mattster1971

I have a hyper 7 I acquired used from craigs. While it was a pig as far as being dirty, once I broke it down and cleaned it I only had to replace two suspension pins, a bent front shock tower and a shock bladder. I had it running today a. nd it is amazingly quick and responsive with the. 28 hyper and the larger 17tooth axial clutchbell.

I was wondering when or at what interval should the front/rear and center differentials be broken down, cleaned and repacked with grease? Are you supposed to grease the dogbones? My thought was no because that would trap the dirt in the drive cups, but still wondered. I am not use to a 4 wheel drive setup and so I haven't had to deal with all the differentials and dogbones before. How do you know when this type of maintenance is needed? Thanks

Anthoop

How often you have to service the diffs will depend on how you use the car and the conditions you run in. Servicing too often is obviously more preferable than not often enough but bear in mind that you will be able to feel if they are getting graunchy/loose/etc.
There is no problem at all with using grease for the diffs but you will find that using oil will provide more tuneability.
I would not use any lubricant on the driveshafts, as you thought- dirt will stick and cause wear. Having said that there are dry lubricants that would be appropriate but in my opinion you do not need to worry about lubing these parts, just ensure they are clean/dry.

mattster1971

We are casual runners. Weekends when weather is nice, maybe 3 or 4 tanks. Nothing major. I think the guy I got this from was rough on his stuff. I wish I had taken a before pic so you could see how ridiculous the previous owner left this thing, dirty filthy. If I hadn't driven an hour to buy I may have just said forget it

Anthoop

Yes buying used stuff can be a lottery...hopefully you can forget it now it is fixed up.
With your useage you can probably "forget" about having to service the diffs and as I said you will be able to feel for problems, simple regular checks will give you a feel for good/mmm/bad.

JohnP2

Anthoop made some great points. One thing to think about, of course, if the previous owner sold it in a "pig-like" state, then he or she probably did not take good care of the car. Especially if the owner did not even bother to clean it prior to selling it.

Consquently, I'd recommend to go ahead and check them out (as they might not have ever been touched).

Most folks (including myself) use the following:
5k - front
7k center
3k - rear

Please post pics and/or videos of it (now that it is cleaned up). Would love to see it.

mattster1971

I thank you all for your suggestions. I took it apart because grease was splattering on the inside of the plastic body shell in a pattern indicating the center diff was leaking. When I opened it the interior was just coated with a thick black grease, no oil. Is that how this comes from the factory, with. Just grease inside the diffs? What indicates the diff is getting "loose" or in need of change? This leak was my indicator that something, thinking the o ring on the gear side, wasnt fitting tight anymore.

Anthoop

From the factory they are packed with grease. Could well be that the O ring needs replacing...I use a little RTV on the O ring for peace of mind.

mattster1971

How do you use rtv on the o ring? Wouldn't that bind it up? I got all the different weights of oil today, the lady at the hobby store is nice.

Anthoop

Nevermind the lady in the store.
I am talking about the large O ring on the casing (where it meets the spur/crown gear), not the smaller O rings on the outputs.

mattster1971

Well I changed it and put it all back together today. That 7k is like the thickness of honey, so thick. Put it back together and it is super stiff, guess that's what was intended. I may tackle the front and rear soon too, but want to run this a little to see what I think. Too cold today and I want to put up a pic but I am usually posting from my phone. I didn't zip tie the pipe manifold tight enough and got some blow back on the pipe so while I had all those parts off I used some alloy polish and shined that baby up like new. I don't like how the body hits the pipe in the front so I trimmed up the body a little more in that area since it melted to the pipe on the front recently.

mattster1971

How do you think the hyper 7 stacks up against other 1/8 scale buggies in its class? I know its on the lower cost side but from my limited experience it seems quite rigid and well handling. Is there an official hyper 7 Thread on here?

Anthoop

It depends what class you put it in I guess......but yes it is a great buggy. I will always recommend it to anyone asking (whether they are new to the hobby or not), it has been around for more than a few years in many different forms, it is well proven/known.
Of course if you are going racing then in the end the Hyper7 is not going to be the best choice.
There maybe an Official Hyper7" thread somewhere (?) , I do not know.....but you can be sure there are plenty of Hyper threads found by searching....

JohnP2

Agreed. The Hyper 7 is a mid-market RTR buggy for those wanting a hobby-grade buggy that does a little bit of everything. It's known more for its durability than its racing prowess (i.e. it'sbuiltto be a basher). Definitely one of the most popularnitro vehicleson the market today, so you'll have no problems finding information on it. Note there are different "flavors" of it ranging from a .21 engine to a .28 engine. I don't believe there is an "official Hyper7" threadon this forum, but imagine there would be solid activity if one were started (hint-hint). ;-)

Anthoop

Personally I do not like those "Official" type threads. If it is a popular item then the thread can go on for many pages meaning that a lot of the information will be forgotten/never read and also questions can easily go un-answered. Many times in the past I have researched some item in threads that are over 50 pages long and after reading the whole thread I find that the useful information I have gained would condense down to less than a page.

Besides that, I think that the guys who knew all about the H7 no longer frequent the forum, however their thoughts are recorded here and can be found by searching. Once you have searched a few old threads you become familiar with the usernames that are dealing out the gold, then you can search their post history.

Just my little rant (8am here and I am grumpy in the mornings). I am sure if someone started a thread now I would participate...along with you John...and...mmmm.

mattster1971

Ok, I had it all rebuilt just as it should be with new seals and ran one tank today and there was a fluid all over the diff and housing.. what gives???

proptop

My Feedback: (8)

First thing that comes to mind is...it might have been over filled...sometimes when over filled, the excess will find it's way out when things warm up and expand.
OR
You HAD it rebuilt, or did you rebuild it yourself?
Just askin', because if you did it yourself, then you'll be more familiar w/ what I'm gonna say...

There are typically 4 places where it will leak...(unless there is a crack somewhere )
2 red O rings, where the output cap joints come out...(to the drive shafts )
The gasket between gear and plastic case...
The small access hole plug, screw (grub screw ) that plugs the cap joint drive pin access hole on the plastic case.

Sounds like something is either missing or not installed properly?

mattster1971

I rebuilt it myself. I definitely put it back together exactly as it was dismantled. Shims and all, maybe I did put a little too much in but it wasn't running over when I screwed the spur on, nothing oozed out. Its just all over the darn thing and the grub is in fine I guess. Doesn't it just screw in? You don't want to put the grub in too far it will hit the gears wont it? I think its coming from the end opposite the spur.. very frustrated.

nitroexpress

Since you bought it used, the diff cups and/or the outdrivescould be original or just plain worn out.If the outdrives have too much wobble, nothing will seal them. Buy a diff cup and some outdrivesand compare with what you have.

mattster1971

That was my thought, the out drives. The diff cup is new also, I got it with the seals in one package.

proptop

My Feedback: (8)

I changed the fluid in the center diff in one of my X1-CR's and re-used the brake cap joints (just changed the O-rings )...the shafts are a bit worn, but not excessively. It seeped a bit for a little while, because I think I over filled it a little bit, but it stopped after a few tanks. (I'm using 7K in it )

The new O rings will help a lot...IMO I would just wipe it off good, and watch it for a few more tanks to see if it continues...

mattster1971

How full should you fill the diff when you are changing it?

Anthoop

Over half is plenty.

mattster1971

Okay so after several more tanks it continues to leak, it does appear to be around the grub screw. I wondering just how much has come out at this point and if I should tear down and do over. I am considering using a small piece of plumbers tape on the grub screw or some loctite on it to try and seal it off. Odd to me because this was a new cup and I believe the grub screw was new too with the set. What do you all think? Should I rebuild it and worry about lost oil or just do something to seal the grub? If seal would my suggestions be adequate? Thanks

proptop

My Feedback: (8)

I wonder if maybe there is a manuf. flaw in the plastic cup, or maybe a hairline crack somewhere around the threaded hole?

Silicone RTV sealer would probably work O.K.? I don't think the silicone diff oil would disolve it, once it's had a chance to cure throughly? Let the sealer cure over-night before introducing the diff oil perhaps? (you probably already know that you don't want to use loctite on plastic parts like that? )

Anthoop

Yes, RTV.
Remove the screw and degrease it and use a cotton bud to degrease the thread in the housing, apply little RTV to screw then wind it in until level with the housing.