Wassup Jaggers! Jaguar Dre Again.lol. I own a 1988 xj6 XJ40 base model and my brakes have gone out.. completely. The pedal is touching the ground and my car is not stopping. On the dash it reads low brake pressure, brake pad low, and anti lock failure. So I do know I have to replace my rear brakes and rotors for starters. I have ordered a rear set and I also ordered a new brake booster figuring that is also a problem because of the easiness of the pedal pressure. I refilled the resovoir with mineral oil and took it to a mechanic and he then noticed that fluid was leaking from the inside of my rear passenger tire and mentioned that my brake line could be damaged. I need to to know from an expert Jagger of the possibilities of what all I need to do to get my brakes back performing.....Thanks

 

If you mechanic has found a leak, I would repair that and inspect the rest of the lines probably replacing all of the hoses. Don't just start throwing parts at it. You'll only end up broke especially if you are paying someone else. Your pedal is probably easy to push because there isn't any fluid behind it to move. Also, as you refill the system don't forget that bleeding the rears is a special case on these. There was a thread just on that procedure. Good luck, hope it's an easy fix

 

Hi Jaguar Dre,

In addition to Jerry's good suggestions, it is possible for brake pads and rotors to wear so thin that the caliper piston can extend too far, allowing fluid to escape from the caliper past the piston seal. Your mechanic will know if this has happened on your car. Cleaning the caliper and reinstalling the piston is not too difficult, but it would be prudent to replace the piston seal and boot in the process, not only because it's just good maintenance, but because they are sometimes damaged when the piston extends too far.

Please keep us informed.

Cheers,

Don

 

Well I did get one rear right rotor replaced that needed it and both rear brake pads replaced also. Yes the seal was pushed out which caused the leak from me using the EBrake. It was almost damaged but My mechanic did manage to "pop" it back in place with grip plyers. Then changed the rotor and pads put calipers and connected sensors back together. After that we bled both sides with me pumping the brakes around 10 or 11 times and him resetting them. Everytime he resets them, my brakes would touch the floor over and over again. We repeated that pumping process about 6 or 7 times or until I felt more of tight brake but the brakes never tighten up as soon as I pump them one pump. Now It takes about 4 sometimes 5 pumps for my brakes to tighten up,not floor and every stop I make I have to pump quickly. My mechanic did mention as you did also, that it may be the Master cylinder or the brake booster or both. More so the Master cylinder. By that time I already ordered and received a used but In great condition original girling brake booster around $80 so it was no turning back. Lol. We did get the rear right leaking to stop and replaced the pads and rotor that needed it so it was progress but still trial and error. (Question) to see am I on the right path: do I need to replace the brake booster and see if that's the problem and if not it's definitely the Master cylinder Correct???? I really appreciate the Help and knowledge Don "the Goat" and everyone else. Much Luv
Jaguar Dre

 

ALSO Thanks to you MR. HOBACK

 

J Dre: Your xj40 should have the Teves abs system. The three main components that often fail are the pressure switch, accumulator and pump assembly. The master cylinder doesn't seem to fail that often but it can happen. The soft pedal is what I find interesting. Often, xj40 owners complain of a hard pedal due to a failed accumulator, pressure switch or pump. I have experienced this twice, once on an '88 Toronado and once on an '88 Eldorado, both having this Teves system. If memory serves me, there is a slightly different bleeding procedure for this system. If you haven't done so already, I strongly recommend that you purchase the service manual(s) either in print or on cd. You can find them on ebay. Good luck.

 

Don't you use the pump with the ignition on to bleed the rears and do the fronts manually? Bleed the furthest wheel from the master cylinder first.

That's what you do on a 94 anyway and I think the manual details the procedure.

Larry

 

Thanks RetroRen and Lawrence. Strangely,my brakes are getting better the more I drive. My jag went from four pumps to make a stop to around 1 and a half pumps to stop and sometimes one pump in most stops. I'm seeing improvement and I haven't even replaced the booster or checked out the three teves. However, my dash still signals low break pads. Low abs and low pressure. I'm Still working on them so I'll keep you guys posted. Thanks 💯