a master cylinder is working fine now it is no assurance that once you try to service the system it will continue to do so.
^ I have learnt a lot about cars and related stuff since acquiring my new-old (recession be damned) Esteem a few months back.

Quote:
Originally Posted by sgiitk View Post
@ashukla: Do not tell me that with 145,000km you have never overhauled the brake system. If so do so pronto! The life you save may be your own!!!
^ As I have mentioned in my post, my car is serviced regularly at HASS. I am sure that brake rehauling must be on their service checklist at some ODO reading.
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Old 11th June 2009, 14:32   #15
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Quote:
Originally Posted by ashukla View Post
As I have mentioned in my post, my car is serviced regularly at HASS. I am sure that brake rehauling must be on their service checklist at some ODO reading.
Looking at your experience I will not be too sure. Check the owners handbook, and also the corresponding bills/job sheets for the brake overhaul. They are supposed to change the brake fluid every 30,000km/18 months. This again can be found from the bills - you will see a charge for 1/4 to 1/2 litre of brake fluid.
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