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Many Thanks for taking the trouble of putting all that together and while I was searching around for a Fix that no one has really come up with, the Ignition ON Engine OFF Scenario was mentioned a Few times and so I think that you could be on the right Track with that one!
Believe it or not I'm Actually Pleased that the ABS has gone wrong as I'm treating that as a Positive!
Because even if I had tried to Rebuild the Calipers, while they were still on the Car, instead of going out and getting New Ones (that incidentally was a much better idea)
I would almost certainly have gone and let the Reservoir Run dry!
Especially as it is so Small, when compared to the Reservoir on the Teves Mk111 which would certainly not be helping matters
So Please Take Note Guys and Gals: If you have ABS on your Car/Truck Never ever-ever! let the Reservoir Run dry or you might be facing the Same problem as I am! and that also applies if you haven't got ABS
Anyway Paul, getting back to the plot: Trying to Fix this ABS Problem will be interesting, as in one way it looks simple but in other ways it seems quite complicated
Where the Go-to Fix I've been reading about, is to take your Car to a Shop (not quite sure how you'd do that without any Brakes!) but maybe a Trailer! and then let them Plug in an OBD Scanner, although apparently not any old OBD Scanner will do
As it has to have the capability of re-setting the ABS, which probably includes something like exciting the Electric Motor and Testing the Valves, that also from what I've been reading from the experience of others, can be quite an expensive procedure
And then if you get the Bad News and Need to get yourself a New ABS Module, then it would almost certainly go from being quite expensive to very, very, expensive!
So using my Car as a Test Bed, if we can manage to fix her for free, just think how many people we can help to get their broken Cars back on the Road, not just XJS's but also lots of other Cars that have ABS
The ever so slightly bad news is that my local Car Accessory Shop (nothing like the ones in the USA) who think that having a pair of Fluffy Dice hanging from the Mirror is a Major Modification are unbelievably right out of DOT4
For that I suppose I am partly to blame, as they only had a couple of 5 Litre Bottles, as they don't sell many that Size and I bought both of those!
So I've got some coming from Amazon, that should hopefully be arriving anytime soon!
Although what I was wondering before we get into that Epic Fix that you so kindly suggested
What would you think about me trying the Bleed Nipple idea that I used on the Master Cylinder, on the ABS Module?
In other words remove the Pipes that go from the ABS Module to the Calipers and then Screw in a Couple of Brake Bleed Nipples and then try and Bleed the Air out just the same as I did with the Master Cylinder
As if I can get the Air Out of the ABS that way, then Theoretically it would be easy to just Bleed the Calipers in the Normal way
I'm thinking that it could be worth a Shot, as the threads on the Bleed Nipples also look the same as the Brake Pipes and then by that time hopefully the Brake Fluid may have turned up
OB look on Amazon for a Phoenix Reverse bleeder kit. It says V5 brake bleeder at the top of it, and is $58.64.
This is the Reverse bleeder kit I bought, and have had good luck with. It simply pushes the fluid and air up through the lines and everything including the ABS modules back into the master cylinder, expelling all the air out of the system. It just might get the air out, as air bubbles try to rise to the top, (Master Cylinder) and if you push them back up the lines??? It should work. No guarantees but hey nothing else has worked? Good Luck.
Whisper It Quietly I'm Thinking But This Might Actually Work!
So as soon as the Brake Fluid had arrived, the experiment could begin, where I was already feeling excited that this might actually Work although as usual there was really only one way to find out!
Where my Plan was to disconnect the Brake Pipes from the Output side of the ABS and then replace them one at a time with a Bleed Screw, exactly the same as I had done with the Master Cylinder, in order to purge it from Air
'Bog Standard' Brake Caliper Bleed Screws from my local Car Accessory Shop, as I used on the Master Cylinder were the Perfect Fit!
The idea being to use the Bleed Screws, to Bleed each one of the outputs from the ABS and then once all the Air was out, replace that Bleed Screw with the Pipe that I had just removed and then go on to Bleed the Air out of the Caliper in the Normal way
In other words to Bleed the Brakes in a Two Stage Process, where the Air would be Bled from the ABS before Bleeding Air from the Caliper, which then produced an Amazing result that I was not expecting!
As having previously Bled the Calipers in the Normal way, with not so much as a 'Bubble' in sight, this had me believing that all the Air was out
Except I was now about to find out that this was not the Case, as loads of Air was still Trapped inside the Valve Block of the ABS, that Normal Bleeding had so far failed to get out!
Having first removed the Brake Pipe, this was then (temporarily) replaced with a Bleed Screw, of exactly the same size as the ones used in the Calipers
'Bog Standard' Bleed Screws the Same as used for the Calipers with a Bleed Tube attached
From the Bleed Screw to the Bleed Tube and then Collected in an empty Pot!
But just Look at that Massive Air Bubble! in between the Clothes Pegs where I have to tell you I was not expecting that!
which had me thinking maybe I was onto something here!
Loads of Air left in the ABS that Normal Bleeding had not taken out!
Then having reconnected the Brake Pipe to the ABS it was time to Bleed the Caliper in the Normal way doing each of them in order until I'd worked my way around the Car
As for what happened next you'll have to just wait to find out, as just before I did the last one, the GF called me in for our evening meal, where I was so Shattered, that after that I just fell asleep!
So you are not the only ones who still don't know if my experiment worked
More Fun and Games for Tomorrow and then we will see (to be continued...........)
Just a slight word of caution: Did that large air bubble really come from the output port? I just ask because it seems to be at the high point of the tube so could be air trapped from originally being in the plastic pipe, which can then stay there as slowly bled fluid passes underneath the air?
Maybe hold the end of the pipe up, let the air rise up to the end, carefully fill the pipe with fluid, then insert into a container with fluid in it, then resume bleeding. Then any further air in the pipe is definitely coming from the output port.
Alex
I have no idea of the internal passageways in that block; but I notice from the photo that the rear brake outlet is at the top. Maybe bleed this one first using your brilliantly thought-through method first?
Not to be pessimistic, but it occurs to me that bleeding the block via the nipples is not really different from bleeding via the calipers, and if this does not clear the air, why should shortening the bleed path do it?
In his post 3031 in the poster's photo of the Jaguar manual, it states that the hydraulic unit is supplied pre-filled from new. This indicates to me that it cannot be bled on-car. Now if the bit you are dealing with IS the hydraulic unit (as you know I am blissfully ignorant of ABS) then you may have to unbolt it, fill it up from all sorts of angles, place small rubber stoppers in the outlets and inlets (such as cover the bleed hoes in new calipers etc). Then re-attach it and after it is in place with great speed and dexterity quickly attach each brakeline and then follow the manual's bleed procedure.
Last edited by Greg in France; 08-08-2023 at 03:11 AM.
I had to re-arrange the Tube for the sake of taking the Photo, to give a better idea of how it all worked and Yes it definitely came from the Output side of the ABS as all the others will do
But what was interesting at least to me anyway, was the amount of Bleeding it took before that Bubble appeared as well as finally managing to Bleed it out of the System altogether
And the open end of the Bleed Tube was always immersed in Brake Fluid, to prevent any Air from being sucked back in
Although that Air Bubble could well have been Trapped in the input pipe leading into the ABS (if that's what you meant)
In any event I hope this Fixes the problem and if it doesn't, well at least I tried
But as an 'aside' I did come up with a nice little 'Hack' to prevent the Brake Fluid Collecting Tub from being knocked over (only works with Plastic!)
Plastic Brake Fluid Collecting Tub, with a Big Metal Washer dropped inside and then sat on Top of a Magnetic Dish, that helps to prevent the Plastic Tub from being knocked over!
Yes, I did the rear ones first and also in the Order that you are meant to do them but decided to use this Photo, as it had the biggest Bubble that more clearly showed what I was doing (or should that be trying to do!)
As for using this Two Stage process, rather than just Bleeding all the Air out from the Calipers
One of the main advantages was, that I could Pump the Brake Pedal while also being able to see any Air Bubbles in the Bleeding Tube, which you cannot do if its under the Car
As for using Bleed Screws, I figured (perhaps incorrectly?) that once Bubble Free Brake Fluid had passed through the ABS there was a much better chance of Air staying out of the System, until you had then gone on to bleed the Calipers
I also read the ABS comes pre-filled with Brake Fluid but I also wanted to see if it were at all possible to do it this way first
Though if I was planning on keeping this Car, just look what a 'Walk in the Park' it would be to remove the ABS and then convert it into Conventional Braking, as like yourself I'm really not a big Fan of ABS
Oh! Your little comment, has really 'Cheered me up!' so Thanks for that
Which is just what I need right now, as the ABS still isn't working! as I too have no idea about the Brake Fluid Pathways that are inside it, so more research is needed, as I'm not giving up on this until I've managed to fix it, being that its possible to do so
You will crack it Alex! You have done FAR more difficult things, e g redoing your old style TEVES actuator wiring. If you could find out exactly what and where the passages inside that block were, I bet you could drill a bleed hole or two somewhere in it that would take a nipple, or even a tiny bolt and copper washer, and solve all these problems!
You will get there. Of course, as I am sure you have realised, you have GOT to use them or they will make you pay for neglecting them!
Courage (pronounced "cour arrhje") as they say in these parts to mates ("copains") facing hard tasks!
I'm really missing the Teves Mk111 at the moment! (Lol)
As fixing that wasn't as difficult as this one is turning out to be, although if I cannot do it for whatever reason, then I think I will Convert it to Non ABS, so I will have a look at 'Car Builder Solutions' to see if they have the Fittings that I'll need
Apols, I've written a LOT of detail below!! Feel free to ignore everything, it's just my suggestion of what I would do on my car! I don't have personal experience of the Teves IV system, but I've read up as much as I can find, so I'm throwing in my 2-pence worth, in case it's of any help.
I've just been catching up on the latest posts.
I know you were keen to start trying to bleed at the abs wheel circuit output ports, but I do think it's time to take a slightly different approach.to get this resolved.
You know my views on trying to work out what is wrong / failing, before changing any parts on a car. And I think it's now necessary to take a very methodical approach to working out why your pedal sinks. We know (I THINK!) that the issue is either a leak, air somewhere in the system, or seals in the compressing part of the system ie the m/c.
To use an analogy, we have a sick patient, so first of all we need to stop the bleeding!
In all seriousness, there are some things we know and some questions we need to answer. I've read back through your posts and realised there may be some clues which MIGHT be important:
1. You've said the pedal sinks when the engine is running. But I don't think you've said if you were already pressing the pedal at the point you started the engine and the pedal sank? So, I think we should agree one principle. Every test you do with engine off and then engine on, you need to start off with your foot NOT touching the brake.
2. On the one occasion that you said the pedal didn't sink down with the engine running, you had one port blanked off from the m/c. And that port was the FRONT brakes. So, in theory, only in theory, mind you, the problem is not in the rear brakes part of the abs module. Because I don't THINK there is any connection between the front and rear chambers in the abs module. And that was why I was slightly questioning about the air bubble when you were bleeding the rear brake output port of the abs. Because the pedal was firm when you were pushing from the m/c to the rear brakes only, with the front brake port plugged. Therefore the implication is that the problem lies in the front brakes, (in either the abs module or the front wheel circuits.)
So, my polite suggestion would be that you connect everything back up and do the following in exactly this order:
Stage 1.
1. Ignition OFF, Don't touch brake pedal, take reservoir cap off, check fluid at correct level (not above max), replace reservoir cap
2. Press brake pedal. Is it very firm? If not, STOP, We will need to re-bleed m/c (but not just yet)
3. If pedal is firm, release pedal and pause a minimum of 10 seconds
4. Don't touch the pedal! Turn on ignition to Pos 2. Wait a few seconds. Press pedal. Is it still exactly the same firmness? If not STOP, there is possibly an issue with the abs electronic valve operation.
5. If pedal is still firm, release pedal and pause a minimum of 10 seconds
6. Don't touch the pedal! Start the engine and let it idle for a few seconds
7. Press the pedal. Is it firm or does it now sink to ground? If it sinks to the ground, we have a problem and now we need to work out where it is. Turn off engine and ignition. (But in the event that it is firm, you've cracked it, so STOP here! Although I would still then go and re-bleed the wheel circuits AGAIN, as you have possibly introduced a bit of air through the abs bleeding.
But it if it did sink, we then work out initially if it is a wheel circuit by isolating them one at a time.
Stage 2
1. Check reservoir. Is it at exactly the same level as previous? If not, we may have a leak. If there is no fluid visibly leaking anywhere, it could be from the back of the m/c into the servo, but we'll consider that later.
2. Disconnect output line from abs module to rear brakes (cap the brake pipe to prevent ingress of dirt and loss of fluid), screw in bleed nipple to that port on abs module.
3. Get in car, press brake pedal. Should be firm. Release pedal, wait 10 seconds.
4. Don't touch pedal. Turn ignition to Pos 2. Press brake pedal. Should be firm. Release pedal, wait 10 seconds.
5. Don't touch pedal. Start engine and let it idle for a few seconds.
6. Press the pedal. Does it sink or is it firm? (will probably sink) But IF it is now firm, the problem is in one of the rear wheel circuits. Unlikely, but possible. Turn off engine and ignition.
7. Remove bleed screw, reconnect brake pipe to abs module. Yes , we could have introduced a tiny amount of air into that circuit, but we'll live with that for now.
If pedal was firm at step 6. above, STOP here. But if pedal had sunk at step 6. above, we'll now assess the front wheel circuits
Stage 3
1. Check brake reservoir level. Is it at exactly same level as previous? Let's assume so.
2. Disconnect output line from abs module to one of the front brake circuits (cap the brake pipe to prevent ingress of dirt and loss of fluid), screw in bleed nipple to that port on abs module.
3. Get in car, press brake pedal. Should be firm. Release pedal, wait 10 seconds.
4. Don't touch pedal. Turn ignition to Pos 2. Press brake pedal. Should be firm. Release pedal, wait 10 seconds.
5. Don't touch pedal. Start engine and let it idle for a few seconds.
6. Press the pedal. Does it sink or is it firm? If it is now firm, the problem is in that front wheel circuit, probably in the caliper. Turn off engine and ignition.
7. Remove bleed screw, reconnect brake pipe to abs module. Yes , we could have introduced a tiny amount of air into that circuit, but we're going to bleeding that wheel at the caliper anyway.
If pedal was firm at step 6. above, STOP here. But if pedal had sunk at step 6. above, now we'll assess the other front wheel circuit.
Stage 4
1. Check brake reservoir level. Is it at exactly same level as previous? Let's assume so.
2. Disconnect output line from abs module to the other front brake circuit (cap the brake pipe to prevent ingress of dirt and loss of fluid), screw in bleed nipple to that port on abs module.
3. Get in car, press brake pedal. Should be firm. Release pedal, wait 10 seconds.
4. Don't touch pedal. Turn ignition to Pos 2. Press brake pedal. Should be firm. Release pedal, wait 10 seconds.
5. Don't touch pedal. Start engine and let it idle for a few seconds.
6. Press the pedal. Does it sink or is it firm? If it is now firm, the problem is in that front wheel circuit, probably in the caliper. Turn off engine and ignition.
7. Remove bleed screw, reconnect brake pipe to abs module. Yes , we could have introduced a tiny amount of air into that circuit, but we're going to bleeding that wheel at the caliper anyway.
IF the pedal sank at 6. above, the problem almost definitely isn't in the wheel circuits. It's further back either in the internals of the abs module or in the m/c. So that's for another day!
How far down the list did you get before the instruction to Stop?
Thank you so much for taking the trouble of doing all that for me, as you know a lot more about this stuff than I do or probably ever will do
But one think I noticed Yesterday, after my abortive Test with the Engine and Ignition OFF was that when I pressed the Pedal, I could see the Brake Fluid moving inside the Polythene Reservoir, which sort of seems to indicate the presence of more Air
That also seems to coincide with what you have been saying, that somehow never occurred to me until I just read your epic set of instructions!
So first of all I will go right round and Bleed the Brakes all over again and check for leaks and then as soon as I have done that I will get back and let you know what happened and then if it still doesn't work we can go to Plan 'B'
I have been following this thread and am amazed at your (OB's) persistence and Pauls great reasoning and logic in trying to get this solved.
I am no expert at all but looked up the brakes section in my service manual (it's a 92 with the Teves 3 system? The one with the accumulator)
I know this is not what your car has but just as it may be relevant in some way Jaguar detail two different bleeding methods. One if you have been messing with the calipers and another additional procedure if you have replace the motor/pump or actuation(ABS) unit.
The second method requires you to bleed the fluid intake hose which I think is the line from the reservoir or MC to to the ABS/pump unit. See the snapshot below.
As I said, don't know if this of any help at all ....
Thank you so much for sending that, as there could be a Nugget of Gold in there but I will have to ask Paul (ptjs)
Because: On the ABS Module, there is an Electric Motor and in all the time I've been working on this (or should that be We've been working on this) as I would be Totally Lost, without the massive amount of help and support that I have had from Paul (ptjs)
I have never seen or heard that Electric Motor Run! (Something in what you just sent me, Suddenly Triggered that Thought!)
What I don't know and will have to ask Paul, is Should that Electric Motor be Running, (1) All the time (2) At Initial Start Up (3) Only when the ABS Kicks in
Maybe that Electric Motor has Never Kicked in or ever Run since the Car was New 28 Years Ago!
This could be the Missing Piece of the Jig Saw that we've been looking for, as up until Now I never gave that Electric Motor a Thought!
All this seems to coincide with why when Garages do this, they use a special kind of ODB device 'That May' (and this is pure guesswork) also Power up that Electric Motor, so maybe I should also put 12volts DC on this, as maybe it resets something somewhere
So don't think that you have been wasting your time, as that could be another little GEM just like those Blue Relays! that I would never have thought of in a Thousand Years!
I've said it before and I'll say it again, that was a real life saver which will never be forgotten
The (slightly) good news is that not hearing the pump run is not an indication of a problem! The 1995.25 Teves IV system is completely different to the earlier Teves system. You literally have to forget everything you learnt about the earlier system.. The earlier system had power-driven rear brakes, and power-assisted front brakes under ABS conditions. So the pump and accumulator were running and necessary for normal brake operation.
The Teves IV system runs as a conventional servo assisted system under normal conditions, albeit with a series of valves in defined static positions. The pump starts and runs and the low-pressure accumulators are used ONLY under ABS conditions. Part of the test sequences I wrote, using the ignition-on steps, was to try and verify if there were faulty abs conditions flagged to the ecu which was causing inappropriate valve operation. But that doesn't seem to be the cause, on the face of it. The only thing I never asked you, but I'm sure you would have mentioned it, was to check that the abs light was extinguishing 2 seconds after you turn on the ignition? As I said, I'm sure you would have mentioned if it didn't go out.
So where to go now? I would start by trying to verify the m/c seals, as we haven't eliminated whether they are failing under the extreme servo-assisted pressure. To do that, you need 2 things, a bleed valve for the output port of the m/c for the front brakes. And a bleed nipple or bolt or something to plug the other port of the m/c that drives the rear brakes.
Then you follow this sequence exactly.
Stage 1
1. Don't touch the pedal. Ignition off, check fluid level is correct in reservoir (presumably it was at exactly the same level throughout all of todays tests?)
2. Press brake pedal. Is it very firm? (I assume it is) Release brake pedal. Wait 10 seconds
3. Don't touch pedal, turn ignition to Pos 2.
4. Press brake pedal. Is it still very firm? (I assume it is). Release brake pedal. Wait 10 seconds.
5. Don't touch pedal. Start engine. Wait a few seconds for servo to charge.
6. Press brake pedal. Does it sink down? (I assume it will). Release pedal. Turn off engine & ignition. Go to Stage 2.
Stage 2.
1. Disconnect output port from m/c for front brakes. Cap the pipe to prevent fluid loss / dirt ingress.
2. Fit bleed nipple tightly.
3. Press brake pedal. Is it very firm? (I assume it is) Release brake pedal. Wait 10 seconds
4. Don't touch pedal, turn ignition to Pos 2.
5. Press brake pedal. Is it still very firm? (I assume it is). Release brake pedal. Wait 10 seconds.
6. Don't touch pedal. Start engine. Wait a few seconds for servo to charge.
7. Press brake pedal. Does it sink down? (I assume it WON'T). Release pedal. Turn off engine & ignition. Record the result.
8. Remove bleed nipple, replace pipe to output port. Go to Stage 3
Stage 3
1. Disconnect output port from m/c for rear brakes. Cap the pipe to prevent fluid loss / dirt ingress.
2. Fit bleed nipple / bolt etc tightly.
3. Press brake pedal. Is it very firm? (I assume it is) Release brake pedal. Wait 10 seconds
4. Don't touch pedal, turn ignition to Pos 2.
5. Press brake pedal. Is it still very firm? (I assume it is). Release brake pedal. Wait 10 seconds.
6. Don't touch pedal. Start engine. Wait a few seconds for servo to charge.
7. Press brake pedal. Does it sink down? (Not sure what it will do here!) Release pedal. Turn off engine & ignition. Record the result.
8. Leave bleed nipple / bolt in place. Go to Stage 4.
Stage 4
1. Disconnect output port from m/c for front brakes again. Cap the pipe to prevent fluid loss / dirt ingress.
2. Fit bleed nipple tightly. Now both ports are plugged.
3. Press brake pedal. Is it very firm? (I assume it is) Release brake pedal. Wait 10 seconds
4. Don't touch pedal, turn ignition to Pos 2.
5. Press brake pedal. Is it still very firm? (I assume it is). Release brake pedal. Wait 10 seconds.
6. Don't touch pedal. Start engine. Wait a few seconds for servo to charge.
7. Press brake pedal. Does it sink down? (I THINK it will be firm) Release pedal. Turn off engine & ignition. Record the result.
8. Remove both bleed nipples / bolts and replace both pipes.
Reminds me of a Seance I once went to but I think I see what you are getting at and that takes the Word 'Clever' to a whole new different level and it certainly won't just be you that is intrigued by what you have come up with
As those who have been following this Saga, will be on the edge of their seats to see the result, so I'm not gonna give the Secret away, as I'll leave that to you!
But when I replace the Pipes, would I be correct in assuming that you want me to bleed the Circuit as well as the Calipers, or should I just replace the Pipes and then just wave a dead chicken over the Bonnet?
You're right; every time you disconnect those pipes, even if the most careful approach of trying to keep the end upright, cap them to prevent fluid loss etc, there is the possibility of introducing small amounts of air. My suggestion would be that, only when you've finally verified the problem and everything is back together again, that you bleed at the output ports of the abs, and only then, bleed at the wheel circuits. So, I wouldn't worry about it for now.
With all the effort that you've expended, it's definitely you that should announce the final result to the world!
It's difficult when we're not in front of the vehicle and seeing what you're seeing, but I have a couple of theories as to the problem. One is annoying but relatively easy to fix. And that's a problem in the m/c that doesn't seem to manifest itself under foot pressure, but does come to light with the significant pressure of the servo in play. A new m/c at worst. The other theory is more complex, which is trapped air in the "abs feedback circuit" to the m/c. When the abs kicks in, two "normally closed" valves open and a circuit which uses the pump and low-pressure accumulators, pushes fluid BACK UP the lines to the m/c. If air is now trapped in the lower part of those circuits, it could get trapped, and because the valve ahead of it is now closed, it may be impossible to remove that air at home. I'll try and draw a diagram to explain. IF that is the case, I'm trying to think of how you could get that sorted without access to the equipment that can bleed the abs electronically. Let's hope it's not that.
08-07-2023, 05:38 AM
