Team-BHP - Brake Fluid Replacement

Quote:

Originally Posted by FlatOut (Post 3207490)

For cars which are a little older or have covered many thousands of km, it is good practice not to depress the pedal to the floor when bleeding the system or pushing the new fluid down the lines. A small ridge often occurs in the master cylinder around three quarters the way along its bore, the point beyond which the pedal never goes in normal use. Repeatedly pushing the master cylinder's piston and seals past this ridge may cause the seals to fail, the result being a sinking pedal or no brakes. A new or rebuilt master cylinder is the solution if this happens.

So depress the pedal to two thirds or so of its travel when bleeding, it will do the job just the same and help prevent master cylinder failure.

Better yet, get yourself one of these "Easy Bleed sets".

http://www.halfords.com/webapp/wcs/s...egoryId_255216

No need to depress the pedal at all and you can do it all by yourself.

http://www.youtube.com/watch?v=UoCV6JSxzH0

If you have a hydraulically operated clutch you can use it on that as well.

Jeroen

Quote:

Originally Posted by Jeroen (Post 3207766)

Better yet, get yourself one of these "Easy Bleed sets".

No need to depress the pedal at all and you can do it all by yourself.

If you have a hydraulically operated clutch you can use it on that as well.

Jeroen

Yes, they work well - I used to use one, but you can easily manage on your own without a special kit, just by feeding the bleed pipe into a jam jar with fluid in. Bizarrely, I really enjoy the feel of depressing the pedal to feel the resistance of the m/cyl seals, the pipes and ABS equipment. Inexplicable!

Somebody else mentioned gravity bleeding if you have time, allowing the fluid to trickle out. This is ok if there is no air anywhere in the lines, but it there was it would't necessarily purge the bubbles.

An important thread, inactive for a while now.

In the Punto owners manual, I see they recommend a DOT4 fluid which must be synthetic. This is a new one.

What is actually meant by synthetic DOT4? Is there a "mineral" DOT4? I also came across an article, which states, reservoir caps are specially marked, if they take ONLY synthetic brake fluid.

Secondly, the Punto brake and clutch circuit is the same. If, the brake fluid is bled, does it automatically ensure it flushes the clutch circuit as well? (This should be similar in other brands as well.)

The ASS has separate codes for brake bleeding and clutch bleeding though.

Quote:

Originally Posted by lapis_lazuli (Post 3719984)

What is actually meant by synthetic DOT4? Is there a "mineral" DOT4? I also came across an article, which states, reservoir caps are specially marked, if they take ONLY synthetic brake fluid.

Secondly, the Punto brake and clutch circuit is the same. If, the brake fluid is bled, does it automatically ensure it flushes the clutch circuit as well? (This should be similar in other brands as well.)

The ASS has separate codes for brake bleeding and clutch bleeding though.

Good question. Actually, I would have thought by simple definition a brake fluid is always synthetic. I think the confusion might be over glycol based versus silicon based. When in doubt never mix!

Although I'm not familiar with the Punto brake and clutch circuit I doubt they are the same. The might share the same reservoir. But they will be two distinct separate circuits requiring separate bleeding instructions.

The clutch circuit is hardly pressurised at all. Years ago I found out the hardway on my Mercedes. I was going to bleed the brakes by means of a so called easy-bleed tool. It puts pressure on the reservoir. As the clutch circuit is not design for much pressure, one of the hoses popped off and I spent the next hours cleaning brake fluid of my car!

Jeroen

Quote:

Originally Posted by Jeroen (Post 3720033)

I doubt they are the same.
Jeroen

I had similar doubts.

So, if I bleed the brakes, is there a residual still trapped in the clutch "circuit"? Is there a chance, that after full bleed of the brake "circuit" the residual from the clutch could contaminate the fresh "brake fluid"?

Further, in such cases, where the brake fluid is being changed, do I need to bleed the clutch to get rid of the old fluid as well? It doesn't quite remain as trivial...then!

It's getting complicated, at the least :uncontrol .

Quote:

Originally Posted by lapis_lazuli (Post 3720047)

You need to check how it is actually hooked up in your particular, but usually it is just a simple tube leading from the reservoir to the master clutch cilinder. Essentially gravity fed. So I dont think there is much chance of it contaminating the fresh brake fluid. But to make sure you could of course also flush the clutch circuit. Usually there is a bleed valve on the slave clutch cilinder. Easy enough to flush some fluid through whilst flusing/bleeding the brakes.

Good luck
Jeroen

Quote:

Originally Posted by sgiitk (Post 1341964)

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.

Hi Sgiitk,

Need your guidance on two issues i just encountered under my car hood. (Diesel Terrano)
I noticed that there is a slight line of carbon deposit in my DOT 4 brake fluid reservoir while i did not see any of that 3-4 months ago.
Curious as to what could cause that and next steps.

A bit different issue alongside, During same time I am shocked to see mirky grey thick fluid almost slimy in my coolant reservoir. This is particularly disappointing as just 3-4 months and 1000kms ago, I myself topped the coolant to full while the previous coolant was clear and till mid level. (the new coolant topped was of a different brand (TVS)).

Your feedback and suggestion would be appreciated.

Ashima

Hello Everyone,

Can anyone tell me the exact duration within which I should replace the brake fluid on a Hyundai Grand i10? The owner's manual suggests just checking the level and topping it off if it's low. There is no replacement duration specified.

The clutch and the brakes are very hard on this particular car. I'm guessing a replacement of the fluid should help in making it a little better. The car is a 1.2l 2016 made Grand i10 which has done about 13k on the odometer.

Quote:

Originally Posted by abhi9044 (Post 5074974)

Quote:

Originally Posted by Gansan (Post 5074979)

^^ Brake fluid should generally be replaced once in two years, along with radiator coolant in most cars. There is no question of "top up". Brake fluid level should not fall. If it does brakes must be inspected and serviced immediately.

I mostly agree with the advice of Gansan except the ‘topping up’ part. Topping up will be required when your brake pads wear. Since disc brakes are self adjustable, as the pads wear with usage, to retain the same tolerance between the disc and the pads, the brake callipers will keep pressing the pads towards the disc. This will create space inside the caliper and the brake line which obviously will be filled up by the brake fluid and consequently the level in reservoir will drop which you’ll need to top up.

For complete flushing, I agree that you should adhere to a two year interval routine.

Regarding hard brakes, if the fluid is not too old, then you should get the brake lines bleeded. It will remove any air present in the brake system. Also take this opportunity to get the caliper pins lubricated. This should solve the issue.

Regards.

^^ It should be ensured the fluid level goes down because of brake wear and nothing else. A couple of years ago my car's brake fluid level used to go down a few mm from full level every few hundred KM. Lifting the car up and inspecting the wheels/under side showed no leaks. They told me to just top up and drive, and a complete inspection could be done during my annual service. But the service was over 8 months away. I told them to carry out a full inspection immediately.

Finally it was diagnosed the booster had a hole in the diaphragm and oil was leaking inside. MSM suggested the booster should be replaced, and I agreed. Since the boosters of latest model Altos did not suit mine, I had to wait a few days till they got the part, but kept driving in the meantime. After the booster was replaced and a complete bleeding/fluid replacement was done, the brake fluid level remains constant.

Got the brake fluid replaced for my MPFI 800 yesterday. When I got back the car, I saw that the brake fluid was above the maximum level. After opening the lid which has some sensor, the level was exactly at the maximum level. After closing the lid the brake oil comes almost to the brim which is about an inch from the maximum level. Is this safe or do I remove the excess oil so that it is at maximum level with the lid closed? Is using a disposable syringe the best way to remove the excess oil?

When I checked the owner's and workshop manuals, the diagrams show maximum oil level with the lid closed. However there is no mention of whether the oil level needs to be maximum with the lid removed or closed.

I have a Honda Jazz. As per the 30,000 kms service, the brake fluid was supposed to be replaced. But they didn't replace it. When I asked them why, they gave some vague response that everything looks good. Need to follow up with them on the next service.

Check your service manuals. They give intervals where they need to be replaced. Ensure the service center does that properly

Recently, during the servicing, after my insistence, the mechanic just bled a little fluid from each tyre and topped up a little instead of replacing all the fluid. I realized this when I got home and noticed that the fluid bottle was mostly full! I am planning to go back and get the fluid replaced but was wondering whether I should use the same bottle since it has been opened once. It seems the online articles suggest that a bottle once opened could be used within 3 months or so. Any expert opinions?
I have a Swift P K Series 2010 with about 44.5 K on the odo. The last time I got the bleeding done was about 2.7 years and about 8.5K kms ago.

Quote:

Originally Posted by heysac (Post 5177843)

Mechanics bleed only a bit just enough to let out the deteriorated fluid in the calipers or brake actuators in case of drum brakes. It also helps let out any trapped air bubbles. The fluid in these parts is goes through heating and cooling cycles which accelerates the deterioration. Most technicians believe it is enough to bleed just a bit, well, you have to consider the rest of the brake circuit especially the ABS.

So rule of the thumb - drain the fluid every 2-3 years especially if you live in a humid climate for e.g. coastal areas. You should stick to the type of fluid for e.g. DOT 3/4 specified for your car.

Do not use fluid in containers that were opened in the past 3 months. Moisture ingress is inevitable and it will deteriorate the fluid in the bottle leading to issues when it is poured into the brake system. Brake fluid is inexpensive just get a sealed bottle to be on the safe side.