C3 wiper door not closing

[tom444634]

1970 350/350 wiper door will open but not close. All hoses have been checked for leaks and the vacuum "tree" next to the master cylinder has been replaced. The door can be closed when the engine is shut off by manually pushing it down. It opens when the wiper switch is activated and the wipers work. The headlights work fine also.

This is on a friend of mines car and he has spent a lot of time chasing vacuum lines and replacing parts all to no avail. The only part he did not replace is the canister that actually opens and closes the door. I let him use the one off of my car (which funtions fine)and he is going to try it today.

Ideas?

Thanks,

Tom

[Phil P.]

Re: C3 wiper door not closing

check the grommet on the actuator cannister closest to the fire wall---the one with the arm---it will be under the accordian rubber boot---it should look like a small black funnel---it is a thin rubber and has probably rotted out---if that is the problem and you cannot find a replacement i have another fix that wors fine---good lusk

[Jack H.]

Re: C3 wiper door not closing

The Chassis Service Manual has a nice write up (theory of operation) on how the wiper door works... When you read this, you'll understand there are 'interlocks' between the electrical and vacuum system to prevent malfunction. One of these deals with the door closing.

You do NOT want the door to close BEFORE the wiper motor has properly parked the wiper arms and shut itself off. Hence, there's a vacuum sensor/switch in the cowl compartment that the RH wiper arm (last to park) rests against when it stops. This vac switch bolts to a cross member and has enlongated mounting holes allowing you to 'adjust' it to properly sense the stopping point of the RH wiper arm.

If the vac switch is bad or it's been installed and NOT adjusted, the RH wiper arm can come to a stop and the vac system will NEVER know it's time to actuate the wiper door closing system....

[Terry M.]

Re: C3 wiper door not closing

The circumstance Jack describes (Passenger side wiper arm not contacting the limit switch) is exacerbated by operating the wipers on a dry windshield. The passenger side wiper will often not travel far enough down to actuate that limit switch on a dry windshield. Be sure to wet the windshield thoroughly when testing and adjusting the wipers.

[Jim T.]

Re: C3 wiper door not closing

Phil the fix you mentioned is that the baby bottle nipple replacement for the original type seal?

[Phil P.]

Re: C3 wiper door not closing

jim you pegged the description perfectly---i have repaired mine using the "nipple" base with another hose that i slid on the actuator shaft (cut the nipple off and used the base)looks like a power brake booster housing seal for the vac. line) and used dielectric grease for lube/sealing---it worked awsome---contacted the seller about my amazing fix---he said look in the ash tray and i would find the new nipple seal---yes it was and still is there---several beers and some mental constipation to solve an easily fixed (look in the ash tray)problem led to my fix---i'm use to working on cars that have no re-pop shop to help with parts

[Jim K.]

Re: C3 wiper door not closing

Hey Phil:
I just bought a 70 350/350 and the actuator is off the car. Ihe piece looks new but the rubber you mentioned is completely ripped out and obviously, no seal. the other end works fine and I seem to have all the parts I need. What is this "other" fix you talk about. I'm still waiting for my CC catalog... Thanks!
Jim

[tom444634]

Re: C3 wiper door not closing

Thanks for all of the ideas! We will try to tackle it on Sunday.

Tom

[Jim T.]

Re: C3 wiper door not closing

Phil I read an article many years ago in Vette Vues about using the baby bottle nipple to replace the seal in the vacuum cannister. I used a silicone baby bottle nipple to replace the seal in my 70's original vacuum cannister about 18 years ago and it is still working great. The base of the nipple fits very well into the vacuum cannister. I used a spent shell casing to cut a hole in the nipple end, smaller than the shaft, and it has sealed well. With the accordian boot over the shaft, the nipple is not visiable.

[Phil P.]

5/16 ac hose fix quick & simple

jim---i used the old nipple minus the thin funnel part which i cut off (save the white plastic funnel support sleeve for future use)---i slid about a 2 inch length (measure your shaft and cut accordingly) of 5/16 (8mm)ac hose (parker futura brand)the id will seal to your shaft and the od will seal to the remainder of the nipple---assemble using dielectric grease as all will be snug check your AIM i think shaft length adjustment is 3/8 + - 1/8 ---good luck--
phil