Brake Bleeder

[John P.]

Hello, does anyone know if they make a thread in fitting for a brake bleeder that fits the two cap holes on a 1966 power brake master cylinder? I have a Motive bleeder that I fabricated two caps; however, I misplaced them. If anyone knows a part number or manufacturer of these adapters, I would greatly appreciate the help. Thanks in advance for any and all help, John

[Mark E.]

Re: Brake Bleeder

I'm not a C2 guy, so I'm not sure if your car has a single or dual reservoir master cylinder.

If single, this may work: https://www.motiveproducts.com/colle...ducts/adapters

If dual, this may work: https://www.motiveproducts.com/colle...erican-adapter
(This is the adapter I use on the 1970.)

Neither "thread in", but rather clamp over the top of the reservoir(s). I use a large C-clamp to fasten it, instead of the provided chains and hooks.

[John P.]

Re: Brake Bleeder

Hello Mark and thank you for the response. I have a dual master cylinder with 2 individual thread in caps. I have the universal covers that you show, however they are tough to seal on this style master cylinder. Using the universal style adapters creates quite a mess and as you know brake fluid and paint don't go well together. I just thought that some manufacturer made the screw in adapters. Again, thank you for your time, John

[Mark E.]

Re: Brake Bleeder

To avoid a mess, I use the Motive Bleeder differently than its instructions suggest. I don't add brake fluid to the Motive, and use the Motive as an air pump to pressurize the reservoirs. No fluid in the Motive's tank, lines or adapter means less chance of a mess.

Why can't you get an air tight seal with the universal adapter? Is it because the reservoirs are at different heights? If so, can you pressurize one reservoir at a time with the small round adapter?

If the Motive just won't work with this master cylinder, you might try using a vacuum pump at each caliper and bleed by drawing fluid out.

[Thomas S.]

Re: Brake Bleeder

To avoid a mess, I use the Motive Bleeder differently than its instructions suggest. I don't add brake fluid to the Motive, and use the Motive as an air pump to pressurize the reservoirs. No fluid in the Motive's tank, lines or adapter means less chance of a mess.

Why can't you get an air tight seal with the universal adapter? Is it because the reservoirs are at different heights? If so, can you pressurize one reservoir at a time with the small round adapter?

If the Motive just won't work with this master cylinder, you might try using a vacuum pump at each caliper and bleed by drawing fluid out.

I also had the same issue with not being able to get a good seal on a dual cylinder (67 standard brakes) and you comments about using air pressure instead of fluid makes sense. Used the Mytivac as well as the Motive cylinder adapters with no luck. Maintaining the fluid level would require you remove the cap often or it will run dry and I just want to make sure I'm not missing anything with the air pressure approach.

[Dave B.]

This is what you need: Amazon.com: Motive Products 1122 Large 1-5/8" Classic Car and Boat Trailer Adapter, Compatible Power Bleeder Attachments : Automotive.

It works beautifully, but you'll need to buy a 1-5/8" square profile rubber gasket instead of using the round one provided with the adapter which doesn't provide a proper seal. I got my gasket from a NAPA store for about 2 bucks. And like many others I do not put brake fluid in the Motive bottle, I only use it as a pressurizer. I once had the vinyl tube burst and it sprayed brake fluid all over the engine, car paint and garage wall. NEVER AGAIN.

I tried the Mighty Vac bleeder first, and it was useless. Don't waste your time with that.

Motive bleeder cap.jpg