Brake fluid
#1
Brake fluid
Hello all, the brakes on my grandmother's 1989 xj6 are pretty much useless. When the brakes are applied nothing happens until the brakes are pumped a few times. After that the car will stop until you need to apply them again than you must repeat the procedure of pumping them again a few more times until the car stops. Since my grandmother is elderly the car is never driven. She has other cars that are her daily driver and his more or less sits (it has 49,000 original miles). In the past year only 150 miles have been put on it. The brakes have always been spungy but have always stopped the car until now. The indicator in the engine bay is green, but I figured it may have gone bad and ordered the correct mineral oil to add anyway. I added the whole 500 ml bottle but the brakes are still bad. My question is could the fluid be so low more is needed, and if so how much should be in the system when it's full? Also, assuming that is not the issue what else could be the issue? Thanks so much for your help.
#2
I may be on the wrong track here as my 94MY car doesn't have the same system ...but AFAIK the green mineral oil system is the brake assistance booster and is separate from the actual brake fluid circuit. Brake fluid is clear and gets added in a different reservoir.
If you have spongy brakes or if you have to pump them, it usually means you have air in the lines and the brakes need to be bled - wouldn't be a bad idea to drain and refill the brakes either ...of course you use regular DOT 3 brake fluid in the main brake system ... I sure hope you didn't fill up the master cylinder reservoir with mineral oil ...
Larry
If you have spongy brakes or if you have to pump them, it usually means you have air in the lines and the brakes need to be bled - wouldn't be a bad idea to drain and refill the brakes either ...of course you use regular DOT 3 brake fluid in the main brake system ... I sure hope you didn't fill up the master cylinder reservoir with mineral oil ...
Larry
#3
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#5
Join Date: Nov 2013
Location: Inverell, NSW, Australia
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Cole; bleeding brake lines is a snap, well documented in JTIS which you can download from Stickys. Having an assistant to sit in car and push brakes is not critical, but handy.
But . . . here is the super critical bit. Brake fluid is hygroscopic . . . ie it starts lapping up moisture vapour once it is exposed to air. After a couple of years in your brake lines it contains sufficient dissolved air and water vapour that rust starts anywhere and everywhere throughout brakes. Steel brake lines start rusting, literally, from the inside out.
So . . . use new brake fluid of correct spec (bright red or green are good) and start bleeding at wheel furthest from master cylinder. Two rules . . . while bleeding, check regularly and top up master reservoir so that air can't enter as fluid drops and . . . after bleeding to remove all air bubbles, keep bleeding until old fluid is expelled and brightly coloured fluid is flowing. Nip up bleed screw and repeat for remaining 3 wheels in turn. Don't be surprised if you go through a full bottle of new fluid.
Cheers,
Ken
But . . . here is the super critical bit. Brake fluid is hygroscopic . . . ie it starts lapping up moisture vapour once it is exposed to air. After a couple of years in your brake lines it contains sufficient dissolved air and water vapour that rust starts anywhere and everywhere throughout brakes. Steel brake lines start rusting, literally, from the inside out.
So . . . use new brake fluid of correct spec (bright red or green are good) and start bleeding at wheel furthest from master cylinder. Two rules . . . while bleeding, check regularly and top up master reservoir so that air can't enter as fluid drops and . . . after bleeding to remove all air bubbles, keep bleeding until old fluid is expelled and brightly coloured fluid is flowing. Nip up bleed screw and repeat for remaining 3 wheels in turn. Don't be surprised if you go through a full bottle of new fluid.
Cheers,
Ken
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Cole Middleton (06-09-2017)
#6
Finally done
Thanks y'all for all the replies. It has taken me a while with some family issues appearing this summer, but I finally got the brakes bled and they work great, actually better then they have in years. The car never gets driven so I imagine the brakes have needed bleeding for a while, but it has taken this long for me to notice they REALLY needed it. Anyway thanks again
I have attached some images of the car in question.
I have attached some images of the car in question.