ABS Purge Problems

[iDemonix]

Hi all,

Breaking away from my build thread to ask this one...

I'm following the guide pinned for ABS purging, but the guide says that the ABS solenoid noise should fade and then stop. I have bled all 4 corners, in the correct order, twice each (2 trips round the car), each time doing 5-10 hard pushes on the brake and then activating the ABS, but the noise never stops. I'm using the correct pins (5 for back, 3 for f/r, 1 for f/l) and fluid is passing through without bubbles or anything (I'm using a pressure bleeder the same as in the guide, 10-20 PSI), but just can't get the ABS to make any other noise than what it's doing in the below video.

As I've now pushed 2-3L of fluid through the system in to my catch bottle, and done the entire car twice, I thought I'd now ask to see if I've done anything wrong? Or has anyone else had the same? Or am I misunderstanding about the noise in the video fading/stopping?

Crap video below to give an example, on pin 1 (front left calliper)

[paultv]

Hi Mate,

So what's the result with the pedal? Is it still soft or is it good?

If you've passed that much clean fluid through whilst the pump and 1, 3 and 5 connections have been cycled through, you should be good.

One point to be clear, you should not connect the earth until you have the pressure bleeder on, your wheel bleed nipple open and your foot on the pedal, then touch the earth lead to chassis and push with your foot - the pump and solenoid should activate then reduce to nothing as the pressure is balanced.

Does the pump run as soon as you connect the earth line? - it shouldn't.

Just as an aside, your pump sounds super noisy - is it? or is it just the video clip?

Paul

[iDemonix]

Hi Paul,

I'm following this set of instructions:

Crack open the nipple on rear right and confirm fluid flow which shows the pressure bleeder is pushing fluid through the system, now push the brake pedal hard and touch cable one croc clip to the battery positive,- this will produce a rapdid clicking sound firing up the solenoid as well as the sound of the pump running - the solenoid clicks will fade and stop after a few seconds- disconnect the power, release the pedal then press hard again, re-apply the power until solenoid stops clicking. Repeat 5 times

Before I started the pedal felt like the throttle and just pushed straight to the floor, it now feels like a brake pedal - although I can't drive it about the car park and test it yet as I've still got some other bits to do before it can move.

I think I'm doing as you've said, except I'm touching the power to the positive lead on the battery instead of the earth at the other end of the circuit, just because that's what the guide says to do.

My process is :

1. Open bleed nipple
2. Push pedal hard
3. Touch cable to battery, noise starts and never stops until I take the cable away, so I take the cable away after 10s or so...
4. Release pedal
4. Repeat 2,3,4
5. Close bleed nipple

Is that right? Or am I being thick? i've bled plenty of motorbike brakes before, but not with a pressure bleeder, just opening + closing the nipple manually as I pump pressure up with the lever - I presumed as I'm using a pressure bleeder on the E30 I can leave the bleed nipple open? Or do I need to close it off at some point during the above process?

Also, as soon as I complete the circuit I get the noise, regardless of anything.

I suppose it is a bit noisy but I've never heard one before so I don't really have much of a reference. The phone + it's mic was at a bit of a crap angle so that could be it.

Here's a vid I did when I had a helper working the pedal...



Either I'm doing something stupid, or the ABS unit isn't working properly. I'm hoping it's the former...

[paultv]

Sorry, my bad - writing from memory - my original instruction is correct - attach earth lead to body and either pins 1,3 or 5 for whichever wheel you want to bleed - then power to pump and
sloenoids - both pin 30's.

I'm wondering if you can't hear the solenoids because of the pump - it sounds really loud - on my video the solenoid is loudish and the pump is real quiet.

Try sending power to the pump pin 30 only, this will run the pump alone - how loud is it - and did I hear it squeeling?

Paul

[iDemonix]

It is a bit loud, so you might be right about not being able to hear the solenoid. I've never heard the noise change at all, so I was assuming both were constantly firing.

Which relay is the solenoid one? Would it be worth me doing the standard process and then removing power to just the pump, to see if the solenoid is firing? Or will the solenoid only fire properly if the pump is operating?

To be honest now it's had about 2-3L of fluid through it, and every corner is passing fluid nicely, I'm tempted to call it done for testing...

Cheers again.

[paultv]

Pump relay is at the back next to the red wire that enters the motor, it has only 4 pins.

If you disconnect the pump power feed, and apply power one of either pins 1, 3 or 5 you should hear the solenoid switching.

Disconnect the solenoid power feed, and connect the pump power - you should hear the pump run, but it should be pretty quiet.

It sounds as though you've got all the air out - especially if the pedal feels good.

Once you have the car driveable - test the ABS by driving somewhere with some gravel at the side of the road. Drive with one wheel in the gravel and the other on tarmac. then brake sharply -
you shoulf feel/hear the ABS kick in on the gravel wheel - switch direction and test the other side. Do this on the very rare "dry day"

Paul

[paultv]

This is what my spare pump sounds like - phone was about a foot away - so pretty close.



Paul

[iDemonix]

Thanks Paul, that's really helpful!

That sounds pretty similar to how mine sounds, I think it's my 6 year old phone that's making it sound a bit crap in my video.

Good idea on the gravel test, wouldn't have thought of that and will have to try that at some point when it's drivable.

Hopefully get time to test this week, but if not will try again at the weekend. Just to check, when you say the solenoid power feed, or the pump power feed - is this just the pins labelled 30 that the relays clip in to? And I'm doing the cabling right by Battery -> Y cable to relay 30 pins, then either pins 1,3,5 to chassis depending on whether I'm purging rear, front left, or front right?

Thanks again mate.

[paultv]

Yes that's right - Y cable from B+ to each of the pin 30's of the relays.

One relay operates the pump ( nearest the end of the pump motor - red wire ) and the other is for the solenoid valve control.

You can test the correct operation of each solenoid valve by feeding B+ to the Solenoid relay pin 30 and then as you earth pin 1. 3. or 5 of the multiway connector, you should hear a distinct click
as the solenoid operates .

Paul

[iDemonix]

Nice one

I'll get that tested and come back with an update soon, can't wait to finally drive this car! It's been on axle stands for 3 years!

[paultv]

yea gods - you must really want to get out on the road - mines in the same place - up on stands with its entire rear end on the floor - major re-furb, but
I'm hoping to get it all back together in the next couple of weeks.

Paul

[iDemonix]

Right, I tried running the same test, but after a few attempts at doing it normally, I disconnected the solenoid relay and just ran the pump - it sounds the same - so I think my issue is that I have a loud pump which is drowning out hearing the solenoid.

Whilst not doing any test, i.e. with the nipple closed and not braking, I sent power to the solenoid and heard a single click, which is better than silence, and obv without the pump I'm presuming that's all I'll hear.

I've put the wheels back on and took it off the stands for now, I'm going to call it a day on the brakes as it's had tons of bleeding so the next best test will be to drive it. Bit of sill welding, viscous fan, few other bits, then I'll hopefully get the MOT sorted and can do it as a rolling project which will be much easier.

Cheers for the help!