Re: Very slow wipers...

Posted by HH56 On 2010/10/21 21:38:36

If you have a good strong vacuum at the wipers at idle, then the vacuum pump is probably OK. It's in series with the manifold vacuum source and doesn't do much of anything but act as a pathway in normal operation. When you are at a load or under acceleration and manifold vacuum drops below what the vacuum pump can provide, then the vacuum pump is stronger and provides the vacuum to wipers. You can test it by disconnecting the hose going to the manifold at pump and see how much is left at the wiper motor. It won't be as strong as manifold provides but if not there or very weak, then the pump or hoses might be leaking and could need attention as well.