Rear brake rod snap

Hi guys,

Here is a picture of what happened last night.. The bike is an 1982 XJ650RJC. The brake rod snapped wrapping itself around the axle.

So what I think happened is that the bolt holding the tension bar/rear plate in place fell off due to vibrations.. I assume there was no cotter pin there and I never noticed. This lead to the brake plate spinning freely and a huge ammount of pressure went straight to the actuating rod when I tried to stop. The brake pedal shot right up and scratched a big gash in the side cover above it. Is my theory correct or could this have been something else? These are brand new EBC brake shoes, the whole drum was cleaned with brake cleaner and parts were greased. It was working fine for the past 3 weeks or so..

I walked down the street and actually found the bolt connecting the tension bar and it looks perfectly fine.. That's what lead me to believe that it just slid out and this whole fiasco could of been prevented by replacing the cotter pin..



The canadian version of mikesxs has that rod. Would they be interchangeable? See http://www.xs650direct.com/products-69.html "Rear Brake Rod" . I'm in Canada, so the exchange rate is killing me and I'm usually hit with duties etc.. so I'd like to be able to source the part close to home. If anyone can provide the OEM part number I'll see what the dealership can offer.

Thanks!

 

Hmmm your set up looks nothing like my xj750 Seca ...the bolt yes but your rod is it wrapped around axle bolt from this? If so you have a nasty gouge in your axle shaft . I also notice you have no cam on the brake arm adjuster.. on mine the nut can be adjusted with some play. From the picture it almost looks line nut is back wards?
The bolt that goes from the rod to the plate on mine has a castle nut and cotter pin, you might not have the correct bolt .. is it drilled? If it is most hardware stores should have metric castle nuts and cotter pins . If all else fails xj4 ever to the rescue. Sorry exchange rate we in US don't think much about it I guess , so I don't know how all this works. I hope you get it sorted out. Just a quick thought (been a while since I had mine a part) If memory serves me the bolt from the plate to rod has a shoulder on it so it is not a common bolt.

 

haha yes I should specified that the rod wrapped around the axle is from it snapping under pressure and wrapping around the axle.. It isn't like that under normal functionning condition. Usually the rear brake arm is facing downwards and IS NOT wrapped around the axle.. The spring loaded brake rod is relatively parralel to the ground and connects to the rear pedal actuator and pulls it fowards and spreads the brake pads inside the drum.

Looks something like normally:


As for the gash, it's mostly just paint rubbed off. you can barely feel it with your finger. It looks worst than it is.

I think all XJs with rear drums have the same; if not very similar setups. I'm wondering if they all use the same spring loaded brake rod. At this point it's the part that was damaged (snapped in half is more like it).. Ideally, if the XS uses the same brake rod, I could have access to a cheap one that would ship in a day or two.

 

That is exactly what happens when the torque rod comes loose.

 

Alright thanks - that was my suspicion! I just wanted to confirm with you guys.

 

Yes.

 

If the whole thing is put on right and adjusted right I think the plate will spin and pull the brake arm enough to lock the wheel before the rod wraps around the axle. The one in the last picture is too far forward

 

Check the other end of the torque rod bolt it to has a hole in it for a cotter pin. I missed it on my own bike.

 

You're right, this happened right after I adjusted the tension on the spring because I found the rear brake to be too soft. Then I read chacal's write up that rear brakes shoes need to get worn in to feel a bit stickier.

Will do, thanks! This made me realise I need to double check all the cotter pins on the bike as I did quite a bit of work and I might of forgotten a few of the smaller ones.

 

They are different part numbers, so they probably are not interchangeable (most probably due to differing lengths, etc.).

 

Yea I cross-checked the part number.. ended up buying one from ebay with the correct part number as the part is discontinued from yamaha. Unfortunately it will take 2 weeks to get here ><

 

part number 5 & 6

 

It should look almost identical. Best have a closer look at your setup.

 

I was reffering to the bent rod lol

 

First pic: Is it just me or is the axle shaft actually too far through the pinch?

Gary H.

 

It is a bit far in. The hole should be clear of the swing arm so it can be useful during assembly/disassembly.

 

Exactly.

Gary H.

 

Any idea as to why? Could it be over torques on the other side?

 

The axle bolt on my 1981 XJ750 Seca looks just like yours, and every time I take it off I use a click torque wrench to put it back on, so I know it is not torqued too tight. Perhaps a PO did torque it too tight, and opened up the spot in the swingarm where it goes in...

 

That could be, or the swingarm is tweaked.

 

Same here. Looks like mine on my 82 XJ650 Maxim.