Where is my brake fluid?

Message

#1 Post by **sorbs** » Sun Mar 25, 2007 3:16 am

Suddenly have a very low brake fluid level on my 1969 mk2 - the pedal felt soft which alerted me.  I check the level frequently so probably no more than 100 miles from full to empty.
The drums came off easily!?! and 1 wheel cylinder has a bit of a weep , can only see it if i pull back the cylinder dust cover , the drum & linings are dry - no other visible leaks though. have had wheel cylinders fail on other cars but no major fluid loss, even with soaked brake linings.
Do you think my master cylinder is shot?  Where\'s the brake fluid going?
Alan

#2 Post by **Clifford Pope** » Sun Mar 25, 2007 12:38 pm

Is this a model where fluid can be sucked into the brake servo if a
master cylinder seal fails? I know on some cars fluid can vanish
without trace, and is in fact burnt in the engine.

#3 Post by **Mike Stevens** » Mon Mar 26, 2007 6:21 pm

Hi Alan,
If there is no obvious leaks from the rear cylinders and the front calipers, that only really leaves the master cylinder!  (Assuming no pipe weeps.  Don\'t ignore it - I\'ve had one in the past!)
Thoughts...
1) Look under the drivers floor carpet.  A leak from the master cylinder can come out the front of it and run down into the footwell.
2) Leak into the servo.  Pull out the \'vacuum\' hose and dip a finger/piece of paper into the servo to check for fluid.
3) As Clifford has said, if fluid in the servo gets VERY high, it can be sucked into the engine and get burnt.  You\'d get some smoke which would probably be noticable.
Hope this helps.
Cheers, and good luck!
Mike.

#4 Post by **sorbs** » Tue Mar 27, 2007 12:11 am

Thanks guys,  got to be the master cylinder really.  Tried dipping the servo but there is some sort of filter in the hose connection. Doh!  The brakes seem to be sticking a bit too so it all points to the m/c.
Car is currently with a local garage as I have no time to fix it, will know more tomorrow.
Am just wondering if one of those Monarch BMW servo / master cylinder conversions for a Stag would fit which would also give me dual circuit brakes......

#5 Post by **sorbs** » Thu Mar 29, 2007 3:36 am

Hmmm, the new wheel cylinder seems to have fixed things , brakes are really good now.  Fingers crossed......

#6 Post by **sorbs** » Wed Apr 18, 2007 1:28 am

As I half expected, the fluid loss continued so I had a recon master cylinder fitted today.  Hopefully this will cure it.
Even if it doesn\'t, its worth it for the improvement in braking performance.  The pedal has a decent travel now, making full effect of the servo.  The pedal was rock hard before so I suspect the old m/c was partially seized.  There is now a slight hiss as I press the pedal which I gather is the servo operating.
The old master cylinder bore was full of silty gunge which couldn\'t have been helping things. I\'m supposed to send the old one back, but may take it apart anyway for a look see.....
 