1957 wiper motor to leak?

[Boozeman]

I recently performed the brake fluid trick on the wiper motor on my '57, which worked perfectly. Probably the easiest repair on the T-bird with the most solid results! My wipers work like new! However, more recently, upon startup, the engine runs a bit rough, and I can hear what sounds like a vacuum leak under the dash. After several seconds to about a minute, I can hear what sounds like a flap being sucked shut and the leak stops, allowing the engine idle to even out. I can put my finger over the port on the front of the wiper motor, but that's apparently not where it's leaking (I can still hear a leak). All of my vacuum lines under the ash are new and the connections are tight. Once the leak stops after startup, it doesn't return until I shut the car off and re-start it. It happens equally when the engine is warm or cold. I've never had the wiper motor out or apart... is it possible for the motor to leak vacuum from somewhere other than the port on the front or the vacuum input port?

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[jack-in-sac]

It may be the "cricket " valve for the heater.

 

[Boozeman]

It may be the "cricket " valve for the heater.

Thanks for the reply, Jack! Please educate me, what is the "cricket" valve on the heater? FWIW, I did away with the vacuum operated switch on the intake manifold, so I've since bypassed the heater in the vacuum system (took the tee out of the vacuum line under the dash).

 

[Ward 57]

If you have a big enough vacuum leak to make it run rough, you have a pretty big leak. The only other vacuum line to the interior is to the wiper switch itself which I wouldn't think could leak that much as the fuel pump helps supply vacuum to that. Do the wipers work during the short time you hear the leak? It could also be the choke circuit. Once the choke is fully open the leak stops and runs smooth. It's a shot gun approach but I would go back and check every connection.

 

[paul5456]

It sounds like the flapper valve in the wiper motor is the problem. The brake fluid trick saturates this (usually leather) valve so it seals in the motor. If it does "fix" itself after a very short while, I would suggest you run the car as normal to see if the flapper works in.

Not familiar with the 57 set up, but you have a vacuum line going to the switch, it might have a leak there as suggested above. Check the condition of the hose at this point (56's don't have a vacuum line going to the switch)

 

[Boozeman]

It sounds like the flapper valve in the wiper motor is the problem. The brake fluid trick saturates this (usually leather) valve so it seals in the motor. If it does "fix" itself after a very short while, I would suggest you run the car as normal to see if the flapper works in.

Not familiar with the 57 set up, but you have a vacuum line going to the switch, it might have a leak there as suggested above. Check the condition of the hose at this point (56's don't have a vacuum line going to the switch)

Thank you for the replies! I'll check both of these places after work tonight.

 

[paul5456]

Another suggestion - pull the wiper blades and run the motor to see if the flapper will work in.