rebuilt brakes loose all fluid from master reservoir

#1
hi there,
I recently rebuilt the front brake calipers , installed new rubber hoses.
Bled and tested and a run of the car up the road, all was good.
2 weeks later and it was today..............as follows.
Today I started the car , pressed the brake pedal and my foot went to the floor..
opened the master brake reservoir and it was empty?
So topped it up, started the engine , pumped the pedal and a very slight pressure was evident, but nothing like a normal brake.
Q: where has the brake fluid gone?
the car is on hard concrete and looking underneath there is no evidence of any fluid on the ground!
this has never ever happened to me in all my years of owning old cars!
has the fluid ended up in the servo?
Peter
 
#2
hi there,
I recently rebuilt the front brake calipers , installed new rubber hoses.
Bled and tested and a run of the car up the road, all was good.
2 weeks later and it was today..............as follows.
Today I started the car , pressed the brake pedal and my foot went to the floor..
opened the master brake reservoir and it was empty?
So topped it up, started the engine , pumped the pedal and a very slight pressure was evident, but nothing like a normal brake.
Q: where has the brake fluid gone?
the car is on hard concrete and looking underneath there is no evidence of any fluid on the ground!
this has never ever happened to me in all my years of owning old cars!
has the fluid ended up in the servo?
Peter
If there is a fault in the servo, the fluid can be drawn through the vacuum hose and into the inlet manifold. That manifests itself as a very smokey exhaust as the fluid is combusted.
 
#5
noticed my brake fluid going down .no leaks found ..topped up.. brakes sticking on .. so removed servo for exchanging ( wins) and lo and behold ..servo full of fluid! I replaced brake master cylinder too. footbrake needs a touch more pressure than last servo..funny that! but handbrake is still only just about passing MOT . ( despite replacement cable .exchange rear callipers .new discs/pads. pipes flexi's and mechanical check for set up cable tension. full movement etc .ggrr never had that on my old mk4 zephyr an that essentially used same rear brakes.. 2-3 click held that easily .now i have to pull hard and expect cable to snap under strain.. one day I might ( pigs flying?) fond out where i am going wrong. still theres a classic car meet in clacton in may ..so will have to see if any P6's come along and politely ask if i can try a handbrake out ..see if theres a real difference.
 

clive P62

Active Member
#6
Hi my handbrake holds on 3 clicks and when pulled up hard to about 6 clicks it locks the wheels on the brake tester when i last MOTd.
Sounds like you have an adjustment issue or faulty internal mechanical ratchet assembly.
Regards.
Clive.
 
#7
my thoughts but having stripped entire rear axle with diff off and checked on a bench .unable to find anything amiss or sticking/not working. probably missing something silly . I was considering stripping down again in summer and checking the actuating pins and pistons are ok. though whats odds of having all four callipers having a problem. though it did pass MOT ( just ) its the effort involved applying handbrake thats worrying. have already removed cable and checked cable is free.handbrake assy is easy and not jammed or sticking. refitted . slight lube , adjusted several times to get cables working easily and pulling well. at this stage a keeping an eye open for a possible brake conversion but so far think its rather exotic such as e type rear dii and brakes ..a touch beyond my pension means.
 
#9
with regard teh original issue...there are two places the fluid can go without spilling everywhere, the brake booster and the mechanism covers for the rear brakes. If you remove the vacuum hose from the booster you can put a dipstick/piece of wood in the hole and see if it has fluid in it... The rear end will eventually start to leak out when the housing fills up.

With regard the second issue somewhere here there is a recent post on setting up the cable correctly. Meanwhile if you get under the car you can see how far the linkage has moved on each side. If it has gone the full way the pads are not adjusted up fully. You can either take the car for a drive and keep braking lots or take the pin out of the linkage and hand adjust them up till they stop clicking. If the cable is not correct one brake can tighten up but the other one will remain loose as the mechanism pulls unevenly.
 

vaultsman

Well-Known Member
#10
Only had to set the handbrake on two occasions, and followed Harvey's method both times....disc out, and adjust the pads up until the disc will just slip in the gap. To avoid having to lug the disc up to the pads every time, I made up an MDF gauge at disc thickness and used that until I was very close. Make sure the quadrants are back on their stops when at rest.
Perfect handbrake on 3 clicks.
 
#11
There is a third place for fluid to go, but it does leave a hint. If the pushrod seal on the master leaks, fluid will escape into the inside of the firewall. However, enough fluid will run down the pushrod that you'll have a small drip inside the car on the pedal.

Yours
Vern
 
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