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two issues I cant figure out....

two issues I cant figure out....

Old 11-02-2010, 07:50 AM
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Default two issues I cant figure out....

I have a rc8te.

I am having two issues that have left me scratching my head...

1. My shocks seem like they don't want to compress all the all the way. I get to about 3/4 compression where the chassis almost hits the ground, then it gets harder. It will compress all the way, but the last 1/4 of compression is harder. I have to really push hard on the truggy to make the chassis hit the ground. The shocks are not over filled, I filled them up to the side of the shock, and put a dab of shock oil the cap. It seems that the rubber shock boot get bunched up when at full compression and makes it harder for the shock to compress all the way.

2. Wheel slop. My rear wheels have what is seems like excess slop. I can move the wheel in and out a decent amount, and up and down (although not as much as in and out). At first I thought it was due to having plastic hub carriers. Last night I replaced the hub carriers with aluminum ones, and rebuilt the hubs. Yet I still have this wheel slop. It seems to me that there should be a tiny washer put in between the cva and the hub carrier to prevent this...

Anybody have any suggestions?? Btw I have not run this truggy yet, so there are no parts that are worn on it. Its all brand new.
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Old 11-02-2010, 07:57 AM
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hey

doesnt that mean there doing there job you dont want to chassis to bottom i thought the whole point of shocks is too stop the chassis bottoming out. So i dont think there any problem there. Like on car if the shocks bottmed out then chasis rubbing on tyre you dont want that issue. If you want it compress more just cut a bit of boot off on the shocks. I had cut mine cause they are too long for shocks.
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Old 11-02-2010, 08:00 AM
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Originally Posted by bardynt
hey

doesnt that mean there doing there job you dont want to chassis to bottom i thought the whole point of shocks is too stop the chassis bottoming out. So i dont think there any problem there. Like on car if the shocks bottmed out then chasis rubbing on tyre you dont want that issue
Every rc car I have even owned has allowed full compression of the shock to allow the chassis to hit the ground. Maybe im wrong....it seems that shock dust boot gets bunched up and wont allow for that last 1/4 of suspension travel
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Old 11-02-2010, 09:57 AM
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ttt
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Old 11-02-2010, 10:19 AM
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Originally Posted by speedin
1. My shocks seem like they don't want to compress all the all the way. I get to about 3/4 compression where the chassis almost hits the ground, then it gets harder. It will compress all the way, but the last 1/4 of compression is harder. I have to really push hard on the truggy to make the chassis hit the ground. The shocks are not over filled, I filled them up to the side of the shock, and put a dab of shock oil the cap. It seems that the rubber shock boot get bunched up when at full compression and makes it harder for the shock to compress all the way.

2. Wheel slop. My rear wheels have what is seems like excess slop. I can move the wheel in and out a decent amount, and up and down (although not as much as in and out). At first I thought it was due to having plastic hub carriers. Last night I replaced the hub carriers with aluminum ones, and rebuilt the hubs. Yet I still have this wheel slop. It seems to me that there should be a tiny washer put in between the cva and the hub carrier to prevent this...
I have owned two RC8Te's and two RC8Be's.

1. The shocks not wanting to compress all the way is almost always a case of too much oil inside. If when you compress the shock as far as you say you can, and it rebounds very quickly, you have too much oil. You wouldn't think it would happen because the oil inside can obviously go through the piston holes, but an overfilled shock will actually be nearly impossible to completely compress. The boot will not cause that fast rebound, because it does not have nearly as much force behind it as the compressed oil and compressed bladder inside the shock. Watch this video on how to build shocks:
http://www.youtube.com/watch?v=rixBJ...layer_embedded

2. This slop problem is fairly common in RC8's. I experienced it in my latest RC8Be's CNC aluminum front knuckles. There was approximately .75mm of a gap that allowed the outdrive to slide back and forth inside the bearings. The only way to fix that would be to install shims between the outdrive and the large, inner 12x18 bearing. But in my cars, I never installed shims, because frankly, I didn't consider it to be enough of a problem to go to the trouble of finding and ordering any. If you do order some shims, try to find ones with as small a face as possible (distance between the inner edge and outer edge). Too large, and you run the risk of binding by virtue of pushing the outer edge of the shim into the bearing. Ideally, your shim should have the same face size as that of the bearing's inner race.
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Old 11-02-2010, 10:20 AM
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take the shocks off and see if they do the same thing off of the car. sounds like there might be a little too much oil in them.
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Old 11-02-2010, 10:22 AM
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How much rebound do the shocks have? I'm with everyone else, sounds like you have too much oil in them.

My RC8B big bore shocks have about .5-.75" of rebound in them.
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Old 11-02-2010, 11:25 AM
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Make sure there is no shock oil behind the bladder. If there is the bladder can't compress and you will have that problem.
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Old 11-02-2010, 11:45 AM
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I will recheck them again tonight....but like i said i refilled them last night, and was pretty sure they were not over filled.....I could be wrong though, as I am no expert by any means.
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Old 11-02-2010, 11:58 AM
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Originally Posted by tq_danpatterson
You wouldn't think it would happen because the oil inside can obviously go through the piston holes, but an overfilled shock will actually be nearly impossible to completely compress.
The issue is that the shock shaft is displacing volume.
Take a top fill shock and remove the cap and bladder. Push the piston almost to the top but still below the oil and note the level. Now pull the shaft down and you'll notice that the oil level decreases as well.
Bladders help, but you have to get the initial fill correct. The bladder usually doesn't displace the same amount as the shaft.
Some shocks when built correctly but without springs, will be easy to fully compress and expand, but will slightly come back out on their own on the compression, AND slightly pull the shafts in when fully extended.
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