Trouble Shooting Wiper Canister Vacuum

[Lonnie Wiggins]

This problem really sucks - actually it doesn't, and that's the problem.

When the push/pull vacuum lines to the wiper cover control cansiter (did I say that right?) are both plugged, The head lights work perfectly.

When the lines are connected to the canister, the headlights are very sluggish and the wiper cover won't move at all.

My conclusion is there has to be a vacuum leak at the cansiter. If it was "upline", it doesn't seem the head lights would work when the push/pull lines are plugged.

I can only suspect that I'm suffering vacuum loss around the push/pull shaft coming out of the canister. It otherwise appears to be a closed system.

Any input would be appreciated, other than sell the car and buy a new one :-(.

Would a heavy grease around he shaft have any effect, or is it useless to pursue fixing this one.

IF I need to replace the canister, are the "large peanut butter jar" shaped canisters available repro or otherwise?

Thanks.

[Roberto L.]

Re: Trouble Shooting Wiper Canister Vacuum

Hello, you may test the canister. Plug the hose inlets and try to move with care the axle, you should feel a lot of resistance. There is a rubber seal which usually fails in the 70 style canister, easy to repair at present.
Could be the case.

Roberto, NCRS #30019, RMC

[Roberto L.]

Re: Trouble Shooting Wiper Canister Vacuum

Hello, you may test the canister. Plug the hose inlets and try to move with care the axle, you should feel a lot of resistance. There is a rubber seal which usually fails in the 70 style canister, easy to repair at present.
Could be the case.

Roberto, NCRS #30019, RMC

[Jim T.]

Re: Trouble Shooting Wiper Canister Vacuum

Lonnie the seal for the shaft on the cannister is very easy to replace. I read about this in a Vette Vues article many years ago and I tried it and it works on my 70. Buy a baby bottle nipple, the standard style. I used the silicone nipple but you can use the rubber one. The base of the nipple fits very good in the cannister. In cutting a hole in the nipple for the shaft a small caliber shell casing would work to give a clean cut for better sealing. This repair is not seen if you still have the rubber dust cover over the shaft. If you want to use the real seal it is available from Dr. Rebuild.

[Jim T.]

Re: Trouble Shooting Wiper Canister Vacuum

Lonnie the seal for the shaft on the cannister is very easy to replace. I read about this in a Vette Vues article many years ago and I tried it and it works on my 70. Buy a baby bottle nipple, the standard style. I used the silicone nipple but you can use the rubber one. The base of the nipple fits very good in the cannister. In cutting a hole in the nipple for the shaft a small caliber shell casing would work to give a clean cut for better sealing. This repair is not seen if you still have the rubber dust cover over the shaft. If you want to use the real seal it is available from Dr. Rebuild.