I installed a new winshield rubber and the it still leaks. should i use some type of silicone for glass or should i try re-installing the rubber with the rubber only again.

 

When I did mine i used just the rubber seal and it leaked as well. I pulled it off and sealed it with the black windshield adhesive/sealant and it never leaked again. I also sealed between the glass and the rubber seal on the exterior. Something else to think about if you have the screw in type of moulding clips is that you need to seal each one of those. Water could migrate through.

 

Don't try to seal with silicone. If it doesn't leak it will eventually and then you'll have a mess trying to remove it to seal it properly.
3M has a sealant in a tube for a caulking gun called glazing and bedding compound. It seals well and gets firm without hardening.

 

+1 on the bedding and glazing compound. it is also used to seal the watersheilds behind your door panels heres a link you can order it here or use the number to sorce it locally

3M Auto Bedding & Glazing Compound Black - 08509

https://www.autobodytoolmart.com/p-10389-12829.aspx