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#1 Brake fluid disappeared

Posted: Sun Oct 31, 2021 10:50 pm
by peters3103
Hi gents,
I’ve just noticed hydraulic fluid under my car thinking clutch slave but upon inspection my inner brake fluid bottle is nearly empty. It looks as though the fluid is dripping from the vacuum tank. Has the fluid syphoned into it? If so what is the cause? I’ve checked the hoses are on the check valve in the correct locations.

Cheers,
Pete

#2 Re: Brake fluid disappeared

Posted: Tue Nov 02, 2021 3:49 pm
by Allrand
Check the brake master cylinder for leaks. I had a similar leak which drips onto the vac tank, runs down the seam & drips off the bottom of the vac tank. Check if the paint down the side of the tank has been disolved by fluid.

#3 Re: Brake fluid disappeared

Posted: Tue Nov 02, 2021 6:51 pm
by cactusman
The 3.8 Kelsey Hayes brake system cannot pull brake fluid directly into the vacuum reservoir. As Allrand says check the master cylinders for weeping. Do also check the reservoir bottles. The repro ones are extremely prone to spitting and the brake fluid seeps down and often drops onto the reservoir and so it may look like that's where it comes from....

#4 Re: Brake fluid disappeared

Posted: Tue Nov 02, 2021 11:08 pm
by Jeremy
...my repro bottles didn't spit....but they did split.... :geek:

#5 Re: Brake fluid disappeared

Posted: Wed Nov 03, 2021 8:44 pm
by peters3103
Thanks gents and yes I removed the air cleaner yesterday and noticed fluid had dripped, presumably from one of the the master cylinders, onto the vacuum tank. No damage to my new paint! Fluid bottles are dry as are the flexible hoses. I’ve encountered the dreaded splitting bottles previously. I’ve washed/wiped everything clean and driven the car and no leaks evident yet. The car hadn’t been driven for a few months prior. I’ll pop the dust boots off the M/C’s and see if there’s any fluid in either. Maybe it’s fixed itself 😂

Pete

#6 Re: Brake fluid disappeared

Posted: Fri Nov 05, 2021 1:18 am
by peters3103
Well it didn’t miraculously fix itself of course! The top master cylinder is weeping. I’ll remove it and strip it down. Hopefully I can repair it with a rubber kit rather than replace it but that will, of course, depend on the condition of the bore. I’d like to keep the cylinders matching if possible.

Pete

#7 Re: Brake fluid disappeared

Posted: Sun Nov 07, 2021 11:12 am
by cactusman
Sadly leaks rarely repair themselves...more is the pity!