Bleed'in Brakes!

t-tony

The Legend
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Dec 31, 2013
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226
Location
Torksey Lock,Lincoln, England
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E89 Z4 23i Auto
Not forced to be 4 pipes Mike. Some do some don't. Hope you get to the bottom of it mate.

Tony.
 

Stevo7682

Zorg Expert (I)
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The M44 Massive
Scottish Zeds
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Apr 1, 2016
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Location
Maybole , South Ayrshire
Model of Z
Z3 Individual Dakar / Orinoco Individual
Only 2 from pipes from master to abs primary and secondary circuit then 4 from abs one to each wheel.
 

mrscalex

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British Zeds
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@Mike68 Can’t remember if I mentioned but I have a complete DSC master cylinder assembly if required.

I seem to have successfully bled my brakes after replacing the 2 rear trailing arm pipes.

It’s the first time in 30 years I’d bled brakes. I’d done it loads of times on my old Mk 1 & 2 Escorts but in those days you just pumped the pedal.

I took a lot of advice from Tony and left the pedal well alone during the bleeding. I used a pressure bleeder and did a flush at the same time. I used around 2 litres but if I was doing it again it would only be 1 litre.

Tony suggested if I was only bleeding rather than flushing not to use the pressure bleeder, so gravity bleeding. I tried that before the flush and to be honest I couldn’t get the hang of it. So it will be the pressure bleeder every time for me.

There are various things that can go wrong. Although once you’ve learnt what they are it’s unlikeky to happen again.

One of the mistakes I made was turning the bleed nipple half a turn which was too much and let air back in. It only needed a quarter turn. The tell-tale is a very fine stream of bubbles after the rest of the air is out.

I also under-tightened the filling cap in the pressure bleeder and it failed to pressurise first time.

I over-tightened the seal on the master cylinder cap and it p*ssed out everywhere. I did that 3 times tighter and tighter until I realised I actually required looser!

Then I spotted the metal union on that same cap wasn’t tightened properly from the factory and leaked.

I didn’t tighten any of the brake pipe unions as much as I should. All but 1 leaked first time. My mistake there was not holding the flexi-hose with mole-grips while I did it. And taking the ‘don’t over-tighten’ advice too literally.

During the work I just had 1 corner of the circuit open at a time. And I held the brake pedal down with a breaker bar. That sounds counter-intuitive but Tony explained why and I barely saw a drip come out.

The fluid that came out of the system was disgusting. And I believe condition is now part of the MOT? New stuff is almost clear!

95D558F1-337F-4B39-9472-104FFEBD695D.jpeg


Appreciate you guys with the issues may have a more involved or different situation to me that caused your original issues. And that regular bleeding won’t help now.
 

Mike68

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Scottish Zeds
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Apr 29, 2015
Points
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That is cheap. I'll pick some up when I get home & may try bleeding the brakes the old fashioned way once with an assistant before I disconnect the pipes from the MC.
 

mrscalex

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That is cheap. I'll pick some up when I get home & may try bleeding the brakes the old fashioned way once with an assistant before I disconnect the pipes from the MC.
Tony left me with the impression that bleeding the old-fashioned way (so pumping the brake pedal) is a likely source of issues as it can blow a seal. But I guess if you have nothing else to lose it's worth a go!
 

Mike68

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Scottish Zeds
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Apr 29, 2015
Points
49
Ok guys, I think I'm going to have to throw in the towel & see if I can get a mobile mechanic to come out & have a look at my zed. Disconnected a brake line from the MC today & went to fit the first 10mm bleed screw, but the port is bigger than 10mm. Only succeeded in getting a lot of brake fluid on the car & more air into the system. It's our second car & we live in the middle of nowhere so i really need to get it back on the road asap. Just goes to show how a simple job can turn into a real PITA.
 

Mike68

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Scottish Zeds
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Apr 29, 2015
Points
49
Alright, having spat the dummy out & then drunk some beer, I've decided to have another crack at the brakes before I give up. I'll go into town on Monday to pick up a big can of DOT 4 & a couple more bleed screws. I'm guessing these are going to be M12 x 1. Anybody know if that's the right size for the DSC master cylinder?

Mike.
 

t-tony

The Legend
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Dec 31, 2013
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Location
Torksey Lock,Lincoln, England
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E89 Z4 23i Auto
Yes, they will be 12mm Mike ,but I don't think you'll get a 12mm bleed screw. I could be wrong. You can make something to do the job using a 12mm Union and a couple of inches of pipe if you have a pipe flaring kit?

Tony.
 

t-tony

The Legend
Deceased
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#ZedShed
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Dec 31, 2013
Points
226
Location
Torksey Lock,Lincoln, England
Model of Z
E89 Z4 23i Auto
If you cant locate a 12mm union let me know and I'll post you one mate.

Tony.
 

Mike68

Zorg Addict
Scottish Zeds
Joined
Apr 29, 2015
Points
49
Blocked off the two pipe outlets from the MC & got a firm pedal, so the MC is still good. Pedal soft with hoses clamped. Bleed another 1/2 liter through each corner - pedal still soft. I assume the air must be in the ABS/DSC assembly, I've already bleed this using the BMW software & I can only bleed through one of the six pipe connections in the block as its so dam inaccessible. I even mutilated some spanners to try get better access, but its no good. I don't think bleeding it either using the ABS pump or my Ezibleeder will shift the air as it hasn't yet.

Has anyone bleed one of these units (located underneath he MC in a very tight space) & if so how. Do you need to remove the box of electrics the sits beside it to gain access & how hard is it to do?

Is it worth sticking the wheel back on & driving it up and down the farm track adjacent to the house to try and shift the air or is this a waste of time as it will only travel back down from the MC back into the block on the ABS?

One fed up Zed owner:banghead:.
 

motco

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Dec 6, 2011
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74
Location
Chilterns
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Z3 2.2i Sport
Mike, I hope someone can advise you - I almost share your frustration because I've been in similar situations with other techy items. However, living where you do (wonderful in most situations) makes you feel isolated from help I'm sure. Best of Luck!
 

Mike68

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Scottish Zeds
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Apr 29, 2015
Points
49
Sadly not. I'm away for work and will be for a few weeks. When I get back I'm going to hire a car trailer and take it into the metropolis of Inverness to get it sorted out plus a new MOT. I'm pretty sure that if I removed the box of electrics beside the ABS module so I could bleed all the pipes there it would get sorted, but my long suffering wife has had a kitchen half fitted for months now while I nursed some broken ribs & then "played" with my car. Time to draw a line under it.

I appreciate all the support from the forum. Next one will be an easier fix :) (I hope).

Mike
 
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