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A corroded brake line sprung a leak just inboard of the rear passenger side wheel. Both rear brake lines were badly corroded in a few spots where the plastic coating had been worn away, apparently some dirt gets kicked up that way. I was able to pierce both lines with just my fingers.
I replaced both rear lines from the factory connection at that passenger side wheel back. I have no idea why the lines both run on the passenger side...? Next I flushed out all the old fluid and bled the system, rear wheels first. I drove around the block and all seemed well.
Today I drove 4 miles and it felt like the brakes were on more and more so I pulled over and touched the rims to see if I had a dragging caliper. All 4 rims we're wayyy hotter than they should have been. I let it cool then drove home in a couple stages.
How can all 4 brakes be dragging? I did not overfill the reservior. The brakes were good right up until the leaking line a few days ago.
Simple, you bled "both rear brakes". This is not how you bleed Jag X brakes. Just do a search in this forum and there are numerous posts on the correct bleeding process and sequence.
Maybe I misspoke, I didn't bleed both rear brakes at the same time. I bled the rear passenger side, then the rear driver side, then the front passenger side, then the front driver side. Same procedure I have used on a dozen cars, same procedure in the X-Type shop manual (shop manual procedure below). The logic I learned is you bleed the longest brake line first which is why you always start at the rear passenger side. Looking at the Jag lines the rear driver side line is longer. Anyway, that is academic, I bled the brakes per the shop manual procedure. Also I only changed brake lines and flushed & bled fluid so in my mind either I got the air out or I didn't, I don't see how I did anything that causes all 4 brakes to drag.
Driving the car again I find all 4 brakes dragging almost all the time, but they will occasionally release properly. Maybe 1 time out of every 10 that I apply the brakes they all release. I didn't get to that leak for a few days so the car sat and leaked out. When I started to replace the brake lines the brake fluid reservoir was dry. Is there a method to bleed the ABS system? I'm thinking I might have air in the ABS hydraulics.
Thanks, that all makes sense but I am not understanding how to bleed the ABS hydraulic control unit. He says "Bleed this like the calipers. Have an assistant pump the brakes then while they hold the pedal down crack loose each line on that HCU and master." When bleeding a caliper the fluid is diverted by a bleeder valve at reduced pressure into a container via a rubber hose on the bleeder valve. There is no bleeder valve on the HCU. If I crack the lines on the HCU while under pressure I am going to get brake fluid squirting out in every direction under high pressure, right?
As all four calipers appear to be sticking On, a likely cause is that you flipped a master cylinder seal when putting it through a much longer stroke than In normal useage when bleeding the brakes. The master cylinder bore maybe worn. A new or refurbished MC is looking probable to me.
To close this up for anyone who finds this thread later, follow the thread Dell mentions just above. Summary: In my case the rod on the brake booster that pushes on the master cylinder was too long. Maybe before the brake job there was enough air in the system that it wasn't noticeable? I don't know why it happened after a brake job but here is what worked. Remove the master cylinder from the brake booster. Have an assistant press the brake pedal, or jam a 2 x 4 or something against the driver's seat to hold the brake pedal so it is fully depressed. In the middle of the brake booster where the master cylinder normally would be you will see an actuator/rod/stem. The end of that stem has a bolt with a 7mm hex that threads in and out to adjust the length. Through careful measurement or trial and error turn the end of the stem with a 7mm socket while holding the female threaded end with pliers so you aren't just spinning the whole thing around. Righty tighty shortens the rod length. Assuming standard metric thread (I have not measured or confirmed this, just a guess) 1 complete turn of the stem end should shorten the thing by about a millimeter. Worked like a charm for me.
dh53: Congrats. Your repair worked because the pistons can now fully retract inside the master cylinder, so they no longer block the compensating ports. Previously, with your foot off the brake pedal, the push rod was ~1mm too long and pressed the master pistons ~1mm into the master cylinder, just enough to block the compensating ports. When brakes heat up, brake fluid thermally expands and, when your foot is off the brake pedal, is supposed to flow backwards thru the compensating ports into the reservoir over the master cylinder. But when the compensating ports are blocked because the master pistons can't fully retract, the expanding hot brake fluid can't escape thru the compensating ports, so instead it pressed the caliber pistons into the brake pads and rotors.
Brakes sticking after bleeding
