For the past two years my 1994 XJS 4L 2+2 brakes stop working after the Winter temperatures arrive. I'm not sure if my mechanic knows how to bleed the brakes. Last year he bled the brakes and everything worked fine all summer, no brake problems. It's Fall again and I have no brakes. The driver front caliper has been replaced but the brakes worked fine up until now. Would appreciate if someone would describe the brake bleed procedure before I allow my mechanic to work on the brakes.

 

Welcome to the forum,

Perhaps you could describe the problem in more detail- Is the brake pedal going all the way to the floor or does it feel normal but the car won't stop? Is the ABS light on? Does the car pull to one side or the other under braking? What kind of outside temperatures seem to trigger this issue?

 

I bought this car in Florida and noticed that I would have to pump the brakes twice when stopping. I took it to a qualified mechanic who only works on Jaguars in Florida. He drained the entire brake system because the car sat for two years without being started or driven. Also changed all the rotors and brake pads. The brakes worked perfectly until I drove it to North Carolina where the climate is much colder. I garaged the car at the end of summer and didn't start it for about two months. The brake light and the ABS light would not turn off. My North Carolina mechanic bled the brakes and everything was fine. About a month later the front driver caliper died and I had a new one installed. The brakes worked fine but I noticed that the new caliper was braking harder than all the others. Possibly I should have replaced both front calipers to balance out the front braking. During the Summer the brakes never gave me any trouble but the weather has now changed with cold nights and the brakes are not working. The ABS light goes out but the Brake light remains on. The reservoir is full and no fluid has leaked on the garage floor. The pedal goes all the way to the floor. I want to take it to the mechanic here in NC but I'm not sure if he knows how to properly bleed the brakes. I would like to know the proper way to bleed the brakes before I take it to the mechanic so I can print out the process. Any suggestions are greatly appreciated.

 

The bleeding procedure is quite different from other cars, note that the front and rear bleed procedure is different.

 

I would concentrate on the fact that the pedal goes all the way to the floor. Assuming this is with the engine running, what happens in cold weather when the engine is NOT running? Does the pedal also go to the floor - even if the effort to make it is higher?

 

 

The above published procedure appears to be for the pump/accumulator type of brake system. Is there a procedure for the vacuum type system which I assume was installed on facelift cars, is completely different, probably more like a conventional brake system with conventional bleed process.

 

I agree to the above, try rebuilding your master.

If you can floor the pedal and you aren't getting movement at the pistons and aren't losing fluid, the master must be the issue.

 

Hi Tom

On your 94 you would have the later Teves System, with a Separate ABS Valve Block on the other Side of the Car but where I feel you have gone wrong is in not replacing 'Both' of the front Calipers

Which sounds like false economy 'in the Scheme' of things, if you have to keep paying out for mechanics to Bleed your Brake with no success

And so the first thing I would do is to replace that Caliper before you go any further, as you need a Solid Base to work from and from my own personal view point, I'm not a Fan of rebuilding these myself

And would rather go New or Service Exchange, as that is a job I would rather leave to the experts

 

Many thanks for the pages that you posted. I did a lot of searching on the Internet for this Brake Bleeding information. This is the only forum that has provided me the exact procedure. Would you please reply and let me know the name of the booklet containing these pages.
When I was staying in Florida the independent mechanic there thoroughly checked out my car and changed all the fluids. It never occurred to me that the braking system was unique to Jaguar. Only when I returned to NC a year later did the brake problem occur. I feel certain that the mechanic serviced the brakes correctly.
I think it's also important to say that the Jaguar Dealership that I visited in Florida was a huge disappointment. When I purchased the car I immediately took it to the dealership to have them check out everything.. It was a horrible experience as NONE of the mechanics there knew very much about my 1994 vehicle. Although they found my car to be well maintained and in good working condition they missed many very important details. The independent mechanic looked over the dealership work invoice and pointed out many things that did not get serviced.
I will share one example of the failure of the dealership with this forum that convinced me that the dealership was in no way qualified to work on a classic Jaguar. There are multiple grease fittings on the XJS. The dealership only serviced half of them. The independent mechanic found 4 grease fittings that were "dry". I returned to the dealership with a long list of issues that were overlooked by the dealership. I met with the Service Manager and also the mechanic who performed the work. All of my money was refunded and I made it clear that I was very disappointed.

 

Yes, when the engine is off the pedal goes to the floor.

 

My 94 XJS has 90K miles. I realize that the Master Cylinder may need to be rebuilt. If you have any kit information please send it to me. Thanks!

 

Thanks for your post. I plan to take my car to a mechanic in Greensboro, NC soon. I understand he's very qualified.

 

It's been a year since the front driver caliper was replaced and no bleeding problems. My mechanic test drove the car when it was replaced and he noted that the new caliper was braking more on that side and suggested that I replace the front passenger caliper to even out the braking. I do plan to go ahead and replace the other caliper. Thanks!

 

Jaguar Heritage has produced the factory service manuals on DVD/ USB sticks over the years. Here is a link to one of the vendors that has the XJS version: Jaguar XJS Repair DVD

 

Excellent! I will place an order.

 

Therefore I concur with SS, the master cylinder is at fault. Could be that in cold weather the seals stop sealing, if they are old and past it.

 

Hi tommusic

The procedure for Bleeding the Teves System is fairly unique and as such I very much doubt if you are going to find the correct procedure detailed in a manual, so best to go by what you have read on the Forum

 

I posted the pages from the Jaguar service manual. Dealership mechanics need to know this information from somewhere, there wasn't forums when the cars were new. They would never use some anonymous person in the internet over an official source anyway.

 

Thanks for you post. I do agree that it would have been wise to replace both front calipers at the same time. It never occurred to me or the mechanic that there would be a noticeable difference in braking.