Hard brakes on 1995 XJS

1) Basically, yes. Just to be safe, I'd drape a rag around the neck of the accumulator to catch any brake fluid that might spray or dribble out of the connection. You don't want brake fluid to get on anything. This is strictly the assist side of the brake system, no bleeding should be necessary.

2) I can't directly speak to whether there is a GM part that would work; wouldn't surprise me though, Teves systems are used on a range of cars. There is a hex recess on the accumulator intended to be for removal, but the thing is usually pretty tight and difficult to break loose. Once loose it will spin right out. I use a heavy, metal band type oil filter wrench to grab hold and break it loose.

Good luck!

William and Steven - many thanks for the helpful comments. The car does have the Teves MkII hydraulic assist with an accumulator. For Steven's test, the lamps both go out after 6 seconds and in the wrong order - Brake goes out first, then ABS.

So I shall now organize a replacement accumulator. Two more questions, if I may.

1) is the replacement as simple as pumping the pedal 40 times to drain the accumulator, then remove the old and install the new? Or does the brake system have to be bled afterwards?
2) I have seen posts indicating that there's a GM accumulator that fits and is much cheaper than the Jaguar unit. Any comments on that?

Thanks again

Edited on 2012-10-02 22:56:06

Ian, you need to settle what brake system each of these cars has first. If the last six digits of the VIN number is 198334 or below, the car will have the Teves MkII hydraulic assist that has an accumulator. VIN's 198335 and above have the Teves MkIV VACUUM assisted brakes. So it's possible you and your friend have different systems. With the MkIV system, you probably have a vacuum booster or vacuum supply problem. With the MkII system you'll need to test the accumulator.

To test the accumulator, turn the ignition OFF and press the brake pedal firmly 30 or 40 times. That will exhaust residual pressure in the accumulator. Then turn the ignition on and watch the two brake lamps on the instrument pack, one ABS and the other BRAKE. If the accumulator is usable, the lamps should stay on for 20-30 seconds as the accumulator charges with pressure. The ABS lamp should then go out first, followed 2-4 seconds later by the Brake lamp, and the electric pump should then stop.

If after the ignition is turned on the two lamps go out much quicker than described above, the accumulator is not charging properly and is defective.

Hope that helps!

Ian. The accumalator is a storage tank for pressurized brake fluid. When the engine is running it is charged by a pump. When the tank is charged, engine running, the pedal should move easily with foot pressure. Now, stop the engine and pump the brake pedal, for the first pump or so there should be some assistance then gradually get harder, it usually takes about 20 times to get very hard. If it was hard on the first push then the pressure pump is likely the problem, if it gradually gets harder then the accumalator is faulty!

Doug - thank you, from your suggestion I find a lot on the web that indicated this may be the problem, also good descriptions of how to replece it. But i can not find any sites that indicate how to test the accumulator - any guidance would be appreciated.

The "brake accumulator", a ball shaped object on the passenger side firewall area, may be bad. Google "XJS hard brake pedal" and there are several sites that explain to check it and also instruct on making sure a related mineral oil supply is full.