# PC7800 Sander help



## Aver (Jan 2, 2014)

Hi guys, 

I have a Porter Cable 7800 sander that just started given me fits after two years of good use. When I was using it yesterday the black drive cable that attaches to the the sanding head twisted itself up in a figure 8 and the motor stopped spinning. I shut it off and straightened it out only to find out that it has melted the threads off the backing pad retaining nut. I put a new nut on today and it worked for 5 minutes and then the cable again twisted and ruined another nut. I took the backing plate off and it was damaged and looked like it melted. Can someone tell me if there should be threads present on the inside of the backing plate? I'm thinking that I need to order another backing plate. 

Thanks
Andy


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## gazman (Apr 29, 2011)

Yes you will have to replace all melted components. The problem is caused by the bearing in the head of the sander, it will need to be removed and replaced. The standard bearing is poor quality, replace it with a quality Japanese bearing. Also you do need to do regular maintenence on the sander. Check out this thread. 
http://www.drywalltalk.com/f9/porta-cable-maintenance-3020/


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## D A Drywall (May 4, 2013)

gazman said:


> Yes you will have to replace all melted components. The problem is caused by the bearing in the head of the sander, it will need to be removed and replaced. The standard bearing is poor quality, replace it with a quality Japanese bearing. Also you do need to do regular maintenence on the sander. Check out this thread.
> http://www.drywalltalk.com/f9/porta-cable-maintenance-3020/


Thanks for the link to that great post. I bought my PC used and had issues with the bearing a few months ago. Now I will be able to clean up my sander properly. You have no doubt saved me and others a bunch of money with this preventative maintenance post


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## gazman (Apr 29, 2011)

No problem DA.


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## Aver (Jan 2, 2014)

Thanks for the good info. I have new parts ordered and will put in a nicer bearing when I fix it this week. Thanks for the help.


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## doitalldrywall (Dec 8, 2014)

I bought a 7800 PC sander and the head brushes stick out past the pad. I have to push a little harder to make it work,any ideas on what I could do to fix it???


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## Bazooka-Joe (Dec 31, 2010)

doitalldrywall said:


> I bought a 7800 PC sander and the head brushes stick out past the pad. I have to push a little harder to make it work,any ideas on what I could do to fix it???


brushes meaning broom type is there to keep dust to go to vacuum 

need more info about why your pushing, as in the screws or ridges dont go away fast, then your sandpaper is not the right grit for the type of mud


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## gazman (Apr 29, 2011)

doitalldrywall said:


> I bought a 7800 PC sander and the head brushes stick out past the pad. I have to push a little harder to make it work,any ideas on what I could do to fix it???


Have you got the soft backer on it? It is like a piece of sponge about half inch thick with velcro on the face. This will pack it out level with the brush.


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## doitalldrywall (Dec 8, 2014)

No, it just came with a sanding pad


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## Bazooka-Joe (Dec 31, 2010)

doitalldrywall said:


> No, it just came with a sanding pad


Gaz is right, when I got the soft pad it sanded better, the ole lady picked it up at home depot

this baby, I bought 2 and the first one is on the sander few years later, I dont run hot on any machine tool but cool down periods with me cleaning bead sand angles, never had melt downs and did reg maintenance like Gaz said


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## gazman (Apr 29, 2011)

BTW. The bearing that I used to replace the dodgy porter cable bearing is.
SKF 6001-2RSH. The size of it is 28mm OD 12mmID width 8mm.


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## D A Drywall (May 4, 2013)

Just took down the bearing number. Hopefully my tool repair guy can source it. Thanks Gazman


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## keke (Mar 7, 2012)

gazman said:


> BTW. The bearing that I used to replace the dodgy porter cable bearing is.
> SKF 6001-2RSH. The size of it is 28mm OD 12mmID width 8mm.


Gaz

how is the short PC ?

did you make it work?


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## gazman (Apr 29, 2011)

Still sitting on my work bench. I have to get a short cable made up. Been slack:yes:


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## keke (Mar 7, 2012)

gazman said:


> Been slack:yes:


didn't expect that for you


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## gazman (Apr 29, 2011)

Got it done Keke. Give it a go tomorrow. :thumbsup:


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## keke (Mar 7, 2012)

gazman said:


> Got it done Keke. Give it a go tomorrow. :thumbsup:


I knew you'd do it


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