Drive shaft bearings for Henglong

[Jpaw33]

Updating my Heng long Panther G 3879 with Mato metal tracks, sprocket and idler. Has anyone used driveshaft bearings. They look like they would stop a lot wobble and add some support to the driveshaft.
The reviews on the plastic ones said they arrived cracked and the seller said it’s normal, so the all metal looks interesting.
Thanks,Jpaw.

[cmdrcody]

I've put drive shaft bearings on all my tanks that have metal tracks due to the extra strain on the drive sprocket. Also helps alot with keeping the track not jumping off.

[Jpaw33]

I've put drive shaft bearings on all my tanks that have metal tracks due to the extra strain on the drive sprocket. Also helps alot with keeping the track not jumping off.

Do you get them locally or Ali Express??
thanks

[cmdrcody]

The axle bearings are 8mm x 12mm x 3.5mm flanged sealed bearings. Google 8 x 12 x 3.5 flanged sealed bearings. Can't remember exactly whom I purchased them from. It was either Walmart, Amazon or Ebay. They are very inexpensive to purchased.

[Jpaw33]

The axle bearings are 8mm x 12mm x 3.5mm flanged sealed bearings. Google 8 x 12 x 3.5 flanged sealed bearings. Can't remember exactly whom I purchased them from. It was either Walmart, Amazon or Ebay. They are very inexpensive to purchased.

Thanks, how would I attach these to the hull, I know they slide over the shaft, but since it’s just the bearing without a housing, unlike the Ali Express 2 piece, do I epoxy the outer edge of the bearing to the hull? I appreciate the help.
Jpaw

[tank_me]

Normally they just press fit in.

Derek

[Jpaw33]

Normally they just press fit in.

Derek

Got it! Flange end out.

[cmdrcody]

Depending on the chassis, you may have to very carefully with a dremil tool, open the diameter of the hole just enough to get a light press fit for the bearing and use a very very light film of adhesive to the outer side of the bearing.

[keilau]

Depending on the chassis, you may have to very carefully with a dremil tool, open the diameter of the hole just enough to get a light press fit for the bearing and use a very very light film of adhesive to the outer side of the bearing.

After I install the metal bearing drive shaft cover on the Leopard 2A6, I found that it runs but the alignment is not perfect. I loosened the gearbox and tightened it again. There is no play to adjust the cover and I don't like the idea of grinding it.

I like the metal bearing drive shaft cover a lot in improving the alignment and integrity of the gearbox. The original HL plastic cover was cosmetic only with 2 screws. My comment applies to the HL Leopard 2A6 only.

[Rubicon99]

After I install the metal bearing drive shaft cover on the Leopard 2A6, I found that it runs but the alignment is not perfect. I loosened the gearbox and tightened it again. There is no play to adjust the cover and I don't like the idea of grinding it.

I like the metal bearing drive shaft cover a lot in improving the alignment and integrity of the gearbox. The original HL plastic cover was cosmetic only with 2 screws. My comment applies to the HL Leopard 2A6 only.

When say alignment are you saying the drive shaft is no longer straight or does it appear to be wobbling? Or are you saying that the sprockets appear out of alignment or are wobbling?

Adding the axle support bears should not have changed anything in regards to gearbox alignment. All they do is support the drive axle to help keep it from wobbling. If you have wobble after the bearings are added then most likely the drive shaft(s) was bent prior to the installation of the bearings. Very common to see. There is a tendency to see the wobble more after installation of the bearings then before, because now there is no "free play" space for the axle to move within hiding the wobble. All movement is now (with bearings) more sharply translated to the sprocket and hull.

If this is you case there are on three options. Live with the wobble, replacing the drive shaft(s) or buy a completely new/upgrade transmission.

If the shaft are not wobbling then your issue is the sprocket. These can a do bend or are molded poorly. Again the issues become more obvious when bearings are added. The simplest solution is to replace the sprocket but that too is a gamble because you might get another set with similar issues. The last solution I could offer is for you to add a small thin rubber "D" ring to the inside of the sprocket where the axle meets the sprocket hub. These tend to balance out of spec sprocket rather well and should not effect reliably.

[keilau]

When say alignment are you saying the drive shaft is no longer straight or does it appear to be wobbling? Or are you saying that the sprockets appear out of alignment or are wobbling?

Adding the axle support bears should not have changed anything in regards to gearbox alignment. All they do is support the drive axle to help keep it from wobbling. If you have wobble after the bearings are added then most likely the drive shaft(s) was bent prior to the installation of the bearings. Very common to see. There is a tendency to see the wobble more after installation of the bearings then before, because now there is no "free play" space for the axle to move within hiding the wobble. All movement is now (with bearings) more sharply translated to the sprocket and hull.

If this is you case there are on three options. Live with the wobble, replacing the drive shaft(s) or buy a completely new/upgrade transmission.

If the shaft are not wobbling then your issue is the sprocket. These can a do bend or are molded poorly. Again the issues become more obvious when bearings are added. The simplest solution is to replace the sprocket but that too is a gamble because you might get another set with similar issues. The last solution I could offer is for you to add a small thin rubber "D" ring to the inside of the sprocket where the axle meets the sprocket hub. These tend to balance out of spec sprocket rather well and should not effect reliably.

The Heng Long tank drive shaft has very good alignment. It may allow a small fraction of a degree off from perpendicular to the moving direction which is well within the tolerance of any plastic tank chassis. I cannot detect any wobbling or track noise as was. The outer bearing on the cover is a tight friction fit and impose a more exact alignment of the gearbox. Since I installed the gearbox first, the very tiny amount of off-alignment was detected. I just loosened the gearbox and tightened them again. That's the beauty of the metal bearing drive shaft cover design. It is self aligned.

I have the very tight tolerance Heng Xin ball bearing gearbox which allowed the small misalignment to be detected. I suspeect that if I had the HL sleeve bearing gearbox, there would be enough play in the drive shaft that the adjustment would not be necessary.

[keilau]

The German Leopard is the first HL I purchased after 3 HL tanks in the mid 2000's. (I also purchased the T34 and Sherman since.) Some of you may see how I gashed about the improvement in quality and ease of upgradee. The tank upper and lower half practically fell into place after any internal upgrade.

After I installed the metal bearing drive shaft cover on the Leopard 2A6, I ran many tests with the top only sitting on top to make sure that it runs smoothly. It took me another 2 days to buttom up the 2 halfs. In addition to the 6 screw poles, the 2A6 has tab and hood at the back and sidewalls on the side to guide the final assembly. The addition of the shaft cover made the alignment more demanding. It took me many tries to get them ALL line up at the same time. The final result is very rewarding. @cmdrcody upgraded the same 2A6 cover. I did not see him having the same difficulty.

[keilau]

I got this single bearing shaft cover from ToucanHobby and am very happy with its fit and quality. No specific manufacturer was mentioned.

https://www.ebay.com/itm/224860217656

Coupled with the gearbox ball bearing on the inside end of the drive shaft, it forms a perfect support with no play.

The bearing on the cover is a tight friction fit and impose a more exact alignment of the gearbox. Since I installed the gearbox first, the very tiny amount of off-alignment was detected. I just loosened the gearbox and tightened them again. That's the beauty of the metal bearing drive shaft cover design. It is self aligned.

The bearing was press fit into the cover first. Since it is polished steel on steel, the bearing slided down the shaft with only a small hint of friction. The left side cover lined up perfectly. I align the screw holes and tighten them up. The right cover was off center and tilted to the side wall slightly. To me, it was an indication that the right side gearbox was NOT aligned correctly. Loosening up the gearbox and the cover fell in place. I ran the motor gearbox a few times at high speed before I tightened everything up. That's what I called self-alignment.

I was a Mechanical engineer at the aerospace industry spending time in the office, laboratory and factory floor. I can feel the tightness of fit and bearing easily. This bearing shaft cover is a good investment if you want more smooth running tank.

[hblake1427]

Adding on to this thread, does anyone have a source for a T-34 bearing set? I've looked all over and can't find any.

I see the 8x12x3.5 bearings mentioned above, anyone have experience with that size in a T-34 hull?

[Rubicon99]

Adding on to this thread, does anyone have a source for a T-34 bearing set? I've looked all over and can't find any.

I see the 8x12x3.5 bearings mentioned above, anyone have experience with that size in a T-34 hull?

The T34 is the one tank HL makes that does not need bearing supports so none have been made except the "one offs" by individuals here and there. Its just a tank that can operate very very well with a loose tolerance and sloppy tracks.

[MrChef]

The T34 is the one tank HL makes that does not need bearing supports so none have been made except the "one offs" by individuals here and there. Its just a tank that can operate very very well with a loose tolerance and sloppy tracks.

Sounds like the Real Russian T-34.

[keilau]

Adding on to this thread, does anyone have a source for a T-34 bearing set? I've looked all over and can't find any.

I see the 8x12x3.5 bearings mentioned above, anyone have experience with that size in a T-34 hull?

The T34-85 tank has a small chassis and no room for external axle cover. You can see the drive gears inside the sidewall of the chassis (in the full scale tank). The 1:16 scale HL T34 uses a short 49 mm drive shaft. However, if you get a ball bearing gearbox, you will have 2 ball bearings for each side of the short drive axle.

[hblake1427]

Ah, I figured the shorter axle would make a bearing a little difficult.

The reason I'm asking is that after upgrading to metal sprockets and a steel gearbox, the left sprocket tends to be... squeaky. Only when the treads are running with weight on them.
Pick up the T-34 and run the tracks, no squeak.

At first I thought is was an interaction between the sprocket and hull of the tank, but after wrapping the outer wall of the sprocket and electrical tape, it still squeaks.

I won't have time for a full teardown until the weekend, but my next guess would be a gearbox component.

Thanks all for the wisdom, in any case.

[Rubicon99]

Ah, I figured the shorter axle would make a bearing a little difficult.

The reason I'm asking is that after upgrading to metal sprockets and a steel gearbox, the left sprocket tends to be... squeaky. Only when the treads are running with weight on them.
Pick up the T-34 and run the tracks, no squeak.

At first I thought is was an interaction between the sprocket and hull of the tank, but after wrapping the outer wall of the sprocket and electrical tape, it still squeaks.

I won't have time for a full teardown until the weekend, but my next guess would be a gearbox component.

Thanks all for the wisdom, in any case.

Squeaky and clacking is absolutely normal for the T34. The real one has the same problem. The squeaky has to do with the way the metal sprocket teeth (more like circles) and metal track guide teeth interact under tension. Lifting the tank off the ground removes the tension.

The squeaking will never go away, it only gets worse, but that is what makes the T34 a T34 it distinctive track noises.

A metal track and sprocket T34 is simply a noisy tank and nothing can change that. If you want it to be quite then you have to run the plastic track and sprocket combination.

[hblake1427]

I see. My first thought when the squeaking started was "wow that sounds just like a T-34 in the movies"

The only weird thing is that the squeaking is just on one side and the tank has plastic tracks, but I can learn to love it.