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Hi, New to Forums, I have a problem with my brakes, let me explain. The front Passenger caliper was sticking, so I've removed it to rebuild it and in the process obviously disconnected the brake line. Probably foolishly, I allowed the stainless steel line just hang into a container for a couple of days, while I rebuilt the caliper, the line drained about a cup. maybe a bit more. I then reassembled the caliper and reconnected the line - I did some research online as to the bleeding sequence for a 94 XJS and became educated quite quickly as too how complicated a Teves 3 system can be! I read some very helpful instructions from this Forum which is why I've joined it. I believe I followed all the instructions correctly using the ignition and pump and accumulator to bleed the rear and then a more conventional approach for the fronts - I read conflicting info regarding whether the ignition should be on or not for the front. Anyway, after much bleeding I don't have brakes! The car is on a hoist (yes very lucky) and when I start the engine and put in Drive the brakes won't even stop the rotors from turning! The pedal becomes spongy indicating more air in the system, but I've become suspicious of the accumulator and whole the system in general! I'm concerned that I allow so much fluid to drain that I need to brake into the system someone else first and bleed a certain area first before working at the nipples. Look for help and confidence in some next steps before I throw the towel in and give up completely. Thxs. Will be back online later today.
I had a similar issue when I had to replace one of my rear caliper. Having followed the correct procedure (as found on this forum) I had little to no brakes (car stopped after about 20meters having got up to about 2mph). To resolve my issue I hade to re-bleed the front brakes (no ignition required just a strong foot) several times to truly get the air out of the system. This was after I had bleed the rear brakes and had done nothing with the front end! It is worth noting that even thought you've only been changing things on the front end and despite abs pump having separate lines for front and back brakes, they do still appear (at least in my case) to still be linked together.
I would strongly recommend bleeding all the brakes, always start with the caliper furthest away from the brake servo/reservoir.
With regards to your accumulator, even if it had failed you would still have brakes as the brake pump would be firing. An easy way to check this once you know for certain that there is no air in the system is to discharge the accumulator by pumping the break 30 - 40 times with the ignition off. Then turn the ignition on and watch to see how long it takes for your accumulator to build pressure and the brake light to go out. If its under 10 seconds then the accumulator may be at fault however if it more like 30 - 40 seconds then the accumulator is working as it should.
Which type of Teves ABS System do you have on your Car?
Is it the all in one Master Cylinder Actuator with the ABS Valve Block on the side, the same type as in this Photo
Does your Teves Master Cylinder Actuator look like this one?
Or is you Car fitted with the Later Type, which has the Brake Booster on the Drivers Side and the ABS Controller on the Passenger Side (on a UK) Car
On the Master Cylinder Actuator as in the Photo above, you need to Bleed the Low Pressure Side of the System, although on the
later type you don't
But in any event do not allow the Brake Pump to run for more than 30 seconds between On and Off Actuations of the Ignition Key, or you could burn out the Brake Pump which are NLA
It sounds like you may be air locked but you must be so careful on how you do the bleeding on this system otherwise you can cause very expensive problems.
The biggest mistake that you (or the mechanic but I was lucky) can make is to press the pistons on the front calipers back to change the pads: this is standard practice on 99% of all vehicles ever made.
True to Jaguar form they designed a fiendishly complicated system, on the back of an envelope, and 5/10/20/30 years later we are all paying the price.
If you back the pressure up the front brake lines you can bugger up the seals in the ABS accumulator block because they are only designed to work one way; the accumulator blocks are rarer than the pooping grandson of the original rocking horseso happens that I have one, still originally wrapped).
I spent quite a bit of readies trying to sort my system out (including several Code Brown moments when hedges/ditches were ever looming) and it just turned out to be a collapsed front brake hose; collapsed as in, no leaks, no obvious structural faults but it had lost its structural integrity so instead of it holding the fluid pressure it just went in to balloon mode.
We did the proper bleed ritual (robes, candles, ex virgins) but didn't spot the hose for quite a while. eventually replaced both front flexibles with race spec hoses, did the full monty bleed again and hey presto, sorted.
Took me a while to get used to braking in a straight line though.
I still have the accumulator block, still wrapped in NASA spec packing; saw one advertised once for £850.
The front hoses cost me a pint from a chum.
Hi, I'm not sure what system I have, I was hoping the MY would help others identify, I believe it's the Teves 3 system, anyway I have taken photo's of my system, both drivers side and passenger side and will post them tonight or tomorrow. I'm in the US so my XJS is Left hand drive, I think you're in the UK, so we'll have to transpose the photo's and I'll be sure to describe with drivers side and passenger side. Thxs for your help.
I didn't push the pistons back in while the caliper was on the vehicle, so I think I'm ok here. The caliper was pretty seized, the wheel wouldn't turn by hand on the hoist. I knocked the old pads out, disconnected the brake line and removed the caliper. I then blow the pistons out with an air line (wasn't that straight forward because it's always the last one that puts up the biggest fight!). So I'm pretty sure I've only let brake fluid come out, not be push back in. Phew.
The Master Cylinder Actuator, as shown in my photo, is the Teves Mk111
Although I think that your Car 'may' have the Teves Mk1V which looks a lot like the Old Type of 'Brake Vacuum Booster' and has a 'Stand Alone' ABS Controller on the opposite side of the Car
So before we can go any further, we need to know which one of those you've got
But if you have the Teves Mk111 as shown in my Photo, you do need to bleed the low pressure side of the System but don't do anything yet until we know, or you could very easily, let the Pump run dry and Burn it out
Steve is Bang on with his comment, if you force the Brake Pads back then it can very easily be 'The Kiss Of Death' to the ABS although in most cases it can be fixed for under $50 so no need to panic just yet, as I can show you how to fix it if you need to
Having now read your reply above, it looks like you just dodged a bullet, in which case I'm now thinking that you may still have a Stuck Piston in the Caliper, so did you renew the Pistons as well as the Seals?
Also do the New Brake Pads slide in and out of the Caliper nice and easy between your finger and thumb, as even if those Pads are Brand New
They sometimes need a few Thou shaved off the Top and Bottom of their metal backing Plate, so that they do
You can see how I did this on Page:9 of my 'Cherry Blossom' restoration Thread and here is a Link to that page
Yes I'm thinking it might be the Teves Mk1V based on the above description, but here are the photo's which hopefully allow you to confirm.
Drivers side (LHD) note; black rubber strip is in front of the wind shield to help with orientation.
Passenger side of vehicle (LHD) note; black rubber strip (on RHS of photo this time) is just in front of the wind shield to help with orienting the photo.
Other points to share and answers to above questions:
1) I'm concerned that I might have nudged the pistons back in their bores a little because of the 'lip' on the outside diameter of the rotor (from wear), I guess when I carefully knocked the pad out with a screw driver and hammer, the pistons might have shifted inwards a small amount - not sure if this amount would cause the trouble described?
2) I renewed two of the pistons with Stainless Steel ones and reused two from the original four - I considered them to be in good condition, all new seals and boots. I can share much to my alarm that none of the four pistons have been popped back out yet with brake system pressure! I have thought about breaking into the brake again and applying air pressure to the rigid line to pop the pistons out against the pads and rotor and have been hesitant to break into the brake line again after so much bleeding effort. The pads were new also. (This is just on the passenger side - I was planning to do the drivers side during the Winter months when I have a little more time to spend in the poll barn).
3) I feel that there was a significant drop in force required on the brake pedal when attempting to bleed the front brakes at the end of yesterdays ordeal, compared to earlier in the day - maybe it's just me. The comment about lots of leg work got me thinking that actually towards the end there seams like barely any pedal resistance at all.
4) Lastly just to share - I did end up applying pressure to the brake reservoir (this is the procedure I use for my Land Rover Disco and Defender) and I did see this referred to an earlier Jag thread on this forum. It didn't seam very effective on the passenger side earlier in the day (at about 7psi), but towards the end of the day (when the pedal resistance was lower using the conventional method) and on the drivers side it was generating good flow (I had cranked the pressure to 15psi). Probably overthinking the possible interactions here.
My plan for tonight (unless I get better advice) is to repeat the complete bleeding process as I understand it in an attempt to increase confidence that all the air is out the system. I will start at the rear passenger side, then rear drivers side using the ignition on and touching the brake pedal to keep the pump running for no more than 10 secs at a time and then resting for a couple of minutes to allow the pump the cool down. I'll then move to the front passenger side, followed by the front drivers side and use the 'pressurized brake reservoir' approach cranked to 15 psi (I'm working on my own).
I'll check this forum before I start (about 5pm EST), to see if I'm redirected. It's great to be talking with others about this challenge! I was getting pretty desperate yesterday. THXS Ian
Your ABS Breaking System is the Teves MK111, which is one of the earlier versions before the Teves MK1V was introduced, where the part with the Nylon Reservoir is the Master Cylinder Actuator with a Valve Block Combined
And the Part on the other side of the Car is the Brake Pump where the Black Ball on the Top is the Accumulator that retains the pressure in the System and that Gold Bolt 'Thingy' with the Blue Cap on Top is the Pressure Switch
Which cuts out the Pump, just as soon as set pressure is reached
Its quite a complicated system that can be hard to try and understand although you don't need to know all that stuff to begin with unless it goes wrong
Where it can often be repaired, providing the Pumps not burned out
Although as far as the Brakes are concerned, they really do need to be 'up to snuff' on an XJS or else they may decide to go wrong when you least expect it
And so it may be worth considering fitting a new set of Calipers 'Service Exchange'
The reason that I do this myself is that 3 years ago, one of the Pistons in one of the Calipers Stuck on my XJS, where I suddenly lost all the Brakes as the Brake Fluid started to boil and the Car nearly burst into flames
Which was so traumatic, that I thought never again and had to call up 'international rescue' where one of my mates turned up to rescue me in his Ferrari 'as you do'
Bleeding the Brakes on an XJS is always a bit of a nightmare at the best of times and so to try and eliminate any problems in the future that may decide to show up
A set of rebuilt Calipers may be the best way to go
Last edited by orangeblossom; 10-16-2018 at 02:53 AM.
ok - fair enough - I will pull ahead my planned winter project and replace all four Calipers now (it's not much more expensive than rebuilding with Stainless steel pistons anyway - I'll save this approach for the Land Rovers). Thxs for the confirmation that I have a Teves Mk3 system. Can you expand a little on what you mean by "needing to bleed the low pressure side of the system" and what that entails? I'll probably be at this point of needing to bleed this weekend after I ordered, received and fitted the new calipers. Also (and lastly) do you have a recommended for the best workshop manual for this vehicle? Could send a link or Picture. For my Land Rovers I have invested in the original Land Rover 2" thick workshop manuals that are like bibles for the vehicles. Many thxs, Ian
Bleeding the low pressure side of the system can be quite a complicated job and so I think it may be best to follow the instructions in the workshop manual, which unfortunately I don't have
Or maybe have a look in a Haynes to see if there is anything in there
Last edited by orangeblossom; 10-16-2018 at 02:46 AM.
Hello again Jaguar Friends, continuing with my 'Brakes' saga......updates are two new front brake calipers, system bled and solid pedal but the problem is still; pulls hard to the right under braking. Brakes feel strong, but pulls to the right, so something is wrong. My hypothesis is that when I inadvertently 'exercised' the ABS system (that might not have been actuated in its entire life!) when I had the vehicle on the hoist, started the engine, put it in drive, (obviously only the rear wheel drive - it's not a Land Rover!), then I applied the brakes and hence, must have actuated the ABS because of the differential in wheel speeds - front stationary and rears spinning! Yes what an idiot!! Anyway, my concern is that the pistons in the ABS manifold block are now 'out of position' and causing uneven braking. Another reason for thinking this is that the LH front side doesn't flow as freely. In order to try and prove out this theory I've attempted to measure resistance at the seven pins of the connector to the ABS manifold block - I would really appreciate thoughts and comments on the validity of this and what the results mean. I believe the front pin is the earth as it measures virtually zero resistance to the negative terminal of the battery (pin towards the front of the car - note mine is LH drive so probably opposite for RH drive). Then measuring the resistance of the subsequent pins relative to pin 1, I get the folllowing readings: 6 Ohms, 3.3 Ohms, 3.3 Ohms, 6 Ohms, 3.3 Ohms & 6 Ohms. Not sure how to interpret these results or even if this is a valid test, I'm trying to prove this manifold block is the problem before tackling it!! Thxs Ian
Last time I fiddled with my brakes, for some reason the wheel alignment was off, causing me to pull to the right when I hit the brakes. Once I got the wheels properly aligned all was good... Fwiw.
Hello again Jaguar Friends, continuing with my 'Brakes' saga......updates are two new front brake calipers, system bled and solid pedal but the problem is still; pulls hard to the right under braking. Brakes feel strong, but pulls to the right, so something is wrong. My hypothesis is that when I inadvertently 'exercised' the ABS system (that might not have been actuated in its entire life!) when I had the vehicle on the hoist, started the engine, put it in drive, (obviously only the rear wheel drive - it's not a Land Rover!), then I applied the brakes and hence, must have actuated the ABS because of the differential in wheel speeds - front stationary and rears spinning! Yes what an idiot!! Anyway, my concern is that the pistons in the ABS manifold block are now 'out of position' and causing uneven braking. Another reason for thinking this is that the LH front side doesn't flow as freely. In order to try and prove out this theory I've attempted to measure resistance at the seven pins of the connector to the ABS manifold block - I would really appreciate thoughts and comments on the validity of this and what the results mean. I believe the front pin is the earth as it measures virtually zero resistance to the negative terminal of the battery (pin towards the front of the car - note mine is LH drive so probably opposite for RH drive). Then measuring the resistance of the subsequent pins relative to pin 1, I get the folllowing readings: 6 Ohms, 3.3 Ohms, 3.3 Ohms, 6 Ohms, 3.3 Ohms & 6 Ohms. Not sure how to interpret these results or even if this is a valid test, I'm trying to prove this manifold block is the problem before tackling it!! Thxs Ian
Ian,
On the face of it, your readings seems fine. There is a difference between the inlet valves and the outlet valves. The inlet valves should read 5-7 ohms and the outlet valves should read 3-4 ohms.
Thank you both for your feedback. Paul, that's such valuable information regarding the resistance ranges! It will deter me from further investigating that ABS manifold block at this stage which I'm very happy about
Although I am aware that 'wheel alignment' and 'worn' suspension components can lead to a car pulling to one side under braking, I'm still suspicious of the ABS braking system because the ABS warning light gets activated during a drive after a couple of braking events. Does anyone have any comments regarding the sensitivity of the wheel speed sensors and sensor rings needing to be super clean and dry? They look difficult to get to and clean properly but I am curious abut this area and if there any checks that can be done.
In the mean time I will focus my attention to suspension & steering bushes and links, I have noticed that the outer tie rod ends 'rubber' is perished but I don't feel any play in the wheel when shaking with my hands in the 9 and 3 o'clock positions! I do feel some play with my hands in the 12 and 6 o'clock position, indicating a lower control arm ball joint issue and the rubber is also perished on these! But the play is small and for the life on me I can't 'see it' to confirm it's in the ball joint, I can only feel it when shaking the wheel. Also both sides feel equally and the braking issue (pulling to one side) only started AFTER my rebuild of the front right caliper with the car on the hoist and my stupid antics as described above of running the engine in drive on the hoist and applying the brakes - this must have actuated the ABS I'm thinking. Anyway, process of elimination, the tie rod ends and ball joints should be replaced anyway, so best get on and do them.
Thxs for any additional comments as I work through this issue. Ian
There is a definite difference between a problem caused by the ABS and that caused by Brake Pads and or Calipers
If the ABS was at fault, when you put the Brakes on very sharply, then you would feel it trying to ****** the Wheel out of your hand, as opposed to just pulling to one side or the other
Double check the Brake Pads to see that they can slide in and out of the Calipers, when just being held between your finger and thumb and also that they are not being jammed by any rust that may be on the Caliper Pins
Should you find that the Brake Pads are Sticking, you can always grind a few thou off the edges of the Brake Pads Metal Backing Plate, which is what I always do whenever I fit New Brake Pads
10-14-2018, 01:27 PM
Brakes - XJS '94 6.0L Coupe
so happens that I have one, still originally wrapped).
