Have a Invacare Pronto m51 Sure step. Trying to change batteries and the seat seems to be stuck

8 flashes is a Controller Fault

https://www.manualslib.com/manual/723349/Invacare-Pronto-M50.html?page=25#manual

https://www.google.com/search?q=m51+pronto+sure+step+flash+codes

Question edited for clarity, full 'make model (what it is)'.

Videos and where to buy.

https://www.google.com/search?q=m51+pronto%2C+replace+carbon+brushes

Service manual

Pronto Series M50 M51 M61 - PDF Free Download

http://docplayer.net > 58262751-Pronto-series-m50-m5...
Refer to Motor Testing on page 31 or Replacing Motor Brushes on page 116. Replace controller or send to Invacare for repair. Refer to Replacing the ...

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It seems to be a known issue. Is it the black disc by the axle in this image?
https://www.monsterscooterparts.com/brands/invacare/models/pronto-m51/motor-and-gearbox-for-the-invacare-pronto-m51-and-pronto-m61-power-chairs.html

I would put a large hose clip around it. If you have the old one, you can probably get a replacement from Home Depot, or contact the company for a free one.

http://www.invacare.com/cgi-bin/imhqprd/contact.jsp

More info and manuals etc

https://www.google.com/search?q=Invacare+Pronto+M51+gearbox+grease+oil+plug

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1. Pronto M51 Troubleshooting‎

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Service Indicator Light Diagnostics - Invacare Pronto M51 ...

www.manualslib.com > ... > Pronto M51 > Maintenance manual

Invacare Pronto M51 Base Manual Online: Service Indicator Light Diagnostics. ... Invacare power wheelchair owner's operator and maintenance manual.

The 3 lights are blinking a diagnostic code. One code for batteries that are to weak is a 2 blink. The 3 lights blink together between 1 and 7 times then they all stop for a second then repeat the same amount again and again. Post the code here if you don't have a manual to look it up.

There is no reset button on a M51 chair. Invacare puts fuses in the battery harnesses. The manual may say there is a reset but trust me there is not.

Judy He has to disconnect the joystick cable and then pull the seat off the post raising up the seat turning lever and twisting and pulling upward on the seat at the same time. It can be hard because the seats are heavy and can be rusted. Just keep pulling and turning at the same time Once he has the seat off he can remove the cover over the batteries and disconect the cables going to the batteries and the large connector going to the power pack. Reinstall the new batteries just like the old ones replace the cover. Put some axle grease or vaseline on the seat post reinstall the seat plug in the joystick cable and you should be good to go Hope this helps

goto invacare.com when the home page comes up on the left side of the page you will see product catalog under that select Wheelchairs and top end. Next screen select Power Wheelchairs. Next screen select Pronto Series. Next screen select non-powered seating. Next screen select Pronto M51 with Sure Step. That is the last screen on the left side you will see owners manual select that and you can print it out with Adobe. Good Luck Hope this helps

Margie,   Yes you may charge it overnight. If you use it everyday,charge it every night. Once the charger senses 24 volts it stops sending a charge,so they cannot be overcharged.  I suggest when you go to bed put on the charger and unplug it when you get up in the morning.