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Top Cat Rebuild Has Begun - Some Questions
Posted: Fri Mar 25, 2011 11:57 am
by RCveteran
I have begun rebuilding my Topcat and have some questions I will post here with pics as I go.
The schocks were seized and I have them apart now, I believe the pistons and o-rings both swelled from sitting in storage, there was still oil. I got them all apart. Are the Brass bushings that the O-rings fit in still available? Also, it appears one of these bushings is inside the shock body besides the 4 you can see I have removed from looking at instructions, I have no idea how to get that out so I will leave it.
Other shock questions?
1) What current Schumacher shock pistons can I use?
2) What size is the snap ring in the bottom of the shock body?
Re: Top Cat Rebuild Has Begun - Some Questions
Posted: Fri Mar 25, 2011 12:22 pm
by 8rad
Are the brass bushings still available? NO!
What new Shumacher pistons will fit? None that I am aware of.
What size is the snap ring in the bottom. Dont know.
A lot of help I am eh? Hehe.
I got some of those bushings if you want? It is possible to get them out without too much trouble. The trick is to insert an allen key in the top of the shock and gently tap around the edge of the bushing until it frees up. Then you can dig it out with a pick.
Are the pistons that came with no good? On my last Cougar build I sanded down some newer 1 piece pistons but thats lot of work. Maybe some RC10 pistons will fit. Have not tried.
Re: Top Cat Rebuild Has Begun - Some Questions
Posted: Fri Mar 25, 2011 12:37 pm
by RCveteran
I may try to rebuild them with these Losi ones. Only 1/10 of 1mm off. Hmmmm? Yellow is original, red is Losi.
And since you didn't answer, I am forced to ask more questions

I need a new thrust bearing cage for the differential (are the balls 1/16") and where do you get these odd size ball bearings to replace the bushings? THe rest of the car appears to use 8x16 replacement ball bearings.
Re: Top Cat Rebuild Has Begun - Some Questions
Posted: Fri Mar 25, 2011 1:01 pm
by 8rad
The thrust bearing assemblies are still available on ebay. U730D. I have read that Losi TB also fits. I am sure you have some of those.
If thats the layshaft bushing then you need the special washer T226 that fits inside the normal sized bearing. They come in plastic or aluminium.
Re: Top Cat Rebuild Has Begun - Some Questions
Posted: Fri Mar 25, 2011 1:14 pm
by RCveteran
Thank you, the losi pistons are too thick however I have Losi shock shafts the are close enough to same length so I think I may be on to an easy to source replacement for shock shaft and piston set up.
I'll need to find some 8mm snap rings before I can test though. Losi shock shaft on right.
Re: Top Cat Rebuild Has Begun - Some Questions
Posted: Fri Mar 25, 2011 1:28 pm
by RCveteran
I was able to salvage a snap ring. I can report the Losi shock shaft and piston work great, no leaks and silky shooth operation. I am using Losi Piston #55 as I had them but any should work. I will likely use a more modern and durable ball end on the shaft as well.
Re: Top Cat Rebuild Has Begun - Some Questions
Posted: Fri Mar 25, 2011 2:03 pm
by CNA75
Nice build. The Topcat is such a great car - I love its uniqueness. Are you going to polish up those shock bodies to get that clean chrome finish?
Re: Top Cat Rebuild Has Begun - Some Questions
Posted: Fri Mar 25, 2011 2:30 pm
by RCveteran
They will get hand polished. I will build this very original but I am not going to get hung up using better ball ends and more readily available parts like the shock pistons and such. I don't intend to drive it much but it will not be a pure shelf queen and if I can get some open practice time on a track I won;t be able to resist.
Re: Top Cat Rebuild Has Begun - Some Questions
Posted: Fri Mar 25, 2011 2:33 pm
by RCveteran
8rad wrote:The thrust bearing assemblies are still available on ebay. U730D. I have read that Losi TB also fits. I am sure you have some of those.
If thats the layshaft bushing then you need the special washer T226 that fits inside the normal sized bearing. They come in plastic or aluminium.
I see U730 but cannot pin down a T226?
Re: Top Cat Rebuild Has Begun - Some Questions
Posted: Fri Mar 25, 2011 3:08 pm
by RCveteran
I may have run into my biggest hurdle. It appears my diff pulley is not so hot. It almost looks like it got too hot as some of the holes appear a bit melted and odd. They will still hold a ball but not normal for sure. Odd for a car that does not seem run much ever.
Re: Top Cat Rebuild Has Begun - Some Questions
Posted: Fri Mar 25, 2011 3:12 pm
by 8rad
MMMMMM.........Melty!
I check my box at home and see what I have.
Re: Top Cat Rebuild Has Begun - Some Questions
Posted: Fri Mar 25, 2011 5:28 pm
by CAT3K
Looks like the diff was run too loose perhaps and got very hot.
If you get stuck for a pulley i probably have one somewhere, not new but it would be better than you have
Paul.
Re: Top Cat Rebuild Has Begun - Some Questions
Posted: Sat Mar 26, 2011 9:27 am
by RCveteran
Spur gears available?
Re: Top Cat Rebuild Has Begun - Some Questions
Posted: Sat Mar 26, 2011 9:40 am
by CAT3K
RCveteran wrote:Spur gears available?
Still available from Schumacher's website.
This one :
http://www.racing-cars.com/sp/category/Old_Cars_and_Parts/subcategory/Club_10_Mk1/templateid/12/searchbox7/Transmission.html
Or search for whisper gear in the search box and you'll have a choice of sizes.
Paul.
Re: Top Cat Rebuild Has Begun - Some Questions
Posted: Sat Mar 26, 2011 5:36 pm
by RCveteran
Thank you. As I was fiddling with these old shocks I got to looking at the new Cougar SV big bore shocks, those might look real pretty on this beast. I am sure the rears would be easy but I suspect the fronts are significanlty longer and not sure if there is chassis clearance, anyone tried this?
As if my JRX2 addiction was not enough to break me I am going down a dangerous path with this beast
