Brake fluid loss

hxroger

New Member
Car brought out of hibernation in March and ran ok, Two weeks ago went for a drive and no brakes! Checked fluid level empty but no sign of leaks. Managed short drive to local garage today, using handbrake, and their report this afternoon said in spite of careful inspection of brake lines, calipers and all connectors no sign of leakage could be found. Their suspect is the brake master cylinder, but before they source a replacement has anyone else had a similar problem? Forgot to mention that after finding empty fluid reservoir I refilled it and it has stayed full for the last week.
 
Leaks with the master cylinder can be detected by feeling the pushrod that joins with the pedal. It will be wet with fluid if there is a leak, in addition, if you have lost all the reservoir fluid, the carpet will also be wet with fluid.
Did they check inside the booster? Pull the vacuum hose out of the vacuum chamber, insert a rolled-up piece of paper to mimic a straw, or better still, a paper straw, insert, and remove. The paper will be wet with fluid if the slave cylinder is leaking.

Ron.
 
I have had similar issues with my car in the past. On occasion I have experienced a leak at the master cylinder but typically it has been fairly small and consistent. You can check the push rod behind the brake pedal and if there is a leak, you will certainly find some brake fluid there. The other way I have had mysterious vanishing brake fluid is due to a failure in the brake servo. It leaks onto the vacuum side of the servo and pools there. A lot of fluid can sit in there before it starts to leak out. You can pull the vacuum line out of the servo and "dip" the cavity with some suitable tool. make sure not to damage the diaphragm. If you find any fluid there, the servo needs rebuilding. On a couple of occasions, I have found what seemed like litres of brake fluid sloshing around in there. Interestingly, the brakes still worked reasonable well but a rebuild became an urgent requirement.
 
Also fluid that leaks through the seals in the rear calipers, will normally stay within the covers, so it won't be that obvious.
 
It will be in the rear caliper covers, as Demetris says. I refurbished Hazel's rear brakes a few weeks ago & the calipers were full of fluid:

image0 (3).jpeg

It's down to the worn seal (old one on piston):

image1 (2).jpeg

..which goes in the bottom hole in the caliper casting:

image0 (2).jpeg

They are spot on now :)
 
Brake fluid level waning light??
I was losing fluid because of a leaking rear calliper. Cured by replacing the callipers. Also losing fluid from leaking clutch slave cylinder. I think that the fluid reservoir servers both clutch and brakes.
I was also getting false 'brake fluid level' warnings because the cork float in the reservoir had become saturated with brake fluid and did not float at the required level. A wine bottle cork makes a good replacement
 
Lost a res full of fluid in a couple of weeks topped up pumped a bit & o.k. for a couple of weeks seems to come from front left and rear slightly to the left also. mobility makes it unable to inspect, does it seem like a major job, or seals, also I'm in hemel hempstead Herts. if anyone knows of a capable mechanics nearby, thanks
 
Unless their LHD, in which case the clutch and Brake reservoir is shared also on 4 cyl cars.
I think it depends on the year. My LHD 1968 2000 TC has separate reservoirs. The clutch reservoir is integral with the master cylinder and the brake fluid reservoir is separate.
 
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@clumsy, I've sent you a private message with the contact info of a mechanic near you who knows the Rover P6 well.
Popprd into a local mechanics in kings langley, a mk2 jag on ramp & capri waiting, guy seemed knowledgable so will let them examine & give a Quote . if i accept and they do a good job, I;ll mention them here.
 
I think it depends on the year. My LHD 1968 2000 TC has seperate reservoirs. The clutch reservoir is integral with the master cylinder and the brake fluid reservoir is seperate.
It might be because we had the dual circuit brakes too now you mention it.
 
Anyone used the Gunson EZBleed? Mine arrived yesterday. One man operation, it does clutch and brakes. Pressure pumped from the spare wheel into a bottle, various sized caps come with it.
 
Anyone used the Gunson EZBleed? Mine arrived yesterday. One man operation, it does clutch and brakes. Pressure pumped from the spare wheel into a bottle, various sized caps come with it.
I've not had a great deal of success with an Ezee Bleed in the past. Best success I've had is with auto bleed nipples such as this one and using the factory manual method of one full pump down, followed by three rapid half pumps before releasing. That works very well.
 
Be very careful with any pressurised bleeding equipment, any leak can lead to fluid spraying everywhere. Cover as much paintwork as you can, and have a large jug of water in reach to immediately pour on any fluid that gets onto paintwork.
 
I've used the gunson pressure bleeder on various cars. Worked fine, but I tended to fear the brake fluid apocalypse that Cobraboy mentions above. Just make sure you don't exceed the pressure it states.
After a near miss, caused by a rubber seal in the cap not sitting right, I have reverted to combining brake bleeding with a marital arguement. Thankfully not a regular event. The brake bleeding at least.
 
If I can I like to use gravity to bleed and just use pedal pressure to get the fluid over high points. I am conscious that some pipe layouts make this very difficult. I changed my flexible hoses and rebuilt the callipers on the front of my 2200 without resorting to any pressure . Replaced the rear callipers on my Rover 45 a few weeks ago, same procedure
 
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