gsa103

I've got an older bike with Shimano 105 components. The brakes completely suck compared with the newer 6600 Ultegras.

The brake lever have about a 20mm dead zone, before the cable even moves. Is this normal for this series?
Overall, the brakes feel very mushy, and its hard to a good stop in.

Pads have been replaced with KoolStop or Shimano, minimal improvement. Brakes are properly centered, rims true, etc.

Any suggestions for what to try?

Airburst

It sounds like your cables may have too much friction, how old are the cable housings?

Pepper Grinder

New cables and housing.

Kimmo

Totally not your brifters' fault. Ergos would fare worse, for the lack of their own return spring.

I was assuming you'd be referring to the shifting action, and was going to suggest checking the little philip-head screws that live up under the flipper pivot.

gsa103

Actually, no. The shifters are mostly fine. Its the brakes that have a huge dead zone. The brake lever moves about 10mm without taking up ANY cable tension.

The cables are old, so that many explain some of the mushy, but I don't understand the deadzone. Its like the tension is designed to have a shim installed, regardless of if you actually have one installed.

Al1943

This

prathmann

+2
The 'deadzone' sounds like there's so much friction in the cable housing that the cable is sticking and the brake spring isn't enough to pull the last few mm of cable through.

Andrew R Stewart 

You need to isolate the issue. You say the lever is the problem but don't mention the other parts of the system and their effects. New cables can still have too much friction, poor casing cutting (and the burrs that result), bad routing, not tight enough, badly seated in the lever. The caliper could be too tight or grimy in it's pivots preventing full and quick rebound. the spring ends could be rusty providing friction, the pivots could be too sloppy and some of the cable movement is just taking up that slop.

I would detach the cable from the caliper and work the caliper by hand to see how it pivots, rebounds without any other influence. Then grab the cable end with your hand/needle nose pliers and pull the lever. Watch for cable movement that is in sync with the lever. Remove the cable from the lever and see how the lever pivot is working. Pull the cable through the casing by hand. Check the cable's routing for tight bends/kinks. If the casing goes under the bar tape check to see that it is well seated. Casing pull through (at a stop or lever) can give what you describe.

Brake systems are pretty easy to diagnose with the right approach. Andy.

Andrew R Stewart 

I mis read the OP's replies. I bet there's rust on the old inner cable inside the casing. Andy.

Kimmo

The brakes' return springs are strongest when the pads are touching the rim; as they leave the rim the stored tension in the springs decreases, until the springs can no longer overcome cable friction and pull the cable all the way back.

But the levers' return springs snap the levers back in place, despite the slack cable, hence the dead zone.

Either you have cheap galvanised cables and possibly also unlined housing (which is utter rubbish), or your cable and/or housing is kinked or otherwise damaged, or both. With SS cables and unlined housing you shouldn't need to mess around with lubing the cables... although it's often still a good idea on the rear gear cable due to the precision required on that one.

If your cables are SS and your housing is lined, the problem might just be one or two kinks that often occur just next to the ferrules that terminate the housing, and one reason this can jappen is that housings are often cut too long.

You can often cut off the kinked bits and reuse the housing (proper housing length is basically as short as possible without being too short - whatever minimises the bends and allows for full movement of the bars, with at least a 2" radius on the RD loop). You can even reuse the ferrules if they're the right type. And if you cut off a couple of inches or more, you can also lose the previously clamped bit of the cable, which is still good if it's SS and not frayed; just straighten out any kinks. And bam, often you can totally rejuvenate a cable system, be it brake or gear, and make it work better than it ever did without buying new stuff.

HillRider

Older Shimano brake calipers of any group from RSX/Sora up to Dura Ace give fine performance so I also conclude you have a cable and/or housing problem. New good quality housing and stainless steel cables should solve your problems completely.

gsa103

Ok, so I checked further about the deadzone. There's definitely cable slack trapped in up inside. So I need new cables.

What kind? It seems to range form $2 SS to $40 Teflon (too expensive for this bike). What's a good cable?

Al1943

You will also need to replace the cable housings.

DOS

I have 5500 105 brakes and 6600 brakes, both stop me equally well using basic stainless brake cable and jagwire housing. Make sure you get brake housing, sis shifter housing is not good for brakes. Once you get everything recalled, go,easy on the first ride else risk flying over the handle bars when your bike comes to sudden stop from new found braking power.

Kimmo

Did you read what I said about rejuvenating cables?

I'd rather buy a cable cutter than a set of cables.

Why not attempt to find the source of friction? It's not like they just wear out; they get damaged, and can often be fixed.

gsa103

I looked for the source of friction and haven't found anything obvious. There's a minor kink in the rear brake cable near the top tube ferrule. The front cable is so short there's really no place for a kink. Both cables are starting to fray.

Hence my conclusion that the best course of action of is a full replacement of cables and housings.

DOS

Working on a friends bike, I did have one experience where the rear brake (Ultegra as I recall) had gotten so gumed up with crud that the pivots stopped pivoting. So in addition to cables and housing, a good clean and oil of caliper pivot points would be good.

Kimmo

Oh yeah, ensure the calipers work freely with the cable disconnected.

cycledogg

Go on your conclusion. New cables and housing would be the best bet in any case from your description. Any common cable/housing for road bike will be just fine. Your LBS should be able to sell you what they use from behind the shop counter or purchase from on-line Shimano brand product.
Cheers

Kimmo

Given the lack of visible damage I'd ensure it isn't just binding calipers first.

There's nothing particularly mysterious about cables; 99% of the time if they look good they should work fine.

Haul on them extra-hard if you're worried about safety; if they don't snap when you apply five times more force than it'd take to throw you over the bars in the wet, they won't let you down.