Bleh ! - RC-Monster Forums

**Bleh ! -** 02.19.2010, 09:00 PM

Well I am in the middle of an LST upgrade for my front and rear diffs and I'm stuck....I have the diffs mounted in the bulkheads perfectly (thanks MC!) But I have run into a problem. I ordered the 8mm Aluminum couplers from Mike and I got them yesterday and they don't fit...The 8mm part is too shallow to fit the whole shaft in...What do I do now? I tried drilling the coupler out longer so it would fit and it just doesn't fit right...Any suggestions??

Bondonutz · 02.19.2010, 11:07 PM

I think I know whats going on here, Mr Mike made me a pair and the grub screw was further up on the coupler than it needed to be. I had to send them back for him to tap a new hole closer to the end.
Contact Mike via email or PM and I'm sure he'll happily remedy the problem.

brian015 · 02.20.2010, 09:28 AM

Quote:

Originally Posted by Bondonutz

I think I know whats going on here, Mr Mike made me a pair and the grub screw was further up on the coupler than it needed to be. I had to send them back for him to tap a new hole closer to the end.
Contact Mike via email or PM and I'm sure he'll happily remedy the problem.

Looking at your picture - this seems to be the answer.

02.20.2010, 09:31 AM

Quote:

Originally Posted by brian015

Looking at your picture - this seems to be the answer.

The grub screw needs to be lower and the hole needs to be deeper by 1/4 of an inch..

mistercrash · 02.20.2010, 10:10 AM

Hmmm. Your couplers really look a bit different than the ones I got from Mike. The ones I bought fit very nicely on my LST output shafts. Just a little tight but they fit fine and the grub screw was in the right place. Bondo might have the best explanation to what happened. Like it was said, contact Mike and tell him about your problem. I know it is disapointing to have to wait again for parts but it will be worth it.

02.20.2010, 10:31 AM

Thanks all for the help! I'll let you all know what mike says...

lincpimp · 02.20.2010, 02:58 AM

Put shims between the coupler and the bearing. I used the adapters that Mike makes to use the stock emaxx center slider driveshafts. They worked perfectly for me. Are you using dogbones? I used ofna hyper cups as well and they did fine too, with mip cvds. Maybe a link to the coupler you are using might be helpful?

02.20.2010, 09:04 AM

Quote:

Originally Posted by lincpimp

Put shims between the coupler and the bearing. I used the adapters that Mike makes to use the stock emaxx center slider driveshafts. They worked perfectly for me. Are you using dogbones? I used ofna hyper cups as well and they did fine too, with mip cvds. Maybe a link to the coupler you are using might be helpful?

No i'm just trying to use stock e revo center drive shafts...

simplechamp · 05:45 AM

Pics would help to show exactly what the problem is here.

02.20.2010, 08:59 AM

Here are the pics...

This is as far down as I can get the coupler

Here is a top view...

Am I stupid? This will not work right?

Bondonutz · 02.20.2010, 10:35 AM

Yup, The grub screw is way to high AND needs deepening for the output shaft.

lincpimp · 02.20.2010, 12:54 PM

Ok, moving the grub screw will not help.

The lst pinion needs to have the couple tight against the inner bearing race of the outside bearing. If not the pinion will "walk" into the diff case and cause mesh issues.

I have the original rcm steel couplers like you pictured, I will get a shot of them at work today and you will see what needs to be done. The center hole needs to be drilled to 8mm all the way thru. that way you can slide the couple down and have it touch the inner race and the pinion will stay centered between the bearings.

02.20.2010, 02:10 PM

Quote:

Originally Posted by lincpimp

Ok, moving the grub screw will not help.

The lst pinion needs to have the couple tight against the inner bearing race of the outside bearing. If not the pinion will "walk" into the diff case and cause mesh issues.

I have the original rcm steel couplers like you pictured, I will get a shot of them at work today and you will see what needs to be done. The center hole needs to be drilled to 8mm all the way thru. that way you can slide the couple down and have it touch the inner race and the pinion will stay centered between the bearings.

I drilled one all the way through and the grub screw still doesnt match...I don't know what I did wrong, but the hole isn't perfectly straight, so I guess i ruined one...the grub was still high, and lowering (the grub screw) it could help but it wont be a perfect fit i can tell you that....I emailed Mike and I'm still waiting for a response....

Bondonutz · 02.20.2010, 05:07 PM

As myself, I found I had to grind down the little lip on the output diff shaft. Sorry I forgot to mention this.

RC-Monster Mike · 02.22.2010, 12:06 PM

In order to make the aluminum coupler work on the LST diff, the coupler needs to be reamed to 8mm all the way through and a new set screw threaded hole needs to be added(to the opposite side) to properly engage the pinion shaft. You can send them back to me for the modification if you like. :)