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Old 13th August 2013, 21:13   #46
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Default Re: Brake Fluid Replacement - IMPORTANT

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Originally Posted by FlatOut View Post
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.



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

Jeroen
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Old 14th August 2013, 03:47   #47
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Default Re: Brake Fluid Replacement - IMPORTANT

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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.

Last edited by Gannu_1 : 1st June 2015 at 12:30. Reason: Removing Youtube URL from the quoted post.
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Old 1st June 2015, 12:25   #48
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Default Re: Brake Fluid Replacement - IMPORTANT

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.

Last edited by lapis_lazuli : 1st June 2015 at 12:36.
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Old 1st June 2015, 12:59   #49
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Default Re: Brake Fluid Replacement - IMPORTANT

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Originally Posted by lapis_lazuli View Post
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!

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Old 1st June 2015, 13:07   #50
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Default Re: Brake Fluid Replacement - IMPORTANT

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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 .
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Old 1st June 2015, 13:13   #51
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Default Re: Brake Fluid Replacement - IMPORTANT

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Originally Posted by lapis_lazuli View Post
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 .

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
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