Another bleeding question

[mid life crisis]

I've got the ABS light permanently on, I've had someone plug in to the car & it's saying abs pump open circuit,
First of all I'm looking for recommendations from anyone who's had one repaired.
Another thing that came up during a conversation with Niall is that he recalls seeing somewhere that when bleeding the system after refitting the abs unit you need to have the computer plugged in to the car to operate the abs unit valves, does anyone know if this is true or is it a straightforward job.
Many thanks
Regards
Gary

 

[colb]

If the ABS pump circuits have been disturbed it will require connecting to INPA and the ABS pump has to be activated to cycle the pump so that any air in it is expelled and new fluid is drawn into it from the reservoir. Ensure the brake fluid reservoir is topped up at all times. Start bleeding the calipers starting at the rear right followed by rear left then front right then front left. BMW state when bleeding depress the brake pedal 10 times expelling air from the line. As soon as no more bubbles are being expelled hold the pedal down and close the bleed valve. Move on to trhe next wheel and repeat until all are done and you have a firm brake pedal.

 

[t-tony]

If you have access to a pressure bleeder you do not have to activate the ABS pump, only if you are doing it manually by pumping the pedal.

Tony.

 

[colb]

Tony make a good point if you use a pressure bleeder thats going to force the fluid through the lines negating the need to cycle the ABS pump using INPA.

 

[Fender2004]

If you have access to a pressure bleeder you do not have to activate the ABS pump, only if you are doing it manually by pumping the pedal.

Tony.

From what you say the Z3 is fine to use a pressure bleeder on the brakes, as I was thinking of buying one?

 

[t-tony]

From what you say the Z3 is fine to use a pressure bleeder on the brakes, as I was thinking of buying one?

I have used a pressure bleeder on many different makes and models over the years including Z3s, Z4 and many otherBMW models. They only pressurise to 15 to 20 psi.

Tony.

 

[Fender2004]

Many thanks Tony

 

[Nodzed]

@mid life crisis
Gary read this, section on ABS pump bleeding. If air has been introduced I don't think you can just use a pressure bleeder.
@Pingu has commented on this on other forums maybe he can advise

 

[t-tony]

I can only go on personal experience but I have fitted, and have seen other new ABS pumps fitted and bled using a pressure bleeder with no issues. Just another reason not to let the system empty while doing brake work, then you won’t need to even consider this.

Tony.

 

[Duncodin]

But before doing anything drastic I'd disconnect, reconnect the big connector a few times on the side of the pump. Maybe spray some contact cleaner spray in there. Then go for a little drive and use the brakes.

Mine had a few abs errors including open circuit and doing the above fixed it.

 

[t-tony]

That’s a good shout.

Tony.

 

[Nodzed]

I can only go on personal experience but I have fitted, and have seen other new ABS pumps fitted and bled using a pressure bleeder with no issues. Just another reason not to let the system empty while doing brake work, then you won’t need to even consider this.

Tony.

The ABS pump will be removed and rebuilt Tony so I am guessing it will be empty of fluid and hence full of air on return.

 

[t-tony]

A good quality unit would likely have been pressure tested before being shipped out I would imagine so I’m not too sure. We fitted new and in some cases used units and always bled them with the pressure bleeder so as far as I’m aware there’s no problem bleeding them with a pressure bleeder. Other people may have differing opinions.

Tony.

 

[NZ00Z3]

If the problem is the pump solder connections on the PC board, then you do not have to touch the hydraulic pipes. There are 4 torx screws that hold the electronics black box to the hydraulic unit. Remove the 4 screws and pull the black box out.

No need to worry about bleeding air out of the hydraulic unit as it has not been opened/ pipes undone.