Wiemann Side Pull 500 front brakes.

[Kins]

How do they come apart? I have them off the bike and they are very stiff so wanted to make sure there wasnt a lot of rust etc on the central spindle that runs through the centre but can't get them apart.

Looks like a locking washer on the threaded side and an allen head on the other but an't get anything to move.

Any clues please?

 

[jim55]

unscrew the front black part!

 

[mrandmrspoves]

Yes the black knurled knob should unscrew ....or sometimes just lever off. Behind it will be the nut you need to loosen to take the caliper apart. Worth giving it all good soak in penetrating oil first.

 

[Kins]

The black knurled knob has an allen key head in it. Whole things just turns. Guess the whole thing is just seized solid.

 

[mickle]

The black plastic bit is a cover for a pair of lock nuts for adjusting the brake arms on the centre bolt. It levers off with a small flat screwdriver.

Visible just inside the end of the cover is the 4mm hex shaped end of the brake centre bolt. Its designed to be used with a Weinnman centring tool - a 4mm socket like an inside out Allen key. In the absence of which, if you leave the plastic cover off until after the brake is reinstalled, you can use a small adjustable spanner on the hex to balance the brake.

 

[HovR]

As above, take off the black plastic cover. Neither of my 2 sets of Weinmann calipers has this black plastic cover, although it should be covering a nut. The black plastic cover is mostly to hide the nut, so no big deal if it breaks in getting it off.

Once that's off unscrew the nut. From this point there is nothing else holding on the caliper arms, except for possibly corrosion, so just work them off. A good soaking/dousing in penetrating oil wouldn't go amiss.

Once all the parts are off you can clean, polish, regrease and reassemble. If I remember rightly the parts go back on to the spindle in this order:

Black plastic piece with spring slot > spring > substantial washer > brass washer > caliper arm > brass washer > caliper arm > brass washer > nut > locknut

I replaced the nut and locknut with a single stainless nylock nut with no issues. That said I believe both of my sets of calipers are slightly older than yours, so there may be some slight differences.

Edit: Cross posted with mickle.

 

[Kins]

nm sorted. Cheers fellas.

Now I know it seemed a dumb question but without knowing, who knew!?

 

[mickle]

No question too dumb for CC.

 

[TheDoctor]

No question too dumb for CC.

Unless it involves WD40...

 

[oldroadman]

How long since they were made? About 30 years, so it's worth checking for wear!

 

[biggs682]

How long since they were made? About 30 years, so it's worth checking for wear!

they were made in a time when things were made not just put together

 

[HovR]

they were made in a time when things were made not just put together

+1 to that. I'm yet to see a Weinmann caliper which is worn out. They may get a bit seized, but that's easy to fix, and they're alu so they don't rust!

Even my 40 to 50 year old GB calipers are in fine working condition (apart from the one I broke a spring on!).

 

[mickle]

Yeahbut lets also not forget that wimpy flexy side-pulls like these were pretty ineffective as brakes - and only slightly improved by the arrival of synthetic brake blocks.

 

[Kins]

Yeahbut lets also not forget that wimpy flexy side-pulls like these were pretty ineffective as brakes - and only slightly improved by the arrival of synthetic brake blocks.

Arh, but to make up for it we had proper chocolate bars called Marathon, decent programmes on our 3 station telly, milk delivered to the door and men didn't wear lycra!

 

[tyred]

My Carlton with Weinmann 500s stops on a sixpence. Hand pressure needed to operate them is higher than modern brakes but put a bit of effort in, they work fine.