I'm looking at a '94 XJ-S Convertible, and it's overall in decent shape. However, under hard braking it pulls strong to the left, enough to force me to turn the wheel to the right about fifteen degrees to compensate. Under soft braking, it doesn't really pull at all, and it tracks fine. The ABS light does not come on ever, neither before nor after starting the car, which makes me think the fault may lie there. I think they said they had "done the brakes" in the last few years, a vague statement that I didn't pry into. It's available for a decent price if it's a straightforward fix, but, having been around the Jag block before, I'm weary of anything that's billed as an easy fix. I'm also not sure about working with the ABS system. I don't think they'll allow me to go poking around their car bridging connectors, unplugging sensors, and bleeding calipers. So, diagnosis by testing before purchase may not be an option. Any suggestions on what the cause may be?

P.S. It may just be my imagination, but it feels like the wheel is ever so slightly easier to turn in one direction than the other. Perhaps that could indicate some sticking?

 

I have had a similar problem on my 93 conv before, caused by seized pistons in the front callipers. I rebuilt the calliper, New aftermarket piston and seal sets are available from Europe, or callipers can be replaced. This is not a difficult job for the home mechanic, but removing stuck pistons can take some time. Tim

 

Probably a sticking caliper, or old hoses that could benefit from replacing. I have a 96 that had the same issue when I got it 5 years ago. I replaced the rotors, calipers, brakes and brake hoses. That seemed to solve the problem but it reappeared within the past year or so, after 20k miles of driving, so I just replaced the fronts all over again and indeed that cured it. The brake pads and rotors were already shot, and trust me I'm not hard on brakes at all. You can find all you need at Rock Auto, very reasonable prices. I have had an ABS light on intermittently since I bought the car, but it's just a sensor and has no affect on driving or braking, so a simple piece of electrical tape over the dash light and voila! No more problem I wouldn't worry about it in your case it is likely the same fix and something you will want to do anyway considering the age of the car. BTW I love mine and will take it on a nice lunch drive today.

 

As you probably know, the Teves II ABS system in your car is very different to the late 95-onwards system. The Teves II system has a number of known recent problems including inoperative / jammed pistons in the valve block which can cause catastrophic diving to one side. This could in theory, cause the car to dive to one side on even gentle brake application. However, the basic symptom description you've given MIGHT indicate that it's more likely a sticking caliper piston or pad. If you can't remove the front wheels and see if the brakes are operating properly, then you may wish to be suspicious and negotiate accordingly.

Both the brake light and ABS light should be coming on when the ignition is turned on and stay on until the pump has pressured the accumulator. Up to 45 seconds from cold in the morning. Is the pump operating on ignition on? (It's quite audible, especially if the bonnet is open). If the pump isn't operating, the brake pedal will be noticeably very heavy as the rear brakes will not be operating.

Good luck

Paul

 

When you first sat in the car and turned the key, did you check all the warning lights?????
They should all light up.

 

Thanks for the suggestions. I thought it might just be as simple as a sticking caliper, but I was worried that it would be something bigger, like the ABS valve block.

The pump is certainly running. Though I didn't listen for it like I should have, the brake pedal being of normal stiffness and the rear brakes certainly working is enough to convince me of that.

As I mentioned, the brake and ABS warning lights do not come on ever, even during startup like they're supposed to. If I remember correctly, the low oil pressure light also doesn't come on when turning the key, which may indicate that the majority of the lights are faulty.

If it is a sticking caliper, wouldn't the car track poorly when not braking? Or, is the issue the caliper not engaging? Anyway, I've done the front brakes on my XJ6 before; I'd never attempt the rear brakes on that or an XJ-S at home, seeing as I don't have a lift. Now I have to think about whether it's worth the gamble. This car is a few grand less than an old Alfa Spider that I've been looking at which comes without really any major mechanical maladies.

 

If some or all the lights didn't come on with the key switched on, I would walk away.
California SMOG requires all lights to be operational before starting.
It's an automatic FAIL before any other tests can be recorded and stays on the DMV record.

 

I am very thankfully not in California. The state I live in now doesn't even to inspections on old cars; so, I'm not too worried about that. But, it does indeed concern me that so few lights would come on.

 

Here's the issue with 1994 Jaguar XJS, It has so many on board computers, dozens of relays and hundreds of fuses it is nearly impossible to have a small solution.
I know the 94 cars too well and chose to give mine away after putting $15000 into repairs and diagnostics, even working for a Jaguar specialist.
Just think, unless you are a electronics genius there is a limited degree of real knowledge even with first hand expert advice.
I went 6 months with a non op fuel pump that had to be hot wired every day to get to work at my Jaguar specialist employer.
After that time the most experienced Jaguar technician took the wiring diagrams home one night and found the problem.