Losing Brake Fluid

[Member 17500]

I'm losing brake fluid in my 1966 Austin Healey 3000, but can find no leaks anywhere. I checked all pipes, hoses, junctions, master cylinder, reservoir, calipers, rear brake pistons, and servo. All dry. The car has a replacement Lockheed booster. Thinking that fluid may be being sucked from a leaky booster into the intake manifold, I rebuilt the entire booster. No change. I've read that white smoke is a sign of burning brake fluid, but my car had whitish exhaust (probably incomplete combustion or water vapor) long before this problem appeared. So that's not much help.
Any advice, assistance, or recommendations would be greatly appreciated.
Thank you!

 

[Keoke]

Most likely the missing fluid is inside the brake booster vacuum tank. Remove the booster,shake it if you hear sloshing it time for good rebuild.---

oh!! yeah that exhaust be tellin U something now-

 

[Member 17500]

Thanks. But I disassembled and rebuilt the booster and it was dry. I'd welcome other ideas.

 

[Michael Oritt]

Roy--

Never having had a Healey with a booster I know nothing more about them than what I read here. However since your car was smoking white prior to the brake fluid loss problem is it possible that condition is masking the brake fluid being burned presently?

Beyond the brake fluid issue if that white smoke is in fact water vapor that might be a sign of a bigger problem that is likely to get worse. Do you have to add coolant?

 

[Member 17500]

Thanks. Coolant level is fine, not a head gasket problem. But you're probably right: the usual white exhaust is masking the burning brake fluid. Where else could it be going? Matter cannot be created or destroyed, merely changed in form. Applies to Healeys, too.

 

[RAC68]

Hi Roy,

I appreciate that you have already checked the master cylinders, however, I would suggest you pull back the rug and see if any fluid has been absorbed into the rug padding. This is a condition that I have experienced where the MCs are leaking very slowly around the seal and collecting in the cap, The leaking fluid eventually runs down the rod when the brake/clutch is applied. Since the leak is slow, and being absorbed under the dash and into the rug padding, it is not obvious and easy to overlook. Although an MC rebuild can cure the issue, sometimes over honing and the present quality of parts will combine to require a new unit.

All the best,
Ray (64BJ8P1)

 

[Patrick67BJ8]

I had a leak in my '67 that was caused by the line from the MC to the reservoir. The line rubbing against metal on the fender well and the fluid was not seen nor was it leaking bad but it was leaking. I assume that driving the car with the engine & drive train vibrating is when it was leaking.

 

[Member 17500]

Thank you, Ray and Patrick, for your helpful suggestions. I followed up on both of them immediately. The carpet and underlayment of the driver side footwell is dry. So too for the line from the fluid reservoir to the master cylinder. I imagine even if the line leaked intermittently or only when being driven and so not visible to the driver, I would still see some residue or other signs of a leak in the dust on the fenderwell, but there was nothing. I'm thinking that if there are no signs of leaking, the brake servo must be leaking internally. However, I checked the vacuum line from the servo to the manifold and it was dry inside, too. No sign of brake fluid. Yet what else can I do but replace the servo (even though I just rebuilt it) and hope for the best. That is, if I can find a replacement Lockheed servo unit.

 

[Keoke]

Well:RoyC

You can send it here [ Power Brake Exchange ] and it will stop the white cloud from following you when you get it back.
Location ; San Jose CA