Upgraded diff bolts
 

http://www.redrc.net/2007/06/hb-gumb...-diff-upgrade/

spring prob now goes nut side
http://www.redrc.net/wp-content/uplo...upgradeset.jpg

big nuts!

Very good! They should have come up with this sooner though! I've already replaced 2 diffs!

damn that is one long nut.

cant see how its going to fit inside the outdrive unless there is a whole lot of spare room in there. its a lot longer than the current nut.

perhaps thats the issue though. on the screws I have been snapping they all have a mark on the thread indicating the snap line and its just at the point of entry to the nut.

This nut would cover that point entirely the there would be a lot more of the screw inside the nut in this arrangement.

http://hb-buggy.img.jugem.jp/20070627_113216.jpg
http://hb-buggy.img.jugem.jp/20070627_113216.jpg

:( The two that I've done have both snapped right in the centre of the diff, hopefully though the extra thickness of the screw should cure this.
These should be supplied free of charge to all D4 owners, if there wasn't a problem you wouldn't need this upgrade and if there is a problem why do we have to pay for their mistakes?:eh?:

Just thought I'd post this for you guys from the aussie thread in RCTECH... Thanks Michael and Ben. Thank god they have reviewed the whole diff issue...

New part numbers are as follows:

61544 Diff Maintenance kit (This includes all items below)
61538 Diff Bolt
61149 Diff Balls
61148 Thrust Washers

:( Bad news is Mirage do not have these in stock and have no due date for them!:(

Yeah they arent quite available yet, they will be very soon though.. Your importer may be able to get some fast tracked for the drivers though if you ask nicely, Thanks BEN haha

:( Still no sign of these upgraded bolts, how long does it take to make a few thousand of these?:(

Used the upgraded Diff bolts on the weekend. No issues with these breaking at 2.6mm. :) Only problem now is on the dusty tracks here in Australia the thrust bearing seem to be more exposed and the diff only lasts a few runs before needing a rebuild.:(

:( Marvellous, replace one problem with another, still at least you've got the bolts down there in Oz so at least your diff should hold together even if it's a bit rough.:)

When the diff bolt snaps, is it generally the front or rear that is prone to going? Does it seem to make a difference how tight etc?

My rear one has just snapped on a routine clean of the car and just spinning the rear wheel by hand to test the freeness of the car?

John

you got pm grindog!

:( Both times mine have snapped it's been the rear ones, still waiting on Mirage to come up with a supply of the upgraded version.:(

Mirage now have the Diff Maintenance Kit in stock.

Cam

:cool: O.k., I have to take back the above, I asked my LHS to enquire about the upgraded diff bolt when they were first mentioned, suggesting that in view of the number of failures they should be supplied FOC. When they finally became available my LHS contacted me and quoted the above price so in disgust I eventually phoned Mirage today.
The price is only if purchasing as a spare part, original owners are being supplied with replacement bolts free of charge, so hats off to Hot Bodies, bit slow in getting them out but alls well that ends well.
Now all I've got to do is find a buyer for the 2 D4's I have for sale, complete with diff bolt upgrade!:)

cool, that sounds good then. So even though i aint had anything wrong with my original diff bolts can i still get my stronger ones free? how do i go about this?
Am I not pushing hard enough, why havent mine snapped yet?

happy days

email mirage, with details of where car was bought from

To put things straight for once and for all.

If you have problems with your diff bolts, please contact Mirage with your details.

The following will help:
Model Shop Purchased From:
Kit Identification Number: (This is printed on the back of the box on a white label in the EU only) Stops nasty grey imports.
Proof of purchase: (If Possible)

You will get 2 diff screws / kit and no more. The replacements will be logged against your kit.

If you bought your D4 from abroad, please contact the hobby shop you got your nasty grey import from!!!!!!:mad:

so no grey imports then Adam, heehee...

I assume the new nut now bottoms out on the outdrive rather than resting on the T part at the top.

no the spring is now at the nut end

Well, my D4 should be arriving tomorrow (touch wood). I saw one running at Southport on Sunday and ordered mine the very next day.
I was just wondering whether the new kits come supplied with the upgraded diff bolts or will I need to get the new and improved ones sent out?

Hi,

Any new kits should have the upgrade diff parts in the kit.

If the kit has been at the shop a while then it might not... in this case contact Mirage and they should send you them.

Well I guess my kit was one of the older batch as it had the old style diff screws. Got in touch with Mirage and spoke to an extremely helpful young lady who has sent me the upgraded diff pack. Top service, totally helpful and I am very glad I chose the Hotbodies. Seems like a very nice car, cant wait to start racing!

Having not experienced the original diff bolt I con't comment, but the diff assembly on mine (with new bolt) was easy to build, super smooth and very easy to adjust.

Ran for a meeting last week and still as smooth as new.

Overall very impressed with the D4 :D :D

Adjusting diff?
 

Hi
Do you still use threadlock on the new diff bolts after adjusting?
I have seen a pic of a diff adjustemnt made by dropping the drive off the side with the screw head. How do you then add T/L?

Jeff

As far as I'm concerned, no threadlock required.

You can also get away without having to take any links off to adjust the diff. You just need a small flat bladed screwdriver, then lock the diff half and diff screw together and adjust by turning the opposite wheel.

Snapping diff bolts
 

Can anyone please explain the previous post... Just how do you adjust the diff without taking off the suspension links.??

I just snapped two diff bolts!

My rear diff seemed a bit looser than the front so I wanted to tighten it a little. I snapped off the suspension link and put a flat screw driver in to tighten it up - I was just doing it up finger tight and SNAP - the diff screw was dead!

So... I got my spare diff out - did the same thing and SNAP - dead diff screw again...

Is this normal? Are you not supposed to tighten the diffs in this way or something? When I first built the diffs I tightened them up pretty tight as per the instructions and they were fine. Much tighter than what I tried today where they both snapped.

They seemed to snap at the same place - right where the thread starts on the screw.
They are also the newer thicker diff screw (as in what comes with the Worlds Edition)

Is it the case that once you've used a diff for a while the screw can get brittle or something? It just doesn't make sense - two in a bloody row.

Any comments or assistance - most appreciated.

Rgds,
Jason.

i had the same problem last week :(

i slide a thin allen key/screwdriver into the outdrive slot and lock the diff bolt up then turn the oposite wheel, that way you can do it without even removing a wheel

How thick are the ones that come in the WE car?

The HB ones that I have are much, much thicker than the std kit items. And I would think that you would have a real job breaking these just by tightening them up.

Although I must say that I ran the std ones for a whole year, and never snapped one. All I can think is, people must be over tightening them.
I tightened my original kit diffs so that there was just a hint of slippage. then went from there as I raced. Usually only tighening it up 16th or 8th of a turn or so, never more than that. If anything I used to leave the rear and just tighten the front.

I've never had a problem with the new style diff bolts.

Are yours black or silver colour? The silver ones are a lot thicker.

G

they're the newer/thicker silver ones... I wonder if they get brittle after quite a bit of usage? I see EDIT has some titanium ones - however I find it impossible to find anyone that sells EDIT stuff that will ship it overseas, which writes them off...

While on the topic of diff bolts and tightening them... is there a way to see if your diff is too loose without taking it out of the car?

yes hold the spur and one wheel, then turn the other wheel

do as Mark says. ideally the slipper should slip before the diff (if the slipper is set correctly!)