DeWALT DCD785 18v cordless drill problem.

[scooby1]

I wondered if anyone would be kind enough to help me please ? I have the above drill but have encountered a problem. The collar that allows changing between different torque settings is working fine but with one exception. I have found that I can no longer turn it to the position where the hammer option is engaged.
I have tried turning it both ways to no effect, and in fact if I try to turn it to the hammer position whilst operating the drill I can just feel a slight hammering action. It feels as if it is trying to engage the gearing (or whatever the hammer action is) but if I let go of the collar thre is no hammer noise. Might this mean that a good clean inside is needed ?
I have looked on YouTube but can't find anything relevant. I think I could get the chuck off, I am certain that it is a T20 headed screw inside there and YouTube videos tell me that it is a LH thread. I am tempted to start a dismantle but everything else about the drill is working fine and I don't want to do anything that will mean that I have to go and buy a new drill.
Any help and/or advice would be much appreciated. Thank you.

 

[cdbe]

They're a bit fiddly to pull apart and get back together again if you haven't done it a few times before. In my experience it would take some extensive "dusty" use to clog it up so unless this is the case I would suspect a mechanical failure.

 

[Wayners]

Dust I guess.

Lash chuck with spray can of lithium grease but maybe it's got dry inside and binding.
Plan B is take apart and if that fails buy another.

 

[scooby1]

Thank you Gentlemen for your quick replies. Really appreciated. I wondered if it might be brick dust or something like that that's got in there but I haven't used the hammer part of the drill very often. I have an airline in the workshop, I'll give it a blast with that and report back. Is there any point in flooding it with WD40 or would that make it worse. Presumably even when I've got the chuck off there is still a gearbox of some sort to deal with ?

 

[Wayners]

Could try wd 40 but that don't last. It dries up vs lithium grease

 

[Keithmac]

The Blue Tin WD40 is terrible full stop.

 

[scooby1]

Thanks again for your help and advice. But can we get one thing clear before I "meddle" Is the "gearbox" (if that's what it's called) all part of the chuck. i.e. If I take the chuck off is that also the bit that holds all the bits and pieces that make up the torque options and the hammer option ?

 

[cdbe]

A while ago but I replaced the entire gearbox assembly on my 996 and I'm pretty sure it all comes off from the "other" end ie you don't need to remove the chuck:

I've pretty much given up spending more than half an hour trying to fix these things now - I tend to just flog them on eBay for parts and buy a new one. I did the 996 because it was nearly new (£125) and the gearbox was about forty quid.

 

[scooby1]

A while ago but I replaced the entire gearbox assembly on my 996 and I'm pretty sure it all comes off from the "other" end ie you don't need to remove the chuck:

View attachment 269669

I've pretty much given up spending more than half an hour trying to fix these things now - I tend to just flog them on eBay for parts and buy a new one. I did the 996 because it was nearly new (£125) and the gearbox was about forty quid.

Mmmm - I can see the reasoning behind your thoughts. It all looks a bit fiddly in there. The only thing is that the rest of the drill works as it should and so I'm tempted to hang on to it and if/when I need a hammer drill I go and buy a specific one. If I did decided to replace the gearbox where would I get one from ? Where do you get spares for these things from ? Thank you for your continued help.

 

[ETAF]

Only a DIYer ,
But i use the Bosch multipurpose drills , and on various brickwalls - (as i say only a diyer , helping out a few people here and there) - I have not needed hammer since i started to use them - you may be lucky
in 2 houses where i used traditional masonry bits , i had to use the hammer , now on the same walls i do not

are you trade , and in a lot of different places ?

just an example of the drill bits
loads of different kits and sizes available from toolstation & screwfix
https://www.screwfix.com/p/bosch-expert-straight-shank-multi-purpose-drill-bits-4-piece-set/138ky

 

[scooby1]

Only a DIYer ,
But i use the Bosch multipurpose drills , and on various brickwalls - (as i say only a diyer , helping out a few people here and there) - I have not needed hammer since i started to use them - you may be lucky
in 2 houses where i used traditional masonry bits , i had to use the hammer , now on the same walls i do not

are you trade , and in a lot of different places ?

just an example of the drill bits
loads of different kits and sizes available from toolstation & screwfix
https://www.screwfix.com/p/bosch-expert-straight-shank-multi-purpose-drill-bits-4-piece-set/138ky

The drill, together with an impact driver, is what I use in the farm workshop for the small stuff. If I can going to drill bigger than 1/4" and can get it into the drill I use one of my pedestal drills. One is a 3ph MT up to No. 3. I do
occasionally use the DeWalt for domestic use if the Boss says she wants a job doing. I only used to use the hammer action if I couldn't get a masonry drill in by drilling normally. I have masonry drills aplenty but thank you for the link.

 

[cdbe]

MMTC or there's a place in Liverpool for parts. It won't be the gearbox on yours. Could well be just the selector jammed - the diagram looks a bit scary because it's exploded - they do come apart in bigger lumps than that if you feel brave!

 

[scooby1]

MMTC or there's a place in Liverpool for parts. It won't be the gearbox on yours. Could well be just the selector jammed - the diagram looks a bit scary because it's exploded - they do come apart in bigger lumps than that if you feel brave!

Thank you very much for that. ! I gave it all a good blow out with the airline but it hasn't fixed it. I must admit it does just feel like something is jammed. Suddenly I feel brave. I'll have another look on YouTube if you think it should be dismantled from the rear. Could you elaborate on "MMTC" please ? I just Googled it but couldn't find anything relevant. Thank you again.

 

[Keithmac]

You may as well take it to bits as it's broken anyway!.

I've learnt most of what I know by dismantling stuff and fixing it (mostly..).

 

[big-all]

You may as well take it to bits as it's broken anyway!.

I've learnt most of what I know by dismantling stuff and fixing it (mostly..).

a man after my own heart
top tip take loads off pictures at every stage for reference