Sammyboy

Hi all

I have an old Gazelle 531 road bike that I picked up cheap on ebay, and I have a bit of an issue with the front brake. It has Weinmann sidepulls, and the front one is rubbing on one side. Looking down at the brake, the arms and pads are not parallel (they are at the back), and the pad on the leading arm (the left as you look down over the bars - by leading arm, I mean the one in front where they meet at the bolt) is further forward than the one on the other side. This leads me to believe they might be bent.

I wanted to quick fix by just realigning, so that when the brake was off, the pads were equal distance from the wheel, but can't figure out how to do it. The brakes are held by a single bolt at the pivot, with a plastic nut that's only finger tight on it. Removing this doesn't seem to facilitate moving (or removing) the caliper at all, so I'm clearly missing something. How the hell does one adjust this thing?

Retro Grouch 

I've never had good luck getting Weinmann sidepulls to stay centered for very long. For that matter, I've not had good luck getting them to stop the bike in anything but ideal conditions either.

I'd much rather have a set of Shimano or even Tektro dual pivot brakes. You might have to drill out the hole in the back of your fork to get the recessed mounting bolts to work.

Sammyboy

I might well upgrade at some stage, but for the moment, I've no money, and a road bike with added friction. I want to get out riding, and I can't. They seem "locked in one place". Does anybody know how to move them?

FlatTop

Two links to check out:
https://yarchive.net/bike/brake_center.html
and
https://www.ctcforum.org.uk/MesReplis...cid=3&id=16014
Let us know how this develops, and resist the impulse to heavily tweak the brake assembly before trying the less extreme measures.
I've been deviled by the same problem in the past, and I have a bike needing attention to this detail right now! So you can assume it is a common problem.

rmfnla

The quick fix at many shops was to tighten the fixing bolt and then use a hammer and a flat punch to hit the return spring to center the alignment. Toe-in was accomplished by bending the brake arms; in fact, Park used to offer a tool just for this (they may still).

Not exactly precision techniques, but these are not exactly precision parts.

Check out ebay; there are lots of used brakes for cheap that will work much better.

Sammyboy

Ok, thanks for the help, specially Flat top (great links), but the answer I was looking for turned out to be simpler. I needed to slacken off the bolt to turn them, and it's an allen key bolt at the back of the forks, not anything at the front! I know it's a noob mistake.....

Still, I had a great 12 mile ride this morning. This is a 26" frame (I'm tall) 531 bike, 700x20 wheels, shimano 105 mechs, etc, and I got it for $50 from ebay. How did we get on without that site?

rmfnla

See the "Screwed by Supergo" thread for some opinions about ebay.

Sammyboy

Dialling in this bike is proving to be an education!

I spent a few minutes trying to centre things up before I realised what was wrong. No matter what I did, it just pulled to the side. Then I saw that the person who had it before (at some point) had fitted aero brake levers (definitely aftermarket - the bike must be 70's, and there's no channel in the bars for the cable), and that he hadn't read Sheldon Browns article on cables! He had in fact cut the front brake cable so short that when connected, it pulls the caliper out of alignment. Which means I have to strip off the bar tape! At least it appears only to be held in place by electrical tape......

bosco boy

Weinmann brakes were at the time a decent brake the problem with them is to center them you need a special tool. If you look in the middle of that plastic nut you will see an allen head, with the correct size allen socket you can center the brake over the rim. Good luck.

Sammyboy

Now that's an educated reply! I'll find something I can turn that with. Cheers.

ZG862

I know this is an ancient thread but I stumbled across it looking for info on a specific Weinmann lever and thought I might chip in on the off chance that someone else wants to know how to adjust a Weinmann brake with a plastic cap.

Overview, attachment and centering
Contrary to web opinion, these brakes are not crap. The braking arms rotate around a steel shaft aligned with the centre of the bike, meaning that both sides travel the same arc to reach the (presumably central) rim. The arms are pulled away from the rim by a spring which is anchored on the shaft, the ends of the spring protruding on each side and engaging on a tab on each arm. The shaft is attached to the frame (either fork crown or rear bridge) by either a nyloc nut (i.e. one with a nylon insert to discourage it from working its way loose) or (in the fancy versions) a fancy Allen cap screw - an alternative to the nyloc nut that gives you that cool aerodynamic effect of which we are all so fond. Either way, tightening this back nut to fix the brake to the bike has a tendency to rotate the shaft and move the spring so the force applied to one arm is greater than the other. When this happens, one brake block may sit closer to the rim than the other in the neutral (not braking) position, even touching the rim if the spring is moved enough.
Weinmann was not daft. The designers figured that if the mechanic could control the rotation of the shaft when the back nut is tightened then there would be complete control over the neutral position, so they designed in a hexagonal head to the non-fastened end of the shaft and a tool (basically a small socket) that fits on it. Thus when you tighten the nut, you waggle the tool (technical process) to set the position of the spring.

Right. Point 2. Washers
There should be thin brass washers between the arms and the surrounding bits of the mechanism - and one between the arms. These exist to stop the arms binding against each other when the mechanism operates. There is normally a standard thickness washer next to the securing nut to further ease the securing of the shaft to the bike. If you have a mudguard or carrier support that needs to be included, the washer goes outside this - i.e. remains next to the nut. There should NOT be a washer between the spring carrier and the frame. Put one here and you will have no end of problems trying to persuade the spring to centre. The idea is that the spring carrier remains in a fixed position relative to the frame.

Finally, point 3. "Unwanted rocky back and forth motion".
When you pull off the stylish black cap, you will find 2 thin nuts on the end of the shaft. If you wind the inner one in towards the arms, eventually the arms bind and won't retract. This is too tight and a bad idea. Wind the nut back (with the skinny spanner Weinmann made for the job) until the arms move without binding. Now tighten the other nut against the 1st so that everyday vibrations don't shake the nuts off the shaft (also bad). There is a tendency for the act of locking the nuts together to wind the nut closer to the arm away from it, reintroducing unwanted rocky back and forth motion - so you need to test the clearance after the nuts are locked and if necessary adjust. Push the stylish black plastic cover back over the lock nuts and admire your work. I'm not going to tell you how to line up your brake blocks with the rim because if you find this task in any way daunting, then you should ignore all the above and take your bike to a professional in any case. If they tell you to fit new brakes, move to the next one.

Hope this helps, although it is clearly too late to keep Weinmann and their well-designed, spares-supported, effective brakes in business. Ah well.

Z
PS/ In the olden days we used to use a special lever (pretty much a spanner whose open end fit over the arm at the brake block mounting face with its shaft pointed laterally out) to bend the arms ever so slightly (a couple of degrees ish) to ensure that the leading edge of the brake block contacted the rim first. This improves feel and discourages the vibrations that get called "judder" and "squeal". Weinmanns (and steel callipers) were quite tolerant to this kind of abuse. CLBs had an irritating tendency to snap. Guess this is the difference in the alloy used.

thumpism

Here's the tool for centering the Weinmann brake caliper that has the black plastic nut cover enclosing the hex ended centerbolt. This is not essential for the task. You can use a 1/4" drive socket the right size (4mm? I can measure if you need to know) and I would use a small breaker bar for leverage rather than a ratchet that would need to be switched frequently if going back and forth. You can also use a nutdriver but will likely need more leverage than twisting that handle will provide if your front brake is tightened down adequately.

Don't know who produced this, if it was Bicycle Research or another tool supplier but I used it several times when bikes with those brakes were current and it's extremely handy but not necessary.
Weinmann.JPG

ZG862

That looks identical to the Weinmann branded tool. There was also one with arms about the same length either side of the bend - think this was easier to use for bikes with carriers etc.

Z

chorlton

May or may not be relevant but I have a bit of NOS lying about. Of course having pulled things to bits I did not pay attention as to how they should go back together. The brass washers are important but in terms of alignment notice that the main 'bolt' has a pair of lugs on it that mate with the, other, bit of black plastic that also carries the return spring.

Having been through similar experience myself in terms of alignment then these days when I have to refit this sort of stuff I strip it down completely and put the main bolt on the frame first and tighten things up making sure that the lugs on the bolt are properly set horizontal. Then I put the rest of the bits back on taking care not to upset that alignment.

Although I have not used one previously I can see how the tool suggested by @thumpism would be useful when setting up the locknut[s] in order to prevent the main bolt rotating and sending things out of alignment. I do not think it would be used to bring things back but rather it is there to stop it happening in the first place.

...

thumpism

That is precisely what I used it for. If the mounting nut on the backside of the centerbolt is not extremely tight, the tool works perfectly for rocking the caliper from side to side in order to center things. Done it dozens of times, and it is much more accurate than using a hammer and punch on the spring when trying to achieve the same result and is gentler on the mechanism to boot.

fietsbob

A Star fangled washer biting into the frame and the back of the mounting bolt/return spring carrier,
is the key to having side pulls not shift about so much..

Campagnolo long ago included a really great one with their brakes , but you can buy spring tempered steel ones for pretty cheap
at auto parts stores