Calling all 'U' Brake owners

[Sithlord]

Hi guys , A while ago I posted a thread regarding set up of U brakes, which your help was much appreciated, I have now had the afternoon free to have a 'proper' go at setting these up..

However, after making sure everything was clean and assembled correctly as per the diagram supplied by retrobikeguy (Cheers fella)

I cant get any 'spring' on the arms ? apart from one side on the front ? :roll: I made sure before tightening the arms up on the studs, that they were spaced away from the rim , to allow for 'Quick Release ' then cranked them down tight, but cant get the arms to return away from the rim as per the one on the front once tight.. any ideas ? or help would be appreciated...

 

[terryhfs]

Make sure that the bolts holding the arms on to the bosses aren't too tight - sounds like they might be from your description. If not try screwing in the adjuster bolts on the side of the arm a little.

If that doesn't work, undo the bolts, then do them back up again. This weirdly works sometimes on my XT-II U-brake. Exactly the same scenario.

 

[yedi]

If above doens't help...

I have XT U's but it has been a while since I have unmounted them. They have worked so well .

Our beloved man tells:

Adjusting U-brakes:
First, remove the arms from the studs, make sure the studs are free of rust. Coat the studs liberally with grease (this is VERY important!)

Install the arms with them at their maximum spread and tighten the bolts that hold them to the frame. This is how you set the springs. Only connnect the transverse cable after this has been done.

There is usually a small setscrew on the side of one of the arms for fine adjustment of spring balance.

Whole thing here:

http://www.sheldonbrown.com/gloss_u-v.html

 

[letmetalktomark]

I picked up a bike at the weekend that has a rear shimano U brake.

Whilst riding the bike home I noticed one arm wasn’t springing back from the rim…

To cut a loooooooooooooooooooooooong storey short: several hours later, many web pages read, lots of dismantling/reassembly, four floor boards lifted and one nasty gash the arm has spring in it!

Now…….

(walking backwards calmly as not to disrupt temperamental crap early 90’s braking)

….let us never speak of the u brake again.

M

 

[Sithlord]

 

[SeeingisBelievingGTMuseum]

Shimano U-brake

Honest to God the easiest brake EVER to set up and adjust bar none. 1) Mount them but leave loose so there is no spring tension, 2) Adjust the pads, this is easy to do because there is no spring tension, 3) Pull arms out as far as possible away from rim and when tightening the bolt the spring tension is set.

Many guys are having problems with them because there's crap, corrosion or rust on the brake mount in the frame. Run some fine emery paper, or steel wool over them. Put on a dab of Phil Oil and mount them brakes with the steps above. I think that inner bushing on the brake arm is brass and brass to steel with a little corrosion or oxidation is not a good mix for success.

 

[Andy R]

Re: Shimano U-brake

Many guys are having problems with them because there's crap, corrosion or rust on the brake mount in the frame. Run some fine emery paper, or steel wool over them. Put on a dab of Phil Oil and mount them brakes with the steps above. I think that inner bushing on the brake arm is brass and brass to steel with a little corrosion or oxidation is not a good mix for success.

But when the brake is operating, the brake arms don't actually pivot on the studs on the frame. Once you tighten the attachment screws movement only takes place within the brake arm assembly, not between the brake and the frame. So, it's fair enough to clean and lube the brake studs - but for just ease of assembly/disasssembly , it won't make them work any better.