1956 Windshield Wiper Motor Brake Fluid “fix”?

[knuckle47]

There are a few posts about brake fluid re-wetting of the leather in the vacuum motor for the windshield wipers but none explain how or where to add the fluid. I may be making more out of it than it really is but: where is the best place to input the brake fluid and about how much?

Thank you…..

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[biddle]

Found these instructions online-

• Connect a clear bottle containing Dot 3 or 4 brake fluid to the inlet tube on the wiper motor located under the dash. I use a plastic bottle with a hole punched in the lid and a rubber vacuum hose that fits snugly on the wiper inlet tube. The wiper inlet tube is located on the side of the motor facing the radio.
• Turn on the wipers, run the engine at idle, turn the wipers and the vacuum should suck the fluid into the wiper motor.
• Then work the wipers by hand until they work on their own. The brake fluid will soften the dried leather seals in the motor.
• Make sure the vacuum hose is always below the level of the fluid. Also, to prevent blade drag on the dry windshield, squirt soapy water on the windshield, this will provide lubrication for the blades.
• It usually takes about a pint of brake fluid to complete the process. It’s a good idea to have an old rag or towel on the floor under the inlet to catch any drips once the fluid hose is removed.
• Run the wipers several minutes after the fluid hose is disconnected to remove excess fluid from the wiper motor. There will be some white smoke from the exhaust as the fluid is sucked into the engine. It will not hurt the engine and will clear up soon after all the fluid is purged from the system.
• Also, check to make sure that the vacuum source lines are connected correctly to the engine.

 

[Boozeman]

Found these instructions online-

• Connect a clear bottle containing Dot 3 or 4 brake fluid to the inlet tube on the wiper motor located under the dash. I use a plastic bottle with a hole punched in the lid and a rubber vacuum hose that fits snugly on the wiper inlet tube. The wiper inlet tube is located on the side of the motor facing the radio.
• Turn on the wipers, run the engine at idle, turn the wipers and the vacuum should suck the fluid into the wiper motor.
• Then work the wipers by hand until they work on their own. The brake fluid will soften the dried leather seals in the motor.
• Make sure the vacuum hose is always below the level of the fluid. Also, to prevent blade drag on the dry windshield, squirt soapy water on the windshield, this will provide lubrication for the blades.
• It usually takes about a pint of brake fluid to complete the process. It’s a good idea to have an old rag or towel on the floor under the inlet to catch any drips once the fluid hose is removed.
• Run the wipers several minutes after the fluid hose is disconnected to remove excess fluid from the wiper motor. There will be some white smoke from the exhaust as the fluid is sucked into the engine. It will not hurt the engine and will clear up soon after all the fluid is purged from the system.
• Also, check to make sure that the vacuum source lines are connected correctly to the engine.

I've used this method with success - it works! There will be a LOT of white smoke from the exhaust, but as Biddle said, it will clear up once the brake fluid is all burned up.

Good luck!

 

[doug7740]

I posted those instructions on the forum. The most probable cause for Thunderbird windshield wipers not working properly is because they are not used regularly. After years of very little use the seals have dried out causing the wiper motor to be sluggish. The internal wiper motor seals need to be cleaned and lubricated. In most cases the brake fluid will soften the dried leather seals in the motor and they will seal once again.

I have done this on a few vacuum wiper motors and it worked like magic. Only on one of them I had to replace the leather seals on inside the motor because of wear.

doug7740
1955 Thunderbird Blue

 

[swatson999]

I've been meaning to do this...what size hose is that? I can pick it up on the way home from work today 🙂

 

[4VE]

I've used this method with success - it works! There will be a LOT of white smoke from the exhaust, but as Biddle said, it will clear up once the brake fluid is all burned up.

Good luck!

Original post said the vacuum motor has leather seals. Would Neatsfoot oil be a better choice? Brake fluid can destroy certain types of rubber and if there is any rubber in the assembly that comes in contact with it, it could cause a major problem.

 

[Boozeman]

Original post said the vacuum motor has leather seals. Would Neatsfoot oil be a better choice? Brake fluid can destroy certain types of rubber and if there is any rubber in the assembly that comes in contact with it, it could cause a major problem.

I can't speak to what neatsfoot oil would do when sucked into the wiper motor or burned in an engine, but the brake fluid trick has been used many many times by many people over many years, and I have yet to hear a story where it actually damaged anything.

 

[doug7740]

A vacuum wiper motor has a semi-circular trough. A pivoting paddle swipes back and forth in the trough; the edges of the paddle fit closely to the sides and bottom of the trough and have leather seals. The shaft of the paddle is hooked to the wiper arm and as the paddle swipes back and forth, the wiper arm moves. At each end of the paddle’s stroke, a cam on the shaft nudges a valve which applies vacuum to the other side of the paddle, moving it back the other way.

doug7740
1955 Thunderbird Blue

 

[rdeleo]

Have a 56 Bird Read where the use of brake fluid could, maybe up to 95%, reactive the motor. Maybe I am the 5%, but no luck. First time the vacuum hose to the inlet port of the motor would not uptake any fluid. Since then I realized I need to turn the wipers on, and it has since sucked up about 5 ozs. But only the most minor flex of the arm. Question is what is the end state of the motor intake. Is it left open, does it need a rubber cap, or does another vacuum line get attached. And why does this work for some? Any help would be wonderful.

 

[cokefirst]

I heard the same thing. I just had my Thunderbird motor rebuilt by Friken Wiper service. He is the only vacuum wiper repair for Trico vacuum motors that I am aware of. He said that the best way to rejuvenate a motor is to carefully disassemble, clean, then reassemble putting a film of heavy grease like axle grease on the flapper and in the well of the motor.

 

[rdeleo]

Found these instructions online-

• Connect a clear bottle containing Dot 3 or 4 brake fluid to the inlet tube on the wiper motor located under the dash. I use a plastic bottle with a hole punched in the lid and a rubber vacuum hose that fits snugly on the wiper inlet tube. The wiper inlet tube is located on the side of the motor facing the radio.
• Turn on the wipers, run the engine at idle, turn the wipers and the vacuum should suck the fluid into the wiper motor.
• Then work the wipers by hand until they work on their own. The brake fluid will soften the dried leather seals in the motor.
• Make sure the vacuum hose is always below the level of the fluid. Also, to prevent blade drag on the dry windshield, squirt soapy water on the windshield, this will provide lubrication for the blades.
• It usually takes about a pint of brake fluid to complete the process. It’s a good idea to have an old rag or towel on the floor under the inlet to catch any drips once the fluid hose is removed.
• Run the wipers several minutes after the fluid hose is disconnected to remove excess fluid from the wiper motor. There will be some white smoke from the exhaust as the fluid is sucked into the engine. It will not hurt the engine and will clear up soon after all the fluid is purged from the system.
• Also, check to make sure that the vacuum source lines are connected correctly to the engine.

There is no white smoke. Doing something wrong? Put almost a bottle of brake fluid. Left the intake open after using. Any other thoughts?