So the wife and I were having a lovely end of season run, up one side of the mountain, down the other, lots of fun 15 mph switchbacks, 150 miles or so, and a mile from the house the brake pedal sinks to the floor, and nothing happens but the right rear locks up. By divine intervention, I was travelling slowly, and there was no traffic, and the light turned green just as I arrived at the intersection.

It is, of course, the Teves. Put an accumulator on it a year or two ago, it pumps up in under 45 seconds, (it's the next size larger than what came originally) and currently takes 4 or 5 squishy pumps for it to turn back on. I bled the system per the book after awakening the car from a 10 year slumber back in 2020.

Symptoms: almost exactly at the halfway point in the trip the right rear brakes squealed coming to a stop. Has never done that before, and didn't do it at all on the way home.
ABS light is on, has been, don't know that it has ever worked
Felt something not quite right at the stop light about 2 miles before the one where the pedal went soft.
upon putting it into it's resting place, the brakes sort of worked, although with a very soft pedal.
now if you press the brake pedal, it sure feels like there is air in the front circuit, with the pedal seemingly finding something solid on the back circuit.
Any other car I would be blaming the master cylinder, because the brakes were working and then the pedal went squishy with no other issues.
But this is the first car I have had with this system, and all I've read says the master rarely decides to quit.

So what's is all yall's opinions on what could be happening here?
Was the squeal was the pistons in the caliper coming loose, and travelling far enough that it took more than one pedal travel to make up? But that wouldn't leave me with a squishy pedal now.
The accumulator ruptured? But it's still pumping up.
Give up on the ABS and put the previous generation master cylinder on it with the booster, and abandon the Teves?
I need something to hang my hat on, my wife already doesn't trust the car, and frankly, if all I do is bleed it and all is working again, I'm not sure I can either.

Thanks
71MKIV AKA Steve
71 Spitfire
91 Jag XJS classic convertible
"reliability is overrated"

 

My 93 lost its brakes when the front right caliper was dragging and the brake fluid boiled, as far as i figured out. However, i know with the teves 3, when you lose the front brakes, you lose the rear brakes, because the system "reads" front brake pressure and then actuates the rears. When mine went i had no brakes at all. Not sure why your rears would lock up if the fronts weren't working unless it was "reading" front pressure. Im not certain when the teves changed from 2 to 3 though. Also not an expert of the brake systems either lol

 

Since you dont care about ABS, scrap the Teeves system and install a pedal box and booster from an early vacuum booster car. Then use an aluminum Master cylinder. I use one from a Mitsubishi Eclipse with a remote reservoir. No more brake problems.

 

Hi 71MK1V

Agree with icsamerica 100%

Though if you're not quite ready to do that Conversion

(1) Check that the Front Brake Pads and Calipers are not Sticking as has been already said, this can cause the Brake Fluid to Boil and you lose all the Brakes and I know as it happened to me

(2) The ABS Light Should go out, as soon as the Brake Pump has built up enough pressure but if the ABS Light does stay on, then there is always a chance the Fuse has Blown and if that happens then you may still have Braking of 'Sorts' but no ABS You can find the Fuses in the Fuse Box just under the knee Panel (Passenger Side on a UK Car) They are one of the 2 Big Green Fuses and are clearly marked

(3) Assuming that they are OK or not as the case may be, the next thing to do is to Bleed the Low Pressure Side of the System or you will be wasting your time when trying to Bleed the Brakes

(4) Try my Gravity Bleeding Method of Bleeding the Brakes that I accidentally discovered having refurbed the IRS Cage on my 1990 V12 XJS it worked for me and also for LnrB and so I think it could be worth a try

How to Gravity Bleed the Brakes on an XJS

How to Bleed the Low Pressure Side of the TEVES M1V ABS Brakes

Good Luck!

Alex (OB)

 

71MKIV,

If the fluid level in the reservoir is at normal level, I wouldn't start by bleeding the circuits initially. you don't have Perhaps try and approach this in a logical manner rather than just trying techniques to resolve the symptoms. I would do the following:

1. As you have an ABS light on, you will probably have one or more stored fault codes in the ABS ECU. So perform the blink test to read the fault codes and report back. If you're not sure how to do the blink test, post back and I'll give you the details.

2. With the ignition off, press the brake pedal once and try and remember how it feels. Now press it 30-40 times to fully utilise the accumulated pressure. It should get increasingly hard. After you've done that, mentally compare how the pedal feels compared to that first press.

3. Without touching the pedal, now turn on the ignition and time how long the pump runs before it cuts out. Once it cuts out, press and hold the brake pedal and see how it feels compared to the 2 stages in 2. above.

As you seem to appreciate, you don't have a separate master cylinder on this system. You have an Actuation Unit, that is generally very robust. However the ABS valve block that is bolted on the side of the Actuation Unit is known to experience 2 types of problem - jammed valves from sediment & deterioration of the ribbon cable that fires the ABS solenoid valves.

With a methodical approach, I'm sure you'll be able to sort this.

Paul

 

So some additional information,
no codes in the ABS computer, last time I checked, might be worth doing it again. I have gone through the whole ABS troubleshooting procedure from the shop manual as well as replacing the computer. It seems like.... :man_shrugging: ..maybe the front sensors are covered with grease oozing from the overly enthusiastically repacked bearings, in which some metallic dust has collected, shorting the sensor to the point that they aren't sending any signals to the computer.
The front calipers were rebuilt with new stainless pistons and new seals during the recommissioning so I don't think they were dragging enough to boil the fluid? But this happened after a trip of over 150 miles, so even not dragging it was probably pretty warm.
If the brake fluid has boiled, wouldn't it condense once cooled and start working again?

Hmmm, bit of an epiphany, two years ago I put ordinary brake fluid in there, this is a standard British system where it's open, right? there's no little flexible seal under the cap, so the fact that I don't have the system filled with the LMA fluid.......
My Spitfire boiled it's fluid once, that was exciting.

I have not dropped the rear subframe out, yet, so the rear calipers have not been gone over, when that happens, my ocd will demand the stainless pistons and new seals, and they will work much more better with new paint.
All the flex lines in the car have been inspected, and do not show cracking or wear or any aneurisms.

The pump for the accumulator seems to operate normally, pumps up in 45 ish seconds, turns back on after 4 or 5 pumps on the pedal.

S

 

Steve,

A few thoughts:

If you've got problems with the sensor signals, you'll have fault codes. Have you performed the blink test since the problem happened?

The 45 second charge time is only relevant IF you have fully discharged the system with 30-40 presses of the brake pedal. So again, I'd suggest Test 2. that I mentioned. How does the pedal feel BEFORE discharging, AFTER dischargng, and then AFTER recharge with ignition on?

Have you also done the 32 continuity tests since the incident?

Paul

 

You wrote: "Symptoms: almost exactly at the halfway point in the trip the right rear brakes squealed coming to a stop. Has never done that before, and didn't do it at all on the way home."
Renew the flexible(s) to the rear brakes, if a brake is binding, old ones can act like non-return valves and hold a brake on.

 

Hi 71MK1V

Not using the correct Brake Fluid probably hasn't helped the situation and if the Brake Fluid has not been changed on a fairly regular basis, then it may have absorbed some water, where in the event that this may have happened, the Brake Fluid/Water combo can easily start to boil if it gets any heat, that could have resulted from the Squealing Brakes

If you are doing any work on the IRS, like Greg said it always pays to renew the Rear Flexy as its easier to do with the IRS out of the Car, as if not then replacing that hose can be a bit of a nightmare job to do, through lack of space

 

Thanks everyone.
Regards to the bleeding, I did not use a vacuum bleeder, and I didn’t pay too much attention to the amount of fluid that was pushed through.
So let me get back out to the barn, it’s harder now that it is cold and dark, and do some things, and I will report back.

S

 

Steve,

And remember that because it is not pedal pressure that pushes fluid to the rear brakes on an early Teves car, you must perform the bleeding routine as per the Teves routine, not in a typical manner. If you haven't got that routine, let me know and I'll post it.

Cheers

Paul

 

Hi Steve

When you were applying the Brakes, especially if you were stabbing them on, did you ever notice your Car violently pulling to the right?
If so this is a Classic Sign of a 'Broken Ribbon Wire' in the Valve Block on the Side of the 'Master Cylinder Actuator'

Where if not then this might Help someone else

A 'Shop' could Charge a Fortune just to try and find the cause of this problem, in the somewhat unlikely event that they may have come across this before, where if they have then 'Megabucks' to Fix it!

The reality is that this is a very 'Simple Fix' that will just cost a 'Few Dollars' and will even make it better than when it was New!

So if anyone gets this Problem, don't despair!

Get back and I'll show you what to do, though if you want to Test the Valve Block to see if the Valves are 'Clicking' this is something you can do, while the 'Master Cylinder Actuator' is still in the Car (See Video)

'Warning!' don't attempt to try and take the Cover off the Valve Block, or what's inside could literally fall to pieces in your hand, including 'O' Rings and the Valves, that could fall out of the 'Valve Block' under their own Weight! and then you could be in more trouble than you know what to do with

Testing the Valve Block of 'The Master Cylinder Actuator' either in or out of the Car (VIDEO)

If you've ever wondered what is under the Cover of the 'Valve Block' of 'The Master Cylinder Actuator' this is your chance to find out! and also why you should Never take the Cover off the Valve Block, as there is a an extremely good chance, that either some or all of those Valves will come tumbling out under their own weight and also break either some or all of those delicate ribbon connectors as they go

Shedloads of Photos all about this that could Help you, where if your XJS should ever start violently Snatching to the right, not just pulling but literally trying to ****** the Steering Wheel out of your Hand, then in the Scheme of things this is a very easy and and inexpensive fix, providing you go about it the right way

 

My car did the pull thing if I stomped the brakes early on after resurrecting it. It hasn't done it recently. Matter of fact I was all kinds of proud of myself because I trhought the car was down to just needing some minors things like a tie rod end and an interior, with pulling the rear subframe as a winter project.

I did the book bleed on the brakes, with the accumulator pushing the fluid out of the back.

Maybe it's time to take the whole thing apart, including the pump and rear calipers. and put new fluid in it.

Or I have a lead on a complete system out of an 88.

Still doesn't explain why it did what it did, and how do I get the wife to trust it again?

Thanks Paul and OB

 

The wifes trust will be the hardest thing to get back imho. My wife still worries about things on my cars that happened years ago. Also still tells anyone that says anything about buying a Buick, that she would NEVER buy another Buick again because we had a 98 century that had some headache issues after we bought it. It doesn't matter that after getting them sorted i drove it for another fairly trouble free 12 or so years after. Lol

 

So an update on the brakes on my car.

I found the leak. Brake fluid was dripping out of the seam at the valve block cover. The only way to see it was to be at the right place at the right time, as the drip went precisely down through the hold In the fender where the fuel return goes through. So what probably happened is that it leaked until the reservoir for the pump was empty and then kapow, nothing.

So anyway, the inside of the valve block is not as bad as I thought it would be, the ribbon cable is even in decent shape. Two of the solenoids are leaking, apparently for a long time as some fluid has crystallized in the bottom.
So has anyone found o-rings that will work in these valve bodies?

 

Good find!