Weak vacuum wiper problem

dman · Post by **dman** » Fri Feb 08, 2008 7:51 pm

I installed NOS vacuum wipers on my M37 the wipers only move when I let off the gas. How can I boost the performance? I am not expecting miracles but just want to keep them moving slowly. Thanks

Lifer · Post by **Lifer** » Fri Feb 08, 2008 7:56 pm

If they're NOS, the grease inside them is probably dried up a bit. Try sucking a little kerosene or ATF through them. It doesn't take much.

dman · Post by **dman** » Fri Feb 08, 2008 8:01 pm

Thesae are the foreign ones from VPW (french?) How would I get a couple fo drops of Kerosene into them? Is it as easy as taking a syringe and shooting a bit into each? Thanks

Lifer · Post by **Lifer** » Fri Feb 08, 2008 8:52 pm

Your vacuum hose is on one side of the motor (usually the right side on an M37). Directly opposite it, on the other side, is the air inlet. Start the engine, turn the wipers on one at a time, and trickle a little "lube oil" into the air inlet as it runs. You should notice an improvement very shortly. A flexible tube or a medicine dropper will help reduce the dribbling, but you will spill some, so have a rag handy to catch your drips.

dman · Post by **dman** » Sat Feb 09, 2008 9:47 am

A few drops of oil really helped hte pasenger side motor it works finw. The drivers side motor almost works it won't quite go all of the way to the left and hangs up. If I move it the last inch by hand it completely cycles but hangs up agina at the same point. I am not sure how much oil becomes too much I have put about 3-4 drops in each of 20 weight oil.

gwalker · Post by **gwalker** » Sat Feb 09, 2008 10:40 am

Do you know if the vac. side of your fuel pump is working? the wipers will do poorly w/o the vac boost from the pump.

Lifer · Post by **Lifer** » Sat Feb 09, 2008 12:13 pm

Have you checked the rubber line for the left wiper to see if you have a vacuum leak? That could be contributing to the problem. Glad you got the passenger side working, anyway. At least "she" can tell you what you're about to hit.

Meanwhile, keep plugging and you'll have both wipers going in no time.

knattrass · Post by **knattrass** » Sat Feb 09, 2008 12:43 pm

Anyone ever use Hemmings to rebuilt the vac wipers? I have two in the "stuff box" I got with my truck. Sid tells me he has new ones for around $50. I do not plan on tossing them out but just wondered if it was worth rebuild or new.

MSeriesRebuild · Post by **MSeriesRebuild** » Sat Feb 09, 2008 2:59 pm

dman wrote:A few drops of oil really helped hte pasenger side motor it works finw. The drivers side motor almost works it won't quite go all of the way to the left and hangs up. If I move it the last inch by hand it completely cycles but hangs up agina at the same point. I am not sure how much oil becomes too much I have put about 3-4 drops in each of 20 weight oil.

Use something that is a solvent/light lubricant liberally first until they get going, then follow up with a little lube oil afterwards. This is likely as good as it gets, so if it works for you, great. Vacuum wipers aren't much even with the pump assist working properly. If you ever get good operating wipers that will offer dependability in any weather, you'll have to install some good quality electric motors. Bear in mind GOOD QUALITY, not something like the JC Whitney China cheapies.

dman · Post by **dman** » Sun Feb 10, 2008 6:07 am

Thansk Charles I don't plan on using them much I just like the idea of them working. I am trying to think what product fits the bill "solvent light lubricant" maybe WD40? I am a bit concerned about solvents I have things like bore cleaner for rifle cleaning etc but don't want to ruin anything in the wiper motor.

Lifer · Post by **Lifer** » Sun Feb 10, 2008 6:31 am

WD40 should do the trick quite nicely!