Just one quick adder to all the good advice.
Check the rubber brake line.

It was the cause of the same issue on my 380SL.

The rubber brake-line line would collapse, keeping the brakes applied when I released the pedal; Only after brakes had been warmed up. It was not even noticeable when the brakes were cold. Replaced the rubber lines and all was good.

Worth checking...

 

Thanks...had hoped for the hose, had heard of numerous experiences such as yours. The hoses and calipers were all replaced early on by my mechanic before he gave up.
Brought it home and am now rewiring and cleaning a replacement A.B.S. block assembly. All solenoids work well, screens are clean and I'm only waiting for some high temp. silicone wire for rewiring the unit. Hopefully this will help but, based on all else tried, I won't get too hopeful yet.

 

This forum has been immensely helpful. The diagnosis and instructions to remedy the hard left pull when braking was apparently spot on. Thanks to Orange Blossom for the detail point by point and pictures.

The issue that was causing the hard left pull when braking was corrected by rebuilding the ABS valve block. One evening I took it apart, removed all solenoids and cleaned the screens and also energized each and blew compressed air through them. Also rewired the plug to solenoid eliminated what others have described as either a fault or one that would be in the ribbon trace circuitry. Used a highly flexible, high temp rated silicone 20 gauge wire.

Installed it this weekend in about an hour including time to drain all fluid and bleed each caliper.

Following the fluid on body warnings I first placed a microfiber towel on the fender and then covered it with heavy plastic and also covered the inner fender beneath the master cylinder. All worked well. We've now test driven it over 100 miles with no issues.

Now I have an extra ABS valve block and master cylinder/reservoir/ABS valve block to sell if anyone needs either. Had I not gotten so eager to get parts that are discontinued and simply followed the free advice I could have done this for a few hundred $ less.

Again, thanks Orange Blossom.

Now there is a problem with the HVAC. It was blowing cold when the temperature was set at max heat....next problem.
Gerry

 

Hi Gerry

Glad you got it sorted but I would hang on to those parts if I were you!

 

I'm considering refurbishing both ABS valves and rewiring. Should I expect more trouble? Incidentally, there was apprehension after rewiring and reinstalling the one unit. A little anxiety as I turned the key and waiting to see if the self diagnosis passed and the light went out...fortunately it did. I haven't slammed the brakes hard enough yet to test the ABS...sort of hate to go that far.

 

Hi Gerry

When repairing the ABS Valve Block, there is No Guarantee it is going to work but since these units are NLA.

What else can you do except to try and fix it or just park your Car up and buy another one.

Having said that there are a couple of options, like swap it for a working unit from another Car and 'Hope' it keeps working.

Or Convert the Braking System to 'NON ABS' like the earlier Cars with a Vacuum Servo.

If you decide to go that way, then be sure to Check that its OK with your Insurance Company or else it could invalidate your Insurance.

From what you have told me about the way you rewired it, then it certainly seems like you have done a 'proper job' in replacing all that old 'crispy wiring'

Which sooner or later was probably doomed to fail. (as it has done)

But you really need to Test it to make sure.

So find yourself a piece of deserted off road Tarmac and while driving at a very low speed, then just 'Jab the Brakes' hard.

Making sure that no matter what happens, your Car can't hit anything or cause an accident of any kind.

In other words take sensible precautions.

If the Car takes a dive to the left or right when driving, immediately release the Brakes and then reapply them gently and progressively, so that

you can keep the Car under Control.

Assuming that nothing bad happens, then I would drive at a sensible speed in order to get confidence that your repair has been successful.

In any event you are no worse off than you were before.

Although it certainly sounds as if you've done a very good job at fixing the problem, although with that kind of system you can of course never be sure.

And since I am aware of what can happen, I have got into the habit of braking well in advance in case it goes wrong.

 

I pretty much agree with your safety concerns for testing. We live in a more metro area of Nebraska but have agricultural ground in the part of the state where the Jag is normally kept. Between the smooth and flat portions of alfalfa and a grass landing strip, safe testing with full braking will be easy. I prefer the turf to pavement testing for many reasons, including the lack of tire wear. This vehicle is only used by our grandkids for proms, homecoming celebrations, parades and by us for a few warm evening summer drives. This minimal use may well cause more issues than if used regularly. Again, thanks for all advice.

 

I am replacing the ABS Brake Block on my 94 XJS Teves System. My question is are there o-rings between the ABS Block and the Master Cylinder? I did not see o-rings on the unit I removed nor on one I bought on e-bay but they are on the two outer ports of the one i had rebuilt. No o-ring on the center port. See the attached picture. So do the O-rings belong or not? Your feedback will be appreciated.

 

Hi XJS Rookie

This is how it should look, if the 'O' rings are not in place, then its for sure your Brakes are going to fail.



New ABS Valve Block with the 'O' rings in place.

 

OB, Where did you get the New ABS Valve Block? And were the o-rings part of the Block or did you buy a Master Cylinder Rebuild Kit?

 

Hi XJS Rookie

I picked up the New ABS Valve Block for £50 at an Auto Jumble he said that he bought it for a Sierra Sapphire, which he later sold for Spares.

What he didn't know was that this Valve Block is the Same as the one for an XJS but more importantly didn't know.

That the ABS Valve Block for an XJS is NLA.

And Yes it came with the 'O' rings, which are absolutely essential so don't try and use it without them.

 

Hi Guys, been through the problem of pulling to one side on my 1989 XJS and solved by fitting an XJ6 ABS unit - exactly the same as XJS as per "orange blossom" findings. Brakes now wonderful but the ABS light now comes on all the time. My garage man suggests its the wheel sensor but I cant see that as it was fine before I changed the ABS unit. the ABS light issue is an MOT failure so cant use the car until its solved. ABS sensors for XJS are no longer available so looking for a replacement fitted to another car/model

Any suggestions as to why the light stays on

 

maccasa,

Don't change any sensors yet. Do the Blink Test which will tell you the fault code and therefore the cause of the light.

Paul

 

Got hold of Blink test details - many thanks

 

Remember it can only show one of each group of codes, until you clear the first one. For example, if there's a 3-1 and a 3-2 code stored, it will only show the 3-1 code until its been fixed. Then it will show the 3-2 code.

Good luck

Paul