Shock Absorber Disassembly - Sketer

[MouthbreatherRC]

Please could someone give me some advice on disassembling the shock absorber on my Sketer.

Whilst cleaning the car today after some bashing in a quarry, I noticed that oil has been leaking from the rear shock. On closer inspection there is a small hole in the top mount/cap where the oil is leaking from. I am unsure if this is damaged, or part of its design.

My problem is that I am unsure on how to unscrew the cap, which seems very tight… Before resorting to the mole grip and vice technique, which undoubtedly end badly, is there a technique for doing this?

I suspect a seal has gone.

Thanks in advance.

 

[ridgehead44]

Hey there!

I suggest investing in a pair of shock pliers. Here's the pair I use, which only costs $13 American. They're very helpful.

If you don't want to go that route, or would rather use what you already have, you can use a crescent wrench to grip the shock firmly (not too tight). From there you can slide one of your hex drivers through the hole at the top of the shock cap. Then turn the hex driver to loosen the shock cap. Use firm but gentle pressure. This is how I've done it with my Arrma vehicles. I haven't disassembled my Sketer shocks yet, but I imagine it should work the same. Let us know how this goes.

 

[MouthbreatherRC]

Thank you very much for your reply, which is very helpful.

I think that buying the pliers (as per your link) is a wise move as good tools are never a waste of money, and I would hate to ‘graunch’ the threads up on the shock by using the wrong tools.

Thanks again for your help. I’ll update the post once I have had a try.

I had to Google Crescent wrench, which I call a shifting spanner. good tip though!

 

[Jeffwazz]

Also try wrapping a length of rubber (a bit of bicycle inner tube is good) around the shock body. Take off the spring first. This might give you enough extra grip to crack open the shock cap with the hex wrench though the hole.
I leave the mounting bolt in the hole and just use that to unscrew the cap.

 

[MouthbreatherRC]

Also try wrapping a length of rubber (a bit of bicycle inner tube is good) around the shock body. Take off the spring first. This might give you enough extra grip to crack open the shock cap with the hex wrench though the hole.
I leave the mounting bolt in the hole and just use that to unscrew the cap.

Thanks. Another great tip, and I guess it will also protect the thread, which seems quite delicate.

I am going to try to do the repair on the weekend. Hopefully these parts will have arrived by then, which I think must have failed to allow oil out of the mysterious hole in the top.

Thank you for your help. Much appreciated.

 

[Jeffwazz]

The new shock bladder should fix the leak from the hole. There's either a hole/split in the bladder, or it's not seated correctly in the body/cap.

 

[MouthbreatherRC]

The new shock bladder should fix the leak from the hole. There's either a hole/split in the bladder, or it's not seated correctly in the body/cap.

Thank you again. Very helpful info.

 

[chipster]

The new shock bladder should fix the leak from the hole. There's either a hole/split in the bladder, or it's not seated correctly in the body/cap.

Don’t tighten the cap on too tight or you will split the shock bladder. I put it on finger tight and the just give it a little nip with a wrench. Gripping the shock tube with a cloth or piece of rubber inner tube is a good idea. Gripping this with a Chrysler Wrench or mole grips could damage it, then you would have to buy a new shock

 

[Horatio]

Please could someone give me some advice on disassembling the shock absorber on my Sketer.

Whilst cleaning the car today after some bashing in a quarry, I noticed that oil has been leaking from the rear shock. On closer inspection there is a small hole in the top mount/cap where the oil is leaking from. I am unsure if this is damaged, or part of its design.

My problem is that I am unsure on how to unscrew the cap, which seems very tight… Before resorting to the mole grip and vice technique, which undoubtedly end badly, is there a technique for doing this?

I suspect a seal has gone.

Thanks in advance.


View attachment 4653

The hole on the side of the shock cap is normal and supposed to be there - it's a vent hole to let air out.

If the cap is very tight (it shouldn't be - no need for these to be over-tight), I suggest using a rag and a pair of stout pliers and grip where you see the blue line:

It shouldn't need much torque to remove.

When you re-fill, don't overfill them and let the bubbles rise out for a few minutes before you refit the cap. See here:

Good luck!

 

[MouthbreatherRC]

Thank you for taking the time to explain the purpose of the hole in the cap, and for the excerpt from the manual.

i actually did the repair this afternoon and it went well, but I fear I may have overtightened the cap unlike your advice. It didn’t seem to leak, but I am taking it to the beach tomorrow for some bashing, so that will be the acid test.

on the subject of the shock oil, is the higher the number the greater the viscosity or the other way around? I am trying to stiffen the shocks a bit to stop the nose diving when jumping, which I think I read was a ‘fix’ somewhere on this forum?

Don’t tighten the cap on too tight or you will split the shock bladder. I put it on finger tight and the just give it a little nip with a wrench. Gripping the shock tube with a cloth or piece of rubber inner tube is a good idea. Gripping this with a Chrysler Wrench or mole grips could damage it, then you would have to buy a new shock

Thank you for the reply. I got it all done today (see post above) I appreciate you help and advice

 

[Horatio]

Thank you for taking the time to explain the purpose of the hole in the cap, and for the excerpt from the manual.

i actually did the repair this afternoon and it went well, but I fear I may have overtightened the cap unlike your advice. It didn’t seem to leak, but I am taking it to the beach tomorrow for some bashing, so that will be the acid test.

on the subject of the shock oil, is the higher the number the greater the viscosity or the other way around? I am trying to stiffen the shocks a bit to stop the nose diving when jumping, which I think I read was a ‘fix’ somewhere on this forum?

View attachment 4660


Thank you for the reply. I got it all done today (see post above) I appreciate you help and advice

You're welcome.

The higher the number, the thicker the oil. CST is the common standard for viscosity, but you'll also find Wt.

Here's a table (attached) to figure out Wt Vs cst.

Regards stopping dive during a jump, the cause of this could due to several reasons.

One thing that can cause this is a take-off ramp that is too short. This will inevitably kick the back of the car up.

Increasing shock oil will make your damping heavier, but your shocks will not be stiffer - they'll just be slower to react. To make your shocks stiffer, you need higher rate springs.

Making your shocks stiffer will make your car less prone to bottoming out on landing, but reduce the grip on bumpier surfaces.

You may also want to try adjusting pre-load. This adjusts the ride height. This can have a very useful effect on the balance of the car, especially on jumps or for increasing off-power steering.

I'll add a chart on pre-load - it's very handy to learn adding/taking away pre-load at either end of the car and how it effects the handling.

Preload Effects

 

[MouthbreatherRC]

You're welcome.

The higher the number, the thicker the oil. CST is the common standard for viscosity, but you'll also find Wt.

Here's a table (attached) to figure out Wt Vs cst.

Regards stopping dive during a jump, the cause of this could due to several reasons.

One thing that can cause this is a take-off ramp that is too short. This will inevitably kick the back of the car up.

Increasing shock oil will make your damping heavier, but your shocks will not be stiffer - they'll just be slower to react. To make your shocks stiffer, you need higher rate springs.

Making your shocks stiffer will make your car less prone to bottoming out on landing, but reduce the grip on bumpier surfaces.

You may also want to try adjusting pre-load. This adjusts the ride height. This can have a very useful effect on the balance of the car, especially on jumps or for increasing off-power steering.

I'll add a chart on pre-load - it's very handy to learn adding/taking away pre-load at either end of the car and how it effects the handling.

The table is very helpful thanks.

The tips on recucing nose diving is also useful. I usually take a shovel to the beach and ’dig out’ some ramps… I’ll make the ramp length a bit longer this time to see if I it improves this very addictive and arguably mechanically destructive part of this hobby

I’ll see if Corally do stiffer springs, maybe just for the rear, but I get your point about making the car trickier to control. Is preload adjusted with the red knurled nut on the shock?

 

[Horatio]

The table is very helpful thanks.

The tips on recucing nose diving is also useful. I usually take a shovel to the beach and ’dig out’ some ramps… I’ll make the ramp length a bit longer this time to see if I it improves this very addictive and arguably mechanically destructive part of this hobby

I’ll see if Corally do stiffer springs, maybe just for the rear, but I get your point about making the car trickier to control. Is preload adjusted with the red knurled nut on the shock?

Yes, jumping is great fun, but can get frustrating if it results in breakages.

Fixing and wrenching is great fun though.

Yes - preload is adjusted by using the collar on the threaded shocks, or by adding/removing spacers on unthreaded socks.

By compressing the spring, this increases ride height at that corner.

As a starting point, try arms level when you drop the car onto a flat surface from about 6" off your bench.

Whilst we're talking about ride height and jumping, don't forget to set droop correctly, otherwise you'll break your shock absorbers. Maximum droop should hit the droop limit screw before your shock reaches it's maximum throw.

I use titanium dome headed droop screws on my rig to save the lugs on my chassis from getting chewed up.

 

[MouthbreatherRC]

Yes, jumping is great fun, but can get frustrating if it results in breakages.

Fixing and wrenching is great fun though.

Yes - preload is adjusted by using the collar on the threaded shocks, or by adding/removing spacers on unthreaded socks.

By compressing the spring, this increases ride height at that corner.

As a starting point, try arms level when you drop the car onto a flat surface from about 6" off your bench.

Whilst we're talking about ride height and jumping, don't forget to set droop correctly, otherwise you'll break your shock absorbers. Maximum droop should hit the droop limit screw before your shock reaches it's maximum throw.

I use titanium dome headed droop screws on my rig to save the lugs on my chassis from getting chewed up.

Hi and thanks again for the reply. I went to the beach with the car and it ran really well. Making a longer ramp certainly reduces the nose diving…thanks.

Now I have cleaned all of the salt & sand off of it and dried it, I will look at the droop setting, but nothing broke after three battery packs. I think these cars are quite tough.

I would have posted some video, but my brother forgot to push the record button on my phone so I thought you might like a picture of all the cars we took on a great morning out… this is a great forum and thanks again

 

[Horatio]

Hi and thanks again for the reply. I went to the beach with the car and it ran really well. Making a longer ramp certainly reduces the nose diving…thanks.

Now I have cleaned all of the salt & sand off of it and dried it, I will look at the droop setting, but nothing broke after three battery packs. I think these cars are quite tough.

I would have posted some video, but my brother forgot to push the record button on my phone so I thought you might like a picture of all the cars we took on a great morning out… this is a great forum and thanks again

View attachment 4681

Now that's my kinda day out!! Nice collection

RC is awesome in all it's forms.

 

[MouthbreatherRC]

I think you win with your collection, the cars in the image I posted aren’t all mine.

I like the look of of all your gear, especially the buggy in the first image you posted… what scale is it and what CC is the engine. It looks like proper exotica

I love this hobby, but it may eventually put me in the poor-house

 

[Horatio]

I think you win with your collection, the cars in the image I posted aren’t all mine.

I like the look of of all your gear, especially the buggy in the first image you posted… what scale is it and what CC is the engine. It looks like proper exotica

I love this hobby, but it may eventually put me in the poor-house

I only have 5 cars now - trimmed back from about 30. In fairness, some of the 30 were cars I bought my kids when they raced.

After a hiatus from racing for a few years, I got back into cars by restoring the HPI Savage SS, then the 1/5th scale HPI Baja 5B SS in the first picture.

The parts are a combination of Bonehead carbon fibre from the UK and GTB machined alloy parts from China. The engine is an original CY 26cc on the Curly pipe, which is loud and proud. It's also surprisingly rapid - 48mph and 0-40 in 2.8 seconds, which for a 1/5th scale Baja is good. Especially a 14 year old one!

The engine is stock other than the mesh mod, outerwears and hi-flow airfilter.

FPV drones, a glider and 1/4 scale 3D aircraft take up some time too. All of which I thoroughly recommend. Filming 4k with an FPV drone and zooming around at 147mph is quite a buzz.

Latest project is the 30cc twin 3DHS Extra.

For chill though, this is where it's at

The trusty Radian Pro on 3S. Flies/Glides forever.

Weekends are far too few and UK weather seriously limits the amount of play time, but it's great to experience different types of RC.

 

[MouthbreatherRC]

Thanks for all the details. You have some nice kit there and obviously a lot of experience With RC stuff.

I would love a drone…. a DJI Mini or something similar, but I am not sure where I could use it. They do look like fun.

I daren’t buy a plane, I think they might be more bank account draining the a RC Car

 

[Horatio]

Thanks for all the details. You have some nice kit there and obviously a lot of experience With RC stuff.

I would love a drone…. a DJI Mini or something similar, but I am not sure where I could use it. They do look like fun.

I daren’t buy a plane, I think they might be more bank account draining the a RC Car

If you like the idea of RC flying, a DJI Mini 3 or something like that (sub 250 gram) would be super easy to use. No piloting as such and excellent for tracking, filming and stills.

If that worked out, you might then might want to try your hand at piloting FPV drones. It requires learning Betaflight software so you can configure flight controllers, but there's lots of videos on YouTube - Joshua Bardwell is excellent at explaining tricky stuff in layman's terms.

RC planes require flight skills that require either time spent with an instructor or on a good RC flight sim.

Fixed wing flying is actually surprisingly straight forward once you have the basics nailed down.

Aircraft generally don't bounce, so when it goes wrong, it goes wrong big time stylee! You'll note Kevin Talbot's flying videos, when his planes are destroyed, don't get mended, unlike his cars and heli's. Oh - and he gets asked not to come back to the flying site.

Speaking of which, heli's are awesome too - loads more options these days with brushless and lipos. These definitely require lots of practice and/or an RC flight simulator.

All forms of UAS flying require Operator ID and Flyer ID from the CAA in the UK. In the US, FPV drone operation also requires Radio Ham qualification as well.

I'm super tempted to get hold of an Sworkz S35 T2E this November. Cars are beautifully engineered and take up less space!

 

[MouthbreatherRC]

Thanks… that’s some great information.