Hi to all. I bought an XJS from Germany and I'm trying to restorinh it. Right now I'm focusing in the braking system. I've installed a rebuilt brake calipers, pump and abs unit because at the start the brake pedal was low and not even oil came out of the calipers. Now see that:
- it work only the front brake
- the abs blink test show 21 and 34 codes
- the abs lamp is on
- I hear the hi pressur pump run when I turn on the acc (15+)

Can you help me please?
Thank to all

Ps: sorry for my english

 

marbax,

The Teves system is not well understood and many owners end up changing parts that aren't actually causing the real problem, particularly the Pump and the Actuation Unit. But hey, you've changed them now. When you say "the abs unit", what do you actually mean? Was it the valve block, the Actuation Unit, or the electronic abs module?

Also, when you're timing how long the pump runs for, the only figure that means anything is the time it takes to recharge from fully discharged. So, turn off the ignition, then press the brake pedal 30-40 times to fully discharge it. The pedal should now be very hard. Now turn on the ignition and count how long the pump runs.

Also, when all the parts were replaced, was the system fully bled in 2 phases:

- the low pressure circuit first
- the wheel circuits, with the rear brakes being done as per the Teves procedure NOT by a conventional pedal press approach?

The 2 codes you have potentially relate to a Main Valve and a wheel sensor problem. But you need to start from a know fully-bled system with pump and accumulator working before you can really trust those codes.

Cheers

Paul

 

The car was out of order from many years and when I 've checked the brake system I've found that the master cylinder not work (the oil not came out from the cylinder) and the calipers was blocked, stopped. So I've dismount all things and sent to a rebuilder to renew the hydraulic parts. (all calipers, the master cylinder, the abs unit, the electric pump and the accumulator. They can not control the last one).

Now I see that when I push the brake pedal, the car slows but only front brakes works. If I open the purges, oil go out from back calipers but only with gravity force, not with pressure.

When I turn the key on, I hear the electric pump work but I'm afraid to damage it if it work too long time so I turn off the key after 30-40 sec. While the pump run, the sound is like free...without stress I don't know if I'm explaining myself very well... I'm sorry

Can you show me the Teves procedure or the manual where I can read it?

Thank you for all things

 

Hi Marbax

If only you had come to the Forum before you sent those items away to be rebuilt, then you could have saved a lot of money, as there are places that sometimes relay on an owners lack of knowledge on how this stuff works and then sometimes charge an absolute fortune to fix it

A case in point could well be the 'Master Cylinder Actuator' with the Plastic Reservoir on Top, where the first sign of trouble could be that the Car dives to the right or left, under sudden Braking, which is a very easy fix that only costs a few Euros, providing you know what to do

As for the Accumulator, this is a fairly Generic Item, that you can get from places like Island 4 X 4 Made by Wabco I think the Model Number is Wabco 2784 but maybe someone on here will give you a double check on that Price around £150 inc Vat but if you don't know what you are doing, get a Shop to take the old one off and put the new one on, as its at such high pressure 2 BAR that it can be dangerous!

As for Bleeding the Low Pressure Side of the System, this is something you MUST do before you Bleed the Brakes, or you will never get rid of the Air inside the System, this is a fairly easy job, in the Scheme of things, as all you have to do is Gravity Bleed it, with no high pressure involved although the Ignition needs to be OFF! when you do this

Just don't spill any Brake Fluid on the Paintwork or it will strip it in an instant, so cover everything up

Then Paul (ptjs) can advise you about the Bleeding Procedure as he is the 'GoTo' Forum Expert on this

But this is how you Bleed the Low Pressure Side (That Paul (ptjs) also showed me how to do)

How to Bleed the Low Pressure Side of the Teves ABS Brakes