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Jun 14, 2021, 05:29 AM
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Originally Posted by Idris Kabir
However, I might want to cut my springs a bit because as of right now they are more stiff than the rear. The rear has the battery so the rear should be stiffer but whatever. How would I go about cutting? Is it as simply as cutting my desired length or do I need to make the end flat again?
The bottom of the shock still needs to fit into the bottom holder. The top still needs to work with the adjusting collar. You pretty much just cut off what you think will work - a little at a time. If you have a Dremel, it makes things easier than using side cutters and having the wire fly off to who knows where.
Getting back to the front shock mount, you would need a series of holes for the top screw or you can use whatever means you have to get the buggy sitting at a level height without the top shock screw attached - where the A-arms are sitting parallel to the ground. Swing the shock up and mark where the top should be screwed into place - done.
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Jun 14, 2021, 05:32 AM
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See post 2253 for more insightful info from our friends down under:
https://www.rcgroups.com/forums/show...rucks!/page151
Jun 14, 2021, 02:14 PM
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Quote:
Originally Posted by kodak_jack
I guess one of my ways of thinking is if the U were clamped and stationary/ not free to rotate, it would be a piece of wire resisting the tire lifting off the ground. The suspension would be pushing against the spring force offered by the wire. If the wire is free to rotate, how effective is that? Stick your hand out and push against one finger while trying to keep it stiff. Now do the same thing, but allow your wrist to be free.
I think the analogy for a sway bar might be:

- make the devil horn symbol with your left hand and hold out from your body palm down (rock'n'roll)
- allow your wrist to rotate (so your hand can move up and down)
- push up on your index finger

At a point you will either break the finger (sway bar arm) or your other, pinky finger will start to rise. That signifies the raising of the opposite suspension arm (lowering of the car at the opposite side).

So if the U can rotate it's a sway bar. In your clamped example, it works on one side only and so becomes sort of half a leaf spring. It would stiffen the suspension (tick) but only act on a side at a time. Similar to installing heavier springs I'd imagine...
Last edited by chemist1111; Jun 14, 2021 at 04:17 PM.
Jun 14, 2021, 02:21 PM
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Quote:
Originally Posted by Idris Kabir
However, I might want to cut my springs a bit because as of right now they are more stiff than the rear. The rear has the battery so the rear should be stiffer but whatever. How would I go about cutting? Is it as simply as cutting my desired length or do I need to make the end flat again?
You need to do the best you can to get the end flat again. So make sure to include the tight coil at the end when you count for cutting, i.e. if you want to lose a coil's height at the middle of the spring, you only end up cutting a short section off the end (but still one coil) and re-flatten. I use two sets of grunty long nosed pliers to bend it back into shape. Take care not to make the diameter too large or small to fit the shock body. It's a fairly easy process. Just don't cut too short!
Jun 14, 2021, 04:20 PM
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Quote:
Originally Posted by kodak_jack
One other source is Jim85IROC. He has vast knowledge of bashers and crawlers and did the video of the 12429. He may be able to share his views on that rear end set up. It's unusual. Did it work or was there nothing special about it?
I'd say the Q46 looks like a different, but not particularly special setup.
Jun 14, 2021, 04:22 PM
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Quote:
Originally Posted by kodak_jack
See post 2253 for more insightful info from our friends down under:
https://www.rcgroups.com/forums/show...rucks!/page151
Ah yes, I see. Please excuse our North Island representatives
Jun 14, 2021, 11:56 PM
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Thanks guys for all the input. So, I am shortening my springs and shocks. I'm having diff problems again. The front diff cup (left side) just keeps coming loose slowly and slowly. I'm investigating.
Jun 15, 2021, 06:04 AM
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Quote:
Originally Posted by Idris Kabir
Thanks guys for all the input. So, I am shortening my springs and shocks. I'm having diff problems again. The front diff cup (left side) just keeps coming loose slowly and slowly. I'm investigating.
The cup keeps coming "loose" as in it wants to come right off? In most cases, the pesky 2 MM flat head screw is thread locked with enough stuff that it takes heat to loosen it. In your case, maybe it has none or too little and the screw loosens up. Remember when you take it apart that this is one case where you do not want too much thread lock.
Jun 15, 2021, 12:57 PM
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Quote:
Originally Posted by kodak_jack
The cup keeps coming "loose" as in it wants to come right off? In most cases, the pesky 2 MM flat head screw is thread locked with enough stuff that it takes heat to loosen it. In your case, maybe it has none or too little and the screw loosens up. Remember when you take it apart that this is one case where you do not want too much thread lock.
So I had put thread lock (blue Loctite). It was soo liquidy that I don't even think it did anything. I bought blue Loctite Super Glue which now should be better. Is blue even the correct strength? I'm confused because even though these screws are coming loose there's nothing to pull them out. The torque is in the rotation of the gears. And the gear's slots are shaped in such a way that the screws are just there to hold them in place.
Jun 15, 2021, 01:26 PM
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Quote:
Originally Posted by Idris Kabir
So I had put thread lock (blue Loctite). It was soo liquidy that I don't even think it did anything. I bought blue Loctite Super Glue which now should be better. Is blue even the correct strength? I'm confused because even though these screws are coming loose there's nothing to pull them out. The torque is in the rotation of the gears. And the gear's slots are shaped in such a way that the screws are just there to hold them in place.
The cup (0081) has a feature machined onto it that slips into a slot in the gear. That feature/ slot does the driving and the silly, useless flat head screw just holds the two together. Blue is the correct color/ strength of adhesive to use. Going to red will require heat to even think of getting the screw out again. If it comes in a small bottle, shake it before applying. If it comes in a small squeeze tube, I think you still have to shake it to mix it. Allow some time for it to set - whatever the package suggest.
Jun 15, 2021, 03:02 PM
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Quote:
Originally Posted by Idris Kabir
So I had put thread lock (blue Loctite). It was soo liquidy that I don't even think it did anything. I bought blue Loctite Super Glue which now should be better. Is blue even the correct strength? I'm confused because even though these screws are coming loose there's nothing to pull them out. The torque is in the rotation of the gears. And the gear's slots are shaped in such a way that the screws are just there to hold them in place.
This part gives lots of trouble. However, once you get it all seated properly it should last for months... There are 2 blue Loctite threadlockers, 242 is for the screw threads and 243 is a medium strength (i.e. stronger than 242) threadlocker that is purportedly for the nut threads. I use the stronger stuff, but any blue will do.

When I reassemble these parts (I did a rear diff with one of our other racers two nights ago), I put the diff cup in a vice, and apply a drop of (shaken) threadlocker to the screw hole. I then poke it in with a finger and clean up the top of the diff cup. That way it doesn't glue the non-threaded parts together and keeps the threadlocker where you want it. I then cinch up the screw just a touch so it keeps the parts together solidly but no more. That screw needs no more stress. Allow it to dry overnight if you can.

Don't use that super glue you purchased mate: that will bond them irreversibly in all likelihood! The threadlocker may be liquidy but it is a mild superglue so will fill up the threads once dried.

If it's a problem on the left side (driver's perspective) then doesn't the rotation of the cup 'try' to loosen that screw?

Also, we've not discussed this but the LHS diff cup seats through the plastic diff housing, unlike the RHS which is housed through the large planet gear 0011 that is metal. Eventually that plastic diff hole must wear and allow slop. Actually I have seen planet gears where the centre hole has worn larger too. The hardened steel planet gear 0011 has a hole that is a full 1mm larger in diameter and that has the same problem as a worn one. I had to shim one recently to reduce that slop (Post #2956 p. 198).

I routinely check the front diff cups for slop. If there's too much, the pesky 2mm screw is likely broken. The LHS gives more trouble, and is usually first to go. The car will run still, as the front driveshafts force the diff cup to stay in place - enough. But accelerated wear is inevitable
Last edited by chemist1111; Jun 15, 2021 at 03:08 PM.
Jun 15, 2021, 03:13 PM
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Quote:
Originally Posted by Idris Kabir
So I had put thread lock (blue Loctite). It was soo liquidy that I don't even think it did anything. I bought blue Loctite Super Glue which now should be better. Is blue even the correct strength? I'm confused because even though these screws are coming loose there's nothing to pull them out. The torque is in the rotation of the gears. And the gear's slots are shaped in such a way that the screws are just there to hold them in place.
Those screws are cursed at the factory. Even ignoring the reasons outlined above, the WLToys engineers will be at their ease having a laugh while you are fuming over this problem. Rumour has it that they all use Traxxas RC cars for their personal pleasure. The screws will give us problems until we find a solution. I have new M2.5 tapered and bottoming taps in the post to continue research in this area
Jun 15, 2021, 04:03 PM
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Quote:
Originally Posted by Idris Kabir
So I had put thread lock (blue Loctite). It was soo liquidy that I don't even think it did anything. I bought blue Loctite Super Glue which now should be better. Is blue even the correct strength? I'm confused because even though these screws are coming loose there's nothing to pull them out. The torque is in the rotation of the gears. And the gear's slots are shaped in such a way that the screws are just there to hold them in place.
Consider the rear diff. It gives much fewer problems. Why? The guts of the diff is identical. The difference is in diff cups vs axles.

The rear axles are held firmly in place by bearings that are relatively far apart, allowing no slop. The front diff cups are held in place by no bearings. They are held by plastic diff housing (LHS) and the hole in the planet gear 0011 (RHS). Slop is inevitable in time with wear and the large tolerances from factory. It is a design weakness

That slop is impossible to get rid of permanently. As the gears wear, it will become worse. The front driveshaft needs to slot into the diff cup at a nice horizontal angle to reduce the 'slop' forces on the diff cup so as not to exacerbate wear, which often shows itself as a broken pesky 2mm screw.

The design differences between front and rear are essentially down to independent vs fixed suspension. The 12428 may not have independent rear, but that means less time on the bench. It may yet become a classic
Jun 16, 2021, 05:42 AM
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FWIW, it wasn't that long ago when the 144001 guys were complaining about worn cups. In a recent post in the LC Racing thread, a guy who put a different body on his and races it on a flat road course (no jumps) showed the wear in his cups. As far as cups are concerned, I know a slot is necessary to go with the pin in the axle, but the cup itself needs to have thicker walls. You would assume the pin is hardened and the cup is not. Oh for the days of Kodak's heat treating department and the LOVE to do "government" jobs (personal stuff done for the fun of it). "What's that part for?" "Oh, I can't talk about it. It's for a job for the government". Let's not talk about the materials engineers who might have a better/ tougher material to use. Tool steel might be a real you know what to tap a 2 MM hole in.
Discussion of cup problems starts at 2492:
https://www.rcgroups.com/forums/show...T-info/page167
Jun 16, 2021, 06:39 AM
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In looking for videos of sway bars on the 12428 as posted on YouTube, I came across a guy rebuilding the diffs for a 144001. He ends up using an aluminum diff housing and then shows how the slop in the cups needs to be shimmed to get rid of it. I had asked him where he got the housing and shims as he did not link to them. His answer was to look on Ebay. Just for giggles, I did look on Ebay. I think this is another example of how a very popular car/ buggy has been left in the dust. I have always been led to believe that the 12428 and 144001 have identical diffs. In that case, you can see there ARE aluminum diff housings for that buggy that do not show up as being for the 12428:

https://www.ebay.com/sch/i.html?_fro...sing&_osacat=0

One of the offerings on that page is for a Losi DBXL. Look at the cups for that thing! Better yet, look at the entire assembly:

https://www.ebay.com/itm/22443604717...IAAOSwn1Bggog2

There may be all kinds of parts out there that might work, but how do you ever find out about them without spending 1/2 of your life reading posts, articles and watching videos.


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