I am still trying to decide how I am going to fix my brake issue. Currently I have no brakes. The pedal goes to the floor and does not engage even when pumped 40 times. The fluid is full and no apparent leaks.

The symptoms lead to a new master cylinder. Problem is that a new one for a 1994 xjs (vin 191###) cost about $800. The later model 1995 (from vin 198###) master cylinder only cost about 100.

Has anyone upgraded the system to the new system? What does this entail? Will it be a direct fit? What other parts are needed?

Thanks

 

Sounds like a a bad master. I would pull the old one out and see if it can be cross referenced to another. I never go to the dealer!

 

I agree. Justasnwer is telling me it is the accumulator ball, though I do not believe he is putting too much thought in to it. He just figures that is usually the issue...

I am intersted in getting rid of the accumulator ball and going with the old booster system Has anyone done this on a 1994 jag. Upgrade the brakes to a 1995.

 

I am back on this project of upgrading to a TEVES IV. Can anyone give me more information on what it entails? Do I need a new brake pedal? Can I use the same sensors and brake control unit?

I keep getting total brake failure and I do not believe it is the MC. I think it may be the actuator. Others are getting total brake failure with a TEVES III 94 as well. I really do not feel comfortable driving this in a city... Either will be going back to pre-ABS or upgrading to the 1995-96 which seems much more reliable and much cheaper to fix.

If someone else has gone through this, or knows about the TEVES IV parts in comparison to the III, please chime in.

 

aren't their rebuild kits for it?

 

I thought the actuator is the MC in the Teves 3 ??

 

Hi Hoodun

Hopefully this may help you but first I will give you a long shot.

Did you renew the Calipers?

If so did you accidentally fit them upside down?

This is exactly what happened to me, where thankfully someone spotted my mistake, from a photo that I enclosed with my Post.

As up until then there was no way that I was able to bleed them, no matter how many times I pumped the pedal.

If its not that then check out this link from someone who had the same problem and found a way to fix it.

Please let us know how you get on, as any feedback will be useful in helping someone else.

https://www.jaguarforums.com/forum/x...xjs-abs-81794/

Also have a look at this.

https://www.jaguarforums.com/forum/x...e-yikes-98875/

 

lol bro, how did you not notice that when you went to bleed them after installing them?

 

Is fluid getting all the way through? I had clogged lines in mine from the reservoir that caused me to think the calipers were bad.

 

if the lines where clogged it would still build pressure. He has no resistance at the pedal, so the master is kaput.

 

It simply never occurred to me that the bleed nipples should have been at the top!

And just to think I had a 50% chance of getting it right.

 

hoodun,

My understanding of the system is that there are a few reasons why you could get no resistance on the pedal. One of the reasons would be if the output solenoid valve(s) on the front wheels had failed in the open position. Under this scenario, the pedal would actuate the master cylinder but the fluid would merely cycle back to the reservoir instead of building pressure in the front circuits.

As you probably know, there is a lot of confusion amongst owners about the existence of a "master cylinder" in the Teves system. Prior to VIN 198335, the system didn't use a conventional master cylinder. It used an actuator unit which itself is combined with the solenoid valve block. It's much more complicated than a master cylinder. However, the very front part of that actuator unit is a small cylinder which controls normal (not ABS) pressure to the front brakes. This is referred to by Teves as the "master cylinder" but it's just the end chamber of the actuator unit. (Only after 198335, did a "traditional" master cylinder get installed as part of the revised Teves system.)

I think (but I'm no expert!) that a soft or failing pedal is caused by either

- failed Positioning Sleeve at the end of the boost piston in the actuator unit
- failed Seals or Central Valve at the end of the Master Cylinder chamber in the actuator unit
- Stuck output Solenoid Valve

You can disconnect the solenoid valve block and check the resistance across each circuit to see if the solenoid valves are failing. That might be the first check. I also understand that you can get replacement seals for the master cylinder end of the actuator unit and I suspect it's easier to buy these on your side of the pond. You have to disassemble all the boost piston components to get to the final MC seal and be very careful not to damage them during the process.

Good luck.

Paul

 

lol I guess I don't blame you, after doing all the work you just kinda want to get them back on and be done with it. Definitely no way that would have worked tho haha

 

I checked the resistance and all is ok. I also put 12v on each solenoid in the actuator and they all clicked. I did notice the circuit strip coming apart but it was still connected... either way I soldered wires to the solenoids replacing the strip.

There is a master cylinder which the actuator attaches to.

One of my hoses was shot so there was definitely air in the system... Now it is empty and I am trying to get fluid through to bleed the system with a small amount of air pressure through the res. It seems to very slowly be working. I am going to spend half the day tomorrow on this and will update.

All of this could have just been the result of a bad hose... at least Im hoping (...the pump could be shot now...).

 

let it gravity bleed

 

hoodun,

Hi, I was interested by your comment that on your car there is a master cylinder that the actuator is attached to. I was confused by that as on my 1994.75 MY car the "master cylinder" is merely the last chamber of the actuator unit. As far as I can see, it's not a separate item that can be removed or replaced (much as I would like it to be!).

People have talked about the Teves Mk II & III and then the change to the Teves Mk IV in April 1995. However, according to Jaguar there doesn't seem to be any difference in the actuator unit part number from 1989 right through to April 1995 so I don't really know what is a Teves Mk III. Do you happen to have a pic of your actuator unit which shows this separate master cylinder?

Tks

Paul

 

This entire topic had me looking up the Teves systems and I don't believe there was a Teves 3. I think the XJS had a Teves 2 thru early 95. The actuator/master cylinder is certainly the same part thru 95

 

Its been a while, but I recall having a VIN that has the Teves III which was used for a brief period in 1994. Either way, I believe my brakes are working now.. there is still air in the lines which I will bleed out once I get my rear brake hoses in, but I am able to pump it and get it to grab. Could have just been drained from the bad hose...

The pedal is very stiff which is how I remember it. It was this way even after the Accumulator was replaced so I may need a pump eventually. I still plan on going to a more reliable system. Either an older Bosch or a newer Teves IV. I'm yet to hear of anyone completely losing brakes with these systems. The Teves III, and or maybe the Teves II is not fail safe.

 

Here it is. If you look it up on ebay it says used on 94 xjs and 95 Vander plas. Its a $650 part:

 

but what does the inside look like?