I have a Bosch CSB 850 2Ret drill . When I try to start it the motor appears to be strainign and the chuchk will not tutne of turns very slowly. If I try and start it very slowly sometinmes it will get going but then If I stop it I have the same problem sometimes even when it is going but not actually being used the chuck will stop as it the torque control has cut in because it is being overloaded.

The user manual doesn't contain much more information than is intuitive to anyone familiar with power tool use and mostly contains safety advice.

You can download a user manual for your diy drill at the link below. If you have questions not covered by the manual you can use the comments facility.

https://www.bosch-diy.com/gb/en/service/user-manuals

You probably have a loose wire at one on the connections inside the unit. Open it up and have a look at all the connections, pay special attention to any push in connections as they tend to get loose over time.

Have you check the continuity of the wires through the drill? Try contacting www.oasistools.com for help

the ancre and / or a part of the electric field damaged. drivinggear must be replaced if ancre was gone too , but in most cases its not worth to repair if it has its working hours on it.

10th March 2013. I experienced the same problem with my Bosch drill. Yes, it also only worked when held in the vertical position. I pulled the drill apart. In my case, the problem was right at the base of the drill where the electrical cord and the drill meet. In that area, there is a flat piece of hard plastic which holds the cord securely in place. This is held down by two screws. Directly beside that is the rubber attachment that hold the drill chuck. Well, right in that spot, there was a gaping hole in the wiring (refer attached photo). It will not be seen, unless you, or a service agent, pull that area apart. Anyway, I shortened the cord, secured the wiring again, and the drill works perfectly. Good luck. Ted.

It is a spring loaded hammer drill. You need to push the chuck down just a bit for it to engage the clutch. If it is still slipping then either the clutch pieces (items 23 and 32) are worn or item 32 is spinning freely on the spindle shaft. Here is a parts diagram.

Bosch CSB470-RLE diagram

If you mean the R/l switch attached to the top of the switch. The wires from the brushes go to diagonally opposite connections and the field leads in the others. If it go slow in forward motion swap the brush wires over with each other.

It could be that the drill bit is not well fixed, so make sure it is well fitted on the drill machine

bosch brushes are unique. they have a spring embedded in the carbon so when the length gets too short, the spring lets go and raises the brush above the commutator and the appliance stops. you need to remove the handle partially or the brush covers and unscrew the brush holder(s) two small screws secure the brushes and holder to the appliance.