Off Topic brake fluid change bleeding sequence

[jocie]

I want to change the brake fluid in my 2009 3 litre comfortmatic Ducato, but how do I make sure I don't damage the A.B.S. system, and in what sequence do I bleed each wheel ? I do not intend to use an eezibleed but would get my wife to do the brake pedal pressing under my shouted instructions !

 

[panda1408]

Do the furthest from the master cylinder first, so start at either the N/S/R or O/S/R, depending on what side the master cylinder is. ABS should not cause any problems.

 

[jocie]

Thanks Panda , that puts my mind at rest a bit.

 

[Peter Pick-Up]

Careful...you may destroy the mastercilinder, bleeding that way....!
I would use a Gunson Eezybleed.

 

[jocie]

Thanks Moderator, I have now researched this further after your comment, and will buy a Gunson eezybleed if I can get it to fit the Ducato reservoir. I actually have a very old eezybleed system in my toolshed which I last used around about 1965 would you believe !!!! (on a Morris Minor convertible). However I would not risk using kit this old, it's bad enough having an old git like me trying to do the job.....

 

[Peter Pick-Up]

http://www.ebay.nl/itm/221197578052?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

 

[s130]

Careful...you may destroy the mastercilinder, bleeding that way....!

I don't think this applies to any ABS system produced within the last 10 years or so. The very early/original ABS systems did require a pressure bleed.

Most technicians I have spoke to generally prefer to use the traditional pedal pump technique, and this is certainly how my Fiat dealer does it and how I do it.

Whilst pressure bleeds are a quick and effective good one man solution they do have the following drawbacks.

1) often getting a good reservoir seal (especially with a universal use kit) can be difficult. Often even if initially good leaks can develop resulting in lots of brake fluid everywhere and a time consuming job to clean up

2) if the supply bottle runs out of fluid then the first you know about it is when air has been blasted through the whole system and out of the caliper you are bleeding. On a normal non ABS system this can be a pain to resolve because any remaining fluid in the system has become heavily aerated. On an ABS system then the internal abs pump reservoir can likewise be aerated and difficult to bleed.

If 2) happens when pedal pumping then it is immediately noticed by both the pedal pusher and the bleeder. Yes you now have an air bubble in the system that has to bled out but you don't have the continuous deluge of pressurised air being blasted through the system.

 

[Peter Pick-Up]

I strongly advise to stay away from ANY modern workshop/dealer that uses the old fashion way to bleed any brake system.
It is dangerous and unsafe!!!!!
By pushing the masterbrake cylinder beyond it's normal working travel/space, the seals will encounter rust and/or dirt, and will start to leak sooner or later, so: DON'T DO IT unless you absolutely have no other choice.

 

[s130]

I hear what you and understand what you say but any braking system that can't tolerate excessive brake pedal travel without stuffing itself is not a car I want to be driving in. This is dangerous and unsafe!

If brake fluid is changed regularly then the fluid can absorb moderate amounts of water and still provide corrosion performance. The brake fluid will boil long before corrosion and piston "ringing/ridging" becomes and issue. Any ringing/ridging in a brake piston/cylinder is not acceptable.

Also a modern ABS system, with traction control, ESB, hill holder etc. are have inbuilt brake pedal creep. I can get our Croma's brake pedal on the floor in around 20 seconds of continuous brake pedal pressure. And no there is not a fault. Turn ignition/engine off and you can lean with two feet on the brake pedal all day an it will not creep. Our local county council MOT testing station have noticed this "feature" on the later systems fitted to many makes of modern cars. Scared me to hell the first time I encountered this but its normal.

Of course if I was presented with an old neglected car with brake fluid of treacle and *hitty colour I would take a completely different approach. Strip and inspect everything or replace all with new.

 

[Peter Pick-Up]

[ame]http://en.wikipedia.org/wiki/Brake_bleeding[/ame]

At least, put a piece of wood under the brake pedal, so it can't be moved all the way to the floor, to prevent seal leaking.

 

[Peter Pick-Up]

http://motiveproducts.3dcartstores.com/0100-European-Bleeder_p_115.html

I like this bleeder.

 

[s130]

http://motiveproducts.3dcartstores.com/0100-European-Bleeder_p_115.html

I like this bleeder.

This power/pressure bleeder is good. It has

1) a pressure guage
2) a very large reservoir bottle

Both of these are most important.

The Gunson Easybleed fluid bottle is so small that the problems I eluded to are most likely.

You need a 2:1 or better volume ratio in any pressure feed system. i.e. if the braking system fluid volume is 1 litre then you ideally need a 2 litre source reservoir, minimum. Only problem with this x:y ration is that if a leak occurs on the interface then you get one hell of a mess to clear up.

A tip for anybody using a pressure bleed system. Couple up all the components with just air and no fluid in the delivery bottle. Pressurise and leave for say 5 minutes. Then unscrew the reservoir cap and listen for escaping air/loss of pressure. If you have a pressure gauge as depicted on Peter's post then use this to indicate/show a pressure leak.

As with all these types of discussions we build up/share a wealth of knowledge and every bit of info (right or wrong) is absolutely valuable information for all concerned.

 

[Peter Pick-Up]

It's on Ebay:

http://www.ebay.com/itm/27117847160...cmd=ViewItem&sspagename=STRK:MEWAX:IT&vxp=mtr

I'm about to order one.
First I'm going to visit the TechnoClassica in Essen Germany next week, largest classic car show in the world.
I'm going to see what types of brake bleeders are on offer overthere, than I will decide which one to buy.

 

[sludgeguts]

Careful...you may destroy the mastercilinder, bleeding that way....!
I would use a Gunson Eezybleed.

I strongly advise to stay away from ANY modern workshop/dealer that uses the old fashion way to bleed any brake system.
It is dangerous and unsafe!!!!!
By pushing the masterbrake cylinder beyond it's normal working travel/space, the seals will encounter rust and/or dirt, and will start to leak sooner or later, so: DON'T DO IT unless you absolutely have no other choice.

If it is so dangerous and unsafe, why are many garages still using this method? Especially main dealers who would be expected to adhere to all the latest elf & safety stuff.
And where do you get rust & dirt from in a master cylinder?

 

[Peter Pick-Up]

Read the other posts.
Again NO decent, official workshop/garage will use that old fashioned way to bleed the brakes today, ABS or not, doesn't matter.
By pushing the brake pedal to the floor you WILL damage the seals, and cause dangerous leaks sooner or later.
Just don't do it.

 

[sludgeguts]

I HAVE read the other posts.
My youngest and his mate were here earlier, one's a Toyota tech, the other's a Renault tech - both say their workshops still pump the brake.
As I said before, if it is so dangerous and unsafe...

 

[s130]

There is a clear difference of opinion on this.

Peter is right in that a rusty / damaged bore that is not normally swept by the master cylinder seal will potentially damage the rubber seal.

The same could be said to slave cylinders which WILL travel to longer limits as brake pads and shoes wear. The only difference is that by definition/practice a pumped pedal will cross such "wear ridges" multiple times.

However a well maintained and clean system should not be affected by "longer travels".

I think what is important is that we understand the possible outcomes and limitations/side effects of either the pressure/vacuum bleed and a pumped pedal bleed.

Personally I would prefer to expose an iffy system earlier with a pedal pump than later with a pressure/vacuum bleed.

EITHER way major/catastrophic system failure is NOT going to happen regardless of bleed method. Each to their own.

 

[jrkitching]

There is a third alternative and that is to vacuum bleed it. Less messy than pressure bleeding and no risk of damaging the seals.

 

[Peter Pick-Up]

There is a third alternative and that is to vacuum bleed it. Less messy than pressure bleeding and no risk of damaging the seals.

Right, but there's the possibility to suck outside air through the bleeding niples....!!
So you never know where the air bubles are coming from...

 

[jrkitching]

Right, but there's the possibility to suck outside air through the bleeding niples....!!
So you never know where the air bubles are coming from...

If you're just changing the fluid then it doesn't matter, since there shouldn't be any air in the system anyway.

Vacuum bleeding will not introduce air into the system unless you let the level in the master cylinder get too low. And it's an excellent way to get the old fluid out of the master before you start.