I replaced brakes on my 88 XJ6. No problems bleeding them until I got to the left front. I just can't seem to get all the air out. Any suggestions what the problem might be, or how to overcome the problem?

 

You might have air leaking past the thread of the bleed nipple. Try cleaning up the thread and adding a little petroleum jelly to help it seal, and / or replacing the nipple for a new one

 

Just how extensive was the "replacement" of your brakes? eg calipers, hoses etc.
There could be any number of things causing air to remain in your lines.
We need more information.

 

Just replaced the caliper brackets, calipers and pads.

 

Hi Phil,
If you are using a vacuum bleeder, they will sometimes suck air past the nipple threads as Andy T has said. The most fool-proof way to bleed the brakes is still the old fashioned two person method. One person in the car gives a couple of pumps and holds the pedal down, the second person, at the bleeder nipple, cracks open the nipple and lets the fluid/air squirt out and then closes the nipple (all while inside person still has brake pedal held down). Nipple closed, up on brake pedal then down on pedal and hold, nipple open and then closed, up on pedal, and repeat until no bubbles or foam are in the fluid. Start with the farthest wheel. Bleed the brakes with the engine OFF.

Other than that, how does the pedal feel when you apply the brakes? Firm/hard and a little mushy, long stroke down to the floor or medium stroke, about half way? No leaks anywhere?

Dave

 

Hi Dave,
I am using the old two person method. I had gotten a good firm brake until I got to the left front. Now I can't get any pressure at the left front at all. I get it pumped up, open the bleeder valve, get air (and a very minute spatter of fluid). Close the bleeder valve and start pumping again. No pressure.

 

Phil,
Does your 1988 XJ6 have ABS? If you do, that might change the whole bleeding process. However, I have bled the brakes on my cars with ABS in the normal method without problems. Have you let the master cylinder (MC) run low on fluid during the bleeding process? Did the MC empty out while you were replacing the calipers and had the line(s) unhooked? How many times would you think you've done the bleed cycle on that front caliper, twice, half a dozen, until the cows came home?

I'm not positive, but a 1988 XJ6 might be a newer, different model than the ones in this section of the Forum. Ours end at 1987. My shop manual does not mention ABS.

If you bled the other brakes before getting to the left front and the MC ran dry or really low, air can be sucked into the system and expelled through caliper nipple with little or no fluid. I top off or check the MC after every caliper.

During the caliper job, did the hose(s) hang free and maybe drain the MC?

I fill the new calipers with brake fluid before I install them, the reservoirs behind each piston hold a lot of air by comparison. If the MC ran dry, bleeding it separately off the car is recommended although I have installed MC's dry and not had an overall problem, just lots more pedal pumping.

If these comments don't lead to something good, try filling the MC reservoir and disconnecting the brake hose at the caliper and letting it hang into a container and do a rudimentary "drain bleed". Just let it hang down as straight as possible and watch until fluid begins to drain out and the level in the MC starts going down, confirming fluid from the MC can reach the left front caliper. Once you get solid fluid out of the hose, reconnect it, make sure the MC is topped off and go through your bleeding cycle, shouldn't take more than half dozen cycles to get fluid at the nipple.

Barring success by now, someone with more experience with Jaguar brakes will chime in.

Dave

 

Thanks Dave, good info. I have heard of drain bleed before, just wasn't if it was what the name implied. Thanks for clarifying that.

 

were you able to resolve your issue? if so please explain to build on our collective knowledge.

 

sounds like the car is a XJ40 with ABS, so it doesn't apply to Series 3 or below.

 

No, unfortunately I haven't really had a chance to work on it, so I haven't been able to resolve it.