1980's Raleigh poor beraking

[Phil1212]

Hello,

My 1980's Raleigh road bike suffers from poor braking at the back, the front is just about acceptable, but obviously much less important. What happens is I pull the handle and nothing happens until the very last part of the travel, when it then it grabs lightly. The 'feel' of the braking action is soft and unresponsive with lots of stretch.This has been going on for a few years now, but gradually getting worse, to the point where I'm not happy cycling around other road traffic, as the bike just doesn't stop in time.

What I've done in attempt to remedy this, is: replaced the brake cable - made no difference, I then replaced the full length of outer cable, this improved things a bit, but I did this a few years ago, and things are worse now. I recently replaced the rear wheel as it was not particularly straight and the rim was heavily scored - I think from dust getting in to the brake blocks. I replaced the brake blocks at the same time as I didn't want the possibility of this happening again on the new wheel. As this hasn't improved performance, I also cut down the outer cable so there's less flex in the cable, and I've just now replaced the inner cable again as well.

How well do you think I need to strap the outer cable at the handlebar end? It does move around a little when pulling the handle. It doesn't look like there's much wrong with handle end - The only thing left is to get new callipers but as the bike is old fashioned now, they seem difficult to find.

 

[midlife]

Welcome . Usually if the brake pads do not touch the rim until the levers have moved quite a bit then they need adjusting or the brake blocks have massive wear. Sometimes if you mis out ferrules then the cable outer compresses instead of the cable moving.

Any pics of the situation?

Shaun

 

[raleighnut]

Have you checked that the caliper arms move freely together on the centre pivot, also a bit of lube on where the springs slide can help. If the whole caliper is stiff to move by hand then a lot of the pressure at the lever is wasted.

 

[tyred]

Raleighnut is bang on the money. Assuming Weinmann type single pull callipers I'd pull it apart, clean and lubricate the pivot and clean where the spring sits on the caliper arms with fine sand paper and then apply a little lube to this point. It's not difficult to do this, when re-tighting the the centre hut which holds the arms on the mounting bolt you want it as tight as can be while still free to release fully and make sure it's centred properly when refitted.

 

[sidevalve]

Caliper brakes tie with the mousetrap for simple machines. Try this - remove wheel and pull lever should be smooth and easy ie one finger easy - if not prob with cable or pivots. Cable must have a straight run with easy curves no sharp kinks or corners. Pivots must be free - strip and clean then lubricate. If above is ok then adjust until blocks are within 1/8 of an inch or so of rim and make sure they are level with it - no brake will be any good if half of it is biting on thin air. When wheel is back in if the levers move much more than half their travel without stopping the wheel then they aren’t adjusted correctly. I assume you have sidepulls - these can be perfectly acceptable if well adjusted / maintained and unless they are actually flexing [highly unlikely] there is no need to replace them.
The only other possibility is have the rims and or blocks been contaminated with something greasy or oily ? If so try cleaning the rims with meths and replace the blocks.

 

[mjr]

Flexing isn't that unlikely on the old brakes that look like bent flat metal. Easy to spot though.

 

[Phil1212]

Thank you for all the answers, it's a great help, I haven't got to the bottom of it yet, but when I previously took the callipers apart and back together, I didn't pay too much attention to how the spring was being tensioned, although now I've greased them up, and they don't make a "creaking" noise as they did before. The callipers are unbranded single pull types and the lever includes a "suicide" lever although I've taken this off for the time being. I will get the callipers disassembled again and make sure all is clean and they can move freely. Although the pictures show a fair bit of dirt, the brakes were clean before I took the bike for a blast down the puddle strewn back roads. I will update this thread when I have looked at this again.

 

[midlife]

Look like Weinmann. Those brake blocks are miles away from the rim and look like later thinner jobbies.

The blocks should only be a couple of mm away from the rim when not braking.

Shaun