Brake fluid in Servo/booster

[Wike]

How do I get brake fluid out of servo/booster in my '74 TR6? Just replace M/C, but either the new M/C did not seal well, or, there already was brake fluid in servo from old M/C. Brake fluid on footwell floor..no dust cover under rubber boot on brake pedal assembly.

 

[TR3driver]

Probably the best option is to remove the booster and have it rebuilt. Conventional brake fluid is somewhat corrosive and frequently the booster will fail soon afterwards anyway.

But last time it happened to me, I used a cheap venturi type vacuum pump linked to a Mason jar to create a kind of vacuum cleaner, and used that to suck the fluid out of the booster with it still mounted on the firewall. Seemed to work OK (although the car has been off the road for other reasons for a few years now, so I don't know if the booster still works today).

 

[Dale]

I think that if the fluid is on the backside of the diaphragm in the booster, then the diaphragm is already shot. The filter has nothing to do with keeping fluid in. It is there to keep big chunks out of the booster when the diaphragm moves towards the front and air is brought in to the booster.

 

[bobh]

Wike,
Something that is mentioned in the other replies, but needs to be more clearly stated.
Brake fluid cause 2 problems
1 It removes Paint
2 It is hydroscopic, attracts and combines with water

When brake fluid leaks into the booster it strips the protective coating of paint on the inside of the booster. Once the paint is gone and the coating of brake fluid mixes with moisture in the air. The inside of the booster will begin to rust. It won't take long for the metal to pit. Ultimately leading to the destruction of your booster from the inside out.

The same thing can happen to the bottom outside of the booster. If your old master cylinder was leaking at the bottom of the seal where the booster rod pushed the master cylinder rod into the MC. The fluid may have also leaked onto the outside of the booster, dripping down the underside. The paint will be gone, metal exposed to the ravages of hydroscopic brake fluid.

I agree with the comments from the others that you need to have the booster taken apart and fixed ASAP. If you are concerned that this is beyond your skills or do not have the tools Brosky mentioned. Ship it to the experts.

I'm in the middle of replacing my master cylinder and upgrading my brakes. My MC began to leak just a little at the bottom of the seal mentioned above. I suspect the initial leakage was very slight but as fluid accumulated it corroded the MC allowing more fluid to escape. Some began to drip down the bottom side of the boosted. It removed the paint and surface rust began to appear. I removed the MC and Booster. I found no evidense of fluid entering the booster. I thoroughly cleaned the outside of the booster with brake cleaner followed by several scrubbings with dish soap. Then removed all the paint with a wire wheel, wire brushed all surface rust until it was gone. Used a phosphoric acid gell (Aluminum jelly) to acid wash the surface twice. (To provide the paint with a freshly etched surface for better adhesion). Dried and painted with VHT Caliper paint, dried over night, then baked it for an hour at 175

Note: even with the scrubbing and hosing down at various steps I never saw any water come from inside the booster. I feel it was safe to assume the seals on the booster are intact and prevented leakage into the body. BTW. I've used the VHT caliper paint on other vehicles. Brake fluid does not affect it.

As fo my Master Cylinder I opted to have it sleeved and rebuilt by White Post. The price was more than the cost of an economy MC and less than the cost of a premium MC. I sent it to them on a Monday. It was back the following Monday.

My reason for the sleeving is that as the seals get old and start to weep brake fluid they will not attack the surface where the seal is made. Brass should not corrode like the original cast iron of the MC. If I'm correct I should not have to buy a new MC in the future. Only install a rebuild kit as the current one begins to age. WP recommends changing the brake fluid every few years. This should minimize the amount of moisture absorbed by the fluid.

White Post provides a writtten lifetime guarantee for their materials and workmanship. I'm sure this does not include the rebuild kit. I have no financial interest in White Post. I do have a considerable financial interest in my TR6! But I will say their service was excellent!

BOBH

 

[SherpaPilot]

Wike,
Something that is mentioned in the other replies, but needs to be more clearly stated.
Brake fluid cause 2 problems
1 It removes Paint
2 It is hydroscopic, attracts and combines with water

When brake fluid leaks into the booster it strips the protective coating of paint on the inside of the booster. Once the paint is gone and the coating of brake fluid mixes with moisture in the air. The inside of the booster will begin to rust. It won't take long for the metal to pit. Ultimately leading to the destruction of your booster from the inside out.

The same thing can happen to the bottom outside of the booster. If your old master cylinder was leaking at the bottom of the seal where the booster rod pushed the master cylinder rod into the MC. The fluid may have also leaked onto the outside of the booster, dripping down the underside. The paint will be gone, metal exposed to the ravages of hydroscopic brake fluid.

I agree with the comments from the others that you need to have the booster taken apart and fixed ASAP. If you are concerned that this is beyond your skills or do not have the tools Brosky mentioned. Ship it to the experts.

I'm in the middle of replacing my master cylinder and upgrading my brakes. My MC began to leak just a little at the bottom of the seal mentioned above. I suspect the initial leakage was very slight but as fluid accumulated it corroded the MC allowing more fluid to escape. Some began to drip down the bottom side of the boosted. It removed the paint and surface rust began to appear. I removed the MC and Booster. I found no evidense of fluid entering the booster. I thoroughly cleaned the outside of the booster with brake cleaner followed by several scrubbings with dish soap. Then removed all the paint with a wire wheel, wire brushed all surface rust until it was gone. Used a phosphoric acid gell (Aluminum jelly) to acid wash the surface twice. (To provide the paint with a freshly etched surface for better adhesion). Dried and painted with VHT Caliper paint, dried over night, then baked it for an hour at 175

Note: even with the scrubbing and hosing down at various steps I never saw any water come from inside the booster. I feel it was safe to assume the seals on the booster are intact and prevented leakage into the body. BTW. I've used the VHT caliper paint on other vehicles. Brake fluid does not affect it.

As fo my Master Cylinder I opted to have it sleeved and rebuilt by White Post. The price was more than the cost of an economy MC and less than the cost of a premium MC. I sent it to them on a Monday. It was back the following Monday.

My reason for the sleeving is that as the seals get old and start to weep brake fluid they will not attack the surface where the seal is made. Brass should not corrode like the original cast iron of the MC. If I'm correct I should not have to buy a new MC in the future. Only install a rebuild kit as the current one begins to age. WP recommends changing the brake fluid every few years. This should minimize the amount of moisture absorbed by the fluid.

White Post provides a writtten lifetime guarantee for their materials and workmanship. I'm sure this does not include the rebuild kit. I have no financial interest in White Post. I do have a considerable financial interest in my TR6! But I will say their service was excellent!

BOBH

Bob: I just found this old post you wrote back in 2012. You addressed my concerns quite well. I looked up White Post and downloaded their info on sleeving. This looks like a long-term fix to the problem. Thanks

 

[Rod-H]

Another thought is Silicone Brake fluid, Dot 5. Some people will most likely chime in and state how you can't use silicone or it will cause a rip in the space time continuum or some such. I've had good luck with it on all my British cars. It won't hurt the paint.

If you need a rebuild on your servo, I've used: Brakes Materials & Parts, 800 Sherman Boulevard, Fort Wayne, IN 46808, 260-426-3331.

I found them from the Buckeye Triumphs page- > Brakes — Buckeye Triumphs <. You can read the article about rebuilding the servo yourself, but, after reading it you may decide (like I did) it is safer to let someone with a lot of experience in brake servos do it.