Changing brake fluid

Z

Zmirzephyr

Zorg Addict
Joined
Jun 6, 2018
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Location
Sweden
Hi guys,

Long time no see!

I'd like to change the brake fluid on my -97. The first idea that comes to mind is:

- Start by emptying the brake fluid reservoar with a syringe (sucking most out)
- Starting rear right, push new fluid with syringe up until clear fluid is seen in the reservoar.
- Same thing rear left
- Same thing front right
- Same thing front left
- (And likely emptying the reservoar periodically)


Any other ideas? :)
 
Jesper N said:
Hi guys,

Long time no see!

I'd like to change the brake fluid on my -97. The first idea that comes to mind is:

- Start by emptying the brake fluid reservoar with a syringe (sucking most out)
- Starting rear right, push new fluid with syringe up until clear fluid is seen in the reservoar.
- Same thing rear left
- Same thing front right
- Same thing front left
- (And likely emptying the reservoar periodically)


Any other ideas? :)
Click to expand...

I prefer to push it out ie not in
 
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Jesper N said:
Ahh you mean using the syringe to suck fluid out and meanwhile fill the reservoar? :)
Click to expand...

I suppose. But I just bribe the missus to get in the driver's seat while I'm twisting the nipple saying 'in' 'out' 'in' etc.

Basically as she presses the pedal I open the bleed nipple then close it before she lifts the pedal - repeat till clean fluid with no bubbles comes out.
 
Always start at the longest run caliper rear left the rear right then front left last front right. Suck old fluid from reservoir but don't empty the internal portion that feeds the clutch slave cylinder unless you are going to bleed that as well. Commence bleeding with a topped up reservoir with fresh fluid. You will need a person to operate the brake pedal. As you bleed each corner keeping the fluid topped up as you go. You do have an option to use a pressure blender if you purchase one either the type that fits on the reservoir or the vacuum type that fits on the bleed nipples, may need a compressor to use that type. Take a look on YouTube for options.
 
I haven't tried my Z3 but trying to do my son's Z4M Coupé proved futile because (I assume) the valve block for the DSC and ABS hampers free flow through of fluid. I use a Gunsons Eezi-Bleed. Someone suggested that a specialised computer has to connect with the large socket in the engine bay and for it to open the valves.
Someone else said simply fill the reservoir as above and open each valve in turn and allow gravity to gently draw the fluid down over an extended period. I have tried neither. Is it model year dependent?
 
Using a helper to operate the brake pedal to bleed the system is the surest way of killing the master cylinder seals. They're not supposed to travel that far. By far better to use a pressure bleeder, they're not expensive.

Tony.
 
I did mine the old fashioned way, driver in the driver's seat pumping; just made sure I drained enough fluid that the old stuff in the reservoir would be flushed away too. I have never yet, after over 30 years of rebuilding classic cars, found a pressure bleeder that worked as well.
 
You must've used some crap presdure bleeders then.

Tony.
 
The whole idea of my way is to not let air in to the system, so I don't have to bleed it again.. ^^
 
That is the point of a pressure bleeder, it keeps the reservoir full and under the pressure that you apply with the hand pump.

Tony.
 
t-tony said:
That is the point of a pressure bleeder, it keeps the reservoir full and under the pressure that you apply with the hand pump.

Tony.
Click to expand...


Yeah but that's not something I'll be investing in, prob only time I'll do this.
 
They're not expensive and will repay you in time saved, and make you money if you do other cars.

Tony.
 
I use a cheap brake blead kit, one that pressurises from your tyre. It is suprisingly effective. Think it cost under £20
 
I used one of those (Gunsons Eezibleed?) once. You have to remember to blow the tyre back up.

Tony.
 
Tomorrow, I’m going to be doing a brake fluid change using a Gunson Eezibleed.

I’ve had my callipers off for a refurb and to replace some sections of brake line.

Before removing the callipers I depressed the brake pedal halfway and wedged it in place as advised to on here.

This is probably a daft question, but at what point is it safe to release the pedal?

I assume it’ll be fine to do it any time now the calipers are back on and the bleed nipples tightened so air can’t be sucked back into the system?
 
Jimbob_OD said:
Tomorrow, I’m going to be doing a brake fluid change using a Gunson Eezibleed.

I’ve had my callipers off for a refurb and to replace some sections of brake line.

Before removing the callipers I depressed the brake pedal halfway and wedged it in place as advised to on here.

This is probably a daft question, but at what point is it safe to release the pedal?

I assume it’ll be fine to do it any time now the calipers are back on and the bleed nipples tightened so air can’t be sucked back into the system?
Click to expand...

Yo. I'm not sure what you're talking about. I actually had one of those cheap compressor driven brake bleeders. Just sucked ALL brake fluid out of the right rear caliper (since I wanted to change out the old stuff) and then after fiddling with all my calipers (repainted all of them) I filled the reservoar up and used the bleeder again on all 4 calipers. Pedal got firm pretty much immediately. That was my method.
 
Does anyone know the capacity of the Z3 brake fluid system; i.e. how much is needed to refill once the old is flushed out?
 
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