Replacing brake fluid

The message from petermcmillan snipped-for-privacy@yahoo.com contains these words:

You'll often find that just opening the nipple with allow fluid to slowly run out. Since I noticed this, I've not been waggling the pedal up and down in the traditional manner.

Do you need to have the engine running? My w/s manual says you do. I would've thought it wouldn't be necessary, especially if you're pumping the pedal.

The message from petermcmillan snipped-for-privacy@yahoo.com contains these words:

No. Though ABS systems will be different.

On tooled-up there's a draper kit which plugs into an air compressor. It's £30, and I already have an air compressor. Are there any kit you'd recommend. A standard kit, like my dad recommends, would be just under £10. Oh yeah, with the proper kit I think one person can do it, but I think you need two for the cheap one.

The big advantage of power bleeders is that when you pump the brake pedal to push fluid through the system you are moving the master cylinder seals to places that they don't normally go in the cylinder. That's not such a problem on newer cars bit it can be if the MS is old. With age there will tend to be some wear around where the seal normally moves & so if you suddenly push the thing beyond that area you can break the seal & things start leaking/not working. If you are going to use the brake pedal then stick a piece of wood under the pedal so it can't go all the way to the floor - that will limit the movement a bit. On VW's and Audis pushing the thing all the way to the floor can damage the MS seals even on a new car.

Also, when changing the fluid the best way to do it is to drain as much as you can from the reservoir using something like a turkey baster. Be careful not to drop any anywhere cos it eats paint. Surround the reservoir with loads of paper towel and have some water & paper towel handy to mop up with if you get a spill.

Then re-fill with fresh fluid & keep topping up as you bleed. Normal routine for bleeding is RR, LR, RF & LF (and then clutch if its hydraulic & on the same system). You should take much more out the first one (maybe 1/2 a pint

+) than the others - this clears all the fluid out the MS and also the long run of pipe to the back of the car. Once you've done that you don't need to take that much out the other 3 because all you are clearing are the individual pipe runs and the wheel cylinder on each wheel.

Lastly, some cars with ABS are bled by turning the ignition on then cracking open the bleed nipple & then holding the brake pedal down 1/2 an inch - the fluid then gets pumped out by the ABS pump - so no power bleeder or pedal pumping needed. Check whether this applies to your car if it has ABS.

rgds

Iain

I'd be wary of one which uses a compressor, somehow.

The Gunson EasiBleed uses your spare tyre, which you deflate to about 20 psi. Provided you take care the lid is carefully fitted to the master cylinder - ie not cross threaded - so it seals well, and all the pipes are ok etc it works very well, and the beauty is you do it all on your own. It also saves pushing the master cylinder past where it normally travels which has been known to damage the seals on occasion - although probably only on an old car.

However, keep an eye on its reservoir as it gets through fluid pretty quickly.

I'ld let it purge the old crap with air and then fill the master cylinder and bottle with clean stuff. Less mixing of new stuff with old in the reservoir the better.

Worked a treat on my Nephews car when I used it but he had had problems - muppet.

That sounds like the most sensible way to do it, but also the most difficult. I think I may try this when I've got a whole day free, but my dad won't like me 'messing about' like this, he'll think I'm mad.

lol

I use the pipe with non return valve and a jamjar. Works well for me, even flushing the system through.

Don't overtighten the bleed screws, remember they are hollow, and some are made of toffee (well that's what is seems like). Slightly tighter than bugger all is where you want to be aiming for otherwise your next post will be how to replace brake calipers I expect....

On tooled-up there's a draper kit which plugs into an air compressor. It's £30, and I already have an air compressor. Are there any kit you'd recommend. A standard kit, like my dad recommends, would be just under £10. Oh yeah, with the proper kit I think one person can do it, but I think you need two for the cheap one.

============ The traditional method using a simple tube (with or without a non return valve) is made much easier if you have the end of the tube in a jam jar with a lid. The original lid with a hole in the centre just big enough to take the tube prevents spillages especially when you remove the tube from the nipple. It (the lid) also helps to keep the end of the tube in the required fluid during the pumping through.

If you need to work by yourself cut a piece of wood just long enough to wedge between the front of the seat and the top of the pedal when it's depressed. Use the piece of wood to push the pedal down and then wedge to hold the pedal down whilst you tighten the nipple.

Cic.

If you're just changign the fluid, I find it's much easier just to sponge out the fluid in the reservoir and fill it with fresh fluid. Then simply undo each bleed nipple in turn and let the fluid gravity bleed.

As long as you don't let air into the system (i.e. let the reservoir empty), you don't need to worry about pumping the pedal or using any particular order.

Keep it flowing until you see the colour change, and then let it run through a little more. I usually go around a second time for just a little more.

Also check what the requirements are for ABS if you have it fitted, a few systems may have particular procedures for fluid changes.

It's traditional to bleed the most remote brake from the master cylinder first. I have no idea why and no-ones ever been able to give me an answer so I suspect this is a myth.

It's usually a method used when you have dismantled part of the system, and need to remove air. I believe the old method of starting from the furthest point ensures that all the air is removed.

In article , Iain Miller writes

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For sucking the old fluid out of the reservoir I use the pump mechanism from an empty 'Windolene' spar bottle; just unscrew the top of the spray bottle and put the syphon tube to the bottom of the reservoir. This way you suck out some of the sediment rather than forcing it through the brake system. Keep topping up with fresh fluid as you bleed each wheel cylinder and continue 'till you get clean fluid coming out of the nipples.

mechanism

Can you tell the difference between clean, and old fuild? Is it a difference colour or something? My dad said 'it is if it's very old', but my dad's idea of very old is probably VERY old! My fluid's likely to be 3.5 years old (assuming that the main dealer changed it on the

2nd service).

Some times you can't. At that age I'd expect the fluid in the reservoir to be quite brown but the stuff in the pipes may not be. Brake fluid is pretty cheap - buy 2 litres and use it all & you'll have cleaned the whole thing out. There's no point in keeping an open bottle of BF anyway - it just absorbs moisture & you probably won't get away with just buying 1 litre - it won't be quite enough. You are unlikely any leftovers before the next change & by that time it will be no good.

rgds

Iain

reservoir to

Argh! I should've ordered it with the spark plugs :-(. It is quite expensive though. Almost =A35/500ml. I've only got 500ml, so I'll probably want another litre. My car only takes 400ml though.

probably want another litre. My car only takes 400ml though.

It is just DOT 3 isn't it? (Googling has proved inconclusive!) If so, go to a different supplier - should be less than half that.

DOT 4. I got it 15% cheaper than Fiat, it cost me =A33.66 + VAT, but then there would be delivery on top of that if I got it on its own. It's the same stuff Fiat uses, so it should be about =A35 (inc VAT) from the local Fiat dealer.

Where the hell do you buy your brake fluid from? Not even Halford's charge that much for DOT3 or DOT4. Find a local motor factor - it'll be a lot cheaper.