This might be a stupid/noob question so I apologize in advance.

I can't seem to keep my rear brakes adjusted properly and it is kind of driving me crazy. I am pretty new at working on bikes but I'm pretty sure there is nothing I'm missing.

The brakes are Dia Compe G 500 with Dia Compe aero levers.

The caliper itself is tight, I line up the pads a few mm from the rim, pull the cable tight and tighten the nut that clamps on to the cable. Brakes beautifully..for about 20 minutes then I check and each pad is half an inch off the braking surface. I have done this 5 times or so now.

I know I am tightening the cable because it is not slipping, could there be something else causing them to keep loosening up. Caliper no good? Or am I just crazy?

Here are a few pictures for reference.






(mind the crappy front wheel/tire, I got a flat yesterday and just threw a spare on there for now)

Maybe you are not tightening it enough and that is why the cable is slipping. It looks like that nut is rounded/stripped pretty bad. I would imagine it is difficult or impossibloe to get it tight enough.

also, make sure your cable housing is tight.

If the pinch bolt is tight I would check the cable housing at the lever to make sure the slack is not being caused by an issue with the cable stop inside the lever.

What you describe is generally a problem when you loosen the cable, then tighten it, and the cable ends, at various points in the route, from the lever to the guides, etc, come out a bit and are not seating fully when you tighten it. Sixty Fiver has identified the most likely place, but check them all from front to rear. This is the time for a "3rd" hand, when you can somehow hold the calipers snug and pull on the cable with one hand, the lever with the other, and make sure there are no "catches" in the motion.

Yes get a third hand tool or have a friend help you. The bolt does look a little bit stripped. If it is too far gone just use the vice grips/say a prayer and cuss up a storm for it to work.

I give three MFER,MFER,MFER shouts and it often is like saying please and thank you to the velo-gods.

Thanks guys. I think the bolt was tight enough but I scavenged another and replaced it anyway as it was pretty bad.

I will try to get a third hand to further diagnose as you have suggested.

I agree with sixtyfiver check you housing at the lever. some older (first gen?) Dia Compe lever required a very special ferrule on the end of the housing. pull on the lever and look behind it where the cable comes out and be sure the housing is not pulling through. also you housing looks real short. a third or fourth or a friend is called for.

there is a small trick using the QR but it takes a bit of practice

BTW that is a great looking Delray. I worked on lots of those when I was living in the Quincy area years ago. a bit of elbow grease and some pledge and it will shine up real nice

For a third hand I use a small wood clamp that is sold at the do-it-yourself stores for about $4. If you are not carefull you can get the brakes too tight

Pic or a link?

https://www.homedepot.com/webapp/wcs/...368321&cj=true

https://www.amazon.com/Irwin-Industri...5132775&sr=1-1

I think this will take you to the type of clamp that I use. The version I use is on the small side and they can be bought for less than $10 I am pretty sure. Off brand of course. One hand operation both clamping and unclamping. It is a real handy tool for lots of things and worth having in the tool box. The clamping surfaces are soft rubber like material so they won't scratch anthing. The C clamp above will work too but you need to be careful about scratches.

Thanks. I really love the bike but I don't have much to compare it to as the only other road bikes I've ridden are a few of the ones listed in my sig.

I think it will clean up nice but the clear coat over the seat tube details is almost gone. Do they still make or sell vintage decals? Not just for the Fuji but for vintage bikes in general?

I had the exact same problem as the OP with a set of new Dia-Cope inverse brake levers. Brakes would be set fine and ride well for a little while and then they'd go loose.

The problem in my case was on the Brake Lever end of things. The hole in the brake levers that you mate the housing up with appeared to just accept the housing directly. Turned out there was a step-down ferrule that you were supposed to use and the brake housing was supposed to sit in the ferrule, which in turn fits in the brake lever body.

The effect of not using the ferrule was the spiral housing was unravelling like a spring inside that hole causing the housing to shorten and effectively lengthening the wire.

perhaps your levers are similar...perhaps not.