I think there is a separate thread for your car, but the Moderators will sort that for you. I suspect you have failing master cylinder seals, rather than a leak from the reservoir. That or failing/leaking caliper seals. What you describe is a classic symptom of master cylider failure. I do not believe your car has any anti-lock systems, which were not available on the 1984 cars AFAIK.

New master cylinders are easily available and straightforward to fit. It would be a sensible idea to check out the entire system at the same time, flexible pipes, calipers and re-bleed with new brake fluid.

Greg

 

Greg's answer is correct in all respects.

You should post in the Ser I-II-III XJ6/XJ12 section.

Welcome aboard :-)

Cheers
DD

 

James,

The o-ring in my 86 was shot however I could not anyone that sold just the o-ring. I finally found a local rubber parts supplier (the guys that make and sell hydraulic hoses and all sorts of other rubber specialty items). I took my reservoir cap in, the gentleman checked his spec sheets and found an O-ring that was resistant to brake fluid (very important) and I was back in business for under a $1.00. If you buy a used cap, you must ensure that the rubber gasket/o-ring is viable or you are right back where you started.

Good luck!

 

I am having no brake pedal pressure and i can't bleed any fluid. I'd like to rebuild but don't know how to remove brake actuator . I don't have shop manual and am low on funds can someone please help. p.s. 1989 xj-s coupe ABS

 

XJS (ABS) Teves Master Cylinder Actuator Problems.

On an XJS with ABS the Master Cylinder and Brake Actuator are all combined in one unit, apart that is from the Black Pressure Ball that is on the other side of the Car.

The Black Pressure Ball would cost you around £100 (uk)

While a New Master Cylinder/Actuator around £2,000! if you could find one.

But when you have picked your 'Jaw' up from the Floor, its not as near to the end of the World as you may be starting to think, as there is a FIX!

Inside the Actuator there are 4 electric valves, that are easy to test to see if they work and inside they are wired up with ribbons instead of 'hard wire'

Because of the Vast amount of heat in the engine room, these electric ribbons can degrade or just break up and in the event that is the case, then it is probably better to replace those ribbons with hard wire.

Providing you know how to solder! or you could end up killing yourself!

So job number (1) is to do an electrical test on the Valves to see if they work, which can be done in 'Situ' with the whole lot still in the car but before you start get an 'O' ring repair kit which should not cost very much.

Also do not lose of break any of the square gaskets as you might have a problem finding New Ones.

If all the Valves are working then the problem could well be the master cylinder that bolts on to the Actuator.

Option (1) get a new one if you can find one.

Option (2) get a repair kit if you can find one.

Option (3) I have heard tell that the Master Cylinder from an XJ6 will bolt straight on but you better check that out with someone who knows.

If you have to re-wire the valves then its best to take the whole thing out of the Car including the Pedal Box.

Be careful you don't break the brake light switch which is under the dashboard £££.

I've had lots of problems with the ABS on my Car and am Considering Retro Fitting, Non ABS from an XJS that I don't use any more.

If you get any problems DJinAustin is the Guy to Contact.

ABS Problems are often the cause of putting in New Brake Pads, without first opening the bleed screws on the Calipers, forcing dirt the wrong way up the System. (ask me how I know!)

https://www.jaguarforums.com/forum/x...l-left-113913/

 

No that's NOT a misprint £2,000 (UK) if you can find one!