I am the owner of a TE 905 Hilti Jackhammer, Serial No. 234137, I need to purchase replacement brushes and a 14" long flat chisel bit for the Hilti Jackhammer

Either one, it will need to use plus size bits, not standard.
https://www.manualslib.com/manual/1266494/Hilti-Te15-C.html

sounds like it needs a rebuild kit. Hilti.com for parts or to contact Hilti to see if you can get parts. It will also have the parts breakdown.

Have seen this problem with some 'none' HILTI bits which do not fit correctly into the SDS chuck.
Tends to be with larger drill bits which have a wider shank than the SDS connector, the wider shank hits the end of the drill nose which stops the end of the drill bit contacting with the internal hammer.
Solution is to purchase original bits from Hilti. If you have OEM bits and chisel it will be another problem. Hope this helps.

I have just dismantled my own TE 905 to see why it was dropping the chisels and have found the following:-

1. The chisel is worn and has almost become too small for the chuck. (mesure the thickness of the chisel at both ends of the hexagonal shaft and see the difference)

2. The chuck is worn and will probably need to be replaced.
I phoned Hilti today and was quoted £100 for ONE PART OF THE CHUCK!!!

a. The chuck as a whole can easily be removed by undoing the four torx screws that hold the chuck on to the main body.

b. The chuck can be dismantled by removing the retaining ring that holds the metal outer case in place at the front of the chuck. This is very fiddly and requires some engineering skill, the use of pointed instruments could easily result in injury.

The third fix is the one I am going to use to 'patch up' my old breaker. This involves welding some small amounts of dissimilar weld onto the points of the hexagonal section at the rear of the chisel then grinding them to near enough the original size of the un-damaged section of the chisel.
This will very crudely stop the chisel from passing the ball bearings inside the chuck. PLEASE NOTE THAT ANY HEAT APPLIED TO THE CHISEL WILL CAUSE STRESS AND POSSIBLE FAILURE OF THE CHISEL. ANY MODIFICATIONS OF THIS NATURE COULD RESULT IN INJURY TO PERSONS WORKING AROUND YOU AND ARE NOT RECOMMENDED IF YOU ARE WORKING AT HEIGHT OR WITH PEOPLE BELOW YOU. This is a fix that should only be attempted by competent engineers for use on a DIY or small job basis. Hope this helps.

Hilti 800-879-8000

If you have the old type TE905, which is the one with the square type handle at the back, the service light will come on for 2 reasons. Either there is a tight bearing which will increase the amount of current used to work the machine. Or more common the carbon brushes need replacing. To reset the light, simply cure the problem.

If you have the newer type TE905 with the large “D” Type handle at the back. It gets a bit more complicated. The service light will come on for the same reasons as mentioned above, but it will also come on after 200 hours of use. It will continue to work for another 50 hours with the light on, then it will shut down completely. This is to ensure that it gets regular service. Once serviced or repaired, it will require resetting. To do this you with need a Hilti optical interface, a PC, and Hilti ODA Software. This is not available to the general public. If your Hilti is less Than 2 years old, call Hilti. They will pick it up, repair it, and send it back to you in 3 working days FREE OF CHARGE. If it is older than 2 years there will be a charge for the repairs.
I hope this helped you. Please leave feedback

If you have the old type TE905, which is the one with the square type handle at the back, the service light will come on for 2 reasons. Either there is a tight bearing which will increase the amount of current used to work the machine. Or more common the carbon brushes need replacing. To reset the light, simply cure the problem.

If you have the newer type TE905 with the large “D” Type handle at the back. It gets a bit more complicated. The service light will come on for the same reasons as mentioned above, but it will also come on after 200 hours of use. It will continue to work for another 50 hours with the light on, then it will shut down completely. This is to ensure that it gets regular service. Once serviced or repaired, it will require resetting. To do this you with need a Hilti optical interface, a PC, and Hilti ODA Software. This is not available to the general public. If your Hilti is less Than 2 years old, call Hilti. They will pick it up, repair it, and send it back to you in 3 working days FREE OF CHARGE. If it is older than 2 years there will be a charge for the repairs.
I hope this helped you. Please leave feedback

Some of them typically to start up slow. Less wear on the motor. Also make sure you're not using too much drop cord. No more than 100 ft 12/3. May be the brushes if you've had it for awhile. Please rate me

Wiring schematics can be found by Hilti 1-800 number but they probally will not help you. The 905 is programed to shut down for service every 40 hours plus 10 warning. Then in my case I am stuck with a 200 dollar bill to send the tool from Winnipeg to Montreal for reprograming. Its a joke in my situation and its on me from Hilti, what a good name but what a scam.