The ABS never working, should have been disclosed in the beginning. Trying to diagnose remotely is difficult at best. When all not disclosed, it's near impossible. Detail is important!
I don't know of a way, air can be introduced into master and out brake lines. Unless a leak or level low. A leak at master, reveals itself if one looks. If air gets in, fluid gets out same point.
It may be leak in accumulator bladder. If this the case, it would be dead by now. It's nitrogen would have depleted. Pumping brake pedal, IG key off. Resevoir level wouldn't raise or raise very little. As there be very little back pressure. The accumulator store energy, about 2K PSI fluid pressure. Which push out the red hard line into master then to caliper via lines, when pedal depressed. If the accumulator dead or a leak, at it's O-ring. The booster motor would run excessively or should. As system would not senses full pressure. It also should run longer than 40 seconds, on run timing test. But ABS never working. Someone may have monkeyed with wiring and or computer.
It is sounding like you need a new booster ASSY with master (The whole brake master).
It sound like you more than one issue??
Have you ever found a leak. Yes! Where?
Does reservoir need fluid added to it from time to time. Amounts that ordinary pad wear doesn't account for?
What brake lines have been replaced and why?
Does any flexible line have a bubble?
Any clue is to why ABS not working?
What dash lights, alarms and or DTC do you have?
When IG key turned on, dash lights go through self check. Any not working?
What is condition of reservoir. i.e. is fluid slower to lower in one area/chamber, Is it stained? Has it been off?
Here's more for you to read, that may help you grade your master.
First and foremost: Brakes should only be worked by those, with high level of mechanical abilities and experienced with brake systems.
With the age of all 100 series today, in our aging fleet. Any issue, with brake master assembly. IMHO, best and safest course of action. Have the whole brake master assembly, replaced with new. If you have to ask question, on "how to", your not qualified to work on the master.
My hope is below link will give better understanding as to what we can do to reduce brake failure and what to watch for. The info is from my experiences and my thinking, as to what...
Hi 2001LC.
Yes my Big mistake not mentioning the non working ABS. I yet again apologise.
I’ve just got so used to using my vehicle without it. I have drove for a many years now without it, in which time I have replaced at least two brake callipers and did have the loud warning squeal from below my dash at a time but between my mechanic and I we always were able to get cruiser brakes bled and the warning squeal to turn off. In one instance a long long time ago i solved the warning squeal by simply adding a small amount of brake fluid to the reservoir.
And yes We do suspect someone did tamper with the wiring before I had the vehicle.
Over the time I have had the vehicle (8-9 years) there has been no “warning” lights coming on post turning on ignition. The only “quick fix” my mechanic did (years ago) was upon realising that someone had been tampering with the wiring re ABS, he had to disconnect the ABS warning light in the dash as he knew that light On would fail the MOT Government Road Test.
There are No visible signs of Fluid Leak at the Msster Cylinder. Non inside the vehicle at the top of brake pedal lever. Non between the master cylinder and the ABS module. Everywhere is bone dry.
The Accumulator seems to be very healthy.
It runs perfectly when it should.
It takes approx 38-39 seconds to recharge after IG off and brake pedal push 40 times.
The brake fluid level does rise as should when doing the 40 Pedal push.
Accumulator did periodically turn on and off yesterday when I was doing the rear wheel flush. From memory the “On” period was only 6 seconds.
when this current saga started, just after I replaced rear rotor and brake calliper, my mechanic found a small “right angle union” which was welded onto the chassis just behind front right hand wheel. (I have a right hand drive vehicle) this union had only two ports with two hard line brake pipes. One coming in from the brake calliper and the other going out and up to the master cylinder.
I think it was a manufacturing fixture allowing the lower chassis to be finished with brakes plumbed and when top body was lowered onto chassis they just plumbed the master cylinder hard line pipe into the little right angle union.
Now my mechanic thought he saw a very very slight dampness where one of the pipes went into the small union. This was after we had already encountered the soft, 2 pedal push, brake pedal.
To eliminate this union as a possible source of air ingress, my mechanic made a new brake pipe going from front calliper and up to master cylinder, thereby bypassing that small union block.
This was the only recent new pipe added since this problem began.
And in answer to your question, No we have never found any actual physical leak of any sort, not in brake lines, brake flexi-hoses callipers or the Master Cylinder, not around accumulator or between Master Cylinder and ABS unit. All is very dry.
Interestingly using the “bridge pin” method in the engine bay OBD11 port we have never had an ABS error code come up. Not even with my mechanics “Hand Held” diagnostic computer.
As for the Fluid Reservoir, I have never had it off. It is a bit tarnished inside making seeing brake fluid level a little difficult but not too bad.
No leaks coming from any of the 3 reservoir grommets , all is bone dry in there.
A point of Note,
Yesterday when going through the 40 brake pedal push Accumulstor evacuate process with IG turned off, interestingly after maybe 10-15 pedal pushes, all of a sudden I was getting a much fuller pedal. Of the pedal became hard to the point I couldn’t push it down to the floor.
I thought that was a good sign indicating that perhaps the master cylinder seals were still capable of creating a hard pedal. However by the time I had replenished the brake reservoir with approx 175ml of brake fluid and went to put “my helper” in place and turned on IG to go for next flush cycle the pedal would have gone soft again with pedal pushing to floor.
So all in all I’m getting a bunch of contradicting indicators making one quite frustrated.
It was the case that All went well yesterday with the Flush and Bleed process upon the rear wheels, and indeed as I found later, although out of synch with proper sequence, even the front right calliper “under the master cylinder” was bleeding properly,
It was during only the Front Left Bleed that I ran into trouble with the spurts of air and the frothy brake fluid evacuating from the bleed nipple.
Sean.
