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barbon

Rere Scorcher build woes

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I’ve been working on finishing up the suspension of my new rere SS, and I’ve come across a problem. The U joints just fall apart and don’t seem to be made right. The pins just fall right out and then the whole u-joint falls to pieces.

 

I’ve tried to figure out what’s wrong with them or what I did to make them fall apart but I can’t figure it out. I have an original SS with original brass u joints and although they have a lot of play, I could throw them against a concrete all and they wouldn’t come apart. These I can just shake lightly and they’re in 5 pieces on my desk. 
 

Have any of you all experienced this? If so, what’s the fix? I’m very disappointed that a $375+ kit has non working critical parts right out of the box, never run.

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I don't remember that being a problem when I built mine. Did you install and tighten all of the grub screws? IIRC the joints themselves come assembled (and can't come apart) but they require two grub screws on each side to keep the output and drive shaft assembly together.

 

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1 hour ago, djmcnz said:

I don't remember that being a problem when I built mine. Did you install and tighten all of the grub screws? IIRC the joints themselves come assembled (and can't come apart) but they require two grub screws on each side to keep the output and drive shaft assembly together.

 

Great tip this and perhaps add a very small amount of the blue lock thread as well.

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The actual joint should be held together by one pin passing through another, in a cross shape.

The 'retaining' pin is, essentially, a rivet - one end is domed and the other end should have a dent in it where the end is swaged out or flared, like the end of a trumpet.
There's no screws holding the joint together, only that rivet

UJ1.jpg

Other end of retaining pin/rivet, with 'dent' for flaring the end

UJ4.jpg

 

You can see the flared end on the right of the pic

UJ3.jpg

UJ5.jpg

 

The other pin should be flat at either end

UJ2.jpg

 

If the retaining pin hasn't been sufficiently flared, then it'll slide out of the assembly.

If you have a centre-punch you could try flaring that end out some more - at a push you might be able to do it with a big nail. You'll need to rest the assembly on a firm hard surface whilst hammering - something like an anvil or the back end of a vice

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Which part is actually falling apart?  As Twinset has noted the pins in the joint shouldn't come out unless they haven't been made properly.

If it's the driveshaft pulling out of the UJ - check the suspension angle when you tighten up the grubs.  The suspension arm follows a slightly different radius to the driveshaft, if you fully insert the driveshaft with the suspension fully extended and then tighten it up, it will either bind the suspension or pull the shaft out when the suspension is compressed.  ISTR having this problem when I first built my re-re, and when doing a 2-hr endurance race a few years ago, having to pull in every 5 laps to tighten up the grub screws.

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The driveshafts are fine, no issues with the grub screws. The issue is the pin that’s supposed to be flared on one end just falls out. Here’s a couple images to illustrate what I’m talking about since I realize it probably doesn’t make any sense unless you see it. It seems to me like these were made incorrectly in the factory. I’m not sure if that pin is supposed to be one piece with the flare, sort of like a rivet, or if it’s 2 pieces and is supposed to be sort of jammed together. Either way the pin seems very short, it doesn’t even make contact with the flare on the other side at all. Both of the u-joints are like this. I noticed that one of the pins just fell out when the head was facing downward while the car was just sitting on the desk. These are brand new so they are not worn out or anything. Whatever is wrong with them is something that happened in the factory (or didn’t happen)

3496F509-77BD-4A42-81D0-22C6FA1D9780.jpeg

image.jpg

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I’ve contacted Tamiya support about the issue and sent them the above photos. Hopefully this was just a random defect and I’m able to get some replacement parts for it. Something is definitely wrong, my thrashed and abused 1979 SS u joints stay together, and trust me, i’ve tried to get them to come apart after seeing this issue. They won’t unless I really went at them with some tools I think.

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So , it isn't a straight through rivet anymore ? . Yours looks like a 'flared' sleeve press fitted onto the pin . I don't have these re-re joints so I can't look at one up close . You could try threadlock to bond it back - or cold steel 2 part mix like JB weld

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4 minutes ago, KEV THE REV said:

So , it isn't a straight through rivet anymore ? . Yours looks like a 'flared' sleeve press fitted onto the pin . I don't have these re-re joints so I can't look at one up close . You could try threadlock to bond it back - or cold steel 2 part mix like JB weld

Definitely seems to be a pin and a flared sleeve. The issue is, the pin doesn’t even make it to the sleeve so it’s impossible to just push it back through the sleeve and mushroom the sleeve end or something. There’s really nothing to put thread lock on. Comparing it to the old ones which seem to be one piece mushroomed pins, this design is an absolutely horrible alternative. I’ve ordered some replacements, thinking this may be just a defective batch, but if those exhibit the same issues, I’ll send them back. In the meantime I’m hoping Tamiya will send me some non defective parts that I can actually use. I dug out all my old RC stuff at my moms that’s been in the basement for 10 years including an original Sand Scorcher and Kyosho Beetle from 1983. I guess if worse comes to worse I can borrow these old brass u joints from my ‘79 SS.

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Does the sleeve look like it has sheared off from the pin ? . It might have been made as one , then flared once pushed through the joint . It could be a design fault / weakness

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13 minutes ago, KEV THE REV said:

Does the sleeve look like it has sheared off from the pin ? . It might have been made as , one then flared once pushed through the joint . It could be a design fault / weakness

Not in my opinion. It’s an awfully clear shear if that’s the case. What it looks like to me is the pin was too short to make it through the sleeve where it should be shoe-horned into if the pin was longer, it could make it through the sleeve. I don’t think it’s been broken, since this car has literally not even left my desk yet. If sitting on a desk breaks that pin. i can only imagine what even the most gentle driving would do to it. At first I thought it must have sheared off, but that just doesn’t seem to be the case since both of them are very clean. There’s nothing to indicate that they were once one-piece. 

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Yes I believe there is definitely a quality control issue there @barbon. I just had a look at my recent Fighting Buggy and the UJ’s are put together the same as yours, mine haven’t come apart and has been run. I suspect yours have missed some kind of press procedure in the factory. Just one of those rare defects, like you mentioned it must be annoying considering the price of these kits. Hope you get it sorted. 

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@barbon Thanks for the heads up.  I will definitely check that before I start assembly.   I am assuming that universal is the same one used on the M38?  If so I have a couple of spares in my parts arsenal.. mine are mostly 35+ yrs old from my restorations.. none have broken so far.

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2 hours ago, Re-Bugged said:

Yes I believe there is definitely a quality control issue there @barbon. I just had a look at my recent Fighting Buggy and the UJ’s are put together the same as yours, mine haven’t come apart and has been run. I suspect yours have missed some kind of press procedure in the factory. Just one of those rare defects, like you mentioned it must be annoying considering the price of these kits. Hope you get it sorted. 

Thank you, good to hear someone else has these same u-joints but they function as intended. Must have just been a bad batch or something. I’m waiting to hear back from Tamiya, I was asked for my receipt and my address so I’m thinking they might be willing to send me replacements. These are ridiculously hard to find online and expensive too. I found some for $28 shipped but would prefer to not have to spend $30 on defective u joints vs $30 on body finishing supplies.

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18 minutes ago, Willy iine said:

@barbon Thanks for the heads up.  I will definitely check that before I start assembly.   I am assuming that universal is the same one used on the M38?  If so I have a couple of spares in my parts arsenal.. mine are mostly 35+ yrs old from my restorations.. none have broken so far.

I do believe so. I know several of the 70s-early 80s pre plastic suspension era kits used those brass u joints. They wear out easily but at least they don’t fall apart like the ones I’m currently dealing with. Have fun with the build, and who knows, you may have perfectly fine u joints. Might have just been this most recent batch that was defective.

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Greetings the rere of the scorcher has a different designed U-joint from the original kit this U joint is one the scorcher the fighting buggy and I cannot remember the third kit that has the same design on the U-joints... IF I can find it I will list it later... IF you contact tamiya they should send you a replacement set .....

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2 hours ago, Original Jardasius said:

Greetings the rere of the scorcher has a different designed U-joint from the original kit this U joint is one the scorcher the fighting buggy and I cannot remember the third kit that has the same design on the U-joints... IF I can find it I will list it later... IF you contact tamiya they should send you a replacement set .....

Buggy Champ also uses the same u-joints (all 3 share the same basic chassis). I'm waiting to hear back from Tamiya. I ordered 2 u joints I found online, I figure if Tamiya does end up replacing my parts, I can use the extra pair on my original SS that I'm eventually going to restore.

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The Guy from Tamiya I had been corresponding with told me that they’ll be sending me replacement parts soon. For the time being, I threw on my old worn out brass u joints from my ‘79 SS. I got a set of VW wheel caps from Shapeways today and had to see how the car looked with them. Slightly disappointed with the product I got but I still think it looks pretty nifty! (Wish there weren’t gaps showing from the stock wheel backings. Might have to cut out some styrene rings or something to fill those in.) Looking forward to starting on the body soon. I’m thinking box art but with TS12 (Rough Rider orange) instead of French Blue. Silver wheel caps and lettered tires!

EBDC3C24-CCB2-411A-A398-64383708FFB8.jpeg
 

Really wish the Buggy Champ was still around, and it looks like I just missed out on the last batch of Fighting Buggies as I would have loved to build another SRB to keep this one company, but I’m glad I got my all time favorite Tamiya and had a blast building it. Is it always this fun? B) I suppose restoring my original SS will have to satisfy my desire to build another SRB.

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@barbon Looks good.  I would paint the factory wheel black where it peeks through the front and it will look clean.  I paint the inner wheel halves often to clean up the look on my cars.   GL. 

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48 minutes ago, Willy iine said:

@barbon Looks good.  I would paint the factory wheel black where it peeks through the front and it will look clean.  I paint the inner wheel halves often to clean up the look on my cars.   GL. 

That’s the plan for me as well. I guess I should have probably painted the inners before putting them inside the tires but I’ll make it work. Can’t decide on silver or white for the outer rims now!

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11 minutes ago, barbon said:

That’s the plan for me as well. I guess I should have probably painted the inners before putting them inside the tires but I’ll make it work. Can’t decide on silver or white for the outer rims now!

Sounds good.  Depends on your car color maybe, but I think silver is going to look very cool on those outer wheels.   

Might even toss in semi-gloss black as well, again depending on your body color.  

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An update,

Today I got a little box from Tamiya with 2 replacement u-joints :). They’re made properly this time and seem quite sturdy. I tried to actually pull the sleeve off the end of the pin and no dice, these are stuck on there good.

 

I did order a pair from RC Mart and they apparently did ship, guess I’ll use those on my OG SS. When I get around to rebuilding that. I stripped the old body from that one this week and boy is it rough… tons of deep gouges that had been covered up by several thick laters of orange and blue paint. Gonna need a lot of filler and several crack repairs, and even some chunks of styrene to replace pieces that are missing. The driprail on the right side is missing several pieces and there’s a large chunk of plastic and a crack running up most of the decklid. Oh the things a thick paint job can hide… Glad I stripped it before bothering to paint it again

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Since I've already got this thread open, I figured I'd ask a question I can't seem to find an answer to...

 

The supplied TBLE-04s speed controller, do I need a receiver with or without a BEC? I read somewhere about this but of course can't find it now. I'm looking for 27mhz only, since I already have a radio for that type of receiver and don't want to get a new one at this point.

 

I got the paint this weekend, TS-26 white and TS-12 orange instead of the typical blue. Going for sort of a Rough Rider/Sand Scorcher mashup with the paint/decals.

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On 9/28/2021 at 2:14 PM, barbon said:

The supplied TBLE-04s speed controller, do I need a receiver with or without a BEC? 

With BEC.

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On 9/3/2021 at 2:27 PM, barbon said:

The driveshafts are fine, no issues with the grub screws. The issue is the pin that’s supposed to be flared on one end just falls out. Here’s a couple images to illustrate what I’m talking about since I realize it probably doesn’t make any sense unless you see it. It seems to me like these were made incorrectly in the factory. I’m not sure if that pin is supposed to be one piece with the flare, sort of like a rivet, or if it’s 2 pieces and is supposed to be sort of jammed together. Either way the pin seems very short, it doesn’t even make contact with the flare on the other side at all. Both of the u-joints are like this. I noticed that one of the pins just fell out when the head was facing downward while the car was just sitting on the desk. These are brand new so they are not worn out or anything. Whatever is wrong with them is something that happened in the factory (or didn’t happen)

3496F509-77BD-4A42-81D0-22C6FA1D9780.jpeg

image.jpg

They look like the universal joints from the hg-p407 (bruiser clone) and as we know tamiya outsource a lot of the metal parts? Maybe these parts are made by the same manufacturer but different specifications and could be a mix up (stranger things have happened) 

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