Rear hinge pin popping out

colmo · #1 09-07-2010

My Madrat is starting to go really well, but the aforementioned problem is driving me to distraction - the rear left hinge pin won't stay in. Starting fourth in the B final on Wednesday, I was just passing the leader inside the first lap when he tapped me on the rear left wheel and it fell apart for the 3rd time that night - despite me changing the rear brace.

It seems to be caused by the inherent flex of the T-piece (the newer toughened one Battleaxe gave me at Oople - thanks again!) and the braces, plus the braces seem to get worn very easily.

I could solve it with the alloy hingepin braces and carbon fibre T-piece, but that would cost nearly as much as a B4, which is ultimately my other solution to the problem.

Are there any other cheaper fixes I can perform?

kaylon · #2 09-07-2010

I've not heard of this issue before...and I've certainly not had an issue myself.

The alloy and CF parts you mentioned would probably fix this... combined they are only £39...that's cheaper then a B4

K

Shannow · #3 09-07-2010

Where is it coming out? Pinging out of the rear brace or pulling out of the front?

I've had it pull out of the front with a heavy collision but certainly not a tap. As a fix I sanded down the ends of the front brace and superglued washers onto it (so metal reinforcing the holes). I've seen rear braces snap and lose the pins but never a pin pop out...

jim76 · #4 09-07-2010

possibly get a pin a couple of mm longer from a different brand of car? Not sure if the kit pin comes up a bit short?

Jaune · #5 09-07-2010

It actually happened to me as well this week. My rear wheel hit a post while jumping so It was kinda expected... Anyways, I'm getting the alu brace.

madmax · #6 09-07-2010

it might be worth looking at the hingpins off the cat due to the fact that they have a screw that goes into eather end of the pin

nikos2002 · #7 10-07-2010

check the u brace to make sure it's not cracked - that is a lot of flex for the pin to come out.

Battle_axe · #8 10-07-2010

i would buy a new t peice it will come with the braces too i am not really sure where the one i gave you had come from

Bazzokajoe · #9 13-07-2010

with metal braces and carbon t plate i have broken many many of my rear arms... anyone else experianced it? brake them less frequently than i used to break braces and t plates so i'm not too bothered... but it seems strange ... the arms break down the middle!!

colmo · #10 13-07-2010

Quote:

Originally Posted by Bazzokajoe

with metal braces and carbon t plate i have broken many many of my rear arms... anyone else experianced it? brake them less frequently than i used to break braces and t plates so i'm not too bothered... but it seems strange ... the arms break down the middle!!

With a completely rigid rear chassis assembly as you have, the wishbones take all the force. It's an argument against the carbon T-piece at least.

I've considered a few solutions - drill out the braces and fit a tube of tougher material to hold the hinge pin, or tap a hole into the side of the braces and capture the pin with grub screws. A new T-piece is likely needed, anyway.

colmo · #11 20-07-2010

I took the rear chassis apart and examined the T-piece; the rear-most screw hole on the side causing the problems is deformed - the hole has stretched backwards, even causing a bump at the back of the T-piece. I'll get a replacement, but no rush, as I hedged my bets and got a B4 FT as well...