Jakobsen sj12

Hello. I am repairing the Jakobsen sj12 surface grinder which I bought on the auction. It was in a pretty bad condition. I have fixed the hydraulic system, all the leaks and electrical problems. Lots and lots of cleaning.... but I have stuck now. Here's the problem. It had no spindle drive belt and spindle drive motor vibration dampers, so I have bought a set. There are four of them on each corner. Two of them are orange and pretty soft and two of them are black and much harder. Im not sure which one goes to the front and which one to the back? Im trying to adjust the belt, but no matter what I do I can not get the motor and the spindle drive pulleys align. The belt is slipping away towards the spindle. I almost managed to make it stay, but I felt like there's not enough belt tension. Is there a specific way to do it? There's no info in the manual. I hope someone can help me. Thanks.

Just a guess but I'm thinking you'd want the softer dampers nearer the motor to absorb vibrations and the stiffer/harder ones closer to the spindle/wheel area to support the grinding wheel more rigidly. Let's see some photos of your specific areas of concern. Have you checked the spindle gibs to ensure they're not excessively loose to be sure the slindle is squared up? If it's not correctly aligned, the belt will probably want to run off. If that's good you may need to realign the motor by shifting it on its mount or shimming it, depending on the way its mounted.

I will speculate, not having seen the machine, you want the two hard
rubber mounts on one side of the motor and the two soft mounts on the
other. In that way, the flexing of the soft mounts to not tilt the
motor causing the belt to misalign and run off. Used in this way
the soft mounts will provide the motor with a little give and will
help keep proper tension on the belt.