Bizarre differential problem - Page 2

Cassp0nk · #21 17-03-2009

I'm not frustrated just don't have much time to spend on RC cars with a new baby. Pretty sure I got the stack in the wrong order though so will try that next. Is there a recommended way of spotting the 0.2mm difference in them? I bought a magnifying glass but haven't tried that yet. Maybe some VERY accurate callipers?

Northy · #22 18-03-2009

Quote:

Originally Posted by Cassp0nk

I'm not frustrated just don't have much time to spend on RC cars with a new baby. Pretty sure I got the stack in the wrong order though so will try that next. Is there a recommended way of spotting the 0.2mm difference in them? I bought a magnifying glass but haven't tried that yet. Maybe some VERY accurate callipers?

Even a pair of cheap hing hong digital calipers will show you the difference, and are a worthy purchase

G

Cassp0nk · #23 19-03-2009

Quote:

Originally Posted by Northy

Even a pair of cheap hing hong digital calipers will show you the difference, and are a worthy purchase

G

Bought some genuine hing hongs with an ABS button on your advice. Dunno what the ABS button is for, but its more buttons that most of the others had

Schumacher would do everyone a favour if they were more upfront in the required tools listing! I'm sure there are lots of us who couldn't visually see the size difference of those spacers and who frigged in the e-clip with some pliers possibly bending it in the process. No wonder there are so many with diff probs!

Pedros20 · #24 20-03-2009

I've had the same trouble with my front diff, coming loose since i fitted the new out drives?
I fitted all new diff internals one at a time to try and get to the bottom of it.
The only part of the diff i hadn't changed was the female outdrive, which i swapped with the old type.
This cured it! Dont know how or why? but it did!
Very frustrating though.
Hope this helps

geerno · #25 21-03-2009

Did you try stretching out the C-clip? Might be even worth picking up a new c-clip.

Seems to me, that if you have put the old female outdrive on, it will only be a matter of time before it breaks. Probably in the A final when you are leading. It is worth having the new outdrives on, if you can get the dif to stop slipping.

Pedros20 · #26 21-03-2009

I put a new e-clip in that comes with the new thrust race, but your right about the old outdrive, its only a matter of time before it breaks,
Not be an A final though! LOL!

Cassp0nk · #27 22-03-2009

Ok think I've fixed my problem and for me at least it was a bit non obvious what I'd done wrong.

I had assumed I'd got those to small disks in the thrust bearing the wrong way round, but using a magnifying glass (callipers not arrived yet

) I could see they were right. What appears to have been wrong is that the actual bearing was upside down between them. It isn't terribly clear from the diagram and there are no notes on it in the instructions, but it seems that the side of the bearing which has the balls sticking out most proud, should be facing into the diff assembly where I had it facing out. Before I stripped and changed this, the diff was undoing itself in about 5 minutes.

So if anyone else is having trouble, worth looking at this as I think it's solved my problem. Need to run it a bit longer though as only had a small bit of charge left in the pack.

MattW · #28 23-03-2009

That doesn't make a difference!!

As long as your problem has gone away though, it's all good.

PaulUpton · #29 23-03-2009

Mine came loose yesterday after rebuilding it, but turns out the grub screw had come out, so make sure this is very tight, and with threadlock!

Paul

Cassp0nk · #30 23-03-2009

Quote:

Originally Posted by MattW

That doesn't make a difference!!

As long as your problem has gone away though, it's all good.

Oh well lol. I also stretched out the eclip, but that hadn't been popping out so can't see how that would help?

maybe I didn't ahve enough battery yesterday to make it undo

sportsman4life · #31 07-04-2009

I ran my cat for the first time friday and my front diff kept loosening

. I rebuilt it, retightened it, threadlocked it but it kept coming loose. It happened about 8 times. I finally discovered that the oring seal was grabbing the adjusting screw and gradually loosening it. I removed the seal and the problem was resolved.

It sounds crazy but I noticed this occuring when turning the diff by hand. It doesn't matter how hard you tighted the set screw because the seal would loosen the screw. Weird, but I ran it the rest of the day and the following sunday and no problems.

Carlos69 · #32 07-04-2009

Quote:

Originally Posted by Chrislong

Schumacher sell a complete assembled diff assembly U3338. You guys are spending ages over this issue which sounds very frustrating, why don't you just cut your losses and drop in a fresh diff.

I popped one of theses in the rear ...3 heats and a final later the inevitable happens....

... only running a 17.5 ty

(i doubt they come with grubs screws loctited... so) tightened it and applied loctite...seems ok after 1 more final...so far !...smells of design weakness IMO

Swiss · #33 07-04-2009

Quote:

Originally Posted by ex-buttmonkey1969

I popped one of theses in the rear ...3 heats and a final later the inevitable happens....

... only running a 17.5 ty

(i doubt they come with grubs screws loctited... so) tightened it and applied loctite...seems ok after 1 more final...so far !...smells of design weakness IMO

No design weaknes, if they are built correctly the diffs don't come loose, and to be perfectly honest some of the nicest diffs I have built.
I admit, I had a couple of diffs when built came loose, but that was due to the c clip not seated properley. I discovered this by spinning the diff a couple of times, so didn't have to run the car. Just took the diffs out and double checked the c clip. Even, no need to put the loctite on the grub screw as long as it is very tight. As with all my RC Cars I carry a spare diff, mainly to save having to build one when I am racing.

Carlos69 · #34 08-04-2009

Quote:

Originally Posted by Swiss

No design weaknes, if they are built correctly the diffs don't come loose, and to be perfectly honest some of the nicest diffs I have built.
I admit, I had a couple of diffs when built came loose, but that was due to the c clip not seated properley. I discovered this by spinning the diff a couple of times, so didn't have to run the car. Just took the diffs out and double checked the c clip. Even, no need to put the loctite on the grub screw as long as it is very tight. As with all my RC Cars I carry a spare diff, mainly to save having to build one when I am racing.

I disagree, too many loose diffs to say the design is not weak...

If the reliability depends on which side the e-clip is facing then its inherently prone to user error.

Another area of design fault is the rubber o-ring grabbing the screw head.

...(no disrespect but) don't stick your head in the sand about the issue....

MattW · #35 08-04-2009

It's such a week design that i don't believe any of us suffered at prototype stage, and the touring car has been using the design for at least 6 years without any major issues. So personally i think it's a great design.

Mossy · #36 08-04-2009

Agree with Matt, no design fault. Aslong as the Diff is built correctly, as per the instructions, there isnt an issue. Surely you can say the same about any car if you dont follow the instructions?

Carlos69 · #37 08-04-2009

Guess all contributors here are lousy diff builders or just unlucky with FT diffs... bunch of winging pikes we are !

Cassp0nk · #38 09-04-2009

That rubber washer is a late amendment (an insert to the build instructions with mine) to the design though so maybe thats why it hasn't come up before. I stripped and rebuilt mine twice and nothing was wrong with how it was assembled. Still not sure if its fixed as not run car since.

geerno · #39 10-04-2009

There has got to be a difference in application from touring car to off road. Maybe that is why there are issues. Saying that, the issue only arrises with the new out-drives.

In defense of the monkey, he actually put in a new Schumacher built dif. So does that mean that the factory are not assembling them correctly?

I built up my second dif using the new out-drives. Had no problems. My rear dif has only just started to slip again, but that is with over 3 hours of driving on 8.5 motor. So it's all good once it's right. Right?

MattW · #40 10-04-2009

It does seem a little odd, i will say that. Is there differences between touring and off rd? don't know. Off rd maybe has more "shock" loading, but touring probably has more torque loading from 3.5 motors etc.

The circlip has been used in off rd diffs since the late 90's. Sure less power then, but same shock loadings.

Both Si and myself have posted to say we've had no problems - and we've had Cat SC longer than anyone else - over 1 year now for us.