I can't recall if I mentioned that for some years of the XJ40 there is a General Motors ACDelco accumulator that is the same. I believe it was used on the Buick Reatta. You might do a little research to see if that accumulator will fit your car, because it might be less expensive from GM parts suppliers than from Jaguar suppliers.

Search the XJ40 archives at the Jag-Lovers forum because I know the GM part number can be found there.

Cheers,

Don

 

About the convertsion kit, I've found conflicting info.
If I got it right, the conversion kit will plug the outgoing lines from the valve block and today I read in one post, the valve block should be looped when converting to regular shocks and springs...

Anyone know if one or both methods are OK?

 

Roland , a few things you should know

The mushy pedal appears to have been introduced AFTER you bled the brakes ,
I have to agree with Don B , air may have entered the brake master cylinder .

This will give you a mushy / spongy pedal and no matter how many times you bleed the brakes it will make no difference .

You can not remove trapped air in the master cylinder via the brake calipers
You must bleed the master cylinder separately , then bleed the rest of your brakes .

Once you have done this your brake pedal should feel normal again
Do you now how to bleed the brake master cylinder ?

BTW , a faulty or damage brake accumulator will give you a hard pedal most times
not a mushy pedal

Cheers ,

Sid

 

No, I don't know how to bleed the master cylinder, although that thought has crossed my mind a few times. I'm guessing one of the lines, connected to the master cylinder has to be bled, or is that way off?

If you please could tell me, it would be VERY MUCH appreciated!

But since it only takes two to three repetitions on the pedal, for the pump to start, the sphere also needs to be replaced...

 

Air is in the master cylinder chamber , not in the brake line

There is NO correlation between brake master cylinder pressure and accumulator pressure

Regardless of the condition of the Nitrogen Bottle ( what you are calling the " sphere " )
the master cylinder can still be bled .

You should have at least 25 brake applications with the engine off before you evacuate the sphere , clearly you don't have more than two or three . This is a very complex and confusing brake system .

I have not yet mentioned the possible damage you may have done to the ABS system when replacing your pads .

Roland , please understand that I have no problem in helping you where I can , how ever
I really feel that this is more than just bleeding the master cylinder .

Sid

 

What could have gone wrong when replacing the pads?
I'm aware the boost pump is taking a beating when the sphere is bad... but I wasn't aware, replacing pads can cause problems...

Do you know the procedure on how to bleed the master cylinder? Or could that cause even moore damage to the system?

Any info would be much appreciated!

 

When replacing disc pads front or rear you need to retract the caliper piston

In effect not only the piston but the brake fluid is also pushed back , any contamination or grit is flushed back through the ABS in order to reach the brake reservoir .

To avoid the risk of this happening there is a procedure .

You need to block off the oil line from the caliper brake hose and open the bleeder nipple
this will allow the old oil to leave externally as you retract the piston .

This is not necessary on later model ABS units as electronic solenoid valves shut the circuit off and allow the fluid to by pass the ABS unit altogether .

Bleeding the master cylinder will cause no damage .

 

Roland,

mastersid's suggestions reminded me that somewhere in the workshop manuals it is mentioned that before a new master cylinder is installed it must be "bench bled" to remove air. I believe there is a procedure in the manual. I found the videos below which may be helpful, and you can probably accomplish the same thing with the MC installed in the car:



Cheers,

Don

 

Any tip/suggestion on how to bleed the master cylinder, anyone?

 

Roland ,

You need an assistant ,
You need to lay enough rags under the master cylinder to soak up the brake fluid ,
Have at least 5 litres of water handy just in case ,
Dot 4 is the recommended brake fluid ,

Throughout the bleeding process do NOT pump the brake pedal

At the brake master cylinder you need to loosen both the outlet pipe nuts about 2 full turns

Then have your assistant push the brake pedal all the way down and keep it down

You then re tighten the outlet pipe nuts

Have your assistant then slowly and steadily release the brake pedal all the way back

Wait about 2 to 3 seconds to allow the master cylinder chamber time to refill with oil

Start again by undoing the outlet pipes and repeat the whole process about 4 to 5 times
that should be sufficient to remove the air , once you have done that you can then
continue to bleed all the brakes as per normal .

Take note that when your assistant releases the brake pedal , the oil level in the brake
reservoir should drop each time .

Hope this helps ,

Sid

 

THANKS guys!!!

I'll do the MC bleeding ASAP, but I'm a bit confused... When bleeding the brakes in the right order on a LHD car, beginning RR, then LR, RF and finally LF... shouldn't that automatically take care of any air trapped in the MC, beginning with the circuit the farthest inside the MC and then the circuit closest to the pedal?

But if my pedal is still mushy the first 1/3 down, doesn't that suggest that the braking procedure is preventing one of the MC chambers to be sufficiently bled and that it might be the circuit closest to the pedal that still has air in the chamber and doesn't that suggest the both chambers might be placed in the wrong order on a LHD car?

Or is my thinking totally off here?

Again, MANY THANKS for all your help!!!

To be continued...

 

Answer to 1st question ......... NO

Answer to 2nd question ........ NO

Answer to 3rd question ........ NO

Answer to 4th question ........ YES

Cheers ,

 

The other day, I received a mail from the german partsonline24.de offering me a new sphere from Lemfoerder and ordered it right away... Yesterday I received a mail from them, saying the sphere is no longer awailable from Lemfoerder...

I'm thinking, shouldn't they have checked that before offering it to me...

So in a hurry I orderad from e-bay a rebuild pump, new sensor and new sphere from USA at 180 USD. All from a crashed Jag.

When I get it and hopefully its ok and as stated, I'll bleed the MC as I replace the whole kit... Fingers crossed...

 

Thanks mastersid for straightening out my question marks!!!

During the seventies and eighties I have bled brakes numerous times without any problems, but must admit that I'm a bit lost on the bleeding procedure on my Jag...

At least I'm learning as I go along... MUCH thanks to you guys!!! I'm truly grateful for all the knowledge and help I get here!!!

 

Roland ,

No doubt you are more than capable at bleeding brakes , I think the air pocket
trapped in the master cylinder may have caused a problem that you were not expecting .

Good luck with your repairs

Sid

 

You're right, I didn't expect any problems bleeding the brakes. Now that I'm aware of the hazards, I'm hoping the things I ordered and the next bleeding, including the MC, will remedy ALL my problems... :-))

 

While waiting for the ABS pump and accumulator, I thought I'd ask if the replacement, in any way can improve the intermittent bounciness in the rear end?

I've read quite a lot, but still I'm not sure if, and if so, in what way these systems can affect/relate to each other...

Still not clear about what does what in this TEVES system... :-/

 

Hello Roland ,

I was hoping someone would answer your questions , but as no one has , I'll try to

Replacement of the pump and accumulator will have no effect on your bounciness problem in the rear end ( sorry to say ) .

The only relation between the brake accumulator and rear suspension is that the ride height is adjustable , it will raise or lower the rear end in relation to where the ride height sensors are set , there is no assistance to the shock's at all . ( you may need new shocks to fix the bounciness ) .

Because the hydraulic brake system is running at high pressures ( about 80 bar / 1200 psi ) some of that pressure is diverted from the brake accumulator to the rear strut housings , think of it as a hydraulic car jack only no pumping is required .

The TEVES system ( hydraulic ) is an alternate to vacuum ( pneumatic ) boosted brake assist .

I have simplified this for you , but it really is much more involved

Hope this helps some

 

Many, many thanks for your input! Much appreciated!

This makes me realize that I need to speed up the conversion...

... While on the subject of conversion... I've seen conflicting info. on how to go about shutting down the SLS...
In one thread they talked about plugging the valve block and in another thread they talked about looping the valve block...

Do you, or anyone else know, which it is, or even if it matters?

 

Roland,

Don't go looking for a new accumulator yet! There are a number of reasons to believe that there may be nothing wrong with your accumulator.

Forgive me if I'm wrong but I think that on your year of XJ40, the brakes and the suspension are nothing to do with each other. (Apols, have read back and realised that you have SLS)

I believe that you have the Teves ABS system. In which case, there are a number of things that you should be aware of. Again, my apols if you already know this.

There does seem to be some misinformation in the replies that you being given.

You do not have a conventional master cylinder and you cannot bleed it by disconnecting the fluid output pipes. The "master cylinder" is merely the last small chamber of a complex actuation unit that has master valve, control valve, actuating piston, boost piston and a small "master cylinder".

The brakes are not bled at all in the conventional manner. The Teves brake system is quite complex and very different to conventional brakes. For example the fluid to the rear brakes is not driven by the brake pedal. Moving the brake pedal merely opens a valve which then allows the pump and accumulator to dynamically drive fluid to the rear brakes.

The pump also provides fluid pressure to the boost piston in the actuation unit which gives a 4:1 ratio assistance to driving the static circuit of the front brakes.

If there is any chance that you ran the reservoir too low, then you HAVE to bleed the low pressure side of the brakes first before you bleed the wheel circuits. Otherwise you can have air in the side of the brakes prior to the pump which would preclude the accumulator from building up the correct pressure.

It's really important that you read through the Jaguar service manual and understand how the system works. However, there are a couple of situations where you should (IMO) deviate from the Jaguar procedures.

First of all, NEVER push back the caliper pistons unless you have connected a tube and undone the bleed nipple on the caliper. Otherwise, you will be pushing fluid back into the ABS valve block assembly. We have seen lots of occasions where this can cause debris to block the ABS valves which can have catastrophic effects. (Head over to the XJS section and do a search for threads on ABS. You will be scared by some of the stories!)

However, now that you have already changed the pads, you have to just hope for the best!

1. Because of the concern that you've run the reservoir too low, you must bleed the low pressure side of the system first by removing the reservoir pipe to the pump and bleeding out any air before reconnecting. Personally I would fit a new O-seal at this point, but I know of people who have just replaced their pipe OK.

2. You must then bleed the brake circuits correctly which is quite different to conventional bleeding. However, Teves recommend a slightly different procedure to the Jaguar manual. Use the Teves procedure as follows:

TURN ON IGNITION AND WAIT UNTIL BOTH ABS AND LOW PRESSURE LIGHTS HAVE EXTINGUISHED AND ALSO THE MOTOR PUMP HAS CUT OUT.

THEN, OPEN REAR LEFT BLEED NIPPLE AND HOLD BRAKE PEDAL DOWN, WITH IGNITION ON FOR 15 SECONDS – NO MORE

TIGHTEN BLEED NIPPLE, TURN OFF IGNITION, RELEASE BRAKE PEDAL.

WAIT ONE MINUTE AND REPEAT FROM RESTORING SYSTEM PRESSURE AS ABOVE FOR OTHER NIPPLE IF FITTED.

THEN WAIT ONE MINUTE AT LEAST BEFORE MOVING TO FRONT BRAKES – THIS PREVENTS THE MOTOR PUMP FROM OVERHEATING.

AT THE FRONT, ENSURE SYSTEM PRESSURE IS CREATED AND THEN BLEED CALIPERS CONVENTIONALLY WITH IGNITION ON, USING SLOW STROKES AND GO THE FULL TRAVEL BUT DO NOT FORCE.

ONCE THE LEFT SIDE HAS BEEN DONE, AGAIN WAIT ONE MINUTE AND THEN RESTORE SYSTEM PRESSURE.


I do hope all of the above is of some help

Good luck

Paul