Technical Break fluid change

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Technical Break fluid change


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Jan 4, 2019
I decided to get a break fluid change for my Linea, considering the age it has. The problem is that I can't find anywhere what cantity is needed for a full fill. Can anyone tell me how much I require? Thanks!
I decided to get a break fluid change for my Linea, considering the age it has. The problem is that I can't find anywhere what cantity is needed for a full fill. Can anyone tell me how much I require? Thanks!
Hi and welcome.

Are you going to do this yourself? Have you done a fluid change before? I'm not trying to put you off but be aware there are things that can go annoyingly wrong. Bleed nipples can snap off because they are corroded in. Paint can be damaged by the fluid if you spill it. Try to suck out (I have a small syringe I use) any solids or "gunge" in the bottom of the reservoir before pouring in the new fluid - It will have been peacefully lying there and you don't want to disturb it so it gets dragged into the system, especially if you have ABS. But the most potentially "easy to do" and expensive can be if you wreck the master cylinder!

Most non professionals will bleed brakes by opening the cylinder bleed nipples in turn and pumping the brake pedal. Think about what the master cylinder is usually doing whilst you drive though. The brake pedal never really goes much more than 1/2 way to the floor does it? So the seals are only "wiping" the first half of the cylinder walls. The other half is free to collect contaminants and even corrosion. So now you're going to plunge the seals past this when you're bleeding it out? Surprisingly they often survive! but they can be damaged (I've even known them to invert so they can't seal at all!) For many years now I've used a Gunsons Eesibleed - other brands are available! You can buy them over here for around £20.00p. It's a simple device which uses reduced pressure from the spare wheel (5 to 10 psi works well) to flush the fluid through the system and you don't pump the pedal at all. Makes it nice and easy if you're on your own too. It's so simple you could make your own if you are "handy"

I would never now risk bleeding with the pedal, but if you must then only push the pedal down half way - not all the way to the floor.

As to how much fluid you will need. I will be changing the fluid in our panda at it's next service and will be buying a litre bottle of Dot4 fluid. I will be surprised if it takes any more.

I hope I haven't put you off with all this as it's one of the simpler things you can do to your car. However it's worth being prepared and able to avoid the problems if you know to expect them. Of course we are talking brakes here, so if you get it very wrong the consequences can be very serious indeed!

Good luck
Don't worry I don't plan to do it myself. I will take the car to a Fiat service, but I prefer to get the parts myself and have them mount them. I plan to buy them separately because in Romania, at least, they tend to overcharge you for them. I spoke to a mechanic from their service and he told me that there isn't any problem if I bring my own parts.
I wanted to know the quantity of break fluid required so I make sure that I buy enough.
As for brake pedal (and pump seals), you can limit the stroke by putting something under the pedal (piece of wood or whatever).

Another amateur mistake is retracting brake caliper pistons back (when changing the brake pads/disks) and pushing old dirty fluid up in the system (this can spoil an ABS pump), instead of bleeding it.
Yes, a diy bfc is full of possible "pifalls", sheared of nipples etc etc etc ...

Yes, suck out master cylinder resovir "old fluid" else the crap ends up in the haudraulic system, which is where it came from in the first place.

Yes, fluid needs changing even the modern less hygroscopic stuff, which can still have internal corrosion problems.

Make sure yo have the correct fluid and ideally change every 2 years. Merc even say seals need changing at that time.

Bleed nipples, clean out nipple central holes with a small drill ( do no, DO NOT break the drill in the hole!!!!! )_ being aware that the hole has a smaller diameter further in. Wire brush/clean the nipple exposed thread and penetrent penetrent penetrent. us esome windscreen washer tubing pointing upwards and fill with penetrent, and leave it to do its thing for as long as possible. The longer the better.

Whilst you are there, wire brush the brake pipe union and penetrent that as well. If you need to renew the wheel cylinder, the brake pipes can seized/corrode into the union, twisting the pipe if the union needs to come out, meaning a new brake pipe etc.

When undoing the nipple, no jerking just steady torque and hopefully it will undo with no issues.

Initally I tend to let gravity help with initial bleeding, with the master cylinder res cap off. When discoloured fluid changes to new colour i shut that nipple off and do the rest in turn.

When all gravity bead, then my assistant is in charge of the brake pedal followning my commands.

1. pump up a few times and then hold pressure, she complies and says so.

2. i undo nipple and watch fluid come out via the clear tube andinto the jam jar. I do the nipple back up. And say up. She complies and says so.

repeat 1 untill satisfied no more old fluid and no air, then move on to the next nipple.

Its usual to bleed the nipple furthest from the master cylinder firt etc, keeping a very keen eye on the fluid level.

Some master cylinder res feed the haudraulic clutch as well, so bear that in mind.

! to 2 litres should be more than enough for a flush and bleed, usually. ALWAYS use new fluid from a sealed container and dispose of old fluid properly.

Check your car manual for any "reset" needed for the cars system.

Remember that the master cylinder is a pump, with the pump being able to pump fluid and not drag in air, so a proper procedure is needed else spend the day and gallons of fluid.....

A slightly pressurised master cylinder res is a single person tool as the res is automatically topped up when the tools is in use.

Its pointless replacing the fluid if the brake system has faults like stuck caliper pistons or bad hoses and leaky wheel cylinders etc. etc. etc.....

so, suck out res old fluid and refill res, pump up command to assistant with her reply, down command with her reply, open nipple and watch fluid flow then close nipple, up command with her reply, wait a few seconds and then repeat. When new fluid an no air, that nipple is blead.

Modern cars have 2 haudraulic circuits. When bleeding only one circuit is bleed, so pedal will only go about half way down, so only go 1/4 way down so that circuit is only at half stoke........

Take your time, dont break anything and dont let the res run out of fluid, ever!
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