Teeves III caliper retraction

[Joespond]

Hi I have a 1989XJS and I am wondering about changing the front brake pads is there anything you need to know about retracting the calipers for the anti lock system on this car

Thanks.

[sbobev (Steve)]

Nothing special. Just open the bleeder valves and when you push the pistons out, the old fluid will not flow back through the ABS valve body.
Obviously, after you’re done with the brake pads, you’ll need to bleed the system, but the front circuit is conventional.
Good luck.

[Robin_O_Connor]

Correction! The fluid WILL flow back through the ABS unit if you do not open the bleed nipple.

[Kirbert (Author of the Book, former owner of an '83 XJ-S H.E.)]

@Robin_O_Connor

The fluid WILL flow back through the ABS unit if you do not open the bleed nipple.

That’s another of those mistakes that will require several applications of high-octane elixor to get over. That ABS unit is stupid expensive to repair after you’ve #$%^ed it up by chucking the old filthy fluid backwards through it.

[Joespond]

Yikes I never thought of that I’m really glad I asked. is there a proper bleeding procedure for the system that I could find somewhere

Thanks again.

[sbobev (Steve)]

@Joespond

Is there a proper bleeding procedure for the system that I could find somewhere

The manual is a good place to start. Searching the archives here also will produce many hits. For example:

Brake Booster failure

The pump operates when the pressure is below certain point, IIRC 140 bar. This is why when the car has sat overnight, the pump runs for 30-40 seconds before both the red and amber lights go out. Then, accumulator becomes critical – the stored pressure should be sufficient for 3-4 successive operations of the brakes Regarding to two circuits — two of you are say the same thing – loss of pressure in the front means no brakes at all but I am still not convinced. If this were true, then, how can…

[sbobev (Steve)]

@Robin_O_Connor

Correction!

Thank you for paraphrasing what I said earlier “Just open the bleeder valves and when you push the pistons out, the old fluid will not flow back through the ABS valve body”

With English being my second language, and not being an automotive engineer, I may have not worded it as strongly as you did, but the exclamation sign was probably not warranted :-))

[Joespond]

So it sounds like if I wanted to put in new front calipers I would just install them and bleed them as I would a conventional system

Is that an oversimplification if I do not disturb anything else

Thanks.

[Timeisrelative (Jason Miller 1993 XJS 4.0 convertible, 1997 XK8 coupe)]

Thats pretty much what I did. Like everyone else said, open nipples, push back pistons, swap calipers (I also put on new brake hoses, it’s a good idea) and I used a vacuum bleeder to bleed. It works very well. Of course I had to do my accumulator ball too. The little extra cost of the hoses is worth the little extra piece of mind, especially when you have found out just how much fun it is having absolutely NO brakes when the front fail.