I did a search but didn't come up with anything?

Any leads would be helpful

thank you

 

I've added ABS to a non ABS car. I don't suggest converting 1993 to non-abs because the 1993 with outboard brakes is more heavily biased toward the rear and the rear brakes will lock and the car will spin in wet weather. Guess how I know this is true? I will offer you an alternative idea to the problematic Teves system that I know works. Retrofit the Bosch ABS system that Jag and many others used in the mid 80's. This early ABS system is very effective, very reliable, and simply to retro fit.

You need this...
90 C4 Corvette ABS Pump and Module Brain Bosch | eBay


You then install an early master cylinder and vacuum booster, get an wiring diagram for the Corvette (I have it) to connect the 4 ABS sensors as inputs to the ABS computer, connect constant 12v, gound, switch 12v, ABS diag lamp, and brake pedal switch. Plumb the lines, bleed and test.
I did this project in a few days working a few hours in the evenings, it's easier than it sounds for an experienced DIY mechanic.


https://www.jaguarforums.com/forum/x...e-works-84536/




This early ABS system is 3 fluid channel so you'll have to bridge your two rear lines into a singe channel. Not an issue on a car with out traction control and power-lock. Jag used this system on the 88 XJ6 and the Series 3 XJ until 1992, Mercedes used it on the 80's S class and Chevrolet used it as the first ABS system on the Corvette, Porsche also used it as their first ABS system on the 928.


I chose to use a corvette system as a donor because those systems are readily available, the weight profile of the vehicle was similar, caliper piston area was similar and technical documentation for the wiring was easy to find.

 

Thanks for the post icsamerica. Interesting conversion.

In my case it turns out that the 93 is an early 93 which happens to have the inboard brakes.

I will consider your writeup as a good possibility

 

Some great info here. Seems like going non-ABS will be like any other rear wheel drive car. ...anything is better than brake failure which is what I am experiencing on TEVES III right now and I do not want to buy a new actuator for a few grand... def not a used one... This Bosch idea seems logical.

If you can send me that diagram it will be much appreciated.

 

It seems that the 1996 xjs pump is similar in style and operation, and not that expensive. Can you use a 1999 or 2001 from an xj8, which also seems similar. These are as cheap as $80 online. Nice thing about using the 95 96 xjs is that I can still keep my abs brain module.

 

I think you would be better off finding a generic/customer type master cylinder setup and adapting it to the ABS system than converting to non-ABS. My falkens do a pretty good job but I have slid a couple of times in the rain from lock-ups. I know the system is simpler but its a hell of a lot less safe.

What is necessary about the current master in its compatibility with the ABS system? Is the ABS block seperate? does it have a certain number of connections? Or is it just because its got a accumulator incorporated?

can you steal parts from an XJ6 to makes things cheaper?

Isn't the teves system used on other cars? If the bore is the same couldn't you find a rebuild kit for one of them?

As far as rebuild kits not being available. There are only so many sizes of bores in existence. I would personally take the master apart and measure all of the parts inside it and then contact several places that make parts and kits for master cylinders and give them the specs to see if they have something from a different application that matches.

 

The 1994 has a different set up than most other jags. It is the Teves III which was only around for one year.

I pulled the actuator out and checked the ohms. I noticed the circuit strip was pulling apart from the ground end (see photo) so I resoldered wire to everything and tossed the circuit strip. Everything measures out fine (3 ohms and 6 ohms). I was getting a hard pull to the right before when the brakes were working. Its possible that actuator issue was causing it. There are right ups with others having the same issue and soldering wire to fix it as well. https://www.jaguarforums.com/forum/x...l-left-113913/

I need to bleed the system entirely before determining if it is the MC. I would be more inclined to think it is the pump. Keep in mind the car was sitting for a year before I used the brakes, at which point they did not work. I found that there is little to no brake fluid in the system from a bad hose. ...? Odd thing is that the res is completely full... When I changed the calipers and hoses nothing came out and the res did not move. It remained full??

I'm going to try to bleed the system with pressure to the res at 10 psi and see what happens.

 

not being to familiar with the ABS system, I would inspect the soft hoses if you got nothing through the lines. I really doubt it, but for a while these cars used a different type rubber that the wrong brake fluid would damage. It could have similar results to some older cars I have worked on where the soft lines swelled inside (look fine outside) until they were completely shut.

Just worth a look, but it sounds like most of your issues are with the abs system itself

 

I personally would not be afraid of converting to non ABS. Most of the cars I have owned throughout my life have not had ABS, and I really do not think ABS is the great lifesaver it is made out to be. You probably would need to install a proportioning valve in the rear brakes, this is not a big deal, adjustable proportioning valves are readily available in the aftermarket, check out hot rod vendors such as Summit Racing and Jegs.com. I have not tried doing it, so I cannot give specific recommendations, but if your car has the same calipers as older XJS with inboard brakes, I would start with that master cylinder, and maybe see if I could come up with an XJS proportioning valve.

 

Abs vs non abs is a personal decision.
Believe me the debates get brutal on the motorcycle forums I'm on about it.

A well skilled driver can stop faster without it, but the average driver in a distracted/panic scenario most likely won't.
I've personally seen icsamericas car and the abs conversation and it is really nice and came out really awesome. If anyone knows.anything about the conversion here it would be him. (To the best of my knowledge)

My car doesn't, because I don't really like abs in a performance car "fun" car.

The problem with a proportion valve is what often feels like your stopping faster isn't actually stopping faster. So tests have to be done measuing actual stopping distance.
(Had to do this on a couple wilwood systems)

 

What does a proportioning valve have to do with feeling like you are stopping faster? The proportioning valve is all about brake bias. You will factually stop faster with more braking done in the front of the car. The caliper are also bigger up front for this very reason. Splitting it 50/50 would be retarded.

Idk how anyone can argue about ABS being safer or more effective at braking. 99% of people with an XJS just drive it around town. Cars come to a stop faster when they maintain traction with the road.

 

Let's remember that the design intent of an ABS system is not a faster stop. The intent of the ABS system to to prevent wheel lock-up *so the driver can still steer the car* !

In a hard stop, or very hard stop, on low traction surfaces an experiencd driver will not over-react. He'll modulate the brakes and stay in control. Of course, a hard stop or very hard stop is most certainly not the same as a panic stop. If you have time to consciously think about steering and modulating the brakes and effectively do so then A) you have a very fast brain or B) it is not really a panic stop.

In a *true panic-stop* situation I'm not sure any driver is experienced or expert enough to modulate the brakes as quickly or effectively as an ABS system can.

Heck, just turn on your TV on any weekend and watch whatever races are being shown. It's a fair bet that at least some of these drivers....but probably most of them.... have had specialized training. It's all but guaranteed that most of them think of themselves as superior drivers. And....what do they do? What do you see at least once but possibly several times during almost any race? You see the car with all four wheel locked, tires smoking, driver hanging on for dear life as the car plows straight-ahead-and-out-of-control into a solidly-mounted object of some sort

Cheers
DD

 

I think ABS is a huge safety advantage.

Problem is, it can result longer stopping distances. Especially some of the earlier design (1980s-early 1990s vintage, mostly) systems that over-modulate.

If a person judged ABS brakes only by some of the not-so-good systems that have come along then they'd swear them off forever.

Yes.

Well, almost always! Depending on tres, brakes, and road surface I'm pretty sure that you can find some situations where all four tires locked might actually mean a shorter stop.

But, yes, in all but a few weird scenarios all four wheels turning but just on the cusp of locking is the best bet for shortest distance and max control.

Cheers
DD

 

I agree older systems aren't designed as well and can overdue it a bit. I will have to disagree with your physic though on the idea that locking up the brakes will make the car stop more. Think of the road and its relationship to the tires. You can parallel this relationship of friction to that of the pads and brake rotor surface.
If in some instance it was possible for the caliper to "lock up" and lose friction at a certain point when grabbing the rotor, do you think it would stop faster or slower than if it was allowed to increase clamping force?
We are talking about traction here, I don't see how anyone could argue that you are in more control of acceleration or deceleration with less of it.

Sorry, not meaning to sound argumentative. I just feel like many people who like classic cars bash technology when they don't understand it and claim it ruins things in car. Not accusing you of this doug, I just know there are certainly people out there that think airbags, seatbelts, ABS, and other safety measures are a waste of time and I just don't get it.

You are more on point in the end when you say That is exactly what ABS systems are meant to do.

 

Not sure what you mean by "stop more".





I'm not sure if I follow you when you say "....for the caliper to lock up and lose friction...."




"Control" or "stopping distance" ? Two different things! Which are you talking about ?

More traction certainly means better control. No argument at all. And, in almost all cases more traction would mean a faster stop as well....which I think is what you were driving at with you're remarks that I couldn't quite follow.

However, I can envision some situations, with the right combination of tires and road surface, where simply locking the brakes and letting the tires dig in (so to speak) would result in a shorter/faster stop than modulating the brakes so they wouldn't lock up.

As I implied, this would be a weird scenario. That is, not common or typical.

And, if we're talking about an older ABS system....the type that so commonly used to way over-modulate....well, I can pretty easily envision locked up wheels giving a faster stop/shorter distance stop with those as well. Very well controlled, mind you, because of steering control...but very possibly longer distance






Well I agree, thus my remark that ABS is a huge safety advantage!





Fair enough!

Cheers
DD

 

To simplify, I believe in a case where the coefficient of friction between the road surface and tire were so high as to immediately stop the car in the event of wheels locking up, the coefficient of traction would be so high that the wheels would never lock up.

Working backwards from there, I dont think there would be any case where locking the wheels and using the friction between the tires and road surface could result in a shorter stopping distance than braking at the limits of traction.

In all cases the coefficient of friction in the braking system is higher than that of the road surfaced and a sliding tire. If this isn't the case, it isn't possible for the tire to lockup to begin with.

sorry if i was confusing or mixed some terms before