Lump Posted September 1, 2008 Share Posted September 1, 2008 Gidday Guys, this is my first post here so I hope you can help. I've got an Jaguar XJ with a chev V8 in it. I recently had the brake booster rebuilt as it wasn't working properly. It worked beutifully for about a week, then yesterday the travel on the pedal gradually got shorter and shorter with the brakes slowing the car down. I managed to get within a couple of metres from my garage before they stuck fast. Couldn't budge it even with the gas pedal halfway down (the brake pedal wouldn't even move at this stage). I cracked open the front LHS bleed nipple which released some fluid (it sounded like the other brakes released at the same time) This allowed me to get the car into the garage - with minimal brake usage. It sounds like a problem with the master cylinder rather than the brake booster to me. Any ideas Quote Link to comment Share on other sites More sharing options...
forced Posted September 1, 2008 Share Posted September 1, 2008 Those flexi hoses block up inside, they swell holding the brakes on. There'll be one going to each front brake and maybe a single one feeding the rear pair. Steve Quote Link to comment Share on other sites More sharing options...
Lump Posted September 8, 2008 Author Share Posted September 8, 2008 Cheers Man, Swapped the front hoses and bled the system and the problem seems to be solved. I've got a pair for the rear too so I might swap those when I change the diff oil this weekend. I suppose as brake problems go its preferable to have them stuck on rather than off - it was still pretty anoying though Quote Link to comment Share on other sites More sharing options...
Lump Posted April 18, 2009 Author Share Posted April 18, 2009 Bloody hell it happened again. Got a warrant this morning (I think the braking test may have set the problem off again). Anyhow the problem was exactly the same as my first post and solved the way although I had further to drive to get home this time. Seeing as all the flexi hoses were replaced I'm guessing something else is blocking the system. I'm going to flush it thoroughly is there anything I should be looking for - stuck calipers, dodgy master cylinders? Quote Link to comment Share on other sites More sharing options...
Hemi Posted April 18, 2009 Share Posted April 18, 2009 Bloody hell it happened again.Got a warrant this morning (I think the braking test may have set the problem off again). Anyhow the problem was exactly the same as my first post and solved the way although I had further to drive to get home this time. Seeing as all the flexi hoses were replaced I'm guessing something else is blocking the system. I'm going to flush it thoroughly is there anything I should be looking for - stuck calipers, dodgy master cylinders? im n ot a expert on hydrualic systems ( work mostly air) but if the bores in treadle valves get dirty or out of round for some reason the piston can jam and not be able to move back .. this is a possibility it will not be a boost problem as the booster only assists the master . pull the master out and have a look .. wel actually just unhook the pipe off it and see if it does stick and jesus if there something big enough the system to block it something must be pretty wrong Quote Link to comment Share on other sites More sharing options...
Unclejake Posted April 19, 2009 Share Posted April 19, 2009 This does seem to be a Jag thing recently. Can't help much more than that though except to say I think you should check the flexilines after you remove them as I suspect they are not the problem Quote Link to comment Share on other sites More sharing options...
CaMpylobacter Posted April 19, 2009 Share Posted April 19, 2009 i can't rmember the name of it but there's a port on the master cylinder which will block up causing this. the small runout on the discs will cause a bit of expansion in the fluid due to heat, when this can't return to reservoir then the brakes slowly come on. mate had to tow a lady whom had this happen to her mazda 323 yesterday. in short, maybe rekit your mastercylidner (you're doing this to pull it apart and clean out, you can't really re-use the seals without having them crap out in a matter of days anyway) and flush the whole system with clean fluid. hope you get to the bottom of your problem. if that's not it then there's not alot mroe to look at Quote Link to comment Share on other sites More sharing options...
Lump Posted April 22, 2009 Author Share Posted April 22, 2009 Thanks for the help guys. Because this has happened twice without much warning I've had the MC rebuilt and resleeved, seems to be fine so far and my variable pedal travel has disapeered. I probably would have been fine with a rekit but decided to play it safe due to the weight and age of the car. Hopefully thats the end of it. Quote Link to comment Share on other sites More sharing options...
CaMpylobacter Posted April 23, 2009 Share Posted April 23, 2009 mean simple rekit often doesn't last long. i think the honing often goes a litle overboard then takes the tolerances out way too far. plus it's not bad price wise to resleeve anywho good luck Quote Link to comment Share on other sites More sharing options...
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