Mad Rat problem - driveshaft touching diff screw

[smithleon]

Hi All,

As a return to RC after 20 years I built the Master Smacker and love it. Great car for the price.

So now i'm building a Mad Rat too.

I pretty much got it finished last night but I have a problem. I'm finding that with camber rods adjusted as specified in the manual, the driveshaft touches the nyloc nut end of the screw that's holding the diff together when the suspension moves up. I hope that makes senses! As the wishbone moves up, the driveshaft is pushed slightly further into the diff and it just touches the diff adjustment screw, causing the suspension to be stiff on that side.

Now I've sorted this by making the camber rods slightly longer but obviously this means that the camber is off (wheels out at the top a bit).

Has anyone else had the same problem? What did you do to fix it?


Cheers,

Leon.

[nicefrog]

I don't have that problem, but I'm not sure how much clearance I have, which side of the car do you have the nut on? I don't even know if that makes a difference, or maybe it's just not screwed up enough, is the nylon nut completely inside the plastic carrier etc?

[zagonielod]

strange issue..... I don't have that either..... have you used the right size screws and everything?

[JezT]

I seem to remember having a similar problem on my first build - I think the plastic piece (that the nyloc fits into) wasn't sliding fully in the slot - When I swapped it to the other side it was able to slidefully - maybe thats it!

[smithleon]

JezT: I've just seen your reply after I posted this - I will double check for that. Thanks!

Thanks for the responses guys. Don't get me wrong, it's not sticking out a lot - it looked absolutely ok as i built it - I mean, the nyloc nut in the plastic carrier IS designed to sit in the draft shaft cup on the diff isn't it(!) It just seems to be protruding just a tiny bit too much (literally like 1mm or so) for the default camber setup to work. I can get around it but it just seems a bit messy on an otherwise very neat kit.

I do believe the screw is the right size, as i've got nothing left that's anything like it! The nyloc nut is on the left side of the car as you are standing behind the car. Again, I believe this is right according to the instructions. Screwing the nyloc nut up more doesn't acually make any difference as its actually the end of the screw the draftshaft touches.

Cheers,

Leon.

I'll post a pic later - that might help :-)

[nicefrog]

Weird, yes left side is where the nut is on both mine. Post your picture and I'll compare how it looks and see if I can see what's going on, there's only one 2.5mm thick screw in the whole kit it's 25mm long and it's for the diff adjustment so you can't really have the wrong one in there. I'm just wondering if there's something missing in the diff that's making it hang out like that. I forgot one of the two bearings on mine when I first assembled the diff:P. I'm pretty sure both hubs are different? from what I remember, maybe they need to go on a specific side

[smithleon]

Thanks for checking nicefrog. The hubs have the same part number but that doesn't mean much in an Ansmann kit ;-) It was getting late last night so it's possible I didn't notice the two were different. I'll take it apart tonight and check. Will post what I find!

Cheers,

Leon.

[zagonielod]

I'm curious too :) Partially because I've also built it night time :)

[JezT]

Thanks for checking nicefrog. The hubs have the same part number but that doesn't mean much in an Ansmann kit ;-) It was getting late last night so it's possible I didn't notice the two were different. I'll take it apart tonight and check. Will post what I find!

Cheers,

Leon.

The internal faces of the 2 pieces are different - having different ridges inside them.... so it is possible the the outsides are subtly different. I do remember now I stripped the diff apart completely and ensured I rebuilt it again exactly as per the plans.

[budgio]

Leon
If your not too far from Bicester why not get down to the PDA i will be happy to check it over for you.
There are a few guys there running the Ansmann cars and i,m sure we could help you sort it.

[smithleon]

Thanks for the offer budgio.....but what's the PDA?

I've sorted it now. It was only touching the driveshaft by 1mm or so, so I just added a couple of small washers at the philips head end of the screw and that's spaced it out enough. The Rat was flying on the skateboard park this morning :-)

Cheers guys.

[Battle_axe]

Thanks for the offer budgio.....but what's the PDA?

I've sorted it now. It was only touching the driveshaft by 1mm or so, so I just added a couple of small washers at the philips head end of the screw and that's spaced it out enough. The Rat was flying on the skateboard park this morning :-)

Cheers guys.
the PDA is the proline dirt arena in bicester its the only indoor dirt track in the uk and we race on a weds night there are 4 regular ansmann drivers there myself included i am part of ansmanns sponsored drivers team and budgio runs the ansmann product too he usually does better than me as well :thumbdown: however im sure i can fix that :)

[smithleon]

Didn't even know that was there! Have just watched some youtube vids - looks amazing! I'm just down the road in Didcot, so may well pop along at some point!

Cheers. Leon.

[Battle_axe]

Didn't even know that was there! Have just watched some youtube vids - looks amazing! I'm just down the road in Didcot, so may well pop along at some point!

Cheers. Leon.
come down we will get you sorted out also if you cant do in the week there is a brca regonal on sunday there if you have a brca membership then pop down and race in the open class

[j4k3blaze]

how did you sort it, as this has now happened to mine

[nicefrog]

I've checked mine and there's a huge amount of clearance, either one of the parts have changed length or somethings in backwards?. Maybe you can measure some things and take some pictures?

[smithleon]

Nicefrog: I am wondering if they've changed the design of something. In my case, I can't see that's it anything on wrong because frankly its pretty straight forward. Screw through ball-diff and the spring+nyloc in plastic carrier at the other end. My driveshaft was only touching the end of the screw by a tiny amount when the suspension was compressed.

j4k3blaze: I fixed it by adding a couple of small washers at the philips head end of the screw, providing it more clearance at the other end.

[nicefrog]

Yeah I think something must have changed somewhere, I'm just wondering what it is!:), common sense says either the shafts or the hubs. Is the diff screw still a 25mm screw? I think it should be changed to hex head btw

[zagonielod]

Ok. Figured out for you, cas I'm having the same problem now. I have thightend the diff to stop it from slipping, and the end of the diff screw is now touching the CVD's head when the rear arm is going up. Have to shorten it 1-1,5mm

[wayne]

hi ..i had this problem ..even after rebuilding the diff ..what i did was place a washer inside the screwhead n bearing .......problem solved ...i think the screw is slightly tooo long

[kedal]

No no, one of the hub is deeper than the other. You have to put the nut inside the deepest one. The manual draw show how to do.

[Battle_axe]

also you may have the rear hubs on the wrong side